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.
A 2016 Cochrane review of speech and language therapy for people with aphasia found that treatments that are higher intensity, higher dose or over a long duration of time led to significantly better functional communication but people were more likely to drop out of high intensity treatment (up to 15 hours per week).Intensity of therapy is also dependent on the recency of stroke. People with aphasia react differently to intense treatment in the acute phase (0–3 months post stroke), sub-acute phase (3–6 months post stroke), or chronic phase (6+ months post stroke). Intensive therapy has been found to be effective for people with nonfluent and fluent chronic aphasia, but less effective for people with acute aphasia. People with sub-acute aphasia also respond well to intensive therapy of 100 hours over 62 weeks. This suggests people in the sub-acute phase can improve greatly in language and functional communication measures with intensive therapy compared to regular therapy. Individualized service delivery
Intensity of treatment should be individualized based on the recency of stroke, therapy goals, and other specific characteristics such as age, size of lesion, overall health status, and motivation. Each individual reacts differently to treatment intensity and is able to tolerate treatment at different times post-stroke. Intensity of treatment after a stroke should be dependent on the persons motivation, stamina, and tolerance for therapy. Outcomes
If the symptoms of aphasia last longer than two or three months after a stroke, a complete recovery is unlikely.