Grip and load force control and coordination in object manipulation during a night of sleep deprivation

Abstract

Although sleep deprivation causes deficits in the performance of several sensorimotor tasks, its effects on object manipulation are underexplored. To investigate the possible effects of sleep deprivation on the control of object manipulation we assessed the relationship between the force components acting on the digits-object interaction (i.e. grip force [GF] and load force [LF]) during two simple manipulation tasks. Sixteen young adults performed two manipulation tasks five times along one night of sleep deprivation, at 23:00, 01:00, 03:00, 05:00, and 07:00 h. In the first task (i.e. holding), participants were asked to hold an instrumented object, as still as possible, during 12 s. In the second task (i.e. shaking), they were instructed to continuously oscillate the object upward and downward at two frequencies, 0.8 Hz and 1.2 Hz. The results revealed that individuals who remained sleep deprived decreased linearly the amount of GF exerted while holding the object still as the night progressed. Also, results revealed that during the shaking task the GF-LF coordination and GF control were negatively affected at 03:00. These results indicate that during the holding task GF control is strongly affected by time awake and that during the shaking, a dynamic task, circadian variations play a major role. These changes could be detrimental to work-related manipulation tasks.