P04-T Wavelet-synchrony research of event-related potentials to naturalistic stimuli in patients in vegetative state and mutism

Abstract

The vegetative state and mutism are long-term states of unconsciousness. Nowadays, brain responses to naturalistic stimuli are studied to investigate the cognitive functions preservation. Wavelet-analysis is a method used to assess the brain’s bioelectrical activity. Thereby, nine patients were investigated. Four of them were in a vegetative state (three patients were later noted consciousness recovery) and five patients were in mutism (four patients had consciousness recovery). The control group consisted of ten healthy subjects. Biopotentials’ recording was performed using thirty-two electrodes located in the system of 10–20%. Six music-passages were used as stimuli. One fragment was repeated eleven times (each fragment duration was four seconds). Wavelet-synchrony was calculated over all electrode pairs. In healthy subjects, the maximum values of wavelet-synchrony in resting-state and when listening to stimuli were detected in the fronto-central-parietal areas. Important feature was the presence of inter-hemispheric and diagonal connections. Also it was revealed for patients in a reversible vegetative state. Resting-state values of wavelet-synchrony in patients in a vegetative state were less the norm, and those in patients in mutism were higher the norm. The patients in a chronic vegetative state have an increase in wavelet-synchrony values relative to the resting-state with a tight localization. In the same time local amplification of wavelet-synchrony was noted in a patient in a chronic mutism. In conclusion, the identified features in the naturalistic stimuli perception can be used as prediction of a possible consciousness recovery in patients in a vegetative state and mutism. The study was supported RFFI 18-013-00967a.