T raumatic brain injury occurs in 100-400 per 100,000 people per year in North America and Europe. The common causes are road traffic accidents, falls, assaults, sport injuries, and domestic accidents. Males are more often affected than women. The most common age group which suffers from traumatic brain injury is 15-35 years. It is the most frequent cause of death between ages 1-15. 1 Sleep related problems secondary to chronic TBI have been described anecdotally or in case-report format since 1941. 2-10 Some commonly reported disorders include hypersomnia, narcolepsy, delayed sleep phase, insomnia, fatigue, alteration of sleepwake schedule, and movement disorders. Sleep disorders are a common finding after the acute phase of TBI. They result in daytime somnolence which in turn may lead to poor daytime performance, altered sleep-wake schedule, heightened anxiety, and poor individual sense of well being, insomnia, and depression.Only recently have the attempts have been made to investigate this relationship more systematically in chronic TBI. [11][12][13][14] The most critical study is that of Guilleminault et al who concluded that impaired daytime functioning and somnolence is present in 98% of all patients with TBI, and sleep disordered breathing is a common finding. 4 Pain caused by associated cervical whiplash may be an important contributing factor. Sleep related abnormalities are more prevalent in more severely head-injured patients, such as those in coma for >24 hours, those with skull fractures, or those requiring neurosurgical intervention. Kauffman et al 14 reached similar conclusions in adolescents with minor head injury and found that sleep disturbances may be long-term. This study was undertaken to extend these systematic observations in the evolving knowledge of sleep disorders in TBI survivors, as the sleep disorders make an impact on the rehabilitation of these patients 15,16 and can exacerbate other symptoms such as pain, cognitive deficits, fatigue, and irritability. 16
METHODS
Study populationPatients with chronic TBI (defined as 3 months to 2 years after the injury) were evaluated by a board-certified neurologist who is also a board-certified sleep specialist. Evaluation included a