Drug treatment of poststroke aphasia

Abstract

Impairment of language function (aphasia) is one of the most common neurological symptoms after stroke. Approximately one in every three patients who have an acute stroke will suffer from aphasia. The estimated incidence and prevalence of stroke in Western Europe is 140 and 800 per 100,000 of the population. Aphasia often results in significant disability and handicap. It is a major obstacle for patients to live independently in the community. When recovery from aphasia occurs, it is usually incomplete and patients are rarely able to return to full employment and other social activities. Currently, the main treatment for aphasia is conventional speech and language therapy. However, the effectiveness of this intervention has not been conclusively demonstrated and empirical observations suggest that spontaneous biological recovery may explain most of the improvement in language function that occurs in aphasics. The generally poor prognosis of the severe forms of poststroke language impairment (Broca, Wernicke and global aphasia), coupled with the limited effectiveness of conventional speech and language therapy has stimulated the search for other treatments that may be used in conjunction with speech and language therapy, including the use of various drugs. Dopamine agonists, piracetam (Nootropil®), amphetamines, and more recently donepezil (Aricept®), have been used in the treatment of aphasia in both the acute and chronic phase. The justification for the use of drugs in the treatment of aphasia is based on two types of evidence. Some drugs, such as dextroamphetamine (Dexedrine®), improve attention span and enhance learning and memory. Learning is an essential mechanism for the acquisition of new motor and cognitive skills, and hence, for recovery from aphasia. Second, laboratory and clinical data suggest that drug treatment may partially restore the metabolic function in the ischemic zone that surrounds the brain lesion and also has a neuroprotective effect following acute brain damage. An example of this is the nootropic agent piracetam. Extensive animal studies have demonstrated the beneficial effects of this and other drugs on neural plasticity, but data on humans are still sparse. This review provides a critical analysis of the current evidence of the effectiveness of these drugs in the treatment of acute and chronic aphasia.