Sleep disturbance after mild traumatic brain injury: indicator of injury?

Concussion and the Sleeping Brain

BACKGROUND

Emerging research has suggested sleep to be a modifier of the trajectory of concussion recovery in adolescent and adult populations. Despite the growing recognition of the relationship between sleep and concussion, the mechanisms and physiological processes governing this association have yet to be established.

MAIN BODY

Following a concussion, a pathophysiologic cascade of events occurs, characterized by numerous factors including microglia activation, ionic imbalance, and release of excitatory neurotransmitters. Importantly, each of these factors plays a role in the regulation of the sleep-wake cycle. Therefore, dysregulation of sleep following injury may be a function of the diffuse disruption of cerebral functioning in the wake of both axonal damage and secondary physiological events. As the onset of sleep-related symptoms is highly variable following a concussion, clinicians should be aware of when and how these symptoms present. Post-injury changes in sleep have been reported in the acute, sub-acute, and chronic phases of recovery and can prolong symptom resolution, affect neurocognitive performance, and influence mood state. Though these changes support sleep as a modifier of recovery, limited guidance exists for clinicians or their patients in the management of sleep after concussion. This may be attributed to the fact that research has correlated sleep with concussion recovery but has failed to explain why the correlation exists. Sleep is a complex, multifactorial process and the changes seen in sleep that are seen following concussion are the result of interactions amongst numerous processes that regulate the sleep-wake cycle.

SHORT CONCLUSION

The assessment and management of sleep by identifying and considering the biological, sociological, and psychological interactions of this multifactorial process will allow for clinicians to address the dynamic nature of changes in sleep following concussion.

Sleep after Concussion: A Scoping Review of Sensor Technologies

Sleep disturbances following a concussion/mild traumatic brain injury (mTBI) are associated with longer recovery times and more comorbidities. Sensor technologies can directly monitor sleep-related physiology and provide objective sleep metrics. This scoping review determines how sensor technologies are currently used to monitor sleep following a concussion. We searched Ovid (Medline, Embase), Web of Science, CINAHL, Compendex Engineering Village, and PsychInfo from inception-June 20, 2022, following PRISMA guidelines for Scoping Reviews. Included studies objectively monitored sleep in participants with concussion. We screened 1081 articles and included 37 in the review. 17 studies implemented Polysomnography (PSG) months to years after injury for a median of 2 nights and provided a wide range of sleep metrics, including sleep-wake times, sleep stages, arousal indices, and periodic limb movements. Sleep stages were most reported in PSG studies, and sleep efficiency most reported in actigraphy studies. 22 studies used actigraphy days to weeks after injury for a median of 10 days and nights and provided information limited to sleep-wake times. For both technologies there was high variability in reported outcome measures. Sleep sensing technologies may be used to identify how sleep affects concussion recovery. High variability in sensor deployment methodologies makes cross-study comparisons difficult and highlights the need for standardization. Consensus on the integration of sleep sensing technologies will ultimately lead to clinical translation for sleep monitoring and improved outcomes post-concussion.

Characterization of Sleep, Emotional, and Cognitive Functions in a New Rat Model of Concomitant Spinal Cord and Traumatic Brain Injuries

Traumatic injuries to the spinal cord or the brain have serious medical consequences and lead to long-term disability. The epidemiology, medical complications, and prognosis of isolated spinal cord injury (SCI) and traumatic brain injury (TBI) have been well described. However, there are limited data on patients suffering from concurrent SCI and TBI, even if a large proportion of SCI patients have concomitant TBI. The complications associated with this "dual-diagnosis" such as cognitive or behavioral dysfunction are well known in the rehabilitation setting, but evidence-based and standardized approaches for diagnosis and treatment are lacking. Our goal was to develop and characterize a pre-clinical animal model of concurrent SCI and TBI to help identifying "dual-diagnosis" tools. Female rats received a unilateral contusive SCI at the thoracic level alone (SCI group) or combined with a TBI centered on the contralateral sensorimotor cortex (SCI-TBI group). We first validated that the SCI extent was comparable between SCI-TBI and SCI groups, and that hindlimb function was impaired. We characterized various neurological outcomes, including locomotion, sleep architecture, brain activity during sleep, depressive- and anxiety-like behaviors, and working memory. We report that SCI-TBI and SCI groups show similar impairments in global locomotor function. While wake/sleep amount and distribution and anxiety- and depression-like symptoms were not affected in SCI-TBI and SCI groups in comparison to the control group (laminectomy and craniotomy only), working memory was impaired only in SCI-TBI rats. This pre-clinical model of concomitant SCI and TBI, including more severe variations of it, shows a translational value for the identification of biomarkers to refine the "dual-diagnosis" of neurotrauma in humans.

Sleep/Wake Disorders After Sports Concussion: Risks, Revelations, and Interventions

SUMMARY

Sleep-wake disturbances (SWDs) are among the most prevalent, persistent, and often disregarded sequelae of traumatic brain injury. Identification and treatment of SWDs in patients with traumatic brain injury is important and can complement other efforts to promote maximum functional recovery. SWDs can accentuate other consequences of traumatic brain injury, negatively affect mood, exacerbate pain, heighten irritability, and diminish cognitive abilities and the potential for recovery. The risk for sports injuries increases when athletes are sleep deprived. Sleep deprivation increases risk-taking behaviors, predisposing to injuries. SWDs are an independent risk factor for prolonged recovery after sports-related concussion. SWDs following sports-related concussion have been shown to impede recovery, rehabilitation, and return to preinjury activities.

The Correlation of Sleep Disturbance and Location of Glioma Tumors: A Narrative Review

Sleep disturbance can occur when sleep centers of the brain, regions that are responsible for coordinating and generating healthy amounts of sleep, are disrupted by glioma growth or surgical resection. Several disorders cause disruptions to the average duration, quality, or patterns of sleep, resulting in sleep disturbance. It is unknown whether specific sleep disorders can be reliably correlated with glioma growth, but there are sufficient numbers of case reports to suggest that a connection is possible. In this manuscript, these case reports and retrospective chart reviews are considered in the context of the current primary literature on sleep disturbance and glioma diagnosis to identify a new and useful connection which warrants further systematic and scientific examination in preclinical animal models. Confirmation of the relationship between disruption of the sleep centers in the brain and glioma location could have significant implications for diagnostics, treatment, monitoring of metastasis/recurrence, and end-of-life considerations.

Electroencephalographic Changes in Sleep During Acute and Subacute Phases After Sports-Related Concussion

Purpose

Little is known about sleep after a concussion, a form of mild traumatic brain injury. Given the importance of sleep for both maintaining brain health and recovery from injury, we sought to examine sleep acutely and subacutely after concussion.

Methods

Athletes who experienced a sports-related concussion were invited to participate. Participants underwent overnight sleep studies within 7 days of the concussion (acute phase), and again eight-weeks after the concussion (subacute phase). Changes in sleep from both the acute and subacute phases were compared to population normative values. Additionally, changes in sleep from acute to subacute phase were analysed.

Results

When compared to normative data, the acute and subacute phases of concussion showed longer total sleep time (p < 0.005) and fewer arousals (p < 0.005). The acute phase showed longer rapid eye movement sleep latency (p = 0.014). The subacute phase showed greater total sleep spent in Stage N3% (p = 0.046), increased sleep efficiency (p < 0.001), shorter sleep onset latency (p = 0.013), and reduced wake after sleep onset (p = 0.013). Compared to the acute phase, the subacute phase experienced improved sleep efficiency (p = 0.003), reduced wake after sleep onset (p = 0.02), and reduced latencies for both stage N3 sleep (p = 0.014) and rapid eye movement sleep (p = 0.006).

Conclusion

This study indicated sleep during both the acute and subacute phases of SRC was characterised by longer and less disrupted sleep, along with improvements in sleep from the acute to subacute phases of SRC.

The Effect of Traumatic Brain Injury on Sleep Architecture and Circadian Rhythms in Mice—A Comparison of High-Frequency Head Impact and Controlled Cortical Injury

Simple Summary

Traumatic brain injury (TBI) is a significant risk factor for the development of sleep and circadian rhythm impairments. In order to understand if TBI models with different injury mechanism, severity and pathology have different sleep and circadian rhythm disruptions, we performed a detailed sleep and circadian analysis of the high-frequency head impact TBI model (a mouse model that mimics sports-related head impacts) and the controlled cortical impact TBI model (a mouse model that mimics severe brain trauma). We found that both TBI models disrupt the ability of brain cells to maintain circadian rhythms; however, both injury groups could still maintain circadian behavior patterns. Both the mild head impact model and the severe brain injury model had normal amount of sleep at 7 d after injury; however, the severe brain injury mice had disrupted brain wave patterns during sleep. We conclude that different types of TBI have different patterns of sleep disruptions.

Abstract

Traumatic brain injury (TBI) is a significant risk factor for the development of sleep and circadian rhythm impairments. In this study we compare the circadian rhythms and sleep patterns in the high-frequency head impact (HFHI) and controlled cortical impact (CCI) mouse models of TBI. These mouse models have different injury mechanisms key differences of pathology in brain regions controlling circadian rhythms and EEG wave generation. We found that both HFHI and CCI caused dysregulation in the diurnal expression of core circadian genes (Bmal1, Clock, Per1,2, Cry1,2) at 24 h post-TBI. CCI mice had reduced locomotor activity on running wheels in the first 7 d post-TBI; however, both CCI and HFHI mice were able to maintain circadian behavior cycles even in the absence of light cues. We used implantable EEG to measure sleep cycles and brain activity and found that there were no differences in the time spent awake, in NREM or REM sleep in either TBI model. However, in the sleep states, CCI mice have reduced delta power in NREM sleep and reduced theta power in REM sleep at 7 d post-TBI. Our data reveal that different types of brain trauma can result in distinct patterns of circadian and sleep disruptions and can be used to better understand the etiology of sleep disorders after TBI.

A novel circular RNA, circIgfbp2, links neural plasticity and anxiety through targeting mitochondrial dysfunction and oxidative stress-induced synapse dysfunction after traumatic brain injury

Traumatic brain injury (TBI) can lead to different neurological and psychiatric disorders. Circular RNAs (circRNAs) are highly expressed in the nervous system and enriched in synapses; yet, the underlying role and mechanisms of circRNAs in neurological impairment and dysfunction are still not fully understood. In this study, we investigated the expression of circRNAs and their relation with neurological dysfunction after TBI. RNA-Seq was used to detect differentially expressed circRNAs in injured brain tissue, revealing that circIgfbp2 was significantly increased. Up-regulated hsa_circ_0058195, which was highly homologous to circIgfbp2, was further confirmed in the cerebral cortex specimens and serum samples of patients after TBI. Moreover, correlation analysis showed a positive correlation between hsa_circ_0058195 levels and the Self-Rating Anxiety Scale scores in these subjects. Furthermore, knockdown of circIgfbp2 in mice relieved anxiety-like behaviors and sleep disturbances induced by TBI. Knockdown of circIgfbp2 in H₂O₂ treated HT22 cells alleviated mitochondrial dysfunction, while its overexpression reversed the process. Mechanistically, we discovered that circIgfbp2 targets miR-370-3p to regulate BACH1, and down-regulating BACH1 alleviated mitochondrial dysfunction and oxidative stress-induced synapse dysfunction. In conclusion, inhibition of circIgfbp2 alleviated mitochondrial dysfunction and oxidative stress-induced synapse dysfunction after TBI through the miR-370-3p/BACH1/HO-1 axis. Thus, circIgfbp2 might be a novel therapeutic target for anxiety and sleep disorders after TBI.

Gender role in sleep disturbances among older adults with traumatic brain injury

Older adults are particularly vulnerable to poor long-term outcomes, and the rate of TBI in this group is increasing. Studies have shown females experience worse outcomes from TBI than males, however this research has been limited. The aim of this study is to examine gender effects on the frequency of sleep disturbances in older adults post-TBI. An analysis was conducted on data obtained from the National Alzheimer's Coordinating Center (NACC) Uniform Data Set. A total of 405 patients greater than 60 years of age were examined. Sleep disturbances were measured using the Nighttime Behavioural Disturbances domain of the Neuropsychiatric Inventory-Questionnaire (NPI-Q). A significant difference (p = 0.025) in reported sleep disturbance was identified in the female TBI population relative to the female non-TBI population. In the male non-TBI group, 14.8% (n = 12) experienced nighttime disturbances while 19.8% (n = 17) of those with TBI experienced nighttime disturbances. This difference was not significant (p = 0.305). These results suggest there is a greater impact from traumatic brain injury on sleep disturbances in older females than males. Further research examining gender differences in older adults related to neuropsychiatric outcomes of TBI should be considered given the implications for treatment.

Differences in sleep between concussed and nonconcussed college students: a matched case-control study

Study Objectives

To describe sleep 2-3 days postconcussion through symptom recovery and make comparison to well-matched nonconcussed controls.

Methods

Twenty college students were physician diagnosed with a concussion and compared with 20 nonconcussed controls matched on age, sex, physical activity, and sleep quality. A wrist-worn ActiGraph GT9X Link was provided during initial evaluation (within 72 hr postinjury for concussed) and worn continuously until symptom resolution (duration matched for nonconcussed). All participants completed a sleep symptom severity checklist, the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale (ESS). Separate 2(group) × 3(time points) mixed model ANOVAs were conducted to compare actigraphy sleep outcomes (sleep onset latency [SOL], normalized wake after sleep onset [WASOnorm], total sleep time [TST], sleep efficiency, and number of awakenings) across recovery stages (2-3 days postinjury, mid-point, and end of recovery). Intraindividual coefficient of variation was calculated for each sleep outcome. Mann-Whitney U tests compared PSQI global score, ESS total score, and sleep symptom severity between groups (α = 0.05).

Results

At 2-3 days postinjury, concussed individuals took longer to fall asleep compared with controls (p = 0.002). Greater intraindividual variability in WASOnorm (p = 0.017) and TST (p = 0.044) existed in concussed individuals across recovery. Poorer sleep quality (p < 0.001), excessive daytime sleepiness (p = 0.014), and worse sleep symptoms (p < 0.001) existed in concussed compared with controls.

Conclusions

Concussed individuals took longer to fall asleep 2-3 days postconcussion, experienced greater variation in sleep fragmentation and sleep time until symptom resolution, and reported worse sleep quality. Our preliminary findings may guide researchers interested in better understanding sleep postconcussion.

Electrophysiological testing in concussion: A guide to clinical applications

The diagnosis of mild traumatic brain injury in concussion is difficult since it is often unwitnessed, the patient’s recall is unreliable and initial clinical examination is often unrevealing, correlating poorly with the extent of brain injury. At present, there are no objective biomarkers of mild traumatic brain injury in concussion. Thus, a sensitive gold standard test is required to enable the effective and safe triage of patients who present to the acute services. As well as triage, objective monitoring of patients’ recovery over time and separate from clinical features that patients may develop following the injury (e.g. depression and migraine) is also needed. In contrast to neuroimaging, which is widely used to investigate traumatic brain injury patients, electrophysiology is readily available, is cheap and there are internationally recognized standardised methodologies. Herein, we review the existing literature on electrophysiological testing in concussion and mild traumatic brain injury; specifically, electroencephalogram, polysomnography, brainstem auditory evoked potentials, electro- and videonystagmography, vestibular evoked myogenic potentials, visually evoked potentials, somatosensory evoked potentials and transcranial magnetic stimulation.

Actigraphically Measured Sleep-Wake Behavior After Mild Traumatic Brain Injury: A Case-Control Study

OBJECTIVE

To characterize and compare the sleep-wake behavior of individuals following a mild traumatic brain injury (mTBI) with that of noninjured healthy controls.

SETTING

Community.

PARTICIPANTS

Fourteen participants with a recent mTBI (Mage = 28.07; SD = 10.45; n = 10 females) and 34 noninjured controls (Mage = 23.70; SD = 7.30; n = 31 females).

DESIGN

Cross-sectional.

MAIN MEASURES

Battery of subjective sleep measures and 14 days of sleep-wake monitoring via actigraphy (objective measurement) and concurrent daily sleep diary.

RESULTS

Participants who had sustained an mTBI self-reported significantly higher sleep-related impairment, poorer nightly sleep quality, and more frequently met criteria for clinical insomnia, compared with controls (d = 0.76-1.11, large effects). The only significant between-group difference on objective sleep metrics occurred on sleep timing. On average, people with a recent history of mTBI fell asleep and woke approximately 1 hour earlier than did the controls (d = 0.62-0.92, medium to large effects).

CONCLUSION

Participants with a history of mTBI had several subjective sleep complaints but relatively few objective sleep changes with the exception of earlier sleep timing. Future research is needed to understand the clinical significance of these findings and how these symptoms can be alleviated. Interventions addressing subjective sleep complaints (eg, cognitive behavior therapy for insomnia) should be tested in this population.

Sleep-Wake Disturbances After Traumatic Brain Injury: Synthesis of Human and Animal Studies

Sleep-wake disturbances following traumatic brain injury (TBI) are increasingly recognized as a serious consequence following injury and as a barrier to recovery. Injury-induced sleep-wake disturbances can persist for years, often impairing quality of life. Recently, there has been a nearly exponential increase in the number of primary research articles published on the pathophysiology and mechanisms underlying sleep-wake disturbances after TBI, both in animal models and in humans, including in the pediatric population. In this review, we summarize over 200 articles on the topic, most of which were identified objectively using reproducible online search terms in PubMed. Although these studies differ in terms of methodology and detailed outcomes; overall, recent research describes a common phenotype of excessive daytime sleepiness, nighttime sleep fragmentation, insomnia, and electroencephalography spectral changes after TBI. Given the heterogeneity of the human disease phenotype, rigorous translation of animal models to the human condition is critical to our understanding of the mechanisms and of the temporal course of sleep-wake disturbances after injury. Arguably, this is most effectively accomplished when animal and human studies are performed by the same or collaborating research programs. Given the number of symptoms associated with TBI that are intimately related to, or directly stem from sleep dysfunction, sleep-wake disorders represent an important area in which mechanistic-based therapies may substantially impact recovery after TBI.

Sleep Quantity and Quality during Acute Concussion: A Pilot Study

STUDY OBJECTIVES

A number of subjective and objective studies provide compelling evidence of chronic post-concussion changes in sleep, yet very little is known about the acute effects of concussion on sleep quality and quantity. Therefore, the purpose of this prospective pilot study was to use actigraphy to examine the changes in sleep quality and quantity acutely following concussion at home rather than in a hospital or sleep laboratory.

METHODS

Seventeen young adults (7 with acute concussion, 10 controls) were recruited for this study. All participants completed two 5-day testing sessions separated by 30 days from intake (controls) or day of injury (concussion). Participants wore actigraphs and kept a sleep journal. Sleep parameter outcomes included nighttime total sleep time (nTST), 24-h total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE). The coefficient of variation (CV) for each sleep parameter was computed for each session.

RESULTS

nTST and TST CV was significantly greater in the concussion group. There is the additional indication that individuals with a concussion may require and obtain more sleep shortly after injury and subsequently have a shorter duration of sleep at 1 mo post-injury. This pattern was not seen in the measures of sleep quality (WASO, SE).

CONCLUSIONS

Individuals with a concussion demonstrated increased nighttime sleep duration variability. This increase persisted at 1 mo post-injury and may be associated with previously documented self-reports of poor sleep quality lasting months and years after a concussion. Additionally, this increase may predispose individuals to numerous negative health outcomes if left untreated.

Circadian Melatonin Rhythm Following Traumatic Brain Injury

BACKGROUND

Sleep-wake disturbances are highly prevalent following traumatic brain injury (TBI), impeding rehabilitaion and quality of life. However, the mechanisms underlying these sleep disturnbances are unclear, and efficacious treatments are lacking. To investigate possible mechanisms underlying sleep disturbance in TBI, we examined characteristics of the circadian rhythm of melatonin, a hormone involved in sleep-wake regulation. We compared TBI patients reporting sleep disturbance with age- and gender-matched healthy volunteers.

METHODS

We conducted an overnight observational study with salivary melatonin samples collected hourly in 9 patients with severe TBI and 9 controls. Salivary dim light melatonin onset (DLMO) as well as melatonin synthesis onset (SynOn) and offset (SynOff) were used to determine circadian timing. Total overnight salivary melatonin production was calculated as the area under the curve from melatonin synthesis onset to offset.

RESULTS

Compared with healthy individuals, TBI patients showed 42% less melatonin production overnight (d = 0.87; P = .034). The timing of DLMO was delayed by approximately 1.5 hours in patients with TBI compared with controls (d = 1.23; P = .003).

CONCLUSIONS

In patients with TBI, melatonin production was attenuated overnight, and the timing of melatonin secretion was delayed. We suggest that disruption to the circadian regulation of melatonin synthesis is a feature of severe TBI, possibly contributing to the sleep difficulties that are commonly reported in this population.

Hypocretinergic and cholinergic contributions to sleep-wake disturbances in a mouse model of traumatic brain injury

Disorders of sleep and wakefulness occur in the majority of individuals who have experienced traumatic brain injury (TBI), with increased sleep need and excessive daytime sleepiness often reported. Behavioral and pharmacological therapies have limited efficacy, in part, because the etiology of post-TBI sleep disturbances is not well understood. Severity of injuries resulting from head trauma in humans is highly variable, and as a consequence so are their sequelae. Here, we use a controlled laboratory model to investigate the effects of TBI on sleep-wake behavior and on candidate neurotransmitter systems as potential mediators. We focus on hypocretin and melanin-concentrating hormone (MCH), hypothalamic neuropeptides important for regulating sleep and wakefulness, and two potential downstream effectors of hypocretin actions, histamine and acetylcholine. Adult male C57BL/6 mice (n=6-10/group) were implanted with EEG recording electrodes and baseline recordings were obtained. After baseline recordings, controlled cortical impact was used to induce mild or moderate TBI. EEG recordings were obtained from the same animals at 7 and 15 days post-surgery. Separate groups of animals (n=6-8/group) were used to determine effects of TBI on the numbers of hypocretin and MCH-producing neurons in the hypothalamus, histaminergic neurons in the tuberomammillary nucleus, and cholinergic neurons in the basal forebrain. At 15 days post-TBI, wakefulness was decreased and NREM sleep was increased during the dark period in moderately injured animals. There were no differences between groups in REM sleep time, nor were there differences between groups in sleep during the light period. TBI effects on hypocretin and cholinergic neurons were such that more severe injury resulted in fewer cells. Numbers of MCH neurons and histaminergic neurons were not altered under the conditions of this study. Thus, we conclude that moderate TBI in mice reduces wakefulness and increases NREM sleep during the dark period, effects that may be mediated by hypocretin-producing neurons and/or downstream cholinergic effectors in the basal forebrain.

Sleep, Sleep Disorders, and Mild Traumatic Brain Injury. What We Know and What We Need to Know: Findings from a National Working Group

Disturbed sleep is one of the most common complaints following traumatic brain injury (TBI) and worsens morbidity and long-term sequelae. Further, sleep and TBI share neurophysiologic underpinnings with direct relevance to recovery from TBI. As such, disturbed sleep and clinical sleep disorders represent modifiable treatment targets to improve outcomes in TBI. This paper presents key findings from a national working group on sleep and TBI, with a specific focus on the testing and development of sleep-related therapeutic interventions for mild TBI (mTBI). First, mTBI and sleep physiology are briefly reviewed. Next, essential empirical and clinical questions and knowledge gaps are addressed. Finally, actionable recommendations are offered to guide active and efficient collaboration between academic, industry, and governmental stakeholders.

A Longitudinal Investigation of Sleep Quality in Adolescents and Young Adults After Mild Traumatic Brain Injury

OBJECTIVE AND BACKGROUND

We examined sleep-related problems in adolescents and young adults after a mild traumatic brain injury (MTBI) or orthopedic injury. We extended the analysis of data from a study of early emotional and neuropsychological sequelae in these populations (McCauley et al. 2014. J Neurotrauma. 31:914).

METHODS

We gave the Pittsburgh Sleep Quality Index to 77 participants with MTBI, 71 with orthopedic injury, and 43 non-injured controls. The age range was 12 to 30 years. We tested sleep quality within 96 hours of injury and at 1- and 3-month follow-up. Participants also completed measures of pain and fatigue, drug and alcohol use, and post-traumatic stress symptoms.

RESULTS

Older participants (mean age=25 years) in the MTBI group exhibited a sharp increase in sleep-related symptoms between the baseline assessment and 1 month, and still had difficulties at 3 months. Younger participants with MTBI (mean age=15 years) and older participants with an orthopedic injury had modest increases in sleep difficulties between baseline and 1 month. The participants with MTBI also had more clinically significant sleep difficulties at all 3 assessments. At 3 months, Pittsburgh Sleep Quality Index scores in younger participants with MTBI and all participants with orthopedic injury did not differ significantly from the non-injured controls'. The controls had no significant change in their sleep symptoms during the 3 months.

CONCLUSIONS

Sleep difficulties in young adults may persist for ≤3 months after MTBI and exceed those after orthopedic injury. Clinicians should seek and treat sleep-related problems after MTBI.

Sleep-wake disturbances after traumatic brain injury

Sleep-wake disturbances are extremely common after a traumatic brain injury (TBI). The most common disturbances are insomnia (difficulties falling or staying asleep), increased sleep need, and excessive daytime sleepiness that can be due to the TBI or other sleep disorders associated with TBI, such as sleep-related breathing disorder or post-traumatic hypersomnia. Sleep-wake disturbances can have a major effect on functional outcomes and on the recovery process after TBI. These negative effects can exacerbate other common sequelae of TBI-such as fatigue, pain, cognitive impairments, and psychological disorders (eg, depression and anxiety). Sleep-wake disturbances associated with TBI warrant treatment. Although evidence specific to patients with TBI is still scarce, cognitive-behavioural therapy and medication could prove helpful to alleviate sleep-wake disturbances in patients with a TBI.

Impact of traumatic brain injury on sleep structure, electrocorticographic activity and transcriptome in mice

Traumatic brain injury (TBI), including mild TBI (mTBI), is importantly associated with vigilance and sleep complaints. Because sleep is required for learning, plasticity and recovery, we here evaluated the bidirectional relationship between mTBI and sleep with two specific objectives: (1) Test that mTBI rapidly impairs sleep-wake architecture and the dynamics of the electrophysiological marker of sleep homeostasis (i.e., non-rapid eye movement sleep delta (1-4Hz) activity); (2) evaluate the impact of sleep loss following mTBI on the expression of plasticity markers that have been linked to sleep homeostasis and on genome-wide gene expression. A closed-head injury model was used to perform a 48h electrocorticographic (ECoG) recording in mice submitted to mTBI or Sham surgery. mTBI was found to immediately decrease the capacity to sustain long bouts of wakefulness as well as the amplitude of the time course of ECoG delta activity during wakefulness. Significant changes in ECoG spectral activity during wakefulness, non-rapid eye movement and rapid eye movement sleep were observed mainly on the second recorded day. A second experiment was performed to measure gene expression in the cerebral cortex and hippocampus after a mTBI followed either by two consecutive days of 6h sleep deprivation (SD) or of undisturbed behavior (quantitative PCR and next-generation sequencing). mTBI modified the expression of genes involved in immunity, inflammation and glial function (e.g., chemokines, glial markers) and SD changed that of genes linked to circadian rhythms, synaptic activity/neuronal plasticity, neuroprotection and cell death and survival. SD appeared to affect gene expression in the cerebral cortex more importantly after mTBI than Sham surgery including that of the astrocytic marker Gfap, which was proposed as a marker of clinical outcome after TBI. Interestingly, SD impacted the hippocampal expression of the plasticity elements Arc and EfnA3 only after mTBI. Overall, our findings reveal alterations in spectral signature across all vigilance states in the first days after mTBI, and show that sleep loss post-mTBI reprograms the transcriptome in a brain area-specific manner and in a way that could be deleterious to brain recovery.

Characterizing self-reported sleep disturbance after mild traumatic brain injury

Sleep disturbance after mild traumatic brain injury (mTBI) is commonly reported as debilitating and persistent. However, the nature of this disturbance is poorly understood. This study sought to characterize sleep after mTBI compared with a control group. A cross-sectional matched case control design was used. Thirty-three persons with recent mTBI (1-6 months ago) and 33 age, sex, and ethnicity matched controls completed established questionnaires of sleep quality, quantity, timing, and sleep-related daytime impairment. The mTBI participants were compared with an independent sample of close-matched controls (CMCs; n = 33) to allow partial internal replication. Compared with controls, persons with mTBI reported significantly greater sleep disturbance, more severe insomnia symptoms, a longer duration of wake after sleep onset, and greater sleep-related impairment (all medium to large effects, Cohen's d > 0.5). No differences were found in sleep quantity, timing, sleep onset latency, sleep efficiency, or daytime sleepiness. All findings except a measure of sleep timing (i.e., sleep midpoint) were replicated for CMCs. These results indicate a difference in the magnitude and nature of perceived sleep disturbance after mTBI compared with controls, where persons with mTBI report poorer sleep quality and greater sleep-related impairment. Sleep quantity and timing did not differ between the groups. These preliminary findings should guide the provision of clearer advice to patients about the aspects of their sleep that may change after mTBI and could inform treatment selection.

Are NREM sleep characteristics associated to subjective sleep complaints after mild traumatic brain injury?

INTRODUCTION

Sleep complaints are common after mild traumatic brain injury (mTBI). While recent findings suggest that sleep macro-architecture is preserved in mTBI, features of non-rapid eye movement (NREM) sleep micro-architecture including electroencephalography (EEG) spectral power, slow waves (SW), and sleep spindles could be affected. This study aimed to compare NREM sleep in mTBI and healthy controls, and explore whether NREM sleep characteristics correlate with sleep complaints in these groups.

METHODS

Thirty-four mTBI participants (mean age: 34.2 ± 11.9 yrs; post-injury delay: 10.5 ± 10.4 weeks) and 29 age-matched controls (mean age: 32.4 ± 8.2 yrs) were recruited for two consecutive nights of polysomnographic (PSG) recording. Spectral power was computed and SW and spindles were automatically detected in three derivations (F3, C3, O1) for the first three sleep cycles. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

mTBI participants reported significant poorer sleep quality than controls on the PSQI and showed significant increases in beta power during NREM sleep at the occipital derivation only. Conversely, no group differences were found in SW and spindle characteristics. Interestingly, changes in NREM sleep characteristics were not associated with mTBI estimation of sleep quality.

CONCLUSIONS

Compared to controls, mTBI were found to have enhanced NREM beta power. However, these changes were not found to be associated with the subjective evaluation of sleep. While increases in beta bands during NREM sleep may be attributable to the occurrence of a brain injury, they could also be related to the presence of pain and anxiety as suggested in one prior study.

Does acute TBI-related sleep disturbance predict subsequent neuropsychiatric disturbances?

PRIMARY OBJECTIVE

To determine whether sleep disturbance in the acute post-traumatic brain injury (TBI) period predicts symptoms of depression, anxiety or apathy measured 6 and 12 months after TBI.

RESEARCH DESIGN

Longitudinal, observational study.

METHODS AND PROCEDURES

First time closed-head injury patients (n = 101) were recruited and evaluated within 3 months of injury and followed longitudinally, with psychiatric evaluations at 6 and 12 months post-injury. Pre- and post-injury sleep disturbances were measured via the Medical Outcome Scale (MOS) for Sleep. Subjects were also assessed for anxiety, depression, apathy, medical comorbidity and severity of TBI.

MAIN OUTCOMES AND RESULTS

Sleep disturbance in the acute TBI period was associated with increased symptoms of depression, anxiety and apathy 12 months post-injury.

CONCLUSIONS

Sleep disturbances experienced soon after trauma (i.e. <3 months after injury) predicted neuropsychiatric symptoms 1 year after injury, raising two important clinical questions: (1) Is sleep disturbance soon after trauma a prognostic marker of subsequent neuropsychiatric symptoms? and (2) Can early treatment of sleep disturbance during the post-TBI period reduce subsequent development of neuropsychiatric symptoms? Future studies with larger sample sizes and appropriate control groups could help to answer these questions, using evidence-based methods for evaluating and treating sleep disturbances.

Sleep disturbance in pediatric PTSD: current findings and future directions

Many studies have provided strong evidence of a fundamental and complex role for sleep disturbances in adult posttraumatic stress disorder (PTSD). Investigations of adult PTSD using subjective and objective measures document sleep architecture abnormalities and high prevalence of sleep disordered breathing, periodic limb movement disorder, nightmares, and insomnia. PTSD treatment methods do appear to significantly improve sleep disturbance, and also studies suggest that treatments for sleep disorders often result in improvements in PTSD symptoms. Further, the most recent evidence suggests sleep abnormalities may precede the development of PTSD. Given the importance of sleep disorders to the onset, course, and treatment of adult PTSD, examination of sleep disturbances far earlier in the life course is imperative. Here we review the literature on what we know about sleep disturbances and disorders in pediatric PTSD. Our review indicates that the extant, empirical data examining sleep disturbance and disorders in pediatric PTSD is limited. Yet, this literature suggests there are significantly higher reports of sleep disturbances and nightmares in children and adolescents exposed to trauma and/or diagnosed with PTSD than in non-trauma-exposed samples. Sleep questionnaires are predominantly employed to assess sleep disorders in pediatric PTSD, with few studies utilizing objective measures. Given the important, complex relationship being uncovered between adult PTSD and sleep, this review calls for further research of sleep in children with PTSD using more specific subjective measures and also objective measures, such as polysomnography and eventually treatment trial studies.

Do sleep problems mediate the relationship between traumatic brain injury and development of mental health symptoms after deployment?

STUDY OBJECTIVES

Military members screening positive for blast-related traumatic brain injury (TBI) may subsequently screen positive for posttraumatic stress disorder (PTSD) or depression. The role of sleep as a mediating factor in the development of mental health symptoms was explored.

DESIGN

Prospective study with symptoms evaluated at two time points.

SETTING

Postdeployment service in Iraq, Afghanistan, or Kuwait during 2008 and 2009.

PARTICIPANTS

There were 29,640 US Navy and Marine Corps men (29,019 who did not screen positive for PTSD at baseline, 27,702 who did not screen positive for depression at baseline, and 27,320 who did not screen positive at baseline for either condition).

MEASUREMENTS AND RESULTS

After controlling for sleep problems, the adjusted odds of receiving a positive PTSD screening at follow-up decreased from 1.61 (95% confidence interval [CI] 1.21-2.14) to 1.32 (95% CI 0.99-1.77) for a subject screening positive for TBI relative to a subject screening negative, suggesting that sleep problems mediated 26% of TBI's effect on development of PTSD. Likewise, after controlling for sleep problems, the adjusted odds of receiving a positive depression screening decreased from 1.41 (95% CI 1.11-1.80) to 1.15 (95% CI 0.90-1.47), suggesting that sleep problems mediated 41% of TBI's effect on development of depression. Results were similar for those with either PTSD or depression (37% mediated).

CONCLUSIONS

These results suggest that sleep problems mediate the effect of a positive TBI screening on the development of mental health disorders, and sleep problems may be an early indicator of risk for PTSD or depression.