Objective measures of sleep and wakefulness in patients with moderate to severe brain injury on an inpatient rehabilitation unit. Pearls and pitfalls of actigraph monitoring

BACKGROUND: As awareness of disrupted sleep in patients with traumatic brain injury (TBI) increases so does interest in finding objective measures of sleep. As a result, many clinicians are turning to actigraphs to monitor sleep in patients with altered consciousness. Actigraphs are accelerometers which have been used in sleep research for over four decades. OBJECTIVE: The purpose of the present study was to determine the best method for scoring actigraphs in a TBI population and to describe the benefits and pitfalls of using actigraphs with patients on a brain injury rehabilitation unit. METHODS: A retrospective chart review of 43 patients compared three different ways of scoring night time rest periods: autoscoring, manual scoring, and set interval scoring for the sleep parameters of sleep efficiency, wakefulness after sleep onset, and total sleep time. Nursing compliance with using the event marker on the device to set rest period was also analyzed. RESULTS: The autoscoring method of determining the rest interval showed an inflation of sleep efficiency. For each sleep parameter compared, the strongest correlations were observed between the manual and set interval scoring methods. Compliance using event markers to set rest interval was low (16.7%). CONCLUSIONS: Set interval scoring is the most efficient method to determine the rest interval in TBI patients. The use of event markers was an unreliable method to determine rest period.