Excessive daytime sleepiness in adults with brain injuries

Objectives: To determine the prevalence, demographics, and causes of excessive daytime sleepiness in adults with brain injuries after the acute phase of their injury and to investigate the relations between self-report and objective measures of hypersomnolence.

Design: A case series of patients enrolled consecutively into a residential rehabilitation program.

Setting: University sleep laboratory, live-in rehabilitation center.

Patients: Adults with brain injuries (n = 71); mean time +/- standard deviation from injury to study, 38 +/- 60 months.

Interventions: A polysomnogram and Multiple Sleep Latency Test (MSLT) were performed in each subject. Each subject also completed the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI) questionnaires.

Main outcome measures: Sleep patterns, by polysomnogram. Daytime hypersomnolence, diagnosed by mean sleep latency on the MSLT <or= 10 minutes. Sleep apnea-hypopnea syndrome, diagnosed by Apnea-Hypopnea Index greater than 10 events/hr. Periodic limb movement disorder, diagnosed by a Periodic Leg Movement Index greater than 10 events/hr.

Results: Mean sleep latency was <or= 10 minutes in 47% of the cohort and <or= 5 minutes in 18.3%. Subjects were classified into 3 groups: nonhypersomnolent (n = 38, 53%), hypersomnolent with abnormal indices (n = 12, 17%), or hypersomnolent with normal indices (n = 21, 30%). Among the 3 groups, no significant differences were present in Glasgow Coma Scale score, length of coma, or time since brain injury. No differences across groups were found in nature of the injury, gender, or medications. No significant correlation existed between the ESS or PSQI results and mean sleep latency on the MSLT.

Conclusions: Hypersomnia is common in adults with brain injuries, with a relatively high prevalence of sleep apnea-hypopnea syndrome, periodic limb movement disorder, and posttraumatic hypersomnia. Subjects with objectively measured sleepiness were not identified on self-reporting questionnaires, suggesting their inability to perceive their hypersomnolence.