Missing peaks in auditory brainstem responses and negative symptoms in schizophrenia

Auditory brainstem responses (ABRs) were examined in 30 schizophrenic patients and 29 normal subjects. The psychotic symptoms were assessed by the Brief Psychiatric Rating Scale (BPRS) and the Scale for Assessment of Negative Symptoms (SANS) in the patients. At least one of the waves I, II or III was found missing on either side at 80 dBHL (hearing level) in 8 (27%) of the patients but in only one (3%) of the normal subjects. There was a significant association between the missing peaks and the BPRS negative symptom cluster or the total score of the SANS. These results suggest that some schizophrenics, especially those with negative symptoms, have an abnormality of input processing of auditory information in the lower brainstem.