Auditory event-related potential of subjects with suspected pre-psychotic state and first-episode psychosis.
BACKGROUND
Recent schizophrenia research exploring the complicated pathogenesis of schizophrenia has focused on the subjects with at-risk mental states in order to exclude the influence of confounding factors. This study explores 3 sets of auditory-related event potentials in subjects with different risk levels of psychosis.


METHODS
Subjects were recruited from the SOPRES study in Taiwan. P50 and N100 using an auditory paired-click paradigm and duration MMN were assessed on 32 first-episode psychosis (FEP), 30 ultra-high risk (UHR), 37 E-BARS (early/broad at-risk mental states) participants and 56 controls.


RESULTS
MMN was correlated with neither P50 nor N100, whereas many parameters of the latter two were intercorrelated with each other. Compared to healthy controls, MMNs were significantly lower in all 3 clinical groups (E-BARS, UHR and FEP). A gradient of sensory-gating deficits, manifested by increased P50 ratios (S2/S1) and decreased N100 differences, across different levels of clinical severity was suggested by a linear trend. For the UHR subjects, P50 gating ratio, N100 gating ratio, N100 difference, and N100S2 amplitude might be potential indicators to discriminate converters from non-converters.


CONCLUSIONS
By including subjects with E-BARS, our results provide new insight regarding pre-attentive auditory event-related potential in subjects across different risk levels of psychotic disorders. Impaired deviance detection shown by MMNs already exists in people at a pre-psychotic state regardless of clinical severity, while sensory-gating deficits shown by P50/N100 varies depending on the risk levels in prodromal period. Further longitudinal research exploring the relationship between ERPs and subjects with a suspected pre-psychotic state is needed.
Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
Ming H
MH
Hsieh
Jia-Chi
JC
Shan
Wei-Lieh
WL
Huang
Wan-Chen
WC
Cheng
Ming-Jang
MJ
Chiu
Fu-Shan
FS
Jaw
Hai-Gwo
HG
Hwu
Chen-Chung
CC
Liu
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D003265:Contingent Negative Variation / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011571:Psychoacoustics; D011618:Psychotic Disorders / Q000175:diagnosis / Q000503:physiopathology*; D011930:Reaction Time; D055139:Sensory Gating / Q000502:physiology*; D013624:Taiwan; D055815:Young Adult