Measurement of serum melatonin in intensive care unit patients: changes in traumatic brain injury, trauma, and medical conditions

Sleep Disturbance During Post-Traumatic Amnesia and Early Recovery After Traumatic Brain Injury

After moderate to severe traumatic brain injury (TBI), sleep disturbance commonly emerges during the confused post-traumatic amnesia (PTA) recovery stage. However, the evaluation of early sleep disturbance during PTA, its recovery trajectory, and influencing factors is limited. This study aimed to evaluate sleep outcomes in patients experiencing PTA using ambulatory gold-standard polysomnography (PSG) overnight and salivary endogenous melatonin (a hormone that influences the sleep-wake cycle) assessment at two time-points. The relationships between PSG-derived sleep-wake parameters and PTA symptoms (i.e., agitation and cognitive disturbance) were also evaluated. In a patient subset, PSG was repeated after PTA had resolved to assess the trajectory of sleep disturbance. Participants with PTA were recruited from Epworth HealthCare's inpatient TBI Rehabilitation Unit. Trained nurses administered overnight PSG at the patient bedside using the Compumedics Somté portable PSG device (Compumedics, Ltd., Australia). Two weeks after PTA had resolved, PSG was repeated. On a separate evening, two saliva specimens were collected (at 24:00 and 06:00) for melatonin testing. Results of routine daily hospital measures (i.e., Agitated Behavior Scale and Westmead PTA Scale) were also collected. Twenty-nine patients were monitored with PSG (mean: 41.6 days post-TBI; standard deviation [SD]: 28.3). Patients' mean sleep duration was reduced (5.6 h, SD: 1.2), and was fragmented with frequent awakenings (mean: 27.7, SD: 15.0). Deep, slow-wave restorative sleep was reduced, or completely absent (37.9% of patients). The use of PSG did not appear to exacerbate patient agitation or cognitive disturbance. Mean melatonin levels at both time-points were commonly outside of normal reference ranges. After PTA resolved, patients (n = 11) displayed significantly longer mean sleep time (5.3 h [PTA]; 6.5 h [out of PTA], difference between means: 1.2, p = 0.005). However, disturbances to other sleep-wake parameters (e.g., increased awakenings, wake time, and sleep latency) persisted after PTA resolved. This is the first study to evaluate sleep disturbance in a cohort of patients as they progressed through the early TBI recovery phases. There is a clear need for tailored assessment of sleep disturbance during PTA, which currently does not form part of routine hospital assessment, to suggest new treatment paradigms, enhance patient recovery, and reduce its long-term impacts.

Melatonin secretion and sleep disorders in patients with spinal cord injuries

STUDY DESIGN

Prospective observational study.

OBJECTIVES

To evaluate melatonin secretion, daytime sleepiness and sleep disorders in patients with spinal cord injuries (SCI), and their association with lesion level.

SETTING

Specialized neuro rehabilitation hospital in France METHODS: Prospective observational study of patients aged over 18 hospitalized in for spinal cord injury. Sleep quality was measured with the Pittsburgh Sleep Quality Index (PQSI), daytime sleepiness with the Epworth Sleepiness scale (ESS), and melatonin secretion by 24 h urinary dosage of 6-sulphatoxy-melatonin.

RESULTS

213 patients were screened, 21 patients were included: 17 complete (AIS A) and 4 lesions (AIS B), 76% of traumatic origin with 12 tetraplegic and 9 paraplegic, mean 10 (range 0.5-40) years after injury. Mean age was 46.8 ± 14.7 years, mean BMI 23.56 ± 4.1 and men outnumbered women (15 vs 6). Melatonin secretion was analyzed by 24 h secretion and by secretion profile. Comparing retained vs abolished secretion, only 23% (4/17) of patients with a lesion above T8 retained melatonin secretion, compared to 80% (4/5) with a lesion below T8 (p = 0.022). Non significant differences were found in secretion profile in patients who retained secretion: no patient with a lesion above T8 had a normal secretion profile compared to 50% with a lesion below T8 and in the impact of partial vs total lesions above T8 in whom 17% (2/12) of complete ASIA-A lesions and 50% (2/4) of incomplete lesions retained secretion.

CONCLUSION

Lesions of the spinal cord above T8 are strongly associated with abolition of melatonin secretion.

Effects of early adjunctive pharmacotherapy on serum levels of brain injury biomarkers in patients with traumatic brain injury: a systematic review of randomized controlled studies

Objectives: Traumatic brain injury (TBI) is one of the top causes of morbidity and mortality worldwide. The review aimed to discuss and summarize the current evidence on the effectiveness of adjuvant neuroprotective treatments in terms of their effect on brain injury biomarkers in TBI patients. Methods: To identify relevant studies, four scholarly databases, including PubMed, Cochrane, Scopus, and Google Scholar, were systematically searched using predefined search terms. English-language randomized controlled clinical trials reporting changes in brain injury biomarkers, namely, neuron-specific enolase (NSE), glial fibrillary acid protein (GFAP), ubiquitin carboxyl-terminal esterase L1 (UCHL₁) and/or S100 beta (S100 ß), were included. The methodological quality of the included studies was assessed using the Cochrane risk-of-bias tool. Results: A total of eleven studies with eight different therapeutic options were investigated; of them, tetracyclines, metformin, and memantine were discovered to be promising choices that could improve neurological outcomes in TBI patients. The most utilized serum biomarkers were NSE and S100 ß followed by GFAP, while none of the included studies quantified UCHL₁. The heterogeneity in injury severity categories and measurement timing may affect the overall evaluation of the clinical efficacy of potential therapies. Therefore, unified measurement protocols are highly warranted to inform clinical decisions. Conclusion: Few therapeutic options showed promising results as an adjuvant to standard care in patients with TBI. Several considerations for future work must be directed towards standardizing monitoring biomarkers. Investigating the pharmacotherapy effectiveness using a multimodal biomarker panel is needed. Finally, employing stratified randomization in future clinical trials concerning potential confounders, including age, trauma severity levels, and type, is crucial to inform clinical decisions. Clinical Trial Registration: [https://www.crd.york.ac.uk/prospero/dis], identifier [CRD42022316327].

Traumatic Brain Injury, Sleep, and Melatonin-Intrinsic Changes with Therapeutic Potential

Traumatic brain injury (TBI) is one of the most prevalent causes of morbidity in the United States and is associated with numerous chronic sequelae long after the point of injury. One of the most common long-term complaints in patients with TBI is sleep dysfunction. It is reported that alterations in melatonin follow TBI and may be linked with various sleep and circadian disorders directly (via cellular signaling) or indirectly (via free radicals and inflammatory signaling). Work over the past two decades has contributed to our understanding of the role of melatonin as a sleep regulator and neuroprotective anti-inflammatory agent. Although there is increasing interest in the treatment of insomnia following TBI, a lack of standardization and rigor in melatonin research has left behind a trail of non-generalizable data and ambiguous treatment recommendations. This narrative review describes the underlying biochemical properties of melatonin as they are relevant to TBI. We also discuss potential benefits and a path forward regarding the therapeutic management of TBI with melatonin treatment, including its role as a neuroprotectant, a somnogen, and a modulator of the circadian rhythm.

Sleep outcomes in pediatric mild traumatic brain injury: a systematic review and meta-analysis of prevalence and contributing factors

OBJECTIVE

The aim was to determine the prevalence of disturbed sleep in children who sustained mild traumatic brain injury (mTBI).

METHODS

We conducted electronic searches of three databases MEDLINE, PsychINFO and EMBASE against pre-determined inclusion/exclusion criteria. We used the Newcastle-Ottawa Scale to assess the risk of bias.

RESULTS

Forty-four articles met the inclusion criteria. The risk of bias was mainly rated as moderate to high. Meta-analysis revealed that prevalence of sleep disturbances decreased as the time since injury increased: 51%, 40% and 9% within 1 week, between 1 week and 1 month, and between 1 and 3 months, respectively, but increased to 21% after 3 months. The sleep symptom drowsiness followed a similar temporal pattern. Other sleep symptoms of hypersomnia (sleeping more than usual) and insomnia (trouble falling asleep and sleeping less than usual) remained stable over time. The prevalence of sleep disturbances in children with mTBI was higher than in the general population. Pre-injury sleep and older age at injury were related to worse sleep outcomes.

CONCLUSIONS

Sleep disturbances are highly prevalent in the acute phase post-mTBI. Given that disturbed sleep can impact daily functioning and recovery, routine screening and management of sleep disturbances in children who sustain mTBI is important.

Melatonin and the Brain–Heart Crosstalk in Neurocritically Ill Patients—From Molecular Action to Clinical Practice

Brain injury, especially traumatic brain injury (TBI), may induce severe dysfunction of extracerebral organs. Cardiac dysfunction associated with TBI is common and well known as the brain–heart crosstalk, which broadly refers to different cardiac disorders such as cardiac arrhythmias, ischemia, hemodynamic insufficiency, and sudden cardiac death, which corresponds to acute disorders of brain function. TBI-related cardiac dysfunction can both worsen the brain damage and increase the risk of death. TBI-related cardiac disorders have been mainly treated symptomatically. However, the analysis of pathomechanisms of TBI-related cardiac dysfunction has highlighted an important role of melatonin in the prevention and treatment of such disorders. Melatonin is a neurohormone released by the pineal gland. It plays a crucial role in the coordination of the circadian rhythm. Additionally, melatonin possesses strong anti-inflammatory, antioxidative, and antiapoptotic properties and can modulate sympathetic and parasympathetic activities. Melatonin has a protective effect not only on the brain, by attenuating its injury, but on extracranial organs, including the heart. The aim of this study was to analyze the molecular activity of melatonin in terms of TBI-related cardiac disorders. Our article describes the benefits resulting from using melatonin as an adjuvant in protection and treatment of brain injury-induced cardiac dysfunction.

Melatonin intervention to prevent delirium in hospitalized patients: A meta-analysis

BACKGROUND

Evaluation of the effectiveness of melatonin is necessary to prevent the development of delirium in hospitalized patients. Melatonin (N-acetyl-5-methoxytryptamine) is a hormone produced by the pineal gland of the brain from the amino acid tryptophan. Synthetic melatonin supplements have been used for various medical conditions, especially sleep-related diseases, and have proved to be successful.

AIM

To determine the effect of melatonin on the prevention of delirium in hospitalized patients.

METHODS

A literature search of the CNKI, Wanfang Database, VIP Database, China Biomedical Literature Database, PubMed, Embase, Cochrane Library, Web of Science, and other databases was conducted. The CNKI, Wanfang Database, VIP Database (VIP), and China Biomedical Literature Database were searched for Chinese studies, and PubMed, Embase, Cochrane Library, Web of Science and other databases were searched for international studies. It will be established in June 2021 in a randomized controlled trial (RCT) whether melatonin treatment for 6 mo prevents delirium in hospitalized patients. Literature screening, quality review, and data extraction were carried out using the Cochrane Manual 5.1.0 systematic evaluation method, and Stata 15.0 software and Review Manager 5.3 were used for meta-analysis and processing.

RESULTS

A total of 18 new RCT articles and 18 experimental subjects were identified. The results of the meta-analysis showed that following the occurrence of delirium, melatonin reduced the incidence of delirium in patients (RR = 0.69, 95%CI: 0.60-0.80), which is of significance, but heterogeneity was significant I² = 62%. Subgroup analysis was performed to examine the source of heterogeneity, and it was found that different patient types were the source of heterogeneity; the research on subgroup analysis was of high quality and homogeneous. To determine the reliability and robustness of the research results, a sensitivity analysis was carried out. The results showed that after excluding individual studies one by one, the effect size was still within 95%CI, which strengthened the reliability of the original meta-analysis results. Melatonin has a significant preventive effect on delirium in hospitalized medical patients [RR = 0.60, 95%CI: 0.47-0.76), P < 0.001].

CONCLUSION

Melatonin can reduce the rate of delirium in medical patients, and the role of melatonin in reducing the incidence of delirium in surgical patients and critical care unit patients requires further study.

Salivary Biomarkers as Indicators of TBI Diagnosis and Prognosis: A Systematic Review

BACKGROUND AND OBJECTIVE

Traumatic brain injuries are physical injuries to the head that result in disruptions to normal brain function. Diagnostic tools such as computed tomography scans have commonly been used to detect traumatic brain injuries but are costly and not ubiquitously available. Recent research on diagnostic alternatives has focused on using salivary biomarkers, but there is no consensus on the utility of these methods.  The objective of this manuscript is to address the gap in the literature pertaining to the effectiveness of salivary biomarkers for TBI diagnosis and prognosis.

METHODS

A systematic review was conducted between November 2020 and October 2021 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases were searched using the terms "traumatic brain injury," "TBI," "saliva," and "biomarkers." Literature published prior to 2010 was excluded, and two authors reviewed each full-text article to ensure its relevance.

RESULTS

A total of 18 articles were included in this review, with nine articles on salivary microRNA, three on salivary hormones, three on salivary extracellular vesicles, and three on salivary proteins.

CONCLUSIONS

Studies reported changes in salivary biomarkers after traumatic brain injuries and indicated a possible link between salivary biomarker expression and traumatic brain injury severity. However, it is unclear the degree to which salivary biomarkers accurately predict traumatic brain injury diagnosis and prognosis; some studies reported significant associations while others reported weaker associations. More research into the robustness of salivary biomarkers is needed to fully elucidate their utility for the traumatic brain injury population.

Hippocampal Astrocyte Response to Melatonin Following Neural Damage Induction in Rats

Introduction:

Brain injury induces an almost immediate response from glial cells, especially astrocytes. Activation of astrocytes leads to the production of inflammatory cytokines and reactive oxygen species that may result in secondary neuronal damage. Melatonin is an anti-inflammatory and antioxidant agent, and it has been reported to exert neuroprotection through the prevention of neuronal death in several models of central nervous system injury. This study aimed to investigate the effect of melatonin on astrocyte activation induced by Traumatic Brain Injury (TBI) in rat hippocampus and dentate gyrus.

Methods:

Animals were randomly divided into 5 groups; Sham group, TBI group, vehicle group, and melatonin-treated TBI groups (TBI+Mel5, TBI+Mel20). Immunohistochemical method (GFAP marker) and TUNEL assay were used to evaluate astrocyte reactivity and neuronal death, respectively.

Results:

The results demonstrated that the astrocyte number was reduced significantly in melatonin-treated groups compared to the vehicle group. Additionally, based on TUNEL results, melatonin administration noticeably reduced the number of apoptotic neurons in the rat hippocampus and dentate gyrus.

Conclusion:

In general, our findings suggest that melatonin treatment after brain injury reduces astrocyte reactivity as well as neuronal cell apoptosis in rat hippocampus and dentate gyrus.

Melatonin as a Potential Regulator of Oxidative Stress, and Neuroinflammation: Mechanisms and Implications for the Management of Brain Injury-Induced Neurodegeneration

This review covers the preclinical and clinical literature supporting the role of melatonin in the management of brain injury-induced oxidative stress, neuroinflammation, and neurodegeneration, and reviews the past and current therapeutic strategies. Traumatic brain injury (TBI) is a neurodegenerative condition, unpredictably and potentially progressing into chronic neurodegeneration, with permanent cognitive, neurologic, and motor dysfunction, having no standard therapies. Due to its complex and multi-faceted nature, the TBI has highly heterogeneous pathophysiology, characterized by the highest mortality and disability worldwide. Mounting evidence suggests that the TBI induces oxidative and nitrosative stress, which is involved in the progression of chronic and acute neurodegenerative diseases. Defenses against such conditions are mostly dependent on the usage of antioxidant compounds, the majority of whom are ingested as nutraceuticals or as dietary supplements. A large amount of literature is available regarding the efficacy of antioxidant compounds to counteract the TBI-associated damage in animal and cellular models of the TBI and several clinical studies. Collectively, the studies have suggested that TBI induces oxidative stress, by suppressing the endogenous antioxidant system, such as nuclear factor erythroid 2–related factor-2 (Nrf-2) increasing the lipid peroxidation and elevation of oxidative damage. Moreover, elevated oxidative stress may induce neuroinflammation by activating the microglial cells, releasing and activating the inflammatory cytokines and inflammatory mediators, and energy dyshomeostasis. Thus, melatonin has shown regulatory effects against the TBI-induced autophagic dysfunction, regulation of mitogen-activated protein kinases, such as ERK, activation of the NLRP-3 inflammasome, and release of the inflammatory cytokines. The collective findings strongly suggest that melatonin may regulate TBI-induced neurodegeneration, although further studies should be conducted to better facilitate future therapeutic windows.

Serum melatonin levels in predicting mortality in patients with severe traumatic brain injury

PURPOSE

A secondary brain injury could appear after traumatic brain injury (TBI) due to neuroinflammation, oxidation and apoptosis. Higher levels of serum melatonin have been found on admission for TBI in non-surviving than in surviving patients. Thus, the objective of this study was to know serum melatonin levels during the first week of TBI in surviving and non-surviving patients, and to know if serum melatonin levels during the first week of TBI can be used to predict mortality.

METHODS

Patients with an isolated and severe TBI were included; that is, if they scored < 10 points in non-cranial aspects of Injury Severity Score and < 9 points in the Glasgow Coma Scale. We measured serum melatonin concentrations at days 1, 4 and 8 of TBI. Thirty-day mortality was the end-point study.

RESULTS

Lower serum melatonin levels were found in the surviving patients (n = 90) than in the non-survivors (n = 34) on days 1 (p < 0.001), 4 (p < 0.001), and 8 (p = 0.02) of TBI. Serum melatonin concentrations on days 1, 4, and 8 of TBI had an area under curve (95% Confidence Interval) for the prediction of 30-day mortality of 0.85 (0.77-0.91; p < 0.001), 0.82 (0.74-0.89; p < 0.001) and 0.71 (0.61-0.79; p = 0.06) respectively.

CONCLUSIONS

The new findings of this study were the presence of higher levels of serum melatonin on days 1, 4 and 8 of TBI in non-survivors than in survivors, and the ability to predict 30-day mortality for serum melatonin levels measured at these time points. However, more research is necessary to confirm our results.

Development and Implementation of a Multicomponent Protocol to Promote Sleep and Reduce Delirium in a Medical Intensive Care Unit

BACKGROUND

Evidence suggests that poor sleep increases risk of delirium. Because delirium is associated with poor outcomes, institutions have developed protocols to improve sleep in critically ill patients.

OBJECTIVE

To assess the impact of implementing a multicomponent sleep protocol.

METHODS

In this prospective, preimplementation and postimplementation evaluation, adult patients admitted to the medical intensive care unit (ICU) over 42 days were included. Outcomes evaluated included median delirium-free days, median Richards-Campbell Sleep Questionnaire (RCSQ) score, median optimal sleep nights, duration of mechanical ventilation (MV), ICU and hospital length of stay (LOS), and in-hospital mortality.

RESULTS

The preimplementation group included 78 patients and postimplementation group, 84 patients. There was no difference in median delirium-free days (1 day [interquartile range, IQR, = 0-2.5] vs 1 day [IQR = 0-2]; P = 0.48), median RCSQ score (59.4 [IQR = 43.2-71.6] vs 61.2 [IQR = 49.9-75.5]; P = 0.20), median optimal sleep nights (1 night [IQR = 0-2] vs 1 night [IQR = 0-2]; P = 0.95), and in-hospital mortality (16.7% vs 17.9%, P = 1.00). Duration of MV (8 days [IQR = 4-10] vs 4 days [IQR = 2-7]; P = 0.03) and hospital LOS (13 days [IQR = 7-22.3] vs 8 days [IQR = 6-17]; P = 0.05) were shorter in the postimplementation group, but both were similar between groups after adjusting for age and severity of illness.

CONCLUSIONS AND RELEVANCE

This report demonstrates that implementation of a multicomponent sleep protocol in everyday ICU care is feasible, but limitations exist when evaluating impact on measurable outcomes. Additional evaluations are needed to identify the most meaningful interventions and best practices for quantifying impact on patient outcomes.

Assessing Sleep Architecture With Polysomnography During Posttraumatic Amnesia After Traumatic Brain Injury: A Pilot Study

BACKGROUND

Early-onset sleep disturbance is common following moderate to severe traumatic brain injury (TBI) and often emerges while patients are in posttraumatic amnesia (PTA). However, sleep disruptions during this subacute recovery phase are not well-defined, and research often utilizes indirect measures (actigraphy) that quantify sleep based on activity. This study aims to examine sleep macro-architecture and sleep quality directly with ambulatory polysomnography (PSG) and measure endogenous salivary melatonin levels for patients experiencing PTA following moderate to severe TBI.

METHOD

Participants were recruited from an inpatient TBI rehabilitation unit. Nighttime PSG was administered at the patient's bedside. Two saliva specimens were collected for melatonin testing on a separate evening (24:00 and 06:00 hours) using melatonin hormone profile test kits.

RESULTS

Of 27 patients in whom PSG was recorded, the minimum required monitoring time occurred in n =17 (adherence: 63%) at a median of 37.0 days (quartile 1 [Q1] to quartile 3 [Q3]: 21.5-50.5) postinjury. Median non-rapid eye movement (NREM) and REM sleep proportions were similar to normal estimates. Slow-wave sleep was reduced and absent in 35.3% of patients. Sleep periods appeared fragmented, and median sleep efficiency was reduced (63.4%; Q1-Q3: 55.1-69.2). Median melatonin levels at both timepoints were outside the normal range of values specified for this test (from Australian Clinical Labs).

CONCLUSION

This study reports that ambulatory PSG and salivary melatonin assessment are feasible for patients experiencing PTA and offers new insight into the extent of sleep disturbance. Further research is necessary to understand associations between PTA and sleep disturbance.

Measuring serum melatonin concentrations to predict clinical outcome after aneurysmal subarachnoid hemorrhage

BACKGROUND

Oxidative stress has a key role in brain injury and melatonin possesses antioxidant effects. We aimed to ascertain the potential relationship between serum melatonin concentrations and functional outcome following aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

This prospective and observational study was conducted of 169 aSAH patients. Baseline serum melatonin concentrations were determined. A worse 6-month functional outcome was defined as a Glasgow Outcome Scale score of 1-3.

RESULTS

Patients with a worse outcome (56 cases) compared to those with a good outcome (113 cases) exhibited significantly higher concentrations of serum melatonin (P < 0.001). An area under the receiver operating curve of 0.819 was revealed for the prediction of 6-month worse outcome by serum melatonin concentrations. Multiple logistic regression analysis showed an independent association of serum melatonin concentrations with 6-month worse outcome (odds ratio = 1.204). An intimate correlation existed between serum melatonin concentrations and World Federation of Neurological Surgeons subarachnoid hemorrhage scale scores as well as between serum melatonin concentrations and modified Fisher scores (P < 0.001).

CONCLUSIONS

Patients with higher serum melatonin concentrations are more likely to have a poor prognosis. Serum melatonin can be considered as an independent predictor of functional outcome after aSAH.

Melatonin to prevent delirium in patients with advanced cancer: a double blind, parallel, randomized, controlled, feasibility trial

BACKGROUND

Delirium is highly problematic in palliative care (PC). Preliminary data indicate a potential role for melatonin to prevent delirium, but no randomized controlled trials (RCTs) are reported in PC.

METHODS

Patients aged ≥18 years, with advanced cancer, admitted to an inpatient Palliative Care Unit (PCU), having a Palliative Performance Scale rating ≥ 30%, and for whom consent was obtained, were included in the study. Patients with delirium on admission were excluded. The main study objectives were to assess the feasibility issues of conducting a double-blind RCT of exogenous melatonin to prevent delirium in PC: recruitment, retention, procedural acceptability, appropriateness of outcome measures, and preliminary efficacy and safety data. Study participants were randomized in a double-blind, parallel designed study to receive daily melatonin 3 mg or placebo orally at 21:00 over 28 days or less if incident delirium, death, discharge or withdrawal occurred earlier. Delirium was diagnosed using the Confusion Assessment Method. Efficacy endpoints in the melatonin and placebo groups were compared using time-to-event analysis: days from study entry to onset of incident delirium.

RESULTS

Over 16 months, 60/616 (9.7%; 95% CI: 7.5-12.4%) screened subjects were enrolled. The respective melatonin (n = 30) vs placebo (n = 30) outcomes were: incident delirium in 11/30 (36.7%; 95%CI: 19.9-56.1%) vs 10/30 (33%; 95% CI: 17.3-52.8%); early discharge (6 vs 5); withdrawal (6 vs 3); death (0 vs 1); and 7 (23%) vs 11 (37%) reached the 28-day end point. The 25th percentile time-to-event were 9 and 18 days (log rank, χ² = 0.62, p = 0.43) in melatonin and placebo groups, respectively. No serious trial medication-related adverse effects occurred and the core study procedures were acceptable. Compared to those who remained delirium-free during their study participation, those who developed delirium (n = 21) had poorer functional (p = 0.036) and cognitive performance (p = 0.013), and in particular, poorer attentional capacity (p = 0.003) at study entry.

CONCLUSIONS

A larger double-blind RCT is feasible, but both subject accrual and withdrawal rates signal a need for multisite collaboration. The apparent trend for shorter time to incident delirium in the melatonin group bodes for careful monitoring in a larger trial.

TRIAL REGISTRATION

Registered on July 21st 2014 with ClinicalTrials.gov : NCT02200172 .

Systematic review of melatonin levels in individuals with complete cervical spinal cord injury

Context: Pineal melatonin production is mediated by afferent signaling pathways that navigate through the cervicothoracic spinal cord. Melatonin profiles in individuals with complete cervical spinal cord injury (SCI) have not been systematically reviewed despite this proposed pathway. Objectives: The primary objective was to understand melatonin profiles in individuals with complete cervical SCI, as compared to healthy controls and those with thoracolumbar and incomplete cervical SCI. Secondary objectives were to understand the impact of injury chronicity and melatonin supplementation on melatonin values in adults with complete cervical SCI. Methods: This review (PROSPERO ID: CRD42017073767) searched several databases and gray literature sources from January 1978 to August 2017. Studies were eligible if they evaluated melatonin levels (blood, saliva or urinary metabolite measurements) in adults with complete cervical SCI. 390 studies were screened and 12 studies met final selection criteria. Given the heterogeneity in study designs, a narrative analysis was performed. Results: There is evidence that adults with complete cervical SCI have absent diurnal melatonin rhythms as compared to healthy controls and individuals with thoracolumbar SCI below T3. There is limited evidence comparing levels in individuals with incomplete tetraplegia. There is insufficient evidence describing profiles immediately (<2 weeks) after cervical SCI. Based on a limited number of studies, melatonin supplementation does not appear to improve sleep outcomes in adults with long-standing complete cervical SCI. Conclusions: Future research should explore melatonin levels acutely after cervical SCI and the impact of supplementation on non-sleep outcomes.

Sleep-wake disturbances in hospitalized patients with traumatic brain injury: association with brain trauma but not with an abnormal melatonin circadian rhythm

STUDY OBJECTIVES

To test whether the sleep-wake cycle disruption in patients hospitalized with traumatic brain injury (TBI) (1) is also found in patients with traumatic injuries other than TBI (non-TBI) and (2) is associated with a weaker or abnormal circadian clock signal.

METHODS

Forty-two non-mechanically ventilated and non-sedated patients hospitalized for moderate-to-severe TBI were compared to 34 non-TBI patients. They wore wrist actigraphs for 9.4 ± 4.2 days, starting 19.3 ± 12.6 days post-injury. Of these, 17 TBI and 14 non-TBI patients had their urine collected every hour for 25 hours, starting 18.3 ± 12.3 days post-injury. We calculated urinary 6-sulfatoxymelatonin concentration to obtain total 24-hour excretion, excretion onset, offset, duration, amplitude, and acrophase. Using Student's t-tests, we compared groups on actigraphy (daytime activity ratio, nighttime total sleep time, and fragmentation index) and melatonin variables. We investigated associations between melatonin and actigraphy variables using Pearson's correlations.

RESULTS

TBI patients had poorer daytime activity ratio (TBI: 77.5 ± 9.4%; non-TBI: 84.6 ± 6.9%), shorter nighttime total sleep time (TBI: 353.5 ± 96.6 min; non-TBI: 421.2 ± 72.2 min), and higher fragmentation index (TBI: 72.2 ± 30.0; non-TBI: 53.5 ± 23.6) (all p-values < 0.01). A melatonin rhythm was present in both groups, and no group differences were found on melatonin variables. No associations were found between melatonin and actigraphy variables in TBI patients.

CONCLUSION

Moderate-to-severe TBI patients have more serious sleep-wake disturbances than non-TBI patients hospitalized in the same environment, suggesting that the brain injury itself alters the sleep-wake cycle. Despite their deregulated 24-hour sleep-wake cycle, TBI patients have a normal circadian clock signal.

The Serum Melatonin Levels and Mortality of Patients with Spontaneous Intracerebral Hemorrhage

Objective: Providing melatonin in animal models with spontaneous intracerebral hemorrhage (SIH) has been associated with beneficial effects. However, to our knowledge, there are no published data on circulating melatonin levels regarding the prognosis of SIH patients. Therefore, the objectives of this study were to determine whether serum melatonin levels in SIH patients were associated with early mortality and whether they could be used as prognostic biomarkers. Methods: This observational and prospective study included patients with supratentorial and clinically severe SIH (defined as Glasgow Coma Scale GCS <9) admitted to the Intensive Care Units of six Spanish hospitals. Serum melatonin levels were determined at the time of severe SIH diagnosis. Mortality at 30 days was the study end-point. Results: Non-surviving patients (n = 46) showed higher serum melatonin levels (p < 0.001) than surviving (n = 54) patients. An area under the curve was found for the prediction of 30-day mortality by serum melatonin levels of 0.89 (95% CI = 0.81-0.94; p < 0.001). Multiple logistic regression analysis showed an association of serum melatonin levels with 30-day mortality (Odds Ratio = 8.16; 95% CI = 2.30-28.95; p = 0.001) after controlling for midline shift, glycemia, early evacuation of SIH, and Intracerebral hemorrhage(ICH) score. Conclusions: The novel findings by our study were the presence of higher serum melatonin levels in non-surviving patients than in surviving patients and the association of these levels with mortality.

Sleep and Circadian Rhythm in Critical Illness

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2019. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2019 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .

Potential for the development of light therapies in mild traumatic brain injury

Light affects almost all aspects of human physiological functioning, including circadian rhythms, sleep-wake regulation, alertness, cognition and mood. We review the existing relevant literature on the effects of various wavelengths of light on these major domains, particularly as they pertain to recovery from mild traumatic brain injuries. Evidence suggests that light, particularly in the blue wavelengths, has powerful alerting, cognitive and circadian phase shifting properties that could be useful for treatment. Other wavelengths, such as red and green may also have important effects that, if targeted appropriately, might also be useful for facilitating recovery. Despite the known effects of light, more research is needed. We recommend a personalized medicine approach to the use of light therapy as an adjunctive treatment for patients recovering from mild traumatic brain injury.

Traumatic Injury Leads to Inflammation and Altered Tryptophan Metabolism in the Juvenile Rabbit Brain

Neuroinflammation after traumatic brain injury (TBI) contributes to widespread cell death and tissue loss. Here, we evaluated sequential inflammatory response in the brain, as well as inflammation-induced changes in brain tryptophan metabolism over time, in a rabbit pediatric TBI model. On post-natal days 5-7 (P5-P7), New Zealand white rabbit littermates were randomized into three groups: naïve (no injury), sham (craniotomy alone), and TBI (controlled cortical impact). Animals were sacrificed at 6 h and 1, 3, 7, and 21 days post-injury for evaluating levels of pro- and anti-inflammatory cytokines, as well as the major components in the tryptophan-kynurenine pathway. We found that 1) pro- and anti-inflammatory cytokine levels in the brain injury area were differentially regulated in a time-dependent manner post-injury; 2) indoleamine 2,3 dioxygeenase 1 (IDO1) was upregulated around the injury area in TBI kits that persisted at 21 days post-injury; 3) mean length of serotonin-staining fibers was significantly reduced in the injured brain region in TBI kits for at least 21 days post-injury; and 4) kynurenine level significantly increased at 7 days post-injury. A significant decrease in serotonin/tryptophan ratio and melatonin/tryptophan ratio at 21 days post-injury was noted, suggesting that tryptophan metabolism is altered after TBI. A better understanding of the temporal evolution of immune responses and tryptophan metabolism during injury and repair after TBI is crucial for the development of novel therapeutic strategies targeting these pathways.

Diagnostic and Treatment Challenges of Sighted Non-24-Hour Sleep-Wake Disorder

STUDY OBJECTIVES

To report the diagnostic and treatment challenges of sighted non-24-hour sleep-wake disorder (N24SWD).

METHODS

We report a series of seven sighted patients with N24SWD clinically evaluated by history and sleep diaries, and when available wrist actigraphy and salivary melatonin levels, and treated with timed melatonin and bright light therapy.

RESULTS

Most patients had a history of a delayed sleep-wake pattern prior to developing N24SWD. The typical sleep-wake pattern of N24SWD was seen in the sleep diaries (and in actigraphy when available) in all patients with a daily delay in midpoint of sleep ranging 0.8 to 1.8 hours. Salivary dim light melatonin onset (DLMO) was evaluated in four patients but was missed in one. The estimated phase angle from DLMO to sleep onset ranged from 5.25 to 9 hours. All six patients who attempted timed melatonin and bright light therapy were able to entrain their sleep-wake schedules. Entrainment occurred at a late circadian phase, possibly related to the late timing of melatonin administration, though the patients often preferred late sleep times. Most did not continue treatment and continued to have a non-24-hour sleep-wake pattern.

CONCLUSIONS

N24SWD is a chronic debilitating disorder that is often overlooked in sighted people and can be challenging to diagnose and treat. Tools to assess circadian pattern and timing can be effectively applied to aid the diagnosis. The progressive delay of the circadian rhythm poses a challenge for determining the most effective timing for melatonin and bright light therapies. Furthermore, once the circadian sleep-wake rhythm is entrained, long-term effectiveness is limited because of the behavioral and environmental structure that is required to maintain stable entrainment.

Notch signaling inhibitor DAPT provides protection against acute craniocerebral injury

Notch signaling pathway is involved in many physiological and pathological processes. The γ-secretase inhibitor DAPT inhibits Notch signaling pathway and promotes nerve regeneration after cerebral ischemia. However, neuroprotective effects of DAPT against acute craniocerebral injury remain unclear. In this study, we established rat model of acute craniocerebral injury, and found that with the increase of damage grade, the expression of Notch and downstream protein Hes1 and Hes5 expression gradually increased. After the administration of DAPT, the expression of Notch, Hes1 and Hes5 was inhibited, apoptosis and oxidative stress decreased, neurological function and cognitive function improved. These results suggest that Notch signaling can be used as an indicator to assess the severity of post-traumatic brain injury. Notch inhibitor DAPT can reduce oxidative stress and apoptosis after acute craniocerebral injury, and is a potential drug for the treatment of acute craniocerebral injury.

Supplements, nutrition, and alternative therapies for the treatment of traumatic brain injury

Studies using traditional treatment strategies for mild traumatic brain injury (TBI) have produced limited clinical success. Interest in treatment for mild TBI is at an all time high due to its association with the development of chronic traumatic encephalopathy and other neurodegenerative diseases, yet therapeutic options remain limited. Traditional pharmaceutical interventions have failed to transition to the clinic for the treatment of mild TBI. As such, many pre-clinical studies are now implementing non-pharmaceutical therapies for TBI. These studies have demonstrated promise, particularly those that modulate secondary injury cascades activated after injury. Because no TBI therapy has been discovered for mild injury, researchers now look to pharmaceutical supplementation in an attempt to foster success in human clinical trials. Non-traditional therapies, such as acupuncture and even music therapy are being considered to combat the neuropsychiatric symptoms of TBI. In this review, we highlight alternative approaches that have been studied in clinical and pre-clinical studies of TBI, and other related forms of neural injury. The purpose of this review is to stimulate further investigation into novel and innovative approaches that can be used to treat the mechanisms and symptoms of mild TBI.

Biomarkers Associated with the Outcome of Traumatic Brain Injury Patients

This review focuses on biomarkers associated with the outcome of traumatic brain injury (TBI) patients, such as caspase-3; total antioxidant capacity; melatonin; S100B protein; glial fibrillary acidic protein (GFAP); glutamate; lactate; brain-derived neurotrophic factor (BDNF); substance P; neuron-specific enolase (NSE); ubiquitin carboxy-terminal hydrolase L-1 (UCH-L1); tau; decanoic acid; and octanoic acid.

Serum melatonin levels in survivor and non-survivor patients with traumatic brain injury

Background

Circulating levels of melatonin in patients with traumatic brain injury (TBI) have been determined in a little number of studies with small sample size (highest sample size of 37 patients) and only were reported the comparison of serum melatonin levels between TBI patients and healthy controls. As to we know, the possible association between circulating levels of melatonin levels and mortality of patients with TBI have not been explored; thus, the objective of our current study was to determine whether this association actually exists.

Methods

This multicenter study included 118 severe TBI (Glasgow Coma Scale <9) patients. We measured serum levels of melatonin, malondialdehyde (to assess lipid peroxidation) and total antioxidant capacity (TAC) at day 1 of severe TBI. We used mortality at 30 days as endpoint.

Results

We found that non-survivor (n = 33) compared to survivor (n = 85) TBI patients showed higher circulating levels of melatonin (p < 0.001), TAC (p < 0.001) and MDA (p < 0.001). We found that serum melatonin levels predicted 30-day mortality (Odds ratio = 1.334; 95% confidence interval = 1.094–1.627; p = 0.004), after to control for GCS, CT findings and age. We found a correlation between serum levels of melatonin levels and serum levels of TAC (rho = 0.37; p < 0.001) and serum levels of MDA (rho = 0.24; p = 0.008).

Conclusions

As to we know, our study is the largest series providing circulating melatonin levels in patients with severe TBI. The main findings were that non-survivors had higher serum melatonin levels than survivors, and the association between serum levels of melatonin levels and mortality, peroxidation state and antioxidant state.

Melatonin Secretion Is Increased in Children with Severe Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) is a leading cause of death and disability in children. Oxidative stress plays a significant role in brain damage and melatonin exhibits both direct and indirect antioxidant effects. The primary aim of the present study was to evaluate serum melatonin levels in children with severe TBI in comparison to critically ill children admitted to the Pediatric Intensive Care Unit for conditions other than TBI.

METHODS

Twenty-four children were evaluated, equally divided into severe TBI and no-TBI. Blood samples for serum melatonin analysis were collected at 22:00, 01:00, 03:00, 05:00, 08:00, and 12:00.

RESULTS

Mean serum melatonin peaks in children of the TBI group were higher compared to the values of no-TBI critically ill children (495 ± 102 vs. 294 ± 119 pg/mL, p = 0.0002). Furthermore, the difference was even more significant in comparison to values reported in literature for healthy age-matched children (495 ± 102 vs. 197 ± 71 pg/mL, p < 0.0001).

CONCLUSION

This study has shown that endogenous serum melatonin levels dramatically increase in children after severe TBI. This elevation is likely to represent a response to oxidative stress and/or inflammation due to severe head injury.

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.

Traumatic Brain Injury and Behavior: A Practical Approach

Traumatic brain injury (TBI) is a complex neurologic and neuropathologic process that may affect the patient's behavior permanently. Clinically, TBI is associated with a wide gamut of neurologic and psychiatric disorders, such as amnesia, cognitive decline, seizures, attention and concentration deficits, depression, manic behavior, psychosis, hostile and violent behavior, and personality alterations. Therapy and rehabilitative efforts should be designed based on the type of injury and the patient's specific needs. Gaining familiarity with the behavioral disorders outlined in this article and understanding how to identify and treat them plays a significant role in the management of patients with TBI.

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.

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.

The role of biomarkers and MEG-based imaging markers in the diagnosis of post-traumatic stress disorder and blast-induced mild traumatic brain injury

BACKGROUND

Pervasive use of improvised explosive devices (IEDs), rocket-propelled grenades, and land mines in the recent conflicts in Iraq and Afghanistan has brought traumatic brain injury (TBI) and its impact on health outcomes into public awareness. Blast injuries have been deemed signature wounds of these wars. War-related TBI is not new, having become prevalent during WWI and remaining medically relevant in WWII and beyond. Medicine's past attempts to accurately diagnose and disentangle the pathophysiology of war-related TBI parallels current lines of inquiry and highlights limitations in methodology and attribution of symptom etiology, be it organic, psychological, or behavioral. New approaches and biomarkers are needed.

PRECLINICAL

Serological biomarkers and biomarkers of injury obtained with imaging techniques represent cornerstones in the translation between experimental data and clinical observations. Experimental models for blast related TBI and PTSD can generate critical data on injury threshold, for example for white matter injury from acceleration. Carefully verified and validated models can be evaluated with gene expression arrays and proteomics to identify new candidates for serological biomarkers. Such models can also be analyzed with diffusion MRI and microscopy in order to identify criteria for detection of diffuse white matter injuries, such as DAI (diffuse axonal injury). The experimental models can also be analyzed with focus on injury outcome in brain stem regions, such as locus coeruleus or nucleus raphe magnus that can be involved in response to anxiety changes.

CLINICAL

Mild (and some moderate) TBI can be difficult to diagnose because the injuries are often not detectable on conventional MRI or CT. There is accumulating evidence that injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (ALFMA, peaked at 1-4Hz) that can be measured and localized by magnetoencephalography (MEG). MEG imaging detects TBI abnormalities at the rates of 87% for the mild TBI, group (blast-induced plus non-blast causes) and 100% for the moderate group. Among the mild TBI patients, the rates of abnormalities are 96% and 77% for the blast and non-blast TBI groups, respectively. There is emerging evidence based on fMRI and MEG studies showing hyper-activity in the amygdala and hypo-activity in pre-frontal cortex in individuals with PTSD. MEG signal may serve as a sensitive imaging marker for mTBI, distinguishable from abnormalities generated in association with PTSD. More work is needed to fully describe physiological mechanisms of post-concussive symptoms.

Sleep in the intensive care unit

Poor sleep quality is a consistently reported by patients in the ICU. In such a potentially hostile environment, sleep is extremely fragmented and sleep architecture is unconventional, with a predominance of superficial sleep stages and a limited amount of time spent in the restorative stages. Among the causes of sleep disruption in the ICU are factors intrinsic to the patients and the acute nature of their condition, as well as factors related to the ICU environment and the treatments administered, such as mechanical ventilation and drug therapy. Although the consequences of poor sleep quality for the recovery of ICU patients remain unknown, it seems to influence the immune, metabolic, cardiovascular, respiratory, and neurological systems. There is evidence that multifaceted interventions focused on minimizing nocturnal sleep disruptions improve sleep quality in ICU patients. In this article, we review the literature regarding normal sleep and sleep in the ICU. We also analyze sleep assessment methods; the causes of poor sleep quality and its potential implications for the recovery process of critically ill patients; and strategies for sleep promotion.

Melatonin protects the brain from apoptosis by enhancement of autophagy after traumatic brain injury in mice

Melatonin has been proven to possess neuroprotection property against various neurological diseases by decreasing cerebral oxidative stress and inhibiting inflammatory process. However, whether administration of melatonin influences the autophagy pathway, which has recently been reported playing a pivotal role in traumatic brain injury, is yet not fully understood. We supposed that treatment of melatonin enhances the autophagy pathway after traumatic brain injury (TBI) in mice and subsequently inhibited the mitochondrion apoptotic pathway. Firstly, we investigated the neurological severity score, brain water content and neuronal apoptosis in mice cortex to demonstrate the neuroprotection of melatonin. Then we determined the autophagy markers, namely Beclin1 and LC3-II, using western blot and immunofluorescence. Next, we evaluated the mitochondrial apoptotic pathway in the presence or absence of melatonin. More significantly, we employed 3-methyladenine (3-MA) to inhibit the autophagy pathway, to further confirm our hypothesis. The results showed that melatonin significantly ameliorated secondary brain injury induced by TBI. In addition, melatonin enhanced autophagy after TBI, which was accompanied by a decrease in both the translocation of Bax to mitochondria and the release of cytochrome C to cytoplasm. Furthermore, simultaneous treatment of 3-MA reversed the beneficial effects of melatonin on mitochondrial apoptotic pathway. Taken together, we conclude that melatonin enhances autophagy, which inhibits mitochondrial apoptotic pathway, thus protecting mice from secondary brain injury after TBI.

Melatonin treatment reduces astrogliosis and apoptosis in rats with traumatic brain injury

OBJECTIVES

Melatonin is known as an anti-inflammatory agent, and it has been proven to exert neuroprotection through inhibition of cell death (apoptosis) in several models of brain injury. Secondary injury following the primary traumatic brain injury (TBI) results in glial cells activation, especially astrocytes. In fact, astrocyte activation causes the production of pro-inflammatory cytokines that may lead to secondary injury. Since most TBI research studies have focused on injured neurons and paid little attention to glial cells, the aim of current study was to investigate the effects of melatonin against astrocytes activation (astrogliosis), as well as inhibition of apoptosis in brain tissue of male rats after TBI.

MATERIALS AND METHODS

The animals were randomly allocated into five groups: sham group, TBI+ vehicle group (1% ethanol in saline) and TBI+ melatonin groups (5 mg/kg, 10 mg/kg and 20 mg/kg). All rats were intubated and then exposed to diffuse TBI, except for the sham group. Immunohistochemical methods were conducted using glial fibrillary acidic protein (GFAP) marker and TUNEL assay to evaluate astrocyte reactivity and cell death, respectively.

RESULTS

The results showed that based on the number of GFAP positive astrocytes in brain cortex, astrogliosis was reduced significantly (P<0.05) in melatonin- treated groups (no dose dependent) compared to the vehicle group. Furthermore, based on TUNEL results, melatonin treatment considerably reduced the number of apoptotic cells (P<0.05).

CONCLUSION

In total, the present findings suggest that melatonin treatment following TBI diminishes astrocyte reactivity and neuronal cells apoptosis in brain cortex in the rat model.

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.

Sleep in traumatic brain injury

More than one-half million patients are hospitalized annually for traumatic brain injury (TBI). One-quarter demonstrate sleep-disordered breathing, up to 50% experience insomnia, and half have hypersomnia. Sleep disturbances after TBI may result from injury to sleep-regulating brain tissue, nonspecific neurohormonal responses to systemic injury, ICU environmental interference, and medication side effects. A diagnosis of sleep disturbances requires a high index of suspicion and appropriate testing. Treatment starts with a focus on making the ICU environment conducive to normal sleep. Treating sleep-disordered breathing likely has outcome benefits in TBI. The use of sleep promoting sedative-hypnotics and anxiolytics should be judicious.

Across the consciousness continuum-from unresponsive wakefulness to sleep

Advances in the development of new paradigms as well as in neuroimaging techniques nowadays enable us to make inferences about the level of consciousness patients with disorders of consciousness (DOC) retain. They, moreover, allow to predict their probable development. Today, we know that certain brain responses (e.g., event-related potentials or oscillatory changes) to stimulation, circadian rhythmicity, the presence or absence of sleep patterns as well as measures of resting state brain activity can serve the diagnostic and prognostic evaluation process. Still, the paradigms we are using nowadays do not allow to disentangle VS/UWS and minimally conscious state (MCS) patients with the desired reliability and validity. Furthermore, even rather well-established methods have, unfortunately, not found their way into clinical routine yet. We here review current literature as well as recent findings from our group and discuss how neuroimaging methods (fMRI, PET) and particularly electroencephalography (EEG) can be used to investigate cognition in DOC or even to assess the degree of residual awareness. We, moreover, propose that circadian rhythmicity and sleep in brain-injured patients are promising fields of research in this context.