Circadian rhythm in the assessment of postconcussion insomnia: a cross-sectional observational study

Abstract

raumatic brain injury (TBI) is the leading cause of disability among young adults, and the incidence is increasing in Canada. 1,2 Mild TBI (mTBI), including concussion, accounts for the majority (70%-90%) of treated TBI cases and has the largest contribution to injuryrelated disability. 3 Early detection and effective management of medical conditions that hinder recovery could prevent disability and substantially reduce societal costs. In this regard, sleep disruptions are key modifiable targets that magnify the sequelae of mTBI. 4 Insomnia-difficulties falling or staying asleep, or early-morning final awakening-is the most common persistent sleep symptom after mTBI 5,6 and is particularly prevalent following mTBI compared to more severe forms. 4 Moreover, insomnia after concussion worsens fatigue, pain, cognition and mood, and predicts poor overall prognosis for recovery, greater disability and mental disorders. 7-11 Given that disorders of sleep and wakefulness can be treated effectively, treatment holds the promise of improving the management of persistent postconcussive symptoms and hastening recovery from mTBI. Recent reports 4,12,13 emphasize the need for multimodal sleep and circadian assessments; however, these are not common practice, and research remains limited. Standard assessment of insomnia relies on patients' subjective report, and the recommended first-line treatment is cog-nitive behavioural therapy. 14,15 Importantly, however, circadian rhythm sleep-wake disorders (CRSWDs) that may underlie symptoms of insomnia require fundamentally different assessment and treatment (Appendix 1, available at www. cmajopen.ca/content/8/1/E142/suppl/DC1). These disorders arise if there is a disruption of the endogenous circadian system or a misalignment between the internal circadian rhythm and the external environment. The best biologic marker of CRSWDs is abnormal dim-light onset of melatonin production, and the behavioural diagnostic feature is that the sleep phase is markedly delayed, advanced or irregular relative to environmental time and social norms 16 (Appendix 1). Rates and mechanisms of CRSWDs in mTBI are not well characterized, but evidence indicates that brain trauma can disrupt systems that regulate circadian rhythms, such as suprachiasmatic nucleus function, gene expression, neural plasticity,

Prognostic Value of Circadian Rhythm of Brain Temperature in Traumatic Brain Injury

“…Our results could potentially be applied to other neurocritical patients, such as patients with SAH and intracerebral hemorrhage [ 38 ]. In addition, circadian rhythm sleep-wake disorders have been identified as an important and addressable issue in mild TBI and post-concussion patients [ 40 , 41 ]. Since non-surgical brain temperature measurement with MRI is feasible [ 41 ], further application to this group of patients is also promising.…”

The interaction of the circadian and immune system: Desynchrony as a pathological outcome to traumatic brain injury

“…Finally, research should aim to not only include both sexes, as a European cohort that analysed gender differences found women exhibit worse outcomes following TBI ( Mikolic et al, 2020 ), but also take comorbid impairments such as sleep disruption into consideration. This is an extremely important consideration given that many mTBI patients who present with insomnia showed a greater number of circadian rhythm sleep wake disorders ( Zalai et al, 2020 ).…”