Visual evoked potential correlates of positive/negative symptoms in schizophrenia

The effect of methylphenidate on auditory information processing in healthy volunteers: a combined EEG/MEG study

“…P200 latency has been observed to occur earlier and amplitude, higher in patients with schizophrenia than in normal controls. These studies have shown that P200 abnormalities may be physiological markers for a positivesymptom subtype (Hegerl et al 1988;Schwarzkopf et al 1990) of schizophrenia. Thus, Roth et al (1981) demonstrated a negative correlation between the P200 latency to frequent tones and the delusion/hallucination score, and Laurent et al (1999) showed a negative correlation between P200 latency and the PANSS positive syndrome score, whereas a study by Shenton et al (1989) revealed that reduced P200 amplitudes correlated significantly with a negative-symptom subtype.…”

Psychiatric symptoms of noradrenergic dysfunction: A pathophysiological view

“…Concerning the EP, the peak latencies tend to be reduced in patients with predominantly positive symptoms, whereas they are prolonged in patients with predominantly negative symptoms …”

“…Concerning the EP, the peak latencies tend to be reduced in patients with predominantly positive symptoms, whereas they are prolonged in patients with predominantly negative symptoms. 129,130 An inverse correlation between the negative symptom scale and the P3 amplitude is well estab-lished. 131 However, the correlation between positive symptoms and the P3 amplitude is not as consistent.…”

Symptom Dimensions of Schizophrenia: A Selective Integration of Neurophysiological and Neuropsychological Correlates

“…Increased EEG alpha activity has been reported in a group of medicated schizophrenics [38] and a sample of medication-free schizophrenics [35], EEG alpha activi ty in schizophrenia may reflect specific aspects of neuro logical organization and anthropomorphic characteristics [35], this premise was based on the observation of identi cal EEG spectral characteristics in monozygotic but not dizygotic twins [39], There are significant neurophysiological differences between schizophrenic patients with predominantly posi tive symptoms compared to those with negative symp toms; these include surface EEG activity and EP [35,40], Clinical correlates relevant to positive and negative syn dromes have been observed in the N100 and P200 EP latencies. The auditory P200 in the left temporocentral region was reduced in patients with predominantly nega tive syndrome [41,42], the amplitude of auditory P200 was strongly correlated with negative symptoms [43], pro longed visual evoked potentials (VEP) latencies were posi tively correlated with negative symptoms of schizophre nias [44], Significant correlations were found between auditory P300 amplitude in the left temporocentral region and pos itive syndrome [41]. Schwarzkopf et al [44] also reported that reduced VEP latencies were negatively correlated with positive symptoms of schizophrenia.…”

“…The auditory P200 in the left temporocentral region was reduced in patients with predominantly nega tive syndrome [41,42], the amplitude of auditory P200 was strongly correlated with negative symptoms [43], pro longed visual evoked potentials (VEP) latencies were posi tively correlated with negative symptoms of schizophre nias [44], Significant correlations were found between auditory P300 amplitude in the left temporocentral region and pos itive syndrome [41]. Schwarzkopf et al [44] also reported that reduced VEP latencies were negatively correlated with positive symptoms of schizophrenia. The correla tions between positive symptom ratings and P200 latency were significant and negative in direction, while the corre lations between negative symptom ratings and P200 la tencies were less robust but positive in direction.…”