According to the results of research published in The American Journal of Psychiatry, patients with schizophrenia have impaired P50 suppression following auditory stimuli. Greater impairment in P50 suppression was associated with more difficulty with attention, worse working memory, and lower processing speed.
Electroencephalography (EEG) P50 recordings were performed in 54 outpatients with schizophrenia and 41 healthy controls during 80 trials of paired auditory stimuli (3 ms duration at 80 dB in sound pressure) presented every 9 to 11 seconds. Averaged P50 recordings across all trials for each participant were assessed. Clinical symptoms and cognitive performance were evaluated with standardized tools and the associations between P50 suppression and symptoms or performance were analyzed.
Based on ratio scores, P50 suppression was poorer in patients with schizophrenia compared with healthy controls (P =.006). According to the study investigators, these data were in line with previous reports of P50 suppression.
P50 ratio scores were significantly positively associated with negative but not positive symptoms of schizophrenia. In analyses of the subscale measures of negative symptoms, only inattention was significantly correlated with P50 ratio scores.
Cognitive performance was significantly negatively associated with P50 ratio scores. The cognitive performance sub-measures of working memory and speed of processing were significantly associated with P50 scores. After adjustment for symptom severity, overall cognitive performance, working memory, and speed of processing remained significantly associated with P50 (all P <.05).
The study investigators concluded that “taken together, results of this study implicate P50 inhibitory processing deficits with core features of schizophrenia.” They added that the results “substantiate P50 as a promising indicator of early sensory processing abnormalities by confirming the presence of inhibitory P50 deficits in schizophrenia and by demonstrating their associations with clinically rated inattention and working memory and processing speed performance.”
Hamilton HK, Williams TJ, Ventura J, et al. Clinical and cognitive significance of auditory sensory processing deficits in schizophrenia. Am J Psychiatry. doi:10.1176/appi.ajp.2017.16111203