Time Course of Motor Activity Wake Inertia Dissipation According to Age

Abstract

The time course of motor activity sleep inertia (maSI) dissipation was recently investigated through actigraphy in an everyday life condition from middle childhood to late adulthood. Motor activity sleep inertia was dissipated in 70 min, and the sleep inertia phenomenon was more evident in younger participants than in older participants. The aim of the current secondary analysis of previously published data was to examine, within the same sample, the time course of motor activity wake inertia (maWI) dissipation, i.e., the motor pattern in the transition phase from wakefulness to sleep, according to age. To this end, an overall sample of 374 participants (215 females), ranging in age between 9 and 70 years old, was examined. Each participant was asked to wear an actigraph around their non-dominant wrist for one week. The variation in the motor activity pattern of the wake–sleep transition according to age was examined through functional linear modeling (FLM). FLM showed that motor activity wake inertia dissipated around 20 min after bedtime. Moreover, a lower age was significantly associated with greater motor activity within the last two hours of wakefulness and the first twenty minutes after bedtime. Overall, this pattern of results seems to suggest that maWI dissipation is comparable to that of maSI.

Dissipation of Motor Sleep Inertia and Motor Wake Inertia in Early Relapsing–Remitting Multiple Sclerosis

“…With reference to the time course of motor wake inertia dissipation, we observed higher motor activity in persons with RRMS compared to HCs between a few minutes after bedtime up to about 30 min after it. Since it has been reported that motor wake inertia dissipates in healthy controls in 20 min [4], we can infer that motor wake inertia is more marked in persons with RRMS than HCs, in line with our expectations. This pattern of results is confirmed by the longer sleep onset latency in RRMS persons than HCs [1].…”

“…This pattern of results is confirmed by the longer sleep onset latency in RRMS persons than HCs [1]. Moreover, if we use the two-process model of sleep regulation [16,17] as a theoretical framework, the observed slower dissipation of motor wake inertia in RRMS persons could involve the homeostatic process more than the circadian, as previously suggested [4], potentially pointing out a lower homeostatic sleep pressure in early RRMS. A further explanation of this result might be related to the hyperactive HPA axis in RRMS persons [2], which may increase difficulty patientsin the transition between wake and sleep.…”

“…Even more recently, the first studies on the time course of motor sleep inertia [3] and motor wake inertia [4] dissipation in healthy controls have been published. Sleep inertia can be defined as a "transitional state between sleep and wake, marked by impaired performance, reduced vigilance, and a desire to return to sleep" [5] (p. 76).…”

“…It was shown [3] that motor sleep inertia dissipation, ecologically assessed through the recording of motor activity with actigraphy, is completed in 70 min. Later [4], the dissipation of motor wake inertia was also examined, namely, the motor activity pattern in the transition between wakefulness and sleep that is completed around 20 min after bedtime. To the best of our knowledge, the time course of motor sleep inertia and motor wake inertia dissipation, ecologically assessed through actigraphy, has not yet been investigated in persons with MS.…”