Work

Detecting emotion in individuals with disorders of consciousness: a pilot study of heart rate deceleration on affective auditory stimuli

Year: 2025

Type: article

Abstract: OBJECTIVE: To evaluate heart rate deceleration on affective auditory stimulations as an objective marker of purposeful affective behaviour, as used in the diagnosis of minimally conscious state (MCS) in brain-injured individuals with disorders of consciousness (DoC), awake but unable to communicate. METHODS: We recorded the heart rate of participants (14 healthy controls and 10 brain injured individuals, conscious or with DoC) on repeated exposure to a random sequence of three emotional sounds of neutral, positive, and negative valence, in an unconditioned manner (experiment 1) or in a trace-conditioning procedure (experiment 2), with successful trace-conditioning assumed to indicate consciousness. RESULTS: In experiment 1, heart rate deceleration after aversive acoustic stimulus was significantly higher in healthy subjects at the group level from the second to the seventh inter-beat interval, with limited sensitivity at the individual level. In experiment 2, there was no evidence of trace-conditioned learning in healthy subjects, precluding any extrapolation to brain-injured individuals. CONCLUSIONS: Heart rate deceleration after aversive acoustic stimulus was significant in passive hearing but not in a trace-conditioning paradigm and was of limited sensitivity at the individual level. SIGNIFICANCE: Heart rate deceleration may constitute an objective marker of purposeful affective behaviour triggered by emotional sounds. The question of whether this response is a reflex or a marker of conscious access needs further study.

Source: Clinical Neurophysiology

DOI: 10.1016/j.clinph.2025.2111469

Authors: Hugo Ardaillon, Anne Dubois, Kate-Mary Ndocko, Jérôme Etienne, Catherine Tallon-Baudry, Jacques Luauté