Effect of sleep deprivation on postural stability

Abstract Background: Maintaining postural control requires the continuous integration of different peripheral inputs that may be altered by sleepiness. The objective of this study was to assess the effects of 24 hours sleep deprivation on postural stability. Methods: healthy subjects underwent 24 hours supervised sleep deprivation after a week of stable sleep schedule. Stability was assessed using a posturographic platform allowing to determine the center of foot pressure (CoP) oscillations in mediolateral (ML) and anteroposterior (AP) axis and thereby total XY displacement, the surface area and the mean speed of CoP displacement. Measurements were performed in the morning before sleep deprivation and every two hours during the night. Vigilance and fatigue were evaluated at the same intervals using the Psychomotor Vigilance Test (PVT), and the Karolinska sleepiness scale (KSS). Results: 30 volunteers (7 men and 23 women, aged 22±2 yo, BMI 18.5-25kg/m2) were included in the study. When comparing pre-and post-sleep deprivation morning stability parameters, there was significant deterioration in the majority of the postural variables: CoP area (P<0.05), AP (P<0.01) and total displacement (P<0.05) as well as in some PVT’s variables: reaction time (P<0.001), lapses (P<0.05) and in subjective sleepiness (P<0.001). During the sleep deprivation night, there was a progressive and parallel deterioration of the stability and vigilance parameters that reached its maxima at 4 a.m., followed by a mild improvement at 6 a.m. Conclusions: Postural control is significantly altered by 24 hours sleep deprivation and seems to fluctuate in a similar pattern as vigilance and subjective sleepiness