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Copeland, Paige

University of British Columbia

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 (<8, 11-24Hz) and EVS-ML force (0.5-9Hz) following SD than the well-rested control. CONCLUSION: Despite a lack of SD-related changes to quiet standing balance parameters, nor changes to the cumulant density estimates and coherence, the gain of the vestibular-evoked balance response increased with SD. The current findings likely indicate that SD leads to higher sensitivity of the central nervous system when transforming vestibular-driven signals for standing balance control.

Text

2021-07-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/79155

Health and Exercise Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/