The impact of traumatic brain injury on sleep and associated neuroimaging changes: A systematic review

Sleep disturbances are among the most common neuropsychiatric symptoms following traumatic brain injury (TBI). However, no review has sought to identify the major neuroimaging correlates of post-TBI sleep disturbances across multiple imaging modalities. This systematic review aimed to describe post-TBI neuroimaging changes associated with self-reported and objective markers of sleep disturbance using computed tomography (CT), magnetic resonance imaging (MRI), and quantitative electroencephalography (qEEG). 21 studies were included in this review, comprising the data of 3176 individual with TBI and 396 individuals without TBI. While acute intracranial abnormalities on CT were not reliable predictors of self-reported symptoms of insomnia, measures of axonal integrity on diffusion tensor imaging (DTI), particularly involving cortico-subcortical white matter tracts such as the uncinate fasciculus, were highly associated with self-reported sleep disturbance. Individuals with TBI were also found to have decreased delta power and increased beta power on qEEG during sleep, providing preliminary support for the functional role of the hypothalamus in the pathogenesis of post-TBI sleep disturbance. Key study limitations include small sample sizes and heterogeneity of TBI severity and chronicity. Functional neuroimaging studies are needed that elucidate which alterations in white matter connectivity may be most implicated in the neurocircuitry of post-TBI sleep disturbance.