ABSTRACT
Aphasics themselves form a very varied population. It is alleged that a large number of factors may affect the outcome—including, for example, age, handedness, site, extent and aetiology of lesion, and type and severity of aphasia. Between them these factors may cause substantial variation in the outcome. Effects of therapy, however real, may then be undetectable. Aphasia therapy is very different: as we have demonstrated in the previous sections, it is axiomatic to every school of treatment that the tasks a patient is asked to do should be determined by his/her particular aphasic symptom complex. Aphasia performance is generally rather unreliable; for example, a patient presented with a picture may find the name one day and not the next. There are two sources of a variability—extrinsic from influences external to the aphasia and intrinsic variation resulting from the language disturbance itself. Clinical trials of aphasia therapy yield a confused picture.
