Effects of one night of sleep deprivation on single- and dual-task gait.

Sleep deprivation (SDEP) impairs cognitive control, which may affect movements that rely on these processes, such as walking. To test whether gait changes after one night of SDEP reflect reduced cognitive capacity, we compared its effects with those of dual-task walking (i.e. walking while performing a simultaneous cognitive task). We hypothesize that SDEP will produce gait changes similar to those under dual-task conditions. Eighteen healthy adults (nine female, nine male; age, mean (s.d.): 22.2 (2.3) years) were tested the morning after a SDEP and a control night. Participants completed two 2-minute trials: single-task walking and walking with a concurrent 2-back working memory task (DT, dual-task walking). Using lateral foot and pelvis marker trajectories, we calculated spatio-temporal parameters, foot placement error in anteroposterior (FPEAP) and mediolateral (FPEML) directions, and mediolateral margin of stability (MoSML). SDEP increased average step time (p < 0.001) and step length (p = 0.002), and DT reduced spatio-temporal variability. Both SDEP (p = 0.004) and DT (p < 0.001) reduced FPEAP, but only DT reduced FPEML (p < 0.001). Additionally, mean MoSML decreased only in SDEP (p = 0.025). Overall, these findings suggest that while SDEP and dual-tasking both affect gait, the effects of SDEP on gait cannot be fully explained by reduced cognitive resources.