P300 asymmetry and positive symptom severity: A study in the early stage of a first episode of psychosis

Renoult, Louis; Prévost, Marie; Brodeur, Mathieu B.; Lionnet, Claire; Joober, Ridha; Malla, Ashok; Debruille, J. Bruno

doi:10.1016/j.schres.2007.03.024

Cited by 26 publications

(13 citation statements)

References 45 publications

(63 reference statements)

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“…However, we found no evidence that these deficits were left-lateralized and this could be due to our paradigm involving a button press; which is thought to diminish the abnormal P300 asymmetry in schizophrenia (Ford et al, 1994;Pfefferbaum et al, 1989;Renoult et al, 2007;Salisbury et al, 2001). …”

Section: Discussioncontrasting

confidence: 64%

Abnormal P300 in people with high risk of developing psychosis

et al. 2008

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Background: Individuals with an "At Risk Mental State" (or "prodromal" symptoms) have a 20-40% chance of developing psychosis; however it is difficult to predict which of them will become ill on the basis of their clinical symptoms alone. We examined whether neurophysiological markers could help to identify those who are particularly vulnerable.Method: 35 cases meeting PACE criteria for the At Risk Mental State (ARMS) and 57 controls performed an auditory oddball task whilst their electroencephalogram was recorded. The latency and amplitude of the P300 and N100 waves were compared between groups using linear regression.Results: The P300 amplitude was significantly reduced in the ARMS group [8.6 ±6.4 microvolt] compared to controls [12.7 ±5.8 microvolt] (p<0.01). There were no group differences in P300 latency or in the amplitude and latency of the N100. Of the at-risk subjects that were followed up, seven (21%) developed psychosis. Please find attached a fully revised manuscript titled "Abnormal P300 in people with high risk of developing psychosis". We also enclose a letter with the comments from the reviewers and our detailed answers on how we have done all the changes requested. (t-test; p=0.93). Those making a transition to psychosis were marginally more educated but this was only at trend level with a 3 year average difference in the age at which they completed their studies (t-test; p=0.07).Similarly, logistic regression analyses showed that compared to those who remained at risk, the seven cases who made a transition to psychosis had no significant differences in P300 amplitude/latency or N100 amplitude/latency (p values ranging from 0.30 to 0.63 for all four analyses). We have reported these comparisons very concisely and cautiously because referee #2 said that these analyses with only 7 individual making a transition were preliminary and power is limited. Please see results section paragraph 2. RESPONSE TO REVIEWER #2:Thank you for your suggestions, which have improved the paper. Below are your comments in blue-italics and how we have amended the manuscript accordingly in black with cross-references to the revised manuscript.This paper addresses an important and timely topic, namely, whether auditory P300 is reduced in subjects with at risk mental states and whether the P300 predicts subsequent conversion to psychosis. The study finds a significant deficit in P300 in ARMS subjects, relative to controls, replicating a previously a previously published report. The study had the potential to incrementally * 2. Response to Reviews 2 contribute to the literature by examining the utility of baseline P300 deficits as a predictor of subsequent conversion to psychosis; however, the negative finding coupled with the lack of power for this analysis (only 7 converters) make this aspect of the study inconclusive. More detailed comments are provided below:We have added a paragraph in the discussion to acknowledge the limitation of our small group of converters and how we have low statistical power to compa...

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Section: Discussioncontrasting

confidence: 64%

Abnormal P300 in people with high risk of developing psychosis

et al. 2008

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“…They also showed a smaller N100 amplitude and a shorter N100 latency in ERPs to target stimuli. These findings are in consistency with previous P300 studies of first episode schizophrenia (Brown et al, 2002;Demiralp et al, 2002;Wang et al, 2003aWang et al, ,b, 2005van der Stelt et al, 2005;Renoult et al, 2007;Ozgürdal et al, 2008). The conventional topographical analysis revealed that P300 amplitude reduction in schizophrenics was significant over left and medial ROIs.…”

Section: Discussionsupporting

confidence: 92%

“…The characteristics of P300 abnormalities in first episode schizophrenia are similar to, but not identical to, those previously reported among patients with a more chronic course. Almost all studies have found P300 amplitude reduction among first episode schizophrenia patients (Hirayasu et al, 1998;Salisbury et al, 1998;McCarley et al, 2002;Brown et al, 2002;Demiralp et al, 2002;Wang et al, 2003bWang et al, , 2005van der Stelt et al, 2005;Renoult et al, 2007;Ozgürdal et al, 2008). Decreased P300 amplitude was also found among individuals clinically at risk for psychosis (Frommann et al, 2008;Ozgürdal et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Decreased P300 current source density in drug-naive first episode schizophrenics revealed by high density recording

Wang

Tang

et al. 2010

International Journal of Psychophysiology

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“…Cortical asymmetry abnormalities in schizophrenia have been reported across a wide range of studies including those investigating EEG, 39 event-related potential, 40 and symptom 41 measures. Abnormalities in cerebral asymmetry, especially in language regions, have been one of the most robust findings in patients with schizophrenia.…”

Section: Discussionmentioning

confidence: 99%