Weaker beta desynchronization indicates impaired emotion recognition in schizophrenia.

Abstract

In schizophrenia, deficits in social cognition, such as facial emotion identification, have a significant impact on patient's daily functioning and quality of life. We analyzed the beta event-related desynchronization (ERD) associated with emotional facial displays to understand better both phase-locked (i.e., neural activity and corresponding EEG response have a fixed latency after the stimulus onset) and non-phase-locked, induced (i.e. the latency of the response is not fixed) electrophysiological correlates of emotion recognition. 128 channels of EEG data from 37 patients with schizophrenia and 40 healthy controls were analyzed. Study groups were matched by sex age, and education. Participants had to identify facial displays of happiness, sadness, and neutral faces from the 'Karolinska Directed Emotional Faces (KDEF)' database. The time window of 300-700 ms was chosen to analyze spectral perturbation in the beta range associated with the presented emotional faces. Beta desynchronization was observed in both groups. We observed weaker beta ERD in patients. Weaker beta desynchronization correlated with poorer emotion recognition performance in the same time window in the patient group with a maximum correlation at the frontocentral region. Our main finding is that impaired emotion processing in patients with schizophrenia manifested as weaker beta desynchronization when perceiving faces reflecting sad and happy emotions or neutral facial expressions. Furthermore, less prominent beta desynchronization was associated with poorer emotion recognition performance in patients.