Reasons for Sleep Disturbances after Traumatic Brain Injury
Sleep disturbance may disrupt recovery via obstructing neuroplasticity, compromising vascular functioning, and/or compromising metabolic functioning. Sleep disruption increases oxidative stress and neuroinflammation, resulting in neurodegeneration. Disrupted sleep decreases synaptogenesis and memory consolidation. Sleep deprivation also dramatically reduces ATP production, prolonging inflammation and resulting in cell death. It may also result in an increased volume of neurofibrillary tangles and tauopathies. 3
There are numerous pathways which have been proposed to explain the relationship between sleep disturbance and TBI. Sleep disturbance may result from damage to sleep-wake regulating centers.4 Direct cortical damage resulting from TBI may be responsible for numerous forms of sleep disturbance. For example, hypersomnia may result from lesions in the reticular activating system, posterior hypothalamus, basal forebrain, and/or thalamus. Sleep disordered breathing may result from damage to the medullary respiratory center. Sleep movement disorders may arise from damage to the lenticulostriate region. Excessive sleepiness may also result from extensive loss of orexin secreting neurons in the hypothalamus following TBI. This neurotransmitter is a key sleep regulator and reduced levels can lead to excessive sleepiness.1
There are also potential secondary contributors to sleep dysfunction following TBI. These include physical and psychosocial factors such as pain, depression, anxiety, medicolegal issues, neuroendocrine disturbance, post-traumatic epilepsy, trauma-induced brain damage, genetic predisposition, analgesic pharmacotherapy, anticonvulsive drugs, and neuropsychological deficits.4,5 Fatigue may also result from impaired attention and processing speed, requiring greater cognitive effort to complete tasks.4
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Lucke-Wold, B., Smith, K., Nguyen, L., Turner, R., et al. (2015). Sleep disruption and the sequelae associated with traumatic brain injury. Neuroscience and Biobehavioral Reviews, 55, 68-77.
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Baumann, C. (2016). Sleep and traumatic brain injury. Sleep Medicine Clinics, 11, 19-23.
Larson, E., & F. Zollman (2010). The effect of sleep medications on cognitive recovery from traumatic brain injury. Journal of Head Trauma Rehabilitation, 25, 1, 61-67.