Return of Memory and Sleep Efficiency Following Moderate to Severe Closed Head Injury

Abstract

Objective. Sleep disturbance is common in the subacute recovery phase following brain injury. A previous study from the authors' group found 68% of patients with closed head injury (CHI) had disrupted sleep on a rehabilitation unit. In the present study, the authors investigated whether improvement in sleep efficiency correlates with duration of posttraumatic amnesia (PTA) after CHI. Methods. Fourteen CHI patients were enrolled and followed prospectively. Mechanism of injury included motor vehicle accident, fall, and blunt assault. An actigraph was placed on each subject's wrist within 72 hours of admission to the rehabilitation unit and recorded data for the duration of their stay. A minimum of 7 days of continuous actigraphy data was obtained on all subjects. PTA was measured daily using the Orientation Log (O-LOG). Results. Seventy-eight percent of subjects had mean week-1 sleep efficiency scores of ≤63%. Patients admitted having already cleared PTA had significantly better week-1 sleep efficiency scores than those with ongoing amnesia ( P = .032). For those patients admitted with ongoing PTA, each 10-unit increase in sleep efficiency score correlated with 1 unit increase in O-LOG score ( P = .056). Conclusions. Disrupted sleep is common in the postacute stage following CHI. Improved sleep efficiency correlates with resolution of PTA. Decreased sleep efficiency may negatively affect memory return after traumatic brain injury. Actigraphy is uniquely suited to study the sleep patterns of these patients.