The Effect of Sleep Deprivation on the Vestibulo-Ocular Reflex and Vestibular Adaptation in Healthcare Night-Shift Workers.

Objective: This study investigates the impact of sleep deprivation on the vestibulo-ocular reflex (VOR) in healthcare night-shift workers, focusing on basic VOR function and its adaptation during head movements with varying target distances.

Methods: A prospective study was conducted with 14 night-shift healthcare workers, with a final analysis of 11 participants. Testing occurred under two conditions: After normal sleep and after a night shift. VOR gain was measured using the video head impulse test (vHIT) system for both active and passive head movements and for near and far targets. Participants also completed the computerized Dynamic Visual Acuity (c-DVA) test to assess gaze stability and a self-reported vigilance questionnaire.

Results: Participants experienced significantly shorter sleep durations and reported lower vigilance levels on the post-night shift. VOR gain was notably reduced (7.5%) only during passive head movements toward a far target after a night shift. Other vestibular functions, such as distance modulation and other measurements including active head impulses, near-target tests, and c-DVA scores, showed no significant differences between normal sleep and sleep-deprived states.

Conclusion: Sleep deprivation in healthcare night-shift workers demonstrated a complex effect on VOR, with significant impairment in only one specific condition (passive-far). Most other VOR functions, including adaptation to target distance, were maintained. This resilience may indicate an adaptive mechanism within the vestibular system under chronic sleep-deprived conditions, warranting further research into the underlying protective processes.

Level of evidence: 3: