Neurocognitive deficits and neurological signs in schizophrenia

Objective: This is a comprehensive study designed to examine the association between specific clusters of neurological abnormalities and several clinically relevant aspects of schizophrenia such as positive and negative symptoms, neurocognitive deficits and psychosocial performance. Methods: Thirty-seven clinically stable schizophrenic (DSM-III-R) patients maintained on antipsychotic medication were comprehensively examined and Convit's Quantified Neurologic Scale (QNS) was completed. In addition, patients' psychopathology was rated on the Positive and Negative Syndromes Scale (PANSS); psychosocial performance was rated on the Global Scale of Adaptive Functioning (GAF) and the Social Performance Schedule (SPS); and neurocognitive deficits were measured with a computer-assisted neurocognitive test battery, COGLAB. The association between these factors was determined using Pearson's correlation coefficients. Results: Frontal and soft neurological scores on the QNS correlated significantly with negative syndrome scores (r=0.45-0.51, p<0.05) and general psychopathology scores (r=0.46-0.49, p<0.02) on PANSS; poor psychosocial performance on GAF (r = 0.43-0.56, p < 0.02) and SPS (r = 0.37-0.54, p < 0.007); and performance on the span of apprehension (r=0.48-0.74, p<0.0001), backward masking (r=0.34-0.54, p<0.01) and Wisconsin card sorting (r=0.48-0.67, p <0.001) tasks. Conclusion: Frontal and soft neurological signs in schizophrenic patients are associated with prominent negative symptoms, relatively poor psychosocial performance and significantly more cognitive impairment. Past research has associated soft neurological signs, cognitive impairment and structural brain abnormalities with poor outcome and prognosis in patients with schizophrenia.