On the clinical and cognitive meaning of impaired sensorimotor gating in schizophrenia

Schizophrenia patients have been shown to have a defective sensorimotor gat ing process as indexed by impaired prepulse inhibition of the startle eyebl ink reflex, Moreover, we have previously reported that schizophrenia patien ts have dysfunctional attentional modulation of prepulse inhibition. The pr esent experiment combined our previous sample of 14 schizophrenia outpatien ts and 12 demographically matched control subjects with a new sample of 10 outpatients and 6 control subjects. All participants performed a tone-lengt h judgement task that involved attending to one pitch of tone (the attended prepulse) and ignoring another pitch of tone (the ignored prepulse). Durin g this task the acoustic startle eyeblink reflex was electromyographically recorded from the orbicularis oculi muscle. The results replicated the find ing of impaired attentional modulation of prepulse inhibition in the new sa mple of schizophrenia outpatients compared to demographically matched contr ol subjects. Specifically, the new control group exhibited greater startle modification during the attended prepulse, whereas the new patient group fa iled to show this differential effect. In addition, impaired prepulse inhib ition following the attended prepulse was significantly correlated with hei ghtened delusions, conceptual disorganization, and suspiciousness as measur ed with the expanded Brief Psychiatric Rating Scale. These correlations wer e significant with prepulse inhibition to the attended prepulse but not wit h prepulse inhibition to the ignored prepulse. Impaired prepulse inhibition was not correlated with negative symptoms, All in all, the results support the hypothesis that impaired attentional modulation of startle prepulse in hibition reflects basic neurocognitive processes related to thought disorde r in schizophrenia. (C) 2000 Elsevier Science Ireland Ltd. All rights reser ved.