Language studies were done on four multilingual dextral Chinese patients who developed dysphasia from various causes. The left hemisphere appeared to be dominant for all the languages in the four patients. All the languages and dialects were universally involved during the development of dysphasia. In one patient,
there was evidence of delayed restitution in the patient's mother tongue (Hokkien) comparing with Mandarin and English which were the languages used in the hospital and for reading.
It has been suggested that formal thought disorder, the incoherent speech of schizophrenia, may involve a language disturbance among other abnormalities, or even be a form of dysphasia. Six patients with and seven without formal thought disorder were evaluated on an aphasia test battery. Spontaneous speech was also analysed using Brief Syntactic Analysis. Poor performance on the aphasia test battery was found to be associated with general intellectual impairment but not with formal thought disorder. Naming was preserved in both groups. Patients with formal thought disorder, but not those without, produced semantic errors in their spontaneous speech, and these were unrelated to general intellectual status. The disorder of language in formal thought disorder thus appears to be one of expressive semantic abnormality, which, however, spares naming. Further analysis of two intellectually preserved patients suggested that formal thought disorder may be associated with an additional difficulty in constructing an appropriate model for generating one's own speech.