Examining the Use of a Rest-Activity Ratio in a Pediatric Rehabilitation Setting

Abstract

Objective: To examine the relationship between an estimate of sleep-wake regulation derived from actigraphy and determine whether it would be sensitive to neurocognitive dysfunction associated with acquired brain injury (ABI) in a pediatric rehabilitation sample.

Design: Cross-sectional design.

Setting: Inpatient pediatric rehabilitation facility.

Participants: A sample (N=43) of 31 males (72.1%) and 12 females (27.9%) admitted to a pediatric rehabilitation hospital wore an actigraph (wrist accelerometer) for 1 week. Participant ages ranged from 8 to 17 years (mean, 13.1y; SD, 2.7y).

Interventions: Not applicable.

Main outcome measures: Raw actigraphy activity counts in 1-minute epochs were used to derive a rest-activity ratio over each 24-hour period; a 5-day average value was calculated for Monday through Friday. Brain injury status was derived through medical record review, resulting in the formation of 3 groups: traumatic brain injury (n=14), nontraumatic brain injury (n=16), and a non-ABI control group (n=13). Functional status was measured using FIM for children (WeeFIM) Cognitive and Motor scores extracted from the medical records.

Results: Unadjusted models showed a significant main group effect for brain injury status (P=.012). Compared with controls, the rest-activity ratio was significantly lower in both the traumatic brain injury (P=.005), and nontraumatic brain injury (P=.023) groups. However, the main group effect was no longer significant in an adjusted model controlling for WeeFIM Cognitive and WeeFIM Motor scores at admission. In the context of the adjusted model, there was a significant relationship between the rest-activity ratio and WeeFIM Cognitive scores at admission.

Conclusions: Individuals with lower functional status at admission, especially in the cognitive domain, had lower rest-activity ratios, suggesting poorer sleep-wake regulation. Similar to findings in adults with ABI, this ratio may have utility in tracking sleep-wake regulation in the pediatric rehabilitation setting. Future studies should investigate sensitivity to change over the course of recovery and responsiveness to clinical interventions to improve sleep.

Keywords: Actigraphy; Brain Injuries; Rehabilitation; Sleep.