Effects of increased homeostatic sleep pressure on postural control and their modulation by attentional resources.

OBJECTIVE

This study aimed to determine how increased sleep pressure interferes with postural control according to the availability of attentional resources and visual input.

METHODS

Thirteen healthy young adults performed a psychomotor vigilance task and postural tasks after a night of sleep and after 25 h of sleep deprivation. Primary outcome variables were calculated from the center of pressure (CoP) displacement measured by two force plates in various cognitive load and visual state conditions.

RESULTS

Sleep deprivation increased CoP anterior-posterior range in the no cognitive load condition and decreased CoP mediolateral range and velocity in the high cognitive load conditions. Sleep deprivation effects on the mediolateral range in the eyes open high cognitive load condition were significantly correlated with its effects on the psychomotor vigilance task.

CONCLUSIONS

Sleep deprivation destabilizes postural control when attentional and sensory resources are not challenged. In high cognitive load condition, sleep loss induces a general freezing effect that seems to be modulated by the degree of impairment in psychomotor speed.

SIGNIFICANCE

This study demonstrates that sleep pressure has a destabilizing effect on postural control independently of circadian factors, therefore suggesting that sleep debt may be a significant risk factor for falls.