Cognitive sequence processing and syntactic comprehension in schizophrenia

It has been repeatedly demonstrated that schizophrenic patients are impaire d in the comprehension of sentences with complex syntax. We investigated th e hypothesis that this syntactic comprehension impairment in schizophrenia is not a purely linguistic dysfunction, but rather the reflection of a cogn itive sequence processing impairment that is revealed as task complexity in creases. We tested 10 schizophrenic patients using a standard measure of sy ntactic comprehension, and a non-linguistic sequence processing task, both of which required simple and complex transformation processing. Patients' p erformance impairment on the two tasks was highly correlated (r(2) = 0.84), and there was a significant effect for complexity, independent of the task . These results are quite similar to those of aphasic patients with left he misphere lesions. This suggests that syntactic comprehension deficits in sc hizophrenia reveal the dysfunction of cognitive sequence processing mechani sms that can be expressed both in linguistic and nonlinguistic sequence tas ks. NeuroReport 11:2145-2149 (C) 2000 Lippincott Williams & Wilkins.