Autonomic pain responses during sleep: A study of heart rate variability

• Published in: European journal of pain Vol. 15; no. 6; pp. 554 - 560
• Main Authors: Chouchou, F, Pichot, V, Perchet, C, Legrain, V, Garcia-Larrea, L, Roche, F, Bastuji, H
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-07-2011; Blackwell Publishing Ltd
• Subjects: Adult; Anesthesia & Perioperative Care; Arousal - physiology; Autonomic nervous system; Autonomic Nervous System - physiopathology; Cerebral Cortex - physiopathology; Electrocardiography; Female; Heart Rate - physiology; Heart rate variability; Humans; Laser stimulation; Male; Pain; Pain - physiopathology; Pain Medicine; Polysomnography; Sleep; Sleep - physiology; Wavelet Analysis; Wavelet analysis; Pain; Sleep; Laser stimulation; Autonomic nervous system; Heart rate variability
• ISSN: 1090-3801; 1532-2149
• DOI: 10.1016/j.ejpain.2010.11.011

Abstract The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether this reaction is contingent to cortical arousal, and whether one of the autonomic arms (sympathetic/parasympathetic) predominates over the other remains unknown. We assessed ANS reactivity to nociceptive stimulation during all sleep stages through heart rate variability, and correlated the results with the presence of cortical arousal measured in concomitant 32-channel EEG. Fourteen healthy volunteers underwent whole-night polysomnography during which nociceptive laser stimuli were applied over the hand. RR intervals (RR) and spectral analysis by wavelet transform were performed to assess parasympathetic (HFWV ) and sympathetic (LFWV and LFWV /HFWV ratio) reactivity. During all sleep stages, RR significantly decreased in reaction to nociceptive stimulations, reaching a level similar to that of wakefulness, at the 3rd beat post-stimulus and returning to baseline after seven beats. This RR decrease was associated with an increase in sympathetic LFWV and LFWV /HFWV ratio without any parasympathetic HFWV change. Albeit RR decrease existed even in the absence of arousals, it was significantly higher when an arousal followed the noxious stimulus. These results suggest that the sympathetic-dependent cardiac activation induced by nociceptive stimuli is modulated by a sleep dependent phenomenon related to cortical activation and not by sleep itself, since it reaches a same intensity whatever the state of vigilance.