What is the number one cause of Broca's aphasia?
Expressive aphasia
In most cases, expressive aphasia is caused by a stroke in Broca's area or the surrounding vicinity. Broca's area is in the lower part of the premotor cortex in the language dominant hemisphere and is responsible for planning motor speech movements. However, cases of expressive aphasia have been seen in patients with strokes in other areas of the brain. Patients with classic symptoms of expressive aphasia in general have more acute brain lesions, whereas patients with larger, widespread lesions exhibit a variety of symptoms that may be classified as global aphasia or left unclassified.
Paul Broca
Broca also spent many of his earlier years researching cancer. His wife had a known family history of carcinoma, and it is possible that this piqued his interest in exploring possible hereditary causes of cancer. In his investigations, he accumulated evidence supporting the hereditary nature of some cancers while also discovering that cancer cells can run through the blood. Many scientists were skeptical of Broca’s hereditary hypothesis, with most believing that it is merely coincidental. He stated two hypotheses for the cause of cancer, diathesis and infection. He believed that the cause may lie somewhere between the two. He then hypothesized that (1) diathesis produces the first cancer (2) cancer produces infection, and (3) infection produces secondary multiple tumors, cachexia, and death.”
Expressive aphasia
Expressive aphasia was first identified by the French neurologist Paul Broca. By examining the brains of deceased individuals having acquired expressive aphasia in life, he concluded that language ability is localized in the ventroposterior region of the frontal lobe. One of the most important aspects of Paul Broca's discovery was the observation that the loss of proper speech in expressive aphasia is due to the brain's loss of ability to produce language, as opposed to the mouth's loss of ability to produce words.
Flicker vertigo
Flicker vertigo, sometimes called the Bucha effect, is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light." It is a disorientation-, vertigo-, and nausea-inducing effect of a strobe light flashing at 1 Hz to 20 Hz, approximately the frequency of human brainwaves. The effects are similar to seizures caused by epilepsy (in particular photosensitive epilepsy), but are not restricted to people with histories of epilepsy.
Neuropsychology
Inspired by the advances being made in the area of localized function within the brain, Paul Broca committed much of his study to the phenomena of how speech is understood and produced. Through his study, it was discovered and expanded upon that we articulate via the left hemisphere. Broca's observations and methods are widely considered to be where neuropsychology really takes form as a recognizable and respected discipline. Armed with the understanding that specific, independent areas of the brain are responsible for articulation and understanding of speech, the brains abilities were finally being acknowledged as the complex and highly intricate organ that it is. Broca was essentially the first to fully break away from the ideas of phrenology and delve deeper into a more scientific and psychological view of the brain.
Amblyopia
Deprivation amblyopia (amblyopia ex anopsia) results when the ocular media become opaque, such as is the case with congenital cataract or corneal haziness. These opacities prevent adequate visual input from reaching the eye, and disrupt development. If not treated in a timely fashion, amblyopia may persist even after the cause of the opacity is removed. Sometimes, drooping of the eyelid (ptosis) or some other problem causes the upper eyelid to physically occlude a child's vision, which may cause amblyopia quickly. Occlusion amblyopia may be a complication of a hemangioma that blocks some or all of the eye. Other possible causes of deprivation and occlusion amblyopia include obstruction in the vitreous and aphakia. Deprivation amblyopia accounts for less than 3% of all individuals affected by amblyopia.
Foix–Chavany–Marie syndrome
In determining a diagnosis between Broca’s aphasia and FCMS, a person must demonstrate their ability in voluntary movement of cranial musculature. People with Broca’s aphasia may not exhibit a complete loss of voluntary movement facial muscles, pharyngeal muscles, laryngeal muscles, brachial muscles, tongue muscles, and muscles of the mouth that aid in chewing. These voluntary functions may still be present, to varying degrees. People with FCMS do not possess this ability. For people with FCMS, voluntary movement of cranial musculature is completely absent.
Expressive aphasia
The discoveries of Paul Broca were made during the same period of time as the German Neurologist Carl Wernicke, who was also studying brains of aphasiacs post-mortem and identified the region now known as Wernicke's area. Discoveries of both men contributed to the concept of localization, which states that specific brain functions are all localized to a specific area of the brain. While both men made significant contributions to the field of aphasia, it was Carl Wernicke who realized the difference between patients with aphasia that could not produce language and those that could not comprehend language (the essential difference between expressive and receptive aphasia).
Speech
Paul Broca identified an approximate region of the brain in 1861 which, when damaged in two of his patients, caused severe deficits in speech production, where his patients were unable to speak beyond a few monosyllabic words. This deficit, known as Broca's or expressive aphasia, is characterized by difficulty in speech production where speech is slow and labored, function words are absent, and syntax is severely impaired, as in telegraphic speech. In expressive aphasia, speech comprehension is generally less affected except in the comprehension of grammatically complex sentences. Wernicke's area is named after Carl Wernicke, who in 1874 proposed a connection between damage to the posterior area of the left superior temporal gyrus and aphasia, as he noted that not all aphasic patients had suffered damage to the prefrontal cortex. Damage to Wernicke's area produces Wernicke's or receptive aphasia, which is characterized by relatively normal syntax and prosody but severe impairment in lexical access, resulting in poor comprehension and nonsensical or jargon speech.
Aphasia
Following are some precautions that should be taken to avoid aphasia, by decreasing the risk of stroke, the main cause of aphasia:
Apraxia of speech
The term apraxia was first defined by Hugo Karl Liepmann in 1908 as the "inability to perform voluntary acts despite preserved muscle strength." In 1969, Frederic L. Darley coined the term "apraxia of speech", replacing Liepmann's original term "apraxia of the glosso-labio-pharyngeal structures." Paul Broca had also identified this speech disorder in 1861, which he referred to as "aphemia": a disorder involving difficulty of articulation despite having intact language skills and muscular function.
Aphasiology
The view of expressive aphasia as an expressive disorder is supported by its frequent co-occurrence with facial motor difficulties, and its anatomical localization. Although expressive aphasia may be caused by brain damage to many regions, it is most commonly associated with the inferior frontal gyrus, a region that overlaps with motor cortex controlling the mouth and tongue, extending into the periventricular white matter. Not surprisingly, this region has come to be known as "Broca's area". However, an intriguing line of research has demonstrated specific comprehension deficits in expressive aphasics as well. These deficits generally involve sentences that are grammatical, but atypical in their word order. The simplest example is sentences in the passive voice, such as "The boy was chased by the girl." Expressive aphasics may have quite a hard time realizing that the girl is doing the chasing, but they do much better with "The mouse was chased by the cat," where world knowledge constraints contribute to the correct interpretation. However, "The cat was chased by the mouse" would likewise be incomprehensible. This evidence suggests that grammatical competence may be a specific function of Broca's area.
Eating disorders and memory
Glucose is the preferred energy source for the brain, accounting for 25% of the body’s glucose consumption, despite being only 2% of the body’s total weight. Glucose, along with serotonin, have been found to have significant effects within the cingulate cortex, frontal lobe, temporal lobe, and parietal lobe regions of the brain, including in those with anorexia. Individuals with eating disorders such as bulimia and anorexia show lower neural metabolism of glucose, possibly due to neural consequences of the disorder and/or due to heightened anxiety or depression. Studies have indicated the importance of glucose on memory, showing that reduced levels of glucose in the brain impair an individual’s ability to retrieve memories. Most evidence suggests that severe negative impairments are due to long term, prolonged glucose deprivation or restriction, such as those seen in individuals affected by eating disorders, however effects have been studied on a more short-term basis with negative memory impairments seen in individuals who consumed breakfast compared to those who did not.
Speech perception
There are two different kinds of aphasic patients: expressive aphasia (also known as Broca's aphasia) and receptive aphasia (also known as Wernicke's aphasia). There are three distinctive dimensions to phonetics: manner of articulation, place of articulation, and voicing.
Arcuate fasciculus
Evidence for the role of the arcuate fasciculus in language use is best represented by conduction aphasia, caused by damage to the inferior parietal lobule that extends into the subcortical white matter and damages the arcuate fasciculus. This type of aphasia inhibits the patient from repeating unfamiliar sounds. A study by Catani, Jones, and Ffytche (2005) provided the first anatomical evidence for the presence of two pathways between Wernicke’s area and Broca’s area. They found one deep pathway, interpreted to directly connect these two regions, and a shallower pathway that consists of two segments; the anterior segment connects frontal cortex with inferior parietal cortex, and the posterior segment connects Wernicke’s area with the inferior parietal cortex. Damage to the direct pathway may produce conduction aphasia, whereas damage to the indirect pathway spares the ability to repeat speech but impairs comprehension. The symptoms of conduction aphasia suggest that the connection between posterior temporal cortex and frontal cortex plays a vital role in short-term memory of words and speech sounds that are new or have just been heard. The arcuate fasciculus connects these two regions and circulates information back and forth, possibly contributing to short-term memory.
Expressive aphasia
Expressive aphasia, also known as Broca's aphasia, is a type of aphasia characterized by partial loss of the ability to produce language (spoken, manual, or written), although comprehension generally remains intact. A person with expressive aphasia will exhibit effortful speech. Speech generally includes important content words, but leaves out function words that have only grammatical significance and not real-world meaning, such as prepositions and articles. This is known as "telegraphic speech". The person's intended message may still be understood but his or her sentence will not be grammatically correct. In very severe forms of expressive aphasia, a person may only speak using single word utterances. Typically, comprehension is mildly to moderately impaired in expressive aphasia due to difficulty understanding complex grammar.
Global aphasia
Although the prognosis for persons diagnosed with global aphasia is poor, improvement in varying aspects of language is possible. For example, in 1992, Ferro performed research in which he studied the recovery of individuals with acute global aphasia, resulting from the five different lesion sites. The first lesion site was in the fronto-tempo-parietal region of the brain; patients with lesions in this location saw the least amount of gains out of all of the participants in the study, and they often never recovered from global aphasia. However, the second lesion site was the anterior, suprasylvian, frontal part of the brain; the third lesion site was the subcortical infarcts; and the fourth lesion site was the posterior, suprasylvian, parietal infarcts. Participants with lesions two, three, and four often recovered to a less severe form of aphasia, such as Broca's or transcortical. The fifth lesion site was a double lesion in both the frontal and temporal infarcts; patients with lesions at this site showed slight improvement. However, studies show that spontaneous improvement, if it happens, occurs within six months, but complete recovery is rare.
Global aphasia
When evaluating the prognosis of a patient, the main contributing participant factors that influence the extent of neuroplasticity, or the brain's ability to change are: age, lesion location, pre-existing cognitive status, motivation, age, overall health, and interaction amongst these. After brain damage, initial signs of global aphasia may appear within the first two days due to brain swelling (cerebral edema). With some time and natural recovery, impairment presentation may progress into expressive aphasia (most commonly) or receptive aphasia. Due to the size and location of the lesion associated with global aphasia, the prognosis for language abilities is poor. Research has shown that the prognosis of long-term language abilities is determined by the initial severity level of aphasia within the first four weeks after a stroke. As a result, there is a poor prognosis for persons who retain a diagnosis of aphasia after one month due to limited initial language abilities. Nonetheless, in the first year post-stroke, patients with global aphasia showed improvement in their Western Aphasia Battery (WAB) scores from baseline. When compared to individuals with Broca’s, Wernicke’s, anomic, and conduction types of aphasia, those with Broca’s aphasia showed the best rate and extent of improvement followed by global aphasia. The rate of improvement in language function was highest in the first four weeks after stroke.
Bromism
Bromism is caused by a neurotoxic effect on the brain which results in somnolence, psychosis, seizures and delirium. Bromism has also been caused by excessive soda consumption, due to the presence of brominated vegetable oil, leading to headache, fatigue, ataxia, memory loss, and eventually inability to walk in one case.
Global aphasia
Global aphasia is a severe form of nonfluent aphasia, caused by damage to the left side of the brain, that affects receptive and expressive language skills (needed for both written and oral language) as well as auditory and visual comprehension. Acquired impairments of communicative abilities are present across all language modalities, impacting language production, comprehension, and repetition. Patients with global aphasia may be able to verbalize a few short utterances and use non-word neologisms, but their overall production ability is limited. Their ability to repeat words, utterances, or phrases is also affected. Due to the preservation of the right hemisphere, an individual with global aphasia may still be able to express themselves through facial expressions, gestures, and intonation. This type of aphasia often results from a large lesion of the left perisylvian cortex. The lesion is caused by an occlusion of the left middle cerebral artery and is associated with damage to Broca's area, Wernicke's area, and insular regions which are associated with aspects of language.
Broca's area
Damage to Broca's area is commonly associated with telegraphic speech made up of content vocabulary. For example, a person with Broca's aphasia may say something like, "Drive, store. Mom." meaning to say, "My mom drove me to the store today." Therefore, the content of the information is correct, but the grammar and fluidity of the sentence is missing.
The Beauty Myth
Perfectionistic, unattainable goals are cited as an explanation for the increasing rates of plastic surgery and anorexia nervosa. Anorexia is one of the most prevalent eating disorders in Western countries "affecting an estimated 2.5 million people in the United States alone." Of this number, more than 90 percent of anorexics are girls and young women. They suffer from a "serious mental health disease that involves compulsive dieting and drastic weight loss". This weight loss is the result of deliberate self-starvation to achieve a thinner appearance, and it is frequently associated with the disorder bulimia. Anorexia's deep psychological roots make it difficult to treat and often extend the recovery process into a life-long journey.
Apraxia of speech
Recent research has established the existence of primary progressive apraxia of speech caused by neuroanatomic motor atrophy. For a long time, this disorder was not distinguished from other motor speech disorders such as dysarthria and in particular primary progressive aphasia. Many studies have been done trying to identify areas in the brain in which this particular disorder occurs or at least to show that it occurs in different areas of the brain than other disorders. One study observed 37 patients with neurodegenerative speech disorders to determine whether or not it is distinguishable from other disorders, and if so where in the brain it can be found. Using speech and language, neurological, neuropsychological and neuroimaging testing, the researchers came to the conclusion that PAS does exist and that it correlates to superior lateral premotor and supplementary motor atrophy. However, because PAS is such a rare and recently discovered disorder, many studies do not have enough subjects to observe to make data entirely conclusive.
Paraphasia
Two areas of the brain, Broca’s area and Wernicke’s area, are responsible for various disruptions in speech when damaged. Each is defined by their distinct characteristics. Broca’s aphasia is characterized by non-fluent or telegraphic-type speech - where articles, conjunctions, prepositions, auxiliary verbs, pronouns and morphological inflections (plurals, past tense) are omitted. The word substitutions are infrequent and distortion of consonants and simplification of consonant clusters is frequent. Content words such as nouns, verbs and adjectives may be preserved. Subjects of this aphasia are aware of their errors in speech. Damage to the Broca’s area does not affect comprehension of speech.
Broca's area
In the classical sense, expressive aphasia is the result of injury to Broca's area; it is often the case that lesions in specific brain areas cause specific, dissociable symptoms, although case studies show there is not always a one-to-one mapping between lesion location and aphasic symptoms. The correlation between damage to certain specific brain areas (usually in the left hemisphere) and the development of specific types of aphasia makes it possible to deduce (albeit very roughly) the location of a suspected brain lesion based only on the presence (and severity) of a certain type of aphasia, though this is complicated by the possibility that a patient may have damage to a number of brain areas and may exhibit symptoms of more than one type of aphasia. The examination of lesion data in order to deduce which brain areas are essential in the normal functioning of certain aspects of cognition is called the deficit-lesion method; this method is especially important in the branch of neuroscience known as aphasiology. Cognitive science - to be specific, cognitive neuropsychology - are branches of neuroscience that also make extensive use of the deficit-lesion method.
Since studies carried out in the late 1970's it has been understood that the relationship between Broca's area and Broca's aphasia is not as consistent as once thought. Lesions to Broca's area alone don't result in a Broca's aphasia, nor do Broca's aphasic patients necessarily have lesions in Broca's area. Lesions to Broca's area alone are known to produce just a transient mutism that resolves inside 3–6 weeks. This discovery suggests that Broca's area may be included in some aspect of verbalization or articulation; however, it does not address its part in sentence comprehension. Still, Broca's area frequently emerges in functional imaging studies of sentence processing. However, it also becomes activated in word-level tasks. This suggests that Broca’s area is not dedicated to sentence processing but supports a function common to both. In fact, Broca's area can show activation in such non-linguistic tasks as imagery of motion.
Ataxia–telangiectasia
Friedreich ataxia (FA) is the most common genetic cause of ataxia in children. Like A–T, FA is a recessive disease, appearing in families without a history of the disorder. FA is caused by mutation in the frataxin gene, most often an expansion of a naturally occurring repetition of the three nucleotide bases GAA from the usual 5–33 repetitions of this trinucleotide sequence to greater than 65 repeats on each chromosome. Most often the ataxia appears between 10 and 15 years of age, and differs from A–T by the absence of telangiectasia and oculomotor apraxia, a normal alpha fetalprotein, and the frequent presence of scoliosis, absent tendon reflexes, and abnormal features on the EKG. Individuals with FA manifest difficulty standing in one place that is much enhanced by closure of the eyes (Romberg sign) that is not so apparent in those with A–T – even though those with A–T may have greater difficulty standing in one place with their eyes open.
Cerebrum
Speech and language are mainly attributed to the parts of the cerebral cortex. Motor portions of language are attributed to Broca's area within the frontal lobe. Speech comprehension is attributed to Wernicke's area, at the temporal-parietal lobe junction. These two regions are interconnected by a large white matter tract, the arcuate fasciculus. Damage to the Broca's area results in expressive aphasia (non-fluent aphasia) while damage to Wernicke's area results in receptive aphasia (also called fluent aphasia).
Broca's area
This specific group of symptoms distinguishes those who have expressive aphasia from individuals with other types of aphasia. There are several distinct "types" of aphasia, and each type is characterized by a different set of language deficits. Although those who have expressive aphasia tend to retain good spoken language comprehension, other types of aphasia can render patients completely unable to understand any language at all, unable to understand any spoken language (auditory verbal agnosia), whereas still other types preserve language comprehension, but with deficits. People with expressive aphasia may struggle less with reading and writing (see alexia) than those with other types of aphasia. Although individuals with expressive aphasia tend to have a good ability to self-monitor their language output (they "hear what they say" and make corrections), other types of aphasics can seem entirely unaware of their language deficits.
Ideational apraxia
In the context of dementia, apraxia is a major cause of morbidity, and progresses with the underlying disease sometimes to the extent that patients may be unable to feed themselves or use simple utensils. Patients often become highly dependent or require nursing home placement because of their inability to properly use objects.
Expressive language disorder
Some of the earliest neuroscientific discoveries were related to the discovery that damage to certain areas of the brain related to impairments in language, such as the discovery of Wernicke's area and Broca's area. Lesions in these parts of the brain impair language comprehension and language production, respectively. Paul Broca was the first to note that the left hemisphere of the brain appeared to be localized for language function, particularly for right handed patients. Modern neuroscientific research has verified this, though language may be lateralizaed to the right hemisphere in some right-handed individuals.
Aphasia
Although localizationist approaches provide a useful way of classifying the different patterns of language difficulty into broad groups, one problem is that a sizeable number of individuals do not fit neatly into one category or another. Another problem is that the categories, particularly the major ones such as Broca's and Wernicke's aphasia, still remain quite broad. Consequently, even amongst individuals who meet the criteria for classification into a subtype, there can be enormous variability in the types of difficulties they experience.
Aphasiology
Receptive aphasia was originally described by the German neurologist Karl Wernicke, a contemporary of Broca. Receptive aphasics produce speech that seems fluent and grammatical, but is largely devoid of sensible content. Comprehension is severely impaired, but while patients display a great deal of difficulty comprehending individual words, they can more easily understand words in context. Receptive aphasia is associated with the posterior third of the superior temporal gyrus in the distribution of the inferior division of the middle cerebral artery, known as "Wernicke's area", an area adjacent to the cortex responsible for auditory processing. If the damage extends posteriorly, visual connections are disrupted, and the patient will have difficulty understanding written language. Therefore, the localization of the two best-known aphasias mirrors the grossest dichotomy in brain organization: anterior areas are specialized for motor output, and posterior areas for sensory processing.
Apraxia
Apraxia is most often due to a lesion located in the dominant (usually left) hemisphere of the brain, typically in the frontal and parietal lobes. Lesions may be due to stroke, acquired brain injuries, or neurodegenerative diseases such as Alzheimer's disease or other dementias, Parkinson's disease, or Huntington's disease. It is also possible for apraxia to be caused by lesions in other areas of the brain including the non-dominant (usually right) hemisphere.
Ideomotor apraxia is typically due to a decrease in blood flow to the dominant hemisphere of the brain and particularly the parietal and premotor areas. It is frequently seen in patients with corticobasal degeneration.
Lateralization of brain function
One of the first indications of brain function lateralization resulted from the research of French physician Pierre Paul Broca, in 1861. His research involved the male patient nicknamed "Tan", who suffered a speech deficit (aphasia); "tan" was one of the few words he could articulate, hence his nickname. In Tan's autopsy, Broca determined he had a syphilitic lesion in the left cerebral hemisphere. This left frontal lobe brain area (Broca's area) is an important speech production region. The motor aspects of speech production deficits caused by damage to Broca's area are known as expressive aphasia. In clinical assessment of this aphasia, it is noted that the patient cannot clearly articulate the language being employed.
Agraphia
Agraphia is an acquired neurological disorder causing a loss in the ability to communicate through writing, either due to some form of motor dysfunction or an inability to spell. The loss of writing ability may present with other language or neurological disorders; disorders appearing commonly with agraphia are alexia, aphasia, dysarthria, agnosia, and apraxia. The study of individuals with agraphia may provide more information about the pathways involved in writing, both language related and motoric. Agraphia cannot be directly treated, but individuals can learn techniques to help regain and rehabilitate some of their previous writing abilities. These techniques differ depending on the type of agraphia.
Asemia
Asemia is the term for the medical condition of being unable to understand or express any signs or symbols.
It is a more severe condition than aphasia, which is the inability to understand linguistic signs. Asemia is caused by damage to the areas of the brain that process communication – more specifically, when there is damage to the left side of the brain in the areas that process communication such as Broca's and Wernicke's areas. Damage can be inflicted by physical trauma to the brain, but is more commonly caused by stroke and sometimes tumors. The onset of this condition is usually quick but not permanent. Treatment of this condition is traditional speech therapy in which the individual must relearn how to read, write, and talk. Depending on the severity of the injury, recovery can take days to years. Considerable recovery is common, but often not to the full extent of baseline ability.
Aphasia
It is important to note that there are typical difficulties with speech and language that come with normal aging as well. As we age language can become more difficult to process resulting in a slowing of verbal comprehension, reading abilities and more likely word finding difficulties. With each of these though, unlike some aphasias, functionality within daily life remains intact.Localizationist approaches aim to classify the aphasias according to their major presenting characteristics and the regions of the brain that most probably gave rise to them. Inspired by the early work of nineteenth-century neurologists Paul Broca and Carl Wernicke, these approaches identify two major subtypes of aphasia and several more minor subtypes:Recent classification schemes adopting this approach, such as the "Boston-Neoclassical Model", also group these classical aphasia subtypes into two larger classes: the nonfluent aphasias (which encompasses Broca's aphasia and transcortical motor aphasia) and the fluent aphasias (which encompasses Wernicke's aphasia, conduction aphasia and transcortical sensory aphasia). These schemes also identify several further aphasia subtypes, including: anomic aphasia, which is characterized by a selective difficulty finding the names for things; and global aphasia, where both expression and comprehension of speech are severely compromised.
Mental lexicon
The following are some hypotheses pertaining to semantic comprehension in the brain:Anomic aphasia, aphasia (expressive + receptive aphasia) and Alzheimer's disease can all affect recalling or retrieving words. Anomia renders a person completely unable to name familiar objects, places and people, a involves specific naming difficulties; sufferers of anomia have difficulties recalling words. Anomia is a lesser level of dysfunction, a severe form of the "tip-of-the-tongue" phenomenon where the brain cannot recall the desired word. Stroke, head trauma and brain tumors can cause anomia.
Fast mapping
Fast mapping in individuals with aphasia has gained research attention due to its effect on speaking, listening, reading, and writing. Research done by Blumstein makes an important distinction between those with Broca's aphasia, who are limited in physical speech, as compared to those with Wernicke's aphasia, who cannot link words with meaning. In Broca's aphasia, Blumstein found that whereas individuals with Wernicke's aphasia performed at the same level as the normal control group, those with Broca's aphasia showed slower reaction times for word presentations after reduced voice onset time stimuli. In short, when stimuli were acoustically altered, individuals with Broca's aphasia experienced difficulty recognizing the novel stimuli upon second presentation. Bloomstein's findings reinforce the crucial difference between one's ability to retain novel stimuli versus the ability to express novel stimuli. Because individuals with Wernicke's aphasia are only limited in their understanding of semantic meaning, it makes sense that the participant's novel stimulus recall would not be affected. On the other hand, those with Broca's aphasia lack the ability to produce speech, in effect hindering their ability to recall novel stimuli. Although individuals with Broca's aphasia are limited in their speech production, it is not clear whether they simply cannot formulate the physical speech or if they actually did not process the stimuli.
Paul Broca
New research has found that dysfunction in the area may lead to other speech disorders such as stuttering and apraxia of speech. Recent anatomical neuroimaging studies have shown that the pars opercularis of Broca's area is anatomically smaller in individuals who stutter whereas the pars triangularis appears to be normal.
Monoplegia
Considering monoplegia as it relates to cerebral palsy, in premature infants, the most common cause of cerebral palsy is periventricular hemorrhagic infarction. In term infants, the underlying causes are often cerebral malformations, cerebral infarction, and intracerebral hemorrhage. Delayed crawling or walking are the usual concerns that arise in infants with paralysis of the limb. In these cases, abnormalities of the legs are the main focus of the attention.
Conduction aphasia
In the late 19th century, Paul Broca studied patients with expressive aphasia. These patients had lesions in the anterior perisylvian region (now known as Broca's area), and produced halting and labored speech, lacking in function words and grammar. For example, "clinician: What brought you to the hospital? patient: yes … ah … Monday … ah … Dad … Peter Hogan, and Dad … ah … hospital … and ah … Wednesday … Wednesday … nine o’clock and ah Thursday … ten o’clock … doctors two … two … an doctors and … ah … teeth … yah … and a doctor an girl … and gums, an I." 
Comprehension is generally preserved, although there can be deficits in interpretation of complex sentences. In an extreme example, one of his patients could only produce a single syllable, "Tan".
Music therapy for non-fluent aphasia
In addition, in spite of some research results indicating that MIT can activate regions potentially responsible for language processing in aphasic patients’ right hemisphere, some studies obtain completely opposite results. Belin et al.’s study showed that Broca’s area and adjacent regions in aphasic patients’ left hemisphere were activated after patients received MIT, while no activation was observed in the right hemisphere. Contrarily, they observed activation in patients’ right hemisphere when patients underwent word repetition tasks without MIT; they interpreted the right hemispheric activation as the persistence of aphasia, instead of cortical reorganization. Unfortunately, these currently conflicting research results demonstrate that the underlying mechanism of music therapy remains unclear. If the neural mechanism of music therapy cannot be elucidated, the effective application of these techniques will remain hard to achieve.
Expressive aphasia
It is caused by acquired damage to the anterior regions of the brain, such as the left posterior inferior frontal gyrus or inferior frontal operculum, also described as Broca's area (Brodmann area 44 and Brodmann area 45). It is one subset of a larger family of disorders known collectively as aphasia. Expressive aphasia contrasts with receptive aphasia, in which patients are able to speak in grammatical sentences that lack semantic significance, and generally also have trouble with comprehension. Expressive aphasia differs from dysarthria, which is typified by a patient's inability to properly move the muscles of the tongue and mouth to produce speech. Expressive aphasia also differs from apraxia of speech which is a motor disorder characterized by an inability to create and sequence motor plans for speech.
Aphasiology
Another less commonly known aphasia is global aphasia, which generally manifests itself after a stroke affecting an extensive portion of the brain occurs, including infarction of both divisions of the middle cerebral artery and generally both Broca's area and Wernicke's area. Survivors with global aphasia may have great difficulty understanding and forming words and sentences, and generally experience a great deal of difficulty when trying to communicate. With considerable speech therapy rehabilitation, global aphasia may progress into expressive aphasia or receptive aphasia.
Expressive aphasia
Because Broca's area is anterior to the primary motor cortex which is responsible for movement of the face, hands, and arms, a lesion affecting Broca's areas may also result in hemiparesis (weakness of both limbs on the same side of the body) or hemiplegia (paralysis of both limbs on the same side of the body). The brain is wired contralaterally, which means the limbs on right side of the body are controlled by the left hemisphere and vice versa. Therefore, when Broca's area or surrounding areas in the left hemisphere are damaged, hemiplegia or hemiparesis often occurs on the right side of the body in individuals with Broca's aphasia.
Stroke recovery
Unlike many effects of stroke, where the clinician is able to judge the particular area of the brain that a stroke has injured by certain signs or symptoms, the causation of apraxia is less clear. A common theory is that the part of the brain that contains information for previously learned skilled motor activities has been either lost or cannot be accessed. The condition is usually due to an insult to the dominant hemisphere of the brain. More often this is located in the frontal lobe of the left hemisphere of the brain. Treatment of acquired apraxia due to stroke usually consists of physical, occupational, and speech therapy. The Copenhagen Stroke Study, which is a large important study published in 2001, showed that out of 618 stroke patients, manual apraxia was found in 7% and oral apraxia was found in 6%. Both manual and oral apraxia were related to increasing severity of stroke. Oral apraxia was related with an increase in age at the time of the stroke. There was no difference in incidence among gender. It was also found that the finding of apraxia has no negative influence on ability to function after rehabilitation is completed. The National Institute of Neurological Disorders and Stroke (NINDS) is currently sponsoring a clinical trial to gain an understanding of how the brain operates while carrying out and controlling voluntary motor movements in normal subjects. The objective is to determine what goes wrong with these processes in the course of acquired apraxia due to stroke or brain injury.
Paul Broca
After Leborgne passed away, due to an uncontrolled infection and resultant gangrene Broca performed an autopsy, hoping to find a physical explanation for Leborgne’s disability. He determined that, as predicted, Leborgne did in fact have a lesion in the frontal lobe of the left cerebral hemisphere. From a comparative progression of Leborgne's loss of speech and motor movement, the area of the brain important for speech production was determined to lie within the third convolution of the left frontal lobe, next to the lateral sulcus. A second case after Leborgne is what solidified Broca’s beliefs that our speech function was localized. Lazare Lelong was an 84-year-old grounds worker who was being treated at Bicêtre for dementia. He had also lost the ability to speak other than 5 words that held real meaning. After his death his brain was also autopsied. Broca found a lesion that encompassed much the same area as had been affected in Leborgne’s brain. This finding concluded that a specific area controlled our ability to produce meaningful sounds, and when it is affected, one can lose their capability to communicate. For the next two years, Broca went on to find autopsy evidence from 12 more cases in support of the localization of articulated language. Broca published his findings from the autopsies of the 12 patients in his paper, “Localization of Speech in the Third Left Frontal Cultivation” in 1865. His work inspired others to perform careful autopsies win the aim of linking more brain regions to sensory and motor functions.
Conduction aphasia
Conduction aphasia is caused by damage to the parietal lobe of the brain, especially in regards to the area associated with the left-hemisphere dominant dorsal stream network. The arcuate fasciculus, which connects Broca's area and Wernicke's area (important for speech and language production and comprehension, respectively), is affected. These two areas control speech and language in the brain. The arcuate fasciculus is a thick band of fiber that connects the two areas and carries messages between them. When this area is damaged, the patient experiences damage to the auditory-motor integration system. This results in disruption to the delayed auditory feedback network, causing the individual to have difficulty correcting themselves on speech repetition tasks. Additionally, recent evidence suggests that conduction aphasia can also be caused by lesions in the left superior temporal gyrus and/or the left supramarginal gyrus.
Alternating hemiplegia of childhood
Alternating hemiplegia of childhood (AHC) is a rare neurological disorder often caused by a mutation in ATP1A3, though growing evidence strongly supports mutation of the ATP1A3 gene as the primary cause of this disease. AHC is named for the transient episodes, often referred to as attacks or episodes, of hemiplegia from which those with the disorder suffer. These hemiplegic attacks can cause anything from mild weakness to complete paralysis on one or both sides of the body, and they can vary greatly in duration. Attacks may also alternate from one side of the body to the other, or alternate between affecting one or both sides during a single attack. AHC is associated with many symptoms besides hemiplegia, and the majority of these become apparent in early infancy. AHC typically presents before the age of 18 months. Normally, hemiplegia and other associated symptoms cease completely with sleep, but they may recur upon waking. The disorder was only recently discovered, having first been characterized in 1971. AHC is also extremely rare – approximately 1 in 1,000,000 people have this disorder. Besides hemiplegia, symptoms of the disorder include an extremely broad range of neurological and developmental impairments which are not well understood.
Broca's area
Examination of the brains of Broca's two historic patients with high-resolution MRI has produced several interesting findings. First, the MRI findings suggest that other areas besides Broca's area may also have contributed to the patients' reduced productive speech. This finding is significant because it has been found that, though lesions to Broca's area alone can possibly cause temporary speech disruption, they do not result in severe speech arrest. Therefore, there is a possibility that the aphasia denoted by Broca as an absence of productive speech also could have been influenced by the lesions in the other region. Another finding is that the region, which was once considered to be critical for speech by Broca, is not precisely the same region as what is now known as Broca's area. This study provides further evidence to support the claim that language and cognition are far more complicated than once thought and involve various networks of brain regions.
Cognitive psychology
With the philosophical debate continuing, the mid to late 19th century was a critical time in the development of psychology as a scientific discipline. Two discoveries that would later play substantial roles in cognitive psychology were Paul Broca's discovery of the area of the brain largely responsible for language production, and Carl Wernicke's discovery of an area thought to be mostly responsible for comprehension of language. Both areas were subsequently formally named for their founders and disruptions of an individual's language production or comprehension due to trauma or malformation in these areas have come to commonly be known as Broca's aphasia and Wernicke's aphasia.
Pediatric acquired brain injury
Pediatric acquired brain injury (PABI) is the number one cause of death and disability for children and young adults in the United States." and effects most children ages (6-10) and adolescent ages (11-17) around the world. The injury can be traumatic or non-traumatic in nature, and most patients never return to normal after suffering from the injury.There are many different symptoms such as amnesia, anhedonia, and apraxia. Currently there isn’t a cure for the injury. PABI effects the family of the patient also, because the families of the patient will need to adapt to the new changes they will experience in their child. It is recommended that the families decide to gain as much information as they can about the injury and what to expect by going to different program events and meetings.
Receptive aphasia
As a result of the occlusion in the left middle cerebral artery, Wernicke's aphasia is most commonly caused by a lesion in the posterior superior temporal gyrus (Wernicke's area). This area is posterior to the primary auditory cortex (PAC) which is responsible for decoding individual speech sounds. Wernicke's primary responsibility is to assign meaning to these speech sounds. The extent of the lesion will determine the severity of the patients deficits related to language. Damage to the surrounding areas (perisylvian region) may also result in Wernicke's aphasia symptoms due to variation in individual neuroanatomical structure and any co-occurring damage in adjacent areas of the brain.
Broca's area
The essential role of the Broca's area in speech production has been questioned since it can be destroyed while leaving language nearly intact. In one case of a computer engineer, a slow-growing glioma tumor was removed. The tumor and the surgery destroyed the left inferior and middle frontal gyrus, the head of the caudate nucleus, the anterior limb of the internal capsule, and the anterior insula. However, there were minimal language problems three months after removal and the individual returned to his professional work. These minor problems include the inability to create syntactically complex sentences including more than two subjects, multiple causal conjunctions, or reported speech. These were explained by researchers as due to working memory problems. They also attributed his lack of problems to extensive compensatory mechanisms enabled by neural plasticity in the nearby cerebral cortex and a shift of some functions to the homologous area in the right hemisphere.
Expressive aphasia
Understanding lateralization of brain function is important for understanding which areas of the brain cause expressive aphasia when damaged. In the past, it has been believed that the area for language production differs between left and right-handed individuals. If this were true, damage to the homologous region of Broca's area in the right hemisphere should cause aphasia in a left-handed individual. More recent studies have shown that even left-handed individuals typically have language functions only in the left hemisphere. However, left-handed individuals are more likely to have a dominance of language in the right hemisphere.
Brain damage
Damage to the Broca’s area typically produces symptoms like omitting functional words (agrammatism), sound production changes, dyslexia, dysgraphia, and problems with comprehension and production. Broca’s aphasia is indicative of damage to the posterior inferior frontal gyrus of the brain.
Neuroanatomy of handedness
Language areas are represented unilaterally in the human brain. In around 95% of right-handers, these brain areas are often located on the left hemisphere, however the proportion reduces in left handers down to around 70%. Therefore 7 in every 100 individuals is right-hemisphered for language and left-hand dominant. It is unclear as to whether or not left-hemisphered left handers suffer any language or writing deficits because of this. Broca's area has been found to have differing grey matter structures depending on handedness. The inferior frontal sulcus, which contains Broca's area, was found to be more continuous in the hemisphere ipsilateral to the dominant hand
Apoptosis-inducing factor
Mutations of AIF due to deletions have stimulated the creation of the mouse model of complex I deficiency. Complex I deficiency is the reason behind over thirty percent of human mitochondrial diseases. For example, complex I mitochondriopathies mostly affect infants by causing symptoms such as seizures, blindness, deafness, etc. These AIF-deficient mouse models are important for fixing complex I deficiencies. The identification of AIF-interacting proteins in the inner mitochondrial membrane and intermembrane space will help researchers identify the mechanism of the signaling pathway that monitors the function of AIF in the mitochondria.
The Language Instinct
Pinker attempts to trace the outlines of the language instinct by citing his own studies of language acquisition in children, and the works of many other linguists and psychologists in multiple fields, as well as numerous examples from popular culture. He notes, for instance, that specific types of brain damage cause specific impairments of language such as Broca's aphasia or Wernicke's aphasia, that specific types of grammatical construction are especially hard to understand, and that there seems to be a critical period in childhood for language development just as there is a critical period for vision development in cats. Much of the book refers to Chomsky's concept of a universal grammar, a meta-grammar into which all human languages fit. Pinker explains that a universal grammar represents specific structures in the human brain that recognize the general rules of other humans' speech, such as whether the local language places adjectives before or after nouns, and begin a specialized and very rapid learning process not explainable as reasoning from first principles or pure logic. This learning machinery exists only during a specific critical period of childhood and is then disassembled for thrift, freeing resources in an energy-hungry brain.
Global aphasia
Global aphasia typically results from an occlusion to the trunk of the middle cerebral artery (MCA), which affects a large portion of the perisylvian region of the left cortex. Global aphasia is usually a result of a thrombotic stroke, which occurs when a blood clot forms in the brain's blood vessels. In addition to stroke, global aphasia can also be caused by traumatic brain injury (TBI), tumors, and progressive neurological disorders. The large areas in the anterior (Broca's) and posterior (Wernicke's) area of the brain are either destroyed or impaired because they are separate branches of the MCA that are supplied by its arterial trunk. Lesions usually result in extensive damage to the language areas of the left hemisphere, however global aphasia can result from damage to smaller, subcortical regions. It is well known that a lesion to the cortex can cause aphasia. However, a study by Kumar et al. (1996) suggests that lesions to the subcortical regions of the cortex such as the thalamus, basal ganglia, internal capsule, and paraventricular white matter can also cause speech and language deficits. This is due to the fact that the subcortical regions are closely associated with the language centers in the brain. Kumar et al. state that while lesions to the subcortical regions could cause certain types of aphasia, a lesion to these regions would rarely cause global aphasia. In a study performed by Ferro (1992), it was found that five different brain lesion locations were linked to aphasia. These locations include: "fronto-temporo-parietal lesions", "anterior, suprasylvian, frontal lesions", "large subcortical infarcts", "posterior, suprasylvian, parietal infarcts", and "a double lesion composed of a frontal and a temporal infarct".
Derek Colanduno
In an interview in 2012, Colanduno stated that his stroke greatly affected the part of his brain that is responsible for a psychological phenomenon called Pareidolia. This is a normal brain's way of interpreting vague or random stimulus as being significant, such as seeing an animal or a face in a cloud or seeing the "Man in the Moon." He also suffered significant Aphasia which affected his ability to speak. Colanduno chose to use Music Therapy to improve (or re-learn) his speech pattern, word formation and word-finding abilities. Speaking a nursery rhyme, for example, to the beat of the music using a metronome helped his condition significantly. Colanduno was also told he would never walk again, however he very adamantly persevered until he was able to walk again. The drug L-DOPA or Levodopa also expedited his recovery.
Apraxia of speech
AOS and expressive aphasia (also known as Broca's aphasia) are commonly mistaken as the same disorder mainly because they often occur together in patients. Although both disorders present with symptoms such as a difficulty producing sounds due to damage in the language parts of the brain, they are not the same. The main difference between these disorders lies in the ability to comprehend spoken language; patients with apraxia are able to fully comprehend speech, while patients with aphasia are not always fully able to comprehend others' speech.
Cause of obsessive-compulsive disorder
Obsessions and compulsions are also very common in several other medical conditions, including: Tourette syndrome, Parkinson disease, epilepsy, schizophrenia, Huntington disease, encephalitis lethargica, Sydenham chorea, and damage to specific brain regions. Similar to OCD, these disorders also exhibit abnormalities in the basal ganglia. This portion of the brain is responsible for mediating cognition, emotion, and movement. Disruption of the basal ganglia results in a host of symptoms that are characterized by compulsivity (behavioral patterns that are released repeatedly) and impulsivity (behavioral patterns that are released suddenly by various stimuli). This suggests that in patients with OCD, the disorder may be the result of abnormal functioning of the basal ganglia.
Aphasiology
Lesions exclusively to Broca's area (the foot of the inferior frontal gyrus) do not produce Broca's aphasia, but instead mild dysprosody and agraphia, sometimes accompanied by word-finding pauses and mild dysarthria. Not much is known about what other areas must be damaged in order to produce Broca's aphasia, but some maintain damage to the inferior pre-Rolandic motor strip (the motor cortex region responsible glossopharyngeal muscle control) is also necessary.
Wernicke's area
Wernicke's area ( or ; ), also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech (the other is Broca's area). It is involved in the comprehension of written and spoken language (in contrast to Broca's area that is involved in the production of language). It is traditionally thought to be in Brodmann area 22, which is located in the superior temporal lobe in the dominant cerebral hemisphere (which is the left hemisphere in about 95% of right handed individuals and 60% of left handed individuals). Damage caused to Wernicke's area results in receptive, fluent aphasia. This means that the person with aphasia will be able to fluently connect words, but the phrases will lack meaning. This is unlike non-fluent aphasia, in which the person will use meaningful words, but in a non-fluent, telegraphic manner.
Aphasia
During the second half of the 19th century, aphasia was a major focus for scientists and philosophers who were working in the beginning stages of the field of psychology.
In medical research, speechlessness was described as an incorrect prognosis, and there was no assumption that underlying language complications existed. Broca and his colleagues were some of the first to write about aphasia, but Wernicke was the first credited to have written extensively about aphasia being a disorder that contained comprehension difficulties. Despite claims of who reported on aphasia first, it was F.J. Gall that gave the first full description of aphasia after studying wounds to the brain, as well as his observation of speech difficulties resulting from vascular lesions. A recent book on the entire history of aphasia is available (Reference: Tesak, J. & Code, C. (2008) Milestones in the History of Aphasia: Theories and Protagonists.Hove, East Sussex: Psychology Press.)
Louis Pierre Gratiolet
With Paul Broca (1824-1880) he performed correlative studies of aphasia and the frontal lobe. Gratiolet was a vocal critic of Broca regarding the latter's belief that a larger brain equated to higher intelligence.
Apraxia of Lid Opening
The exact cause of ALO is not yet fully understood. Despite its name, it is not a true apraxia, but thought to be due to a supranuclear origin of abnormal neuronal activity. Voluntary eyelid opening involves the simultaneous activation of the levator palpebrae superioris muscle and the inhibition of the orbicularis oculi muscle. Electromyographic studies have shown that ALO may involve either involuntary levator palpebrae superioris muscle inhibition, persistent pretarsal orbicularis oculi muscle contraction, or both. Hypometabolism of glucose may play a part, and has been documented in the basal ganglia, frontal lobe, and the primary visual cortex in some cases of ALO.
Conduction aphasia
Left-hemisphere damage involving auditory regions often result in speech deficits. Lesions in this area that damage the sensorimotor dorsal stream suggest that the sensory system aid in motor speech. Studies have suggested that conduction aphasia is a result of damage specifically to the left superior temporal gyrus and/or the left supra marginal gyrus. The classical explanation for conduction aphasia is that of a disconnection between the brain areas responsible for speech comprehension (Wernicke's area) and speech production (Broca's area), due specifically to damage to the arcuate fasciculus, a deep white matter tract. Patients are still able to comprehend speech because the lesion does not disrupt the ventral stream pathway.
Aphasia
Aphasia affects about 2 million people in the US and 250,000 people in Great Britain. Though nearly 180,000 people in the US acquire the disorder a year, 84.5% of people have never heard of the condition.
People with aphasia may experience any of the following behaviors due to an acquired brain injury, although some of these symptoms may be due to related or concomitant problems such as dysarthria or apraxia and not primarily due to aphasia. Aphasia symptoms can vary based on the location of damage in the brain. Signs and symptoms may or may not be present in individuals with aphasia and may vary in severity and level of disruption to communication. Often those with aphasia will try to hide their inability to name objects by using words like "thing". So when asked to name a pencil they may say it is a thing used to write.
Given the previously stated signs and symptoms the following behaviors are often seen in people with aphasia as a result of attempted compensation for incurred speech and language deficits:Aphasia is most often caused by stroke, but any disease or damage to the parts of the brain that control language can cause aphasia. Some of these can include brain tumors, traumatic brain injury, and progressive neurological disorders. In rare cases, aphasia may also result from herpesviral encephalitis. The herpes simplex virus affects the frontal and temporal lobes, subcortical structures, and the hippocampal tissue, which can trigger aphasia. 
In acute disorders, such as head injury or stroke, aphasia usually develops quickly. When caused by brain tumor, infection, or dementia, it develops more slowly.
Paragrammatism
However, ever since the introduction of the term paragrammatism some students have
pointed out that paragrammatic and agrammatic phenomena, which in classical theory form
part of Broca’s aphasia, may co-occur in the same patient.
Broca's area
Patients with expressive aphasia, also known as Broca's aphasia, are individuals who know "what they want to say, they just cannot get it out". They are typically able to comprehend words, and sentences with a simple syntactic structure (see above), but are more or less unable to generate fluent speech. Other symptoms that may be present include problems with fluency, articulation, word-finding, word repetition, and producing and comprehending complex grammatical sentences, both orally and in writing.
Akathisia
Akathisia is a movement disorder characterized by a feeling of inner restlessness and inability to stay still. Usually the legs are most prominently affected. People may fidget, rock back and forth, or pace. Others may just feel uneasy. Complications include suicide.
Antipsychotics, particularly the first generation antipsychotics, are a leading cause. Other causes may include selective serotonin reuptake inhibitors, metoclopramide, reserpine, Parkinson’s disease, and untreated schizophrenia. It may also occur upon stopping antipsychotics. The underlying mechanism is believed to involve dopamine. Diagnosis is based on symptoms. It differs from restless leg syndrome in that akathisia is not associated with sleeping.
Treatment may include switching to an antipsychotic with a lower risk of the condition. Medications with tentative evidence of benefit include diphenhydramine, trazodone, benztropine, mirtazapine, and beta blockers. Vitamin B6 or correcting iron deficiency may also be useful. Around half of people on antipsychotics develop the condition. The term was first used by Ladislav Haškovec, who described the phenomenon in 1901. It is from Greek "a-" meaning "not" and "kathízein" meaning "to sit" or in other words an "inability to sit".
Trypanosoma brucei
"Trypanosoma brucei gambiense" causes 97% of human cases of sleeping sickness. Resistance to ApoL1 is principally mediated by the hydrophobic ß-sheet of the "T. b. gambiense" specific glycoprotein. Other factors involved in resistance appear to be a change in the cysteine protease activity and TbHpHbR inactivation due to a leucine to serine substitution (L210S) at codon 210. This is due to a thymidine to cytosine mutation at the second codon position.
Agnosia
The term 'agnosia' comes from the Ancient Greek ἀγνωσία ("agnosia"), "ignorance", "absence of knowledge". It was introduced by Sigmund Freud in 1891: "For disturbances in the recognition of objects, which Finkelnburg classes as asymbolia, I should like to propose the term 'agnosia'." Prior to Freud's introduction of the term, some of the first ideas about agnosia came from Carl Wernicke, who created theories about receptive aphasia in 1874. He noted that individuals with receptive aphasia did not possess the ability to understand speech or repeat words. He believed that receptive aphasia was due to lesions of the posterior third of the left superior temporal gyrus. Due to these lesions, Wernicke believed that individuals with receptive aphasia had a limited deafness for certain sounds and frequencies in speech.
Broca's area
Considering the hypothesis that Broca's area may be most involved in articulation, its activation in all of these tasks may be due to subjects' covert articulation while formulating a response. Despite this caveat, a consensus seems to be forming that whatever role Broca's area may play, it may relate to known working memory functions of the frontal areas. (There is a wide distribution of Talairach coordinates reported in the functional imaging literature that are referred to as part of Broca's area.) The processing of a passive voice sentence, for example, may require working memory to assist in the temporary retention of information while other relevant parts of the sentence are being manipulated (i.e. to resolve the assignment of thematic roles to arguments). Miyake, Carpenter, and Just have proposed that sentence processing relies on such general verbal working memory mechanisms while Caplan and Waters consider Broca’s area to be involved in working memory specifically for syntactic processing. Friederici (2002) breaks Broca's area into its component regions and suggests that Brodmann's area 44 is involved in working memory for both phonological and syntactic structure. This area becomes active first for phonology and later for syntax as the time course for the comprehension process unfolds. Brodmann's area 45 together with Brodmann's area 47 is viewed as being specifically involved in working memory for semantic features and thematic structure where processes of syntactic reanalysis and repair are required. These areas come online after Brodmann's area 44 has finished its processing role and where comprehension of complex sentences must rely on general memory resources. All of these theories indicate a move towards a view that syntactic comprehension problems arise from a computational rather than a conceptual deficit. Newer theories are taking a more dynamic view of how the brain integrates different linguistic and cognitive components and are examining the time course of these operations.
Amusia
Amusia can also be related to aprosody, a disorder in which the sufferer's speech is affected, becoming extremely monotonous. It has been found that both amusia and aprosody can arise from seizures occurring in the non-dominant hemisphere. They can also both arise from lesions to the brain, as can Broca's aphasia come about simultaneously with amusia from injury. There is a relation between musical abilities and the components of speech, however, they are not understood very well.
Esophageal dysphagia
Achalasia is an idiopathic motility disorder characterized by failure of lower esophageal sphincter (LES) relaxation as well as loss of peristalsis in the distal esophagus, which is mostly smooth muscle. Both of these features impair the ability of the esophagus to empty contents into the stomach. Patients usually complain of dysphagia to both solids and liquids. Dysphagia to liquids, in particular, is a characteristic of achalasia. Other symptoms of achalasia include regurgitation, night coughing, chest pain, weight loss, and heartburn. The combination of achalasia, adrenal insufficiency, and alacrima (lack of tear production) in children is known as the triple A (Allgrove) syndrome. In most cases the cause is unknown (idiopathic), but in some regions of the world, achalasia can also be caused by Chagas disease due to infection by "Trypanosoma cruzi".
Scleroderma is a disease characterized by atrophy and sclerosis of the gut wall, most commonly of the distal esophagus (~90%). Consequently, the lower esophageal sphincter cannot close and this can lead to severe gastroesophageal reflux disease (GERD). Patients typically present with progressive dysphagia to both solids and liquids secondary to motility problems or peptic stricture from acid reflux.
Spastic motility disorders include diffuse esophageal spasm (DES), nutcracker esophagus, hypertensive lower esophageal sphincter, and nonspecific spastic esophageal motility disorders (NEMD).Rare causes of esophageal dysphagia not mentioned above
Astasis
Currently, physical therapy and rehabilitation are widely accepted as the best treatments for the symptoms of astasia. There is, however, evidence to suggest that regulation of a patient's social situation and behavioral influences can influence the effectiveness of rehabilitation. A 1975 study shows that when a patient is given direct encouragement and social distractions their physical recovery proceeds much faster than when only basic instructions are provided to them.
Paul Oscar Blocq was the first to describe astasis as the inability to maintain an upright posture despite normal function of the legs while sitting. He recognized that paralysis and other deficits could all be observed along with the syndrome astasia-abasia. Jean-Martin Charcot, Charles Lasègue, and other physicians prior to Blocq's description described astasis as "a special variety of motor feebleness of the legs from want of coordination in standing position.” Astasia-abasia is also known as "Blocq's disease". Blocq is credited with diagnosing the first eleven cases and is credited with inventing the chair test for diagnoses. This test involves each patient first walking for 20–30 feet forward then 20–30 feet backward. The patients were then to sit in a swivel chair that had wheels and to push the chair forward and backward. In a follow-up study, these trials were compared with a control group of 9 patients with movement disorders with regard to the gait that were non-psychogenic.
Infant mortality
Seven out of ten childhood deaths are due to infectious diseases: acute respiratory infection, diarrhea, measles, and malaria. Acute respiratory infection such as pneumonia, bronchitis, and bronchiolitis account for 30% of childhood deaths; 95% of pneumonia cases occur in the developing world. Diarrhea is the second-largest cause of childhood mortality in the world, while malaria causes 11% of childhood deaths. Measles is the fifth-largest cause of childhood mortality. Folic acid for mothers is one way to combat iron deficiency. A few public health measures used to lower levels of iron deficiency anemia include iodize salt or drinking water, and include vitamin A and multivitamin supplements into a mother's diet. A deficiency of this vitamin causes certain types of anemia (low red blood cell count).
Dissociation (neuropsychology)
Paul Broca and Carl Wernicke were two physicians of the 1800s whose patients were evidence of the double dissociation between generating language (speech) and understanding language. Broca's patients could no longer speak but could understand language (non-fluent aphasia) while Wernicke's patients could no longer understand language but could produce jumbled speech (fluent aphasia). Post-mortems revealed lesions in separate areas of the brain in each case (now referred to as Broca's area and Wernicke's area respectively). Although the neurophysiology of language is now known to be more complicated than described by Broca or Wernicke, this classic double dissociation acted to begin modern neuropsychological investigation of language.
Pica (disorder)
According to the DSM 5, mineral deficiencies are occasionally associated with pica; however, biological abnormalities are rarely found in individuals with pica. People practicing forms of pica, such as geophagy, pagophagy and amylophagy, are more likely anemic, have low hemoglobin concentration in their blood, lower levels of red blood cells (hematocrit), or have lower plasma zinc levels. Specifically, practicing geophagy is more likely to be associated with anemia or low hemoglobin. Practicing pagophagy and amylophagy were more highly associated with anemia. Additionally, being a child or pregnant woman practicing pica was associated with higher chance of being anemic or having low hemoglobin relative to the general population. More recently, cases of pica have been tied to the obsessive–compulsive spectrum, and there is a move to consider OCD in the cause of pica. However, pica is currently recognized as a mental disorder by the widely used "Diagnostic and Statistical Manual of Mental Disorders" (DSM-IV). Sensory, physiological, cultural and psychosocial perspectives have also been used by some to explain the causation of pica. It has been proposed that mental-health conditions, such as obsessive-compulsive disorder (OCD) and schizophrenia, can sometimes cause pica.
Broca's area
Broca's area has been previously associated with a variety of processes, including phonological segmentation, syntactic processing, and unification, all of which involve segmenting and linking different types of linguistic information. Although repeating and reading single words do not engage semantic and syntactic processing, they do require an operation linking phonemic sequences with motor gestures. Findings indicate that this linkage is coordinated by Broca's area through reciprocal interactions with temporal and frontal cortices responsible for phonemic and articulatory representations, respectively, including interactions with motor cortex before the actual act of speech. Based on these unique findings, it has been proposed that Broca's area is not the seat of articulation per se, but rather is a key node in manipulating and forwarding neural information across large-scale cortical networks responsible for key components of speech production.
Postmortem studies
The area of the brain that Broca identified is now known as Broca's area; damage to this section of the brain can lead to Expressive aphasia.
Aphasia
The first recorded case of aphasia is from an Egyptian papyrus, the Edwin Smith Papyrus, which details speech problems in a person with a traumatic brain injury to the temporal lobe.
Head injury
Ten years later, Paul Broca examined two patients exhibiting impaired speech due to frontal lobe injuries. Broca’s first patient lacked productive speech. He saw this as an opportunity to address language localization. It wasn’t until Leborgne, formally known as "tan", died when Broca confirmed the frontal lobe lesion from an autopsy. The second patient had similar speech impairments, supporting his findings on language localization. The results of both cases became a vital verification of the relationship between speech and the left cerebral hemisphere. The affected areas are known today as Broca’s area and Broca’s Aphasia.
Paul Broca
Although history credits this discovery to Broca, another French neurologist, Marc Dax, made similar observations a generation earlier, but he died shortly after with no chance to further his evidence. The brains of many of Broca's aphasic patients are still preserved and available for viewing on a limited basis in the special collections of the Pierre-and-Marie-Curie University (UPMC) in Paris. The collection was formerly displayed in the Musée Dupuytren. His collection of casts is in the Musée d'Anatomie Delmas-Orfila-Rouvière. Broca presented his study on Leborgne in 1861 in the Bulletin of the Société Anatomique.
Language
Early work in neurolinguistics involved the study of language in people with brain lesions, to see how lesions in specific areas affect language and speech. In this way, neuroscientists in the 19th century discovered that two areas in the brain are crucially implicated in language processing. The first area is Wernicke's area, which is in the posterior section of the superior temporal gyrus in the dominant cerebral hemisphere. People with a lesion in this area of the brain develop receptive aphasia, a condition in which there is a major impairment of language comprehension, while speech retains a natural-sounding rhythm and a relatively normal sentence structure. The second area is Broca's area, in the posterior inferior frontal gyrus of the dominant hemisphere. People with a lesion to this area develop expressive aphasia, meaning that they know what they want to say, they just cannot get it out. They are typically able to understand what is being said to them, but unable to speak fluently. Other symptoms that may be present in expressive aphasia include problems with fluency, articulation, word-finding, word repetition, and producing and comprehending complex grammatical sentences, both orally and in writing. Those with this aphasia also exhibit ungrammatical speech and show inability to use syntactic information to determine the meaning of sentences. Both expressive and receptive aphasia also affect the use of sign language, in analogous ways to how they affect speech, with expressive aphasia causing signers to sign slowly and with incorrect grammar, whereas a signer with receptive aphasia will sign fluently, but make little sense to others and have difficulties comprehending others' signs. This shows that the impairment is specific to the ability to use language, not to the physiology used for speech production.
Tip of the tongue
Anomic aphasia is the inability to recall words and names and is a common symptom of patients with Aphasia and Alzheimer's disease (AD). Research has been conducted to find out how these particular diseases affect TOTs in these individuals. In a study by Beeson, Holland, and Murray (1997), participants with Alzheimer's disease and three classic aphasic syndromes (Broca’s, anomic, and conduction aphasia) were instructed to name famous people. Those with anomic aphasia showed to be superior to the other groups in their ability to naming famous people that were presented. This finding was expected as the group has relatively mild aphasia. However, the Broca’s conduction and AD groups did not differ in immediate or delayed naming of famous faces. All of the groups provided some basic identifying semantic information for at least half of the items presented, suggesting a fair number of items potentially in TOT. Conduction and Broca’s groups showed strongest evidence of TOT, performing better than the other groups in identification of initial letters.
Lateralization of brain function
German physician Karl Wernicke continued in the vein of Broca's research by studying language deficits unlike expressive aphasia. Wernicke noted that not every deficit was in speech production; some were linguistic. He found that damage to the left posterior, superior temporal gyrus (Wernicke's area) caused language comprehension deficits rather than speech production deficits, a syndrome known as receptive aphasia.
Auditory agnosia
The language model proposed by Wernicke and Lichtheim wasn’t accepted at first. For example, in 1897 Bastian argued that, because aphasic patients can repeat single words, their deficit is in the extraction of meaning from words. He attributed both aphasia and auditory agnosia to damage in Lichtheim’s auditory word center. He hypothesized that aphasia is the outcome of partial damage to the left auditory word center, whereas auditory agnosia is the result of complete damage to the same area. Bastian localized the auditory word center to the posterior MTG (middle temporal gyrus).
Scleral reinforcement surgery
Myopia is one of the leading causes of blindness in the world. It is caused by both genetic and environmental factors, such as mechanical stretching, excessive eye work and accommodation, as well as an elevated intraocular pressure. It affects both children and adults. In many cases, myopia will stabilize once the growth process has been completed, but in more severe chronic cases, loss of vision can occur.
Transcortical sensory aphasia
Transcortical sensory aphasia is caused by lesions in the inferior left temporal lobe of the brain located near Wernicke's area, and is usually due to minor hemorrhage or contusion in the temporal lobe, or infarcts of the left posterior cerebral artery (PCA). One function of the arcuate fasciculus is the connection between Wernicke’s and Broca’s area. In TSA Wernicke’s and Broca’s areas are spared, meaning that lesions do not occur in these regions of the brain. However, since the arcuate fasciculus, Wernicke's area, and Broca's area are secluded from the rest of the brain in TSA, patients still have intact repetition (as information from the arcuate fasciculus is relayed to Broca’s area), but cannot attach meaning to words, either spoken or heard.
Psychoanalytic conceptions of language
One of Freud's earliest papers, "On Aphasia" (1891), was concerned with the speech disorder the neurological mechanisms of which had been investigated earlier in the century by Paul Broca and Carl Wernicke. Freud was skeptical of Wernicke's findings, citing a paucity of clinical observation as his reason. Although he conceded the fact that language is linked to neurological processes, Freud repudiated a model of localization of brain function, according to which specific regions of the brain are responsible for certain cognitive functions. In contrast to most of his contemporaries, Freud rejected the notion that in most cases pathological phenomena are manifestations of physiological dysfunctions (Lanteri-Laura, 2005a).
Aphasia
Melodic intonation therapy is used to treat non-fluent aphasia and has proved to be effective in some cases. However, there is still no evidence from randomized controlled trials confirming the efficacy of MIT in chronic aphasia. MIT is used to help people with aphasia vocalize themselves through speech song, which is then transferred as a spoken word. Good candidates for this therapy include people who have had left hemisphere strokes, non-fluent aphasias such as Broca's, good auditory comprehension, poor repetition and articulation, and good emotional stability and memory. An alternative explanation is that the efficacy of MIT depends on neural circuits involved in the processing of rhythmicity and formulaic expressions (examples taken from the MIT manual: “I am fine,” “how are you?” or “thank you”); while rhythmic features associated with melodic intonation may engage primarily left-hemisphere subcortical areas of the brain, the use of formulaic expressions is known to be supported by right-hemisphere cortical and bilateral subcortical neural networks.
Aphasia
Most acute cases of aphasia recover some or most skills by working with a speech-language pathologist. Recovery and improvement can continue for years after the stroke. After the onset of Aphasia, there is approximately a six-month period of spontaneous recovery; during this time, the brain is attempting to recover and repair the damaged neurons. Improvement varies widely, depending on the aphasia's cause, type, and severity. Recovery also depends on the person's age, health, motivation, handedness, and educational level.
Music therapy
Broca’s aphasia, or non-fluent aphasia, is a language disorder caused by damage to Broca’s area and surrounding regions in the left frontal lobe. Those with non-fluent aphasia are able to understand language fairly well, but they struggle with language production and syntax.
Aphasia
Substantial damage to tissue anywhere within the region shown in blue on the figure below can potentially result in aphasia. Aphasia can also sometimes be caused by damage to subcortical structures deep within the left hemisphere, including the thalamus, the internal and external capsules, and the caudate nucleus of the basal ganglia. The area and extent of brain damage or atrophy will determine the type of aphasia and its symptoms. A very small number of people can experience aphasia after damage to the right hemisphere only. It has been suggested that these individuals may have had an unusual brain organization prior to their illness or injury, with perhaps greater overall reliance on the right hemisphere for language skills than in the general population.
Dyslexia
Dyslexia, also known as reading disorder, is characterized by trouble with reading despite normal intelligence. Different people are affected to varying degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. When someone who previously could read loses their ability, it is known as alexia. The difficulties are involuntary and people with this disorder have a normal desire to learn.
Dyslexia is believed to be caused by both genetic and environmental factors. Some cases run in families. It often occurs in people with attention deficit hyperactivity disorder (ADHD) and is associated with similar difficulties with numbers. It may begin in adulthood as the result of a traumatic brain injury, stroke, or dementia. The underlying mechanisms of dyslexia are problems within the brain's language processing. Dyslexia is diagnosed through a series of tests of memory, spelling, vision, and reading skills. Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching.
Treatment involves adjusting teaching methods to meet the person's needs. While not curing the underlying problem, it may decrease the degree of symptoms. Treatments targeting vision are not effective. Dyslexia is the most common learning disability and occurs in all areas of the world. It affects 3–7% of the population, however, up to 20% may have some degree of symptoms. While dyslexia is more often diagnosed in men, it has been suggested that it affects men and women equally. Some believe that dyslexia should be best considered as a different way of learning, with both benefits and downsides.
Dyslexia is thought to have two types of cause, one related to language processing and another to visual processing. It is considered a cognitive disorder, not a problem with intelligence. However, emotional problems often arise because of it. Some published definitions are purely descriptive, whereas others propose causes. The latter usually cover a variety of reading skills and deficits, and difficulties with distinct causes rather than a single condition. The National Institute of Neurological Disorders and Stroke definition describes dyslexia as "difficulty with phonological processing (the manipulation of sounds), spelling, and/or rapid visual-verbal responding". The British Dyslexia Association definition describes dyslexia as "a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling" and is characterized by "difficulties in phonological awareness, verbal memory and verbal processing speed".
Hyperkinesia
In children, primary dystonia is usually inherited genetically. Secondary dystonia, however, is most commonly caused by dyskinetic cerebral palsy, due to hypoxic or ischemic injury to the basal ganglia, brainstem, cerebellum, and thalamus during the prenatal or infantile stages of development. Chorea and ballism can be caused by damage to the subthalamic nucleus. Chorea can be secondary to hyperthyroidism. Athetosis can be secondary to sensory loss in the distal limbs; this is called "pseudoathetosis" in adults but is not yet proven in children.