Neurological soff signs and neuropsychological performance in first episode schizophrenia

Abstract

history, cognitive deficits and illness severity. Unlike other sensory systems, the primary olfactory projections are largely ipsilateral and may therefore be sensitive to lateralized abnormalities. However no study has yet examined unilateral presentation of olfactory stimuli in patients with schizophrenia. Forty-six schizophrenia patients (24 men, 22 women) and 39 healthy controls (23 men. 16 women) were administered the University of Pennsylvania Smell Identification Test (UPSIT) and odor detection threshold for phenyl ethyl alcohol (PEA). Schizophrenia patients performed more poorly on the UPSIT for both nostrils relative to controls (F[1,81]=7.4. p=0.008). Similarly, PEA thresholds were also significantly poorer for both rightand left-nostrils relative to controls (F[1,58]= 9.93. p=0.OO3). No gender effects or gender x diagnosis interaction was observed for either task. No clear laterality of deficit was seen in nostril presentation for either identification or threshold performance. These data suggest that patients with schizophrenia evidence bilateral deficits in olfactory identification and odor detection thresholds, and suggest a more generalized dysfunction in olfactory identification and odor detection thresholds. and suggest a more generalized dysfunction in olfactory brain regions. Future studies examining the relationship between unilateral measures and structural and functional imaging indices may help elucidate any possible lateralized relationships.