Association between electroencephalographic modulation, psychotic-like experiences and cognitive performance in the general population

Abstract

Aim: An association between deficit of electroencephalographic (EEG) modulation during an oddball task and psychotic symptoms has been described in clinical samples, in agreement with the proposed role of altered salience in psychosis. To discard the possible influence of medication, the relation between psychotic-like experiences (PLE) and EEG modulation in the general population was explored. Methods: EEG and PLE were assessed in 194 healthy subjects during a P300 paradigm. EEG modulation was assessed as changes from pre-stimulus to response windows in spectral entropy (SE; a measurement of signal irregularity), median frequency (MF; a quantifier of the frequency distribution of oscillatory activity) and theta, alpha, beta-1, beta-2 and gamma relative power (RP; a summary of the distribution of spectral components). Results: A significant widespread decrease in SE and MF from baseline to response was found, with a significant increase in RP for theta and a decrease for higher frequency bands, supporting an increase in EEG regularity and a slowing of brain oscillations during the response. Furthermore, a significant association was found between SE modulation and distress of negative PLE, as well as between verbal memory and RP modulation for beta-1. Performance in verbal fluency was associated with the increase in theta RP during the response. Conclusion: EEG irregularity of healthy subjects decreased at the expense of a larger contribution of theta RP and a decreased contribution of fast frequency bands. Subjects with smaller modulation showed poorer cognitive scores and greater distress of negative PLE.