Selective preservation of changes to standing balance control despite psychological and autonomic habituation to a postural threat

Sci Rep. 2021 Jan 11;11(1):384. doi: 10.1038/s41598-020-79417-5.

Abstract

Humans exhibit changes in postural control when confronted with threats to stability. This study used a prolonged threat exposure protocol to manipulate emotional state within a threatening context to determine if any threat-induced standing behaviours are employed independent of emotional state. Retention of balance adaptations was also explored. Thirty-seven adults completed a series of 90-s standing trials at two surface heights (LOW: 0.8 m above ground, away from edge; HIGH: 3.2 m above ground, at edge) on two visits 2-4 weeks apart. Psychological and autonomic state was assessed using self-report and electrodermal measures. Balance control was assessed using centre of pressure (COP) and lower limb electromyographic recordings. Upon initial threat exposure, individuals leaned backward, reduced low-frequency centre of pressure (COP) power, and increased high-frequency COP power and plantar/dorsiflexor coactivation. Following repeated exposure, the psychological and autonomic response to threat was substantially reduced, yet only high-frequency COP power and plantar/dorsiflexor coactivation habituated. Upon re-exposure after 2-4 weeks, there was partial recovery of the emotional response to threat and few standing balance adaptations were retained. This study suggests that some threat-induced standing behaviours are coupled with the psychological and autonomic state changes induced by threat, while others may reflect context-appropriate adaptations resistant to habituation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accidental Falls / prevention & control
  • Adaptation, Physiological / physiology*
  • Adult
  • Anxiety / physiopathology
  • Anxiety / psychology
  • Autonomic Nervous System / physiopathology
  • Choice Behavior / physiology
  • Emotional Regulation / physiology
  • Emotions
  • Fear / psychology*
  • Female
  • Habituation, Psychophysiologic / physiology*
  • Humans
  • Male
  • Postural Balance / physiology*
  • Risk-Taking
  • Standing Position*
  • Young Adult