These tests do not pick up diffuse metabolic changes associated with dementia in a person who shows no gross neurological problems (such as paralysis or weakness) on a neurological exam.The functional neuroimaging modalities of SPECT and PET are more useful in assessing long-standing cognitive dysfunction, since they have shown similar ability to diagnose dementia as a clinical exam and cognitive testing. The ability of SPECT to differentiate vascular dementia from Alzheimers disease, appears superior to differentiation by clinical exam.The value of PiB-PET imaging using Pittsburgh compound B (PiB) as a radiotracer has been established in predictive diagnosis, particularly Alzheimers disease. Prevention
Risk factors
An influential review increased the number of associated risk factors for dementia from nine to twelve in 2020. The three newly added risks are over-indulgence in alcohol, traumatic brain injury, and air pollution. The other nine risk factors are: lower levels of education, high blood pressure, hearing loss, smoking, obesity, depression, inactivity, diabetes, and low social contact. Many of these identified risk factors including, the lower level of education, smoking, physical inactivity and diabetes, are modifiable. Several of the group are known vascular risk factors that may be able to be reduced or eliminated. Managing these risk factors can reduce the risk of dementia in individuals in their late midlife or older age. A reduction in a number of these risk factors can give a positive outcome.
Aphasia is not caused by damage to the brain that results in motor or sensory deficits, which produces abnormal speech; that is, aphasia is not related to the mechanics of speech but rather the individuals language cognition (although a person can have both problems, as an example, if they have a haemorrhage that damaged a large area of the brain). An individuals language is the socially shared set of rules, as well as the thought processes that go behind communication (as it affects both verbal and nonverbal language). It is not a result of a more peripheral motor or sensory difficulty, such as paralysis affecting the speech muscles or a general hearing impairment. Neurodevelopmental forms of auditory processing disorder are differentiable from aphasia in that aphasia is by definition caused by acquired brain injury, but acquired epileptic aphasia has been viewed as a form of APD. Prevalence
Aphasia affects about two million people in the U.S. and 250,000 people in Great Britain. Nearly 180,000 people acquire the disorder every year in the U.S., 170,000 due to stroke. Any person of any age can develop aphasia, given that it is often caused by a traumatic injury. However, people who are middle aged and older are the most likely to acquire aphasia, as the other etiologies are more likely at older ages. For example, approximately 75% of all strokes occur in individuals over the age of 65.