Traumatic brain injury linked to sleep disorders

Research Summary
Meg Guard
Research Assistant

Traumatic Brain Injury (TBI) is the dysfunction of the brain caused by external force to the head. Some common causes of TBI are falls, motor vehicle accidents, being hit by objects, and assaults. According to one review, sports-related injuries cause TBI in 1.6 to 3.8 million people annually in the United States. Common symptoms of TBI include persistent headaches, dizziness, fatigue, and changes in behavior and cognitive function. Symptoms of sleep disturbances are also extremely common after traumatic brain injury, but often go unrecognized by clinicians. It is estimated that 30-80% of patients with TBI have associated sleep problems.

A comprehensive review of literature revealed that common sleep disorders associated with TBI include sleep apnea (disrupted breathing during sleep), post-traumatic hypersomnia, narcolepsy (both hypersomnia and narcolepsy are characterized by excessive daytime sleepiness), and periodic limb movements of sleep (involuntary movement of limbs causing sleep disruption). Other sleep complaints, that are not formal disorders, include delayed sleep onset, early awakenings, poor sleep quality, snoring, nightmares, poor sleep efficiency, and excessive daytime sleepiness. Another study of sleep disorders associated with TBI found that patients who reported more severe headaches, dizziness, and psychiatric symptoms also had a higher likelihood of being diagnosed with severe sleep disorders.

Scientists have uncovered a few explanations for the many sleep symptoms associated with TBI. One literature review revealed that brain structures involved with sleep regulation may be damaged by traumatic brain injury. Another study of patients with TBI found a loss of brain cells that are thought to play a role in promoting wakefulness, reduced levels of a chemical in the brain that is involved in regulating the sleep-wake cycle, and decreased amounts of a small protein molecule that communicates with brain cells to regulate wakefulness. In other studies, people with TBI were found to have less melatonin, a hormone that regulates sleep.

However, the cause of sleep disturbances following TBI is often multifaceted. Not only can sleep disruptions occur as a result of the injury itself, but secondary conditions, such as psychiatric disorders or the pain from the injury, may also contribute to sleep difficulties. Furthermore, many medications used to treat TBI and its symptoms have side effects that disrupt sleep.

Given the frequency of sleep disorders associated with TBI, sleep assessment methods should be used to identify sleep symptoms in individuals who have been diagnosed with TBI. If a sleep disorder is diagnosed, it is important for patients to receive appropriate counseling and medication to treat their specific disorder and its associated symptoms. As sleep disorders are also common in children who suffer TBI, parents should be vigilant for sleep disturbances if their child has been diagnosed with a traumatic brain injury.