Impact of prepulse characteristics on the detection of sensorimotor gatingdeficits in schizophrenia

Schizophrenia patients have prominent deficits in information processing th at can be detected by measures of prepulse inhibition (PPI) of the startle response. Deficient PPI in schizophrenia is thought to reflect a failure of brain-based information 'protective' mechanisms that normally inhibit resp onsivity for 30-500 ms after a weak prepulse stimulus. The relationship bet ween specific prepulse stimulus characteristics and PPI deficits in this st udy was examined in 31 schizophrenia patients and 34 normal comparison subj ects, Schizophrenia patients had overall deficits in PPI across four condit ions where the prepulse was either discrete (abrupt) or continuous (sustain ed) and consisted of either white noise or a pure tone. On inspection and a nalysis of the data. it appears that the white noise conditions, rather tha n tone conditions, account for the group differences. Thus, the discrete wh ite noise prepulse was most effective in eliciting PPI deficits, resulting in a large effect size between groups (d = 0.85; P < 0.01). Deficits in inf ormation-protective mechanisms in schizophrenia may be differentially sensi tive to specific stimulus characteristics; this observation may be relevant both to the neurobiology of information processing deficits in schizophren ia and to the methodologies for studying these deficits experimentally. (C) 2001 Elsevier Science B.V. All rights reserved.