Hypersomnia following traumatic brain injury.

STUDY OBJECTIVES

To evaluate the prevalence and natural history of sleepiness following traumatic brain injury.

METHODS

This prospective cohort study used the Sickness Impact Profile to evaluate sleepiness in 514 consecutive subjects with traumatic brain injury (TBI), 132 non-cranial trauma controls, and 102 trauma-free controls 1 month and 1 year after injury.

RESULTS

Fifty-five percent of TBI subjects, 41% of non-cranial trauma controls, and 3% of trauma-free controls endorsed 1 or more sleepiness items 1 month following injury (p < .001). One year following injury, 27% of TBI subjects, 23% of non-cranial trauma controls, and 1% of trauma-free controls endorsed 1 or more sleepiness items (p < .001). Patients with TBI were sleepier than non-cranial trauma controls at 1 month (p < .02) but not 1 year after injury. Brain-injured subjects were divided into injury-severity groups based on time to follow commands (TFC). At 1 month, the non-cranial trauma controls were less sleepy than the 1- to 6-day (p < .05), 7- to 13-day (p < .01), and 14-day or longer (p < .01) TFC groups. In addition, the < or = 24-hour group was less sleepy then the 7- to 13-day and 14-day or longer groups (each p < .05). At 1 year, the non-cranial trauma control group (p < .05) and the < or = 24-hour TFC group (p < .01) were less sleepy than the 14-day or longer TFC group. Sleepiness improved in 84% to 100% of subjects in the TBI TFC groups, as compared with 78% of the non-cranial trauma control group (p < .01).

CONCLUSIONS

Sleepiness is common following traumatic injury, particularly TBI, with more severe injuries resulting in greater sleepiness. Sleepiness improves in many patients, particularly those with TBI. However, about a quarter of TBI subjects and non-cranial trauma control subjects remained sleepy 1 year after injury.