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Abstract

Sleep deprivation (SD) is a common condition in today’s society. SD can impair cognitive and sensorimotor functioning, including that of the vestibular system, as increases in vestibulo-ocular reflex gain have been documented following SD. Further, SD can influence postural control negatively, though results are not conclusive, and the physiological reasoning behind the observed impairments in standing balance remains unclear. PURPOSE: The purpose was to examine the effect of 24-h SD on the vestibular control of standing balance. It was hypothesized that after 24-h SD, vestibular-evoked balance responses would increase compared to the well-rested control state. METHODS: During a well-rested and SD condition, nine healthy females (22.8 ± 2.9 years) completed two 90-s trials of binaural, bipolar stochastic electrical vestibular stimulation (EVS; 0-25 Hz, root-mean-square = 1.1 mA) and two 120-s trials of quiet stance on a force plate. Mediolateral (ML) ground reaction forces and surface electromyography of the right medial gastrocnemius (MG) were sampled and cross-correlated against the EVS signal to quantify vestibular control of balance within the frequency (gain and coherence) and time (cumulant density) domain. RESULTS: Overall, SD did not alter any quiet stance parameters (p ≥ 0.06). In the time domain, sleep deprivation did not alter the EVS-MG (p=0.51) nor the EVS-ML force (p=0.06) peak-to-peak amplitude. Sleep deprivation had limited effect on the EVS-MG and EVS-ML force coherence, but there were greater normalized gain amplitudes for EVS-MG (