Music-elicited EEG Activity and Emotional Responses are Altered in Schizophrenia

Abstract

Studies of patients with schizophrenia using facial affect recognition and voice discrimination tasks have identified emotional dysfunction as a prominent clinical feature. In the present study we examine whether emotion processing in patients is also impaired in a less explicitly social context -- continuous self-report of emotions during music using a two-dimensional (pleasantness X activation) emotion space. Electroencephalographic (EEG) activity was also recorded during this task since previous studies using EEG measures have found underlying cortical processes related to emotion. Twelve patients with schizophrenia and eleven controls listened to five 25-second songs. These songs included J.S. Bach‟s Invention #13 in A minor (BWV 784) (designated the original piece), and four computer-generated pieces of which two were designed to be similar to the original, and two were designed to be different. While no significant effects were found in the activation dimension of the self-report measures, the pattern of pleasantness ratings was significantly less differentiated among songs in the patient group than in controls. EEG asymmetry indices at frontal and central electrodes provided evidence of greater hemispheric activation asymmetry (with higher activation on the left) in controls than in patients, a difference that was significant at the central electrodes (C3 and C4). These findings indicate that individuals with schizophrenia interpret emotion-eliciting music differently than do controls, even in a relatively non-social setting, possibly because of less differentiated hemispheric representations.

Estimation of nonlinear measures of schizophrenia patients' EEG in emotional states

“…In this study, auditory stimuli (music and noise) were used as an emotion inducing way. This is consistent with studies on emotional experience of sounds showing that it constitutes an emotional communication of more or less pure form [2,25]. In light of previous studies [23,24], we hypothesized that patients would have a decreased dimensional complexity and their nonlinear measures of EEG data in response to emotion-inducing auditory stimuli would be different than those of controls.…”

“…On the other hand, it was claimed that emotions are not always associated with http socially expressive behaviors [11]. Hence, to investigate only emotion impairments with less social contribution, music is suggested as an alternative emotion-eliciting source in some studies with healthy subjects [2,12,13]. These studies report that music can be used as an important stimulus for assessing deficits of emotion and to find underlying mechanism in brain by using EEG methodology [14][15][16][17].…”

“…Schizophrenia is an important psychiatric disorder characterized by both positive symptoms such as hallucinations, delusions, catatonic behavior and disorganized speech and negative symptoms such as loss of motivation, inability to experience pleasure, blunted emotional responses [1,2]. Although schizophrenia patients are known to have some deficits in emotional processing as a negative symptom of the disorder, the underlying mechanisms of this impairment are still under debate [3].…”

“…Similarly, it has been reported that EEG methodologies can be used to shed light on the underlying mechanism of emotion processing deficits in schizophrenia patients brain through music exposure [2][3][4][5][6][7][8][9][10]. Alpha band can be used as an indicator of the arousal level of subject exposed any specific stimulus [2].…”

“…Alpha band can be used as an indicator of the arousal level of subject exposed any specific stimulus [2]. Differentiated activation of alpha band between different regions of the brain has been reported while schizophrenia patients listened to music.…”