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Sleep Disturbances After Traumatic Brain Injury

Sleep Disturbances After Traumatic Brain Injury

Neuroanatomy of sleepFigure. Neuroanatomy of sleep
Sleep disturbances after TBITABLE 1: Sleep disturbances after TBI
Evaluation of TBI sleep disturbancesTABLE 2: Evaluation of TBI sleep disturbances
A structured approach to formulating TBI sleep disturbancesTABLE 3: A structured approach to formulating TBI sleep disturbances
Key elements of sleep hygieneTABLE 4: Key elements of sleep hygiene
Treatment of common TBI sleep disturbancesTABLE 5: Treatment of common TBI sleep disturbances

Traumatic brain injury (TBI) is best defined as an alteration in brain functioning or brain pathology caused by an external force. The rapid acceleration or deceleration external forces can be caused by blunt trauma, penetrating objects, or blast waves. The resulting primary damage includes shearing/tearing injuries of white matter, focal contusions, hematomas, or cerebral edema. Soon after the primary damage, a cascade of metabolic events sets in, which can cause secondary brain damage that may result from the generation of free radicals, release of neurotransmitters, inflammatory responses, calcium-mediated damage, mitochondrial dysfunction, and gene activation. TBI is associated with both focal and diffuse neuronal damage at the site of impact and in more distant brain regions.

TBI is classified as mild, moderate, or severe using the Glasgow Coma Scale (mild, 13 to 15; moderate, 9 to 12; severe, 8 or less); by the duration of loss of consciousness (mild, 30 minutes or less; moderate, 30 minutes to 24 hours; severe, more than 24 hours); or by the duration of posttraumatic amnesia (mild, 1 hour or less; moderate, 1 to 24 hours; severe, 1 to 7 days; and very severe, more than 1 week).

Sleep-related problems are among the most disabling consequences of TBI, with multiple influences: impairment of neuronal plasticity, metabolomic alterations, loss of vascular homeostasis, and disruption of the blood-brain barrier. Moreover, patients with TBI sleep disturbances are more sensitive to pain; are at greater risk for neuropsychiatric problems, such as depression and anxiety; perform poorly on neuropsychological tests of memory, attention, and executive function; and have worse social functioning.1 They have longer hospitalization stays and once discharged from the hospital are at increased risk for suicide.2,3

Sleep disturbances can occur during both the acute and chronic phases of injury. Acute posttrauma phase sleep problems have the potential to interfere with neuronal recovery that may be complicated further by treatment with medications, such as benzodiazepines and haloperidol, which can be detrimental to the recovering nervous system. In the subacute and chronic phases, daytime drowsiness can impair participation in rehabilitation while nighttime wakefulness is often associated with psychiatric problems, behavioral dyscontrol syndromes, and overall poorer quality of life.

Patients with all severities of TBI are at risk for sleep problems, although some studies have noted increased rates with mild compared with severe TBI.4-6 However, these findings may be due to a lack of awareness or underreporting in persons with severe TBI, or perhaps because of the increased sensitivity to changes after mild TBI. Some findings suggest that there are changes in polysomnographic measures following TBI, such as longer sleep onset latencies, shorter REM onset latencies, frequent nighttime awakenings, and higher proportion of stage 1 sleep.7-10

Pathophysiology

The sleep-wake cycle depends on the coordinated function of multiple brain regions, including the brain stem, basal forebrain, hypothalamus, and the frontal-subcortical system, as well as a balance between the arousal activating and inhibitory systems (Figure). CT and other structural imaging devices can miss sleep-associated microstructural abnormalities in the brain. For example, in one study, CT scans did not pick up any brain damage, but when polysomnography was done, significant differences in electroencephalogram power spectra data were seen.11

The causes of sleep disturbances after TBI are not well understood. However, the mechanisms underlying sleep-wake cycle problems may include the disruption of neural circuits as well as a myriad of other medical and psychiatric disturbances and environmental factors.

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