Speech perception
Agnosia is "the loss or diminution of the ability to recognize familiar objects or stimuli usually as a result of brain damage". There are several different kinds of agnosia that affect every one of our senses, but the two most common related to speech are speech agnosia and phonagnosia.
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.