Deficient motor synchrony in schizophrenia.

Introduced a laboratory measure of motor function, synchronization of tapping with an auditory stimulus, as an index of motor disorganization in schizophrenia. It was hypothesized that (a) schizophrenics' performance on this task would be distinguishable from that of controls and would reflect a relative inability to take advantage of stimulus predictability, independent of task difficulty; (b) clinical measures of disturbed motor behavior would be associated with poorer synchronization; and (c) synchronization performance would be associated with clinical ratings of formal thought disorder and type-token ratio assessment of disorganization in spoken language. 16 schizophrenic, 8 affective, and 8 normal controls (18–48 yrs) were studied. The schizophrenics showed a specific pattern of disrupted synchrony not consistent with explanations based on S motivation, task difficulty, motor dexterity, a general psychosis factor, drug effects, or tapping speed ability. Deficient motor performance was associated with clinical evidence of abnormal movement and disturbed thinking and with the type-token ratio. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Left-handedness and thought disorder in the schizophrenias.

The relation between language dysfunction and handedness was examined in a sample of 58 male schizophrenic patients. Severity and type of language dysfunction were assessed using ratings on categories of thought disorder derived from the Schedule of Affective Disorders and Schizophrenia (Spitzer & Endicott, 1977). Hand preferred for writing was the criterion for handedness. In this sample, the incidence of left-handedness was raised and left-handedness was associated with the presence and severity of thought disorder. These findings are congruent with the hypothesis that a sizable proportion of left-handed schizophrenic individuals are left-handed because of a disruption in the pattern of hemispheric dominance that also impairs language functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)