Shortcomings of Research
Recent studies addressing sleep disorders in patients with TBI have numerous limitations. Many are retrospective reviews of questionnaire data assessing subjective measures of sleep disturbances. These studies are inherently affected by recall bias. Premorbid sleep disease is not well described in the TBI literature. As such, in certain subsets of TBI, such as those resulting from motor vehicle accidents, it is difficult to discern what impact the patient's preexisting daytime somnolence may have played in the development of the injury or its consequences. Similarly, research evaluating insomnia is often limited to subjective data, frequently does not differentiate between initiation and maintenance insomnia, and doesn't necessarily limit enrollment to those who meet accepted diagnostic criteria for insomnia syndrome. Furthermore, few studies differentiate between the subjective complaint of insomnia, insomnia syndrome, and CRSDs. Prospective studies and randomized trials have been conducted, but they are typically limited by small sample sizes. Most of the published research does not differentiate between mechanism, severity, or time since injury.
Most research shows that sleep disturbances are more common in patients with mTBI than in those with severe TBI. Whether milder brain injuries are truly linked with poorer sleep quality, patients with milder injuries are better able to articulate complaints, or the underlying sleep disorder is the primary cause of symptoms is difficult to evaluate. Many patients who are recovering from TBI have medical or psychiatric comorbidities related to the physical and emotional stresses of their injuries, and the impact of these conditions, their treatments and potential adverse effects of therapies, further confound the clinical picture.
Given these limitations, it is difficult to fully understand and appreciate the association of sleep disorders with TBI and the potential influence they have on outcomes. However, with growing evidence that sleep disruptions are not only common but adversely affect prognosis, further investigation and research in this field is greatly needed.
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Cite this: Jacob F. Collen, Christopher J. Lettieri. Sleep Disorders in Traumatic Brain Injury - Medscape - May 24, 2011.