Parallel recovery of consciousness and sleep in acute traumatic brain injury

Sleep spindles as a predictor of cognitive motor dissociation and recovery of consciousness after acute brain injury

Cognitive motor dissociation (CMD) can improve the accuracy to predict recovery of behaviorally unresponsive patients with acute brain injury, but acquisition and analysis of task-based electroencephalography (EEG) are technically challenging. N2 sleep patterns, such as sleep spindles on EEG, have been associated with good outcomes, rely on similar thalamocortical networks as consciousness and could provide less technically challenging complementary outcome predictors. In this prospective observational cohort study of 226 acutely brain injured patients, well-formed sleep spindles (WFSS) were more likely present in those with CMD than in those without CMD, often preceding the detection of CMD. WFSS were associated with a shorter time to recovery of consciousness, and both CMD and WFSS independently predicted recovery of independence, controlling for age, admission neurological status and injury type. WFSS are seen in approximately every third behaviorally unresponsive patient after acute brain injury, frequently precede detection of CMD and are a promising complementary predictor for recovery of consciousness and functional independence.

Electroencephalographic differences between waking and sleeping periods in patients with prolonged disorders of consciousness at different levels of consciousness

Objective

This study aimed to explore differences in sleep electroencephalogram (EEG) patterns in individuals with prolonged disorders of consciousness, utilizing polysomnography (PSG) to assist in distinguishing between the vegetative state (VS)/unresponsive wakefulness syndrome (UWS) and the minimally conscious state (MCS), thereby reducing misdiagnosis rates and enhancing the quality of medical treatment.

Methods

A total of 40 patients with prolonged disorders of consciousness (pDOC; 27 patients in the VS/UWS and 13 in the MCS) underwent polysomnography. We analyzed differential EEG indices between VS/UWS and MCS groups and performed correlation analyses between these indices and the Coma Recovery Scale-Revised (CRS-R) scores. The diagnostic accuracy of the differential indices was evaluated using receiver operating characteristic (ROC) curves.

Results

1. The fractal dimension (Higuchi's fractal dimension (HFD)) of patients in the MCS tended to be higher than that of patients in the VS/UWS across all phases, with a significant difference only in the waking phase (p < 0.05). The HFD in the waking phase was positively correlated with the CRS-R score and exhibited the highest diagnostic accuracy at 88.3%. The Teager-Kaiser energy operator (TKEO) also showed higher levels in patients in the MCS compared to those in the VS/UWS, significantly so in the NREM2 phase (p < 0.05), with a positive correlation with the CRS-R score and diagnostic accuracy of 75.2%. The δ-band power spectral density [PSD(δ)] in the patients in the MCS was lower than that in those in the VS/UWS, significantly so in the waking phase (p < 0.05), and it was negatively correlated with the CRS-R score, with diagnostic accuracy of 71.5%.

Conclusion

Polysomnography for the VS/UWS and MCS revealed significant differences, aiding in distinguishing between the two patient categories and reducing misdiagnosis rates. Notably, the HFD and PSD(δ) showed significantly better performance during wakefulness compared to sleep, while the TKEO was more prominent in the NREM2 stage. Notably, the HFD exhibited a robust correlation with the CRS-R scores, the highest diagnostic accuracy, and immense promise in the clinical diagnosis of prolonged disorders of consciousness.

Sleep and circadian rhythms after traumatic brain injury

Traumatic brain injury (TBI) is a serious public health concern and is one of the major causes of death and chronic disability in young individuals. Sleep-wake disturbances are among the most persistent and debilitating consequences of TBI and are reported by 50%-70% of TBI patients regardless of TBI severity. Excessive daytime sleepiness, fatigue, hypersomnia, and insomnia are the most common sleep disturbances in TBI patients. Post-TBI sleep-wake disturbances are often associated with pain, anxiety, depression, and posttraumatic stress disorder. They may exacerbate cognitive impairment following TBI, reduce community integration, and delay recovery and return to normal life. Changes in sleep architecture following TBI have been reported in the literature but cannot fully explain the extent and intensity of the sleep-wake disturbances reported by TBI patients. The alteration in the circadian timing system is another factor that may partially account for the presence of post-TBI sleep-wake disturbances. Current literature supports cognitive behavioral therapy and sleep hygiene education, light therapy, and certain pharmacologic interventions for treating sleep disturbances in TBI patients. Due to heterogeneous consequences of TBI, early screening and individualized approaches to treatment must be prioritized to improve sleep in TBI patients and consequently speed up recovery.

Role of sleep and neurochemical biomarkers in synaptic plasticity related to neurological and psychiatric disorders: A scoping review

Sleep is vital for maintaining physical and mental well-being, impacting cognitive functions like memory and learning through neuroplasticity. Sleep disturbances prevalent in neurological and psychiatric disorders exacerbate cognitive decline, imposing societal burdens. Exploring the relationship between sleep and neuroplasticity elucidates the mechanisms influencing cognition, particularly amidst the prevalent sleep disturbances in these clinical populations. While existing reviews provide valuable insights, gaps remain in understanding the neurophysiological mechanisms underlying sleep and cognitive function. This scoping review aims to investigate the characteristic patterns of sleep parameters and neurochemical biomarkers in reflecting neuroplasticity changes related to neurological and psychiatric disorders and to explore how these markers interact and influence cognition at the molecular level. Studies involving adults and older adults were included, excluding animal models and the paediatric population. Selected studies explored the relationship between sleep parameter or neurochemical biomarker changes and cognitive impairment, reflecting underlying neuroplasticity changes. Peer-reviewed articles, clinical trials, theses, and dissertations in English were included while excluding secondary research and non-peer-reviewed sources. A three-step search strategy was executed following the updated Joanna Briggs Institute methodology for scoping reviews. Published studies were retrieved from nine databases, grey literature, expert recommendations, and hand-searching of the included studies' bibliography. A basic qualitative content synthesis of 34 studies was conducted per JBI's scoping review guidance. Slow-wave and Rapid-Eye Movement sleep, sleep spindles, sleep cycle disruption, K-Complex(KC) density, Hippocampal sEEG, BDNF, IL-6, iNOS mRNA expression, plasma serotonin, CSF Aβ-42, t-tau and p-tau proteins, and serum cortisol revealed associations with cognitive dysfunction. Examining the relationship between sleep parameters, neurochemical biomarkers, and cognitive function reveals neuronal mechanisms that guide potential therapeutic interventions and enhance quality patient care.

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.

Characteristics and Neural Mechanisms of Sleep-Wake Disturbances After Traumatic Brain Injury

Sleep-wake disturbances (SWDs) are one of the most common complaints following traumatic brain injury (TBI). The high prevalence and socioeconomic burden of SWDs post-TBI have only been recognized in the past decade. Common SWDs induced by TBI include excessive daytime sleepiness (EDS), hypersomnia, insomnia, obstructive sleep apnea (OSA), and circadian rhythm sleep disorders. Sleep disturbances can significantly compromise quality of life, strain interpersonal relationships, diminish work productivity, exacerbate other clinical conditions, and impede the rehabilitation process of TBI patients. Consequently, the prompt regulation and enhancement of sleep homeostasis in TBI patients is of paramount importance. Although studies have shown that abnormal neural network function, neuroendocrine changes, disturbance of sleep-wake regulators, and immune inflammatory responses related to brain structural damage induced by TBI are involved in the development of SWDs, the exact neuropathological mechanisms are still poorly understood. Therefore, we systematically review the current clinical and experimental studies on the characteristics and possible neural mechanisms of post-TBI SWDs. Elucidating the neural underpinnings of post-TBI SWDs holds the potential to diversify and enhance therapeutic approaches for these conditions. Such advancements could hasten the recuperation of TBI patients and ameliorate their overall quality of life. It is our aspiration that departments specializing in neurosurgery, rehabilitation, and neuropsychiatry will be able to recognize and address these conditions promptly, thereby facilitating the healing journey of affected individuals.

Use of actigraphy for monitoring agitation and rest-activity cycles in patients with acute traumatic brain injury in the ICU

BACKGROUND

In traumatic brain injury patients (TBI) admitted to the intensive care unit (ICU), agitation can lead to accidental removal of catheters, devices as well as self-extubation and falls. Actigraphy could be a potential tool to continuously monitor agitation. The objectives of this study were to assess the feasibility of monitoring agitation with actigraphs and to compare activity levels in agitated and non-agitated critically ill TBI patients.

METHODS

Actigraphs were placed on patients' wrists; 24-hour monitoring was continued until ICU discharge or limitation of therapeutic efforts. Feasibility was assessed by actigraphy recording duration and missing activity count per day.

RESULTS

Data from 25 patients were analyzed. The mean number of completed day of actigraphy per patient was 6.5 ± 5.1. The mean missing activity count was 20.3 minutes (±81.7) per day. The mean level of activity measured by raw actigraphy counts per minute over 24 hours was higher in participants with agitation than without agitation.

CONCLUSIONS

This study supports the feasibility of actigraphy use in TBI patients in the ICU. In the acute phase of TBI, agitated patients have higher levels of activity, confirming the potential of actigraphy to monitor agitation.

Modulation of brain activity in brain-injured patients with a disorder of consciousness in intensive care with repeated 10-Hz transcranial alternating current stimulation (tACS): a randomised controlled trial protocol

INTRODUCTION

Therapeutic interventions for disorders of consciousness lack consistency; evidence supports non-invasive brain stimulation, but few studies assess neuromodulation in acute-to-subacute brain-injured patients. This study aims to validate the feasibility and assess the effect of a multi-session transcranial alternating current stimulation (tACS) intervention in subacute brain-injured patients on recovery of consciousness, related brain oscillations and brain network dynamics.

METHODS AND ANALYSES

The study is comprised of two phases: a validation phase (n=12) and a randomised controlled trial (n=138). Both phases will be conducted in medically stable brain-injured adult patients (traumatic brain injury and hypoxic-ischaemic encephalopathy), with a Glasgow Coma Scale score ≤12 after continuous sedation withdrawal. Recruitment will occur at the intensive care unit of a Level 1 Trauma Centre in Montreal, Quebec, Canada. The intervention includes a 20 min 10 Hz tACS at 1 mA intensity or a sham session over parieto-occipital cortical sites, repeated over five consecutive days. The current's frequency targets alpha brain oscillations (8-13 Hz), known to be associated with consciousness. Resting-state electroencephalogram (EEG) will be recorded four times daily for five consecutive days: pre and post-intervention, at 60 and 120 min post-tACS. Two additional recordings will be included: 24 hours and 1-week post-protocol. Multimodal measures (blood samples, pupillometry, behavioural consciousness assessments (Coma Recovery Scale-revised), actigraphy measures) will be acquired from baseline up to 1 week after the stimulation. EEG signal analysis will focus on the alpha bandwidth (8-13 Hz) using spectral and functional network analyses. Phone assessments at 3, 6 and 12 months post-tACS, will measure long-term functional recovery, quality of life and caregivers' burden.

ETHICS AND DISSEMINATION

Ethical approval for this study has been granted by the Research Ethics Board of the CIUSSS du Nord-de-l'Île-de-Montréal (Project ID 2021-2279). The findings of this two-phase study will be submitted for publication in a peer-reviewed academic journal and submitted for presentation at conferences. The trial's results will be published on a public trial registry database (ClinicalTrials.gov).

TRIAL REGISTRATION NUMBER

NCT05833568.

Sleep Disruptions in Hospitalized Adults Sustaining a Traumatic Brain Injury: A Scoping Review

OBJECTIVE

Adults sustaining a traumatic brain injury (TBI) are at risk of sleep disturbances during their recovery, including when such an injury requires hospitalization. However, the sleep-wake profile, and internal and external factors that may interfere with sleep initiation/maintenance in hospitalized TBI patients are poorly understood. This review aimed to: (1) identify/summarize the existing evidence regarding sleep and sleep measurements in TBI adults receiving around-the-clock care in a hospital or during inpatient rehabilitation, and (2) identify internal/external factors linked to poor sleep in this context.

METHODS

A scoping review was conducted in accordance with the PRISMA Scoping Review Extension guidelines. A search was conducted in MEDLINE, PsycINFO, CINAHL, and Web of Science databases.

RESULTS

Thirty relevant studies were identified. The most common sleep variables that were put forth in the studies to characterize sleep during hospitalization were nighttime sleep time (mean = 6.5 hours; range: 5.2-8.9 hours), wake after sleep onset (87.1 minutes; range: 30.4-180 minutes), and sleep efficiency (mean = 72.9%; range: 33%-96%) using mainly actigraphy, polysomnography, and questionnaires (eg, the sleep-wake disturbance item of the Delirium Rating Scale or the Pittsburgh Sleep Quality Index). Twenty-four studies (80%) suggested that hospitalized TBI patients do not get sufficient nighttime sleep, based on the general recommendations for adults (7-9 hours per night). Sleep disruptions during hospitalization were found to be associated to several internal factors including TBI severity, cognitive status, and analgesia intake. External and modifiable factors, such as noise, light, and patient care, were consistently associated with sleep disruptions in this context.

CONCLUSION

Although the literature on sleep disturbances in hospitalized TBI patients has been increasing in recent years, many gaps in knowledge remain, including phenotypes and risk factors. Identifying these factors could help clinicians better understand the multiple sources of TBI patients' sleep difficulties and intervene accordingly.

Electrophysiological monitoring of neurological functions at the acute phase of brain injury: An overview of current knowledge and future perspectives in the adult population

The continuous monitoring of physiological parameters is now considered as a standard of care in intensive care units (ICU). While multiple techniques are available to guide hemodynamic or respiratory management, the monitoring of neurological function in unconscious patients is usually limited to discontinuous bedside neurological examination or morphological brain imaging. However, cortical activity is accessible at the bedside with electroencephalography (EEG), electrocorticography (ECoG) or evoked potentials. The analysis of the unprocessed signal requires a trained neurophysiologist and could be time consuming. During the past decades, advances in neurophysiological signal acquisition make it possible to calculate quantified EEG parameters in real-time. New monitors also provide ICU friendly display for a dynamic and live assessment of neurological function changes. In this review, we will describe the technical aspects of EEG, ECoG and evoked potentials required for a good signal quality before interpretation. We will discuss how to use those electrophysiological techniques in the ICU to assess neurological function in comatose patients at the acute phase of brain injuries such as traumatic brain injuries, haemorrhagic or ischemic stroke. We will discuss, which quantitative EEG or evoked potentials monitoring parameters can be used at the bedside to guide sedation, evaluate neurological function during awaking and look for new neurological (encephalic or brainstem) injuries. We will present the state of the art and discuss some analyses, which may develop shortly.

Central autonomic network and early prognosis in patients with disorders of consciousness

The central autonomic network (CAN) plays a crucial role in modulating the autonomic nervous system. Heart rate variability (HRV) is a valuable marker for assessing CAN function in disorders of consciousness (DOC) patients. We used HRV analysis for early prognosis in 58 DOC patients enrolled within ten days of hospitalization. They underwent a five-minute electrocardiogram during baseline and acoustic/visual stimulation. The coma recovery scale-revised (CRS-R) was used to define the patient's consciousness level and categorize the good/bad outcome at three months. The high-frequency Power Spectrum Density and the standard deviation of normal-to-normal peaks in baseline, the sample entropy during the stimulation, and the time from injury features were used in the support vector machine analysis (SVM) for outcome prediction. The SVM predicted the patients' outcome with an accuracy of 96% in the training test and 100% in the validation test, underscoring its potential to provide crucial clinical information about prognosis.

The visual stimulation in disorders of consciousness

Severe brain damage usually leads to disorders of consciousness (DOC), which include coma, unresponsive wakefulness syndrome (UWS) and a minimally conscious state (MCS). Visual stimulation is widely used, especially in the diagnosis and treatment and treatment of DOC. Researchers have indicated that tests based on visual stimulation including visual pursuit, when used in conjunction with the Coma Recovery Scale-Revised, are able to differentiate between UWS from an MCS. Recently, targeting patients' circadian rhythms has been proposed to be a possible treatment target for DOC. Indeed, light therapy has been applied in some other fields, including treating seasonal affective disorder, sleep problems, and Parkinson's disease. However, at present, although visual stimulation and light therapy are frequently used in DOC, there is still no international unified standard. Therefore, we recommend the development of an international consensus in regard to the definitions, operational criteria and assessment procedures of visual stimulation and light therapy. This review combines visual stimulation, circadian rhythm recovery, and light therapy in DOC patients and presents the mechanisms and current advances in applications related to light therapy and visual stimulation in an attempt to provide additional ideas for future research and treatment of DOC.

Twenty-four-hour rhythmicities in disorders of consciousness are associated with a favourable outcome

Fluctuations of consciousness and their rhythmicities have been rarely studied in patients with a disorder of consciousness after acute brain injuries. 24-h assessment of brain (EEG), behaviour (eye-opening), and circadian (clock-controlled hormones secretion from urine) functions was performed in acute brain-injured patients. The distribution, long-term predictability, and rhythmicity (circadian/ultradian) of various EEG features were compared with the initial clinical status, the functional outcome, and the circadian rhythmicities of behaviour and clock-controlled hormones. Here we show that more physiological and favourable patterns of fluctuations are associated with a higher 24 h predictability and sharp up-and-down shape of EEG switches, reminiscent of the Flip-Flop model of sleep. Multimodal rhythmic analysis shows that patients with simultaneous circadian rhythmicity for brain, behaviour, and hormones had a favourable outcome. Finally, both re-emerging EEG fluctuations and homogeneous 24-h cycles for EEG, eye-opening, and hormones appeared as surrogates for preserved functionality in brainstem and basal forebrain, which are key prognostic factors for later improvement. While the recovery of consciousness has previously been related to a high short-term complexity, we suggest in this exploratory study the importance of the high predictability of the 24 h long-term generation of brain rhythms and highlight the importance of circadian body-brain rhythms in awakening.

The growing gap: A study of sleep, encoding, and consolidation of new words in chronic traumatic brain injury

Word learning is an iterative and dynamic process supported by multiple neural and cognitive systems. Converging evidence from behavioral, cellular, and systems neuroscience highlights sleep as an important support for memory and word learning over time. In many lab-based word learning experiments, participants encode and subsequently retrieve newly learned words in a single session. These designs are inadequate to capture the full dynamic word learning process, making them less ecologically valid. Single timepoint studies also limit investigation of the role of behavioral and lifestyle factors, like sleep, in supporting word learning over time. Adults with a history of traumatic brain injury (TBI), who commonly exhibit deficits in the memory systems that support word learning and report concomitant sleep disturbance, provide a unique opportunity to examine the link between memory, sleep, and word learning. Here we examined word learning over time and the influence of sleep on short- and long-term word recall in 50 adults with chronic moderate-severe TBI and 50 demographically matched neurotypical peers. We used a randomized within-participant crossover design to assess immediate encoding of new words and the consolidation of those words over time across intervals that did or did not involve sleep. Participants completed this study over the course of two weeks in their own homes to capture the iterative, dynamic process of real-world word learning. We also measured sleep in free living conditions using actigraphy throughout the experiment. Participants with TBI exhibited a word learning deficit that began at encoding and persisted across time. Critically, this deficit grew over the course of the week. The performance gap between groups was larger at the 1-week post-test than the immediate post-test, suggesting deficits in both encoding and consolidation of new words in individuals with TBI. Participants with and without TBI remembered more words when they slept after learning. Ecologically valid research designs that examine the relationship between memory, sleep, and word learning over time promise to advance mechanistic accounts of word learning and improve the long-term retention of new words in individuals with and without brain injury.

Optimising recovery of consciousness after coma. From bench to bedside and vice versa

BACKGROUND

Several methods have been proposed to foster recovery of consciousness in patients with disorders of consciousness (DoC).

OBJECTIVE

Critically assess pharmacological and non-pharmacological treatments for patients with chronic DoC.

METHODS

A narrative mini-review, and critical analysis of the scientific literature on the various proposed therapeutic approaches, with particular attention to level of evidence, risk-benefit ratio, and feasibility.

RESULTS AND DISCUSSION

Personalised sensory stimulation, median nerve stimulation, transcranial direct current stimulation (tDCS), amantadine and zolpidem all have favourable risk-benefit ratios and are easy to implement in clinical practice. These treatments should be proposed to every patient with chronic DoC. Comprehensive patient management should also include regular lifting, pain assessment and treatment, attempts to restore sleep and circadian rhythms, implementation of rest periods, comfort and nursing care, and a rehabilitation program with a multi-disciplinary team with expertise in this field. More invasive treatments may cause adverse effects and require further investigation to confirm preliminary, encouraging results and to better define responders' intervention parameters. Scientific studies are essential and given the severity of the disability and handicap that results from DoC, research in this area should aim to develop new therapeutic approaches.

Hierarchical clustering of prolonged post-concussive symptoms after 12 months: symptom-centric analysis and association with functional impairments

BACKGROUND

Following a concussion, approximately 15% of individuals experience persistent symptoms that can lead to functional deficits. However, underlying symptom-clusters that persist beyond 12 months have not been adequately characterized, and their relevance to functional deficits are unclear. The aim of this study was to characterize the underlying clusters of prolonged post-concussive symptoms lasting more than 12 months, and to investigate their association with functional impairments.

METHODS

Although hierarchical clustering is ideally suited in evaluating subjective symptom severities, it has not been applied to the Rivermead Post-Concussion Questionnaire (RPQ). The RPQ and functional impairments questions were administered via a smartphone application to 445 individuals who self-reported prolonged post-concussive symptoms. Symptom-clusters were obtained using agglomerative hierarchical clustering, and their association with functional deficits were investigated with sensitivity analyses, and corrected for multiple comparisons.

RESULTS

Five symptom-clusters were identified: headache-related, sensitivity to light and sound, cognitive, mood-related, and sleep-fatigue. Individuals with more severe RPQ symptoms were more likely to report functional deficits (p < 0.0001). Whereas the headache and sensitivity clusters were associated with at most one impairment, at-least-mild sleeping difficulties and fatigue were associated with four, and moderate-to-severe cognitive difficulties with five (all p < 0.01).

CONCLUSIONS

Symptom-clusters may be clinically useful for functional outcome stratification for targeted rehabilitation therapies. Further studies are required to replicate these findings in other cohorts and questionnaires, and to ascertain the effects of symptomatic intervention on functional outcomes.

Sleep from acute to chronic traumatic brain injury and cognitive outcomes

STUDY OBJECTIVES

Traumatic brain injuries (TBIs) cause persistent cerebral damage and cognitive deficits. Because sleep may be a critical factor for brain recovery, we characterized the sleep of patients with TBI from early hospitalization to years post-injury and explored the hypothesis that better sleep during hospitalization predicts more favorable long-term cognitive outcomes.

METHODS

We tested patients with moderate-to-severe TBI in the hospitalized (n = 11) and chronic (n = 43) stages using full-night polysomnography, with 82% of the hospitalized group being retested years post-injury. Hospitalized patients with severe orthopedic and/or spinal cord injury (n = 14) and healthy participants (n = 36) were tested as controls for the hospitalized and chronic TBI groups, respectively. Groups had similar age and sex and were compared for sleep characteristics, including slow waves and spindles. For patients with TBI, associations between sleep during hospitalization and long-term memory and executive function were assessed.

RESULTS

Hospitalized patients with TBI or orthopedic injuries had lower sleep efficiency, higher wake after sleep onset, and lower spindle density than the chronic TBI and healthy control groups, but only hospitalized patients with brain injury had an increased proportion of slow-wave sleep. During hospitalization for TBI, less fragmented sleep, more slow-wave sleep, and higher spindle density were associated to more favorable cognitive outcomes years post-injury, while injury severity markers were not associated with these outcomes.

CONCLUSION

These findings highlight the importance of sleep following TBI, as it could be a strong predictor of neurological recovery, either as a promoter or an early marker of cognitive outcomes.

Effects of Cognitive Behavioral Therapy on Pain and Sleep in Adults with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

The objective of this study was to systematically review the literature on the effects of cognitive behavioral therapy (CBT) on insomnia and pain in patients with traumatic brain injury (TBI). PubMed, Embase, the Cochrane Library, Cumulative Index to Nursing and Allied Health, and Web of Science databases were searched. Outcomes, including pain, sleep quality, and adverse events, were investigated. Differences were expressed using mean differences (MDs) with 95% confidence intervals (CIs). The statistical analysis was performed using STATA 16.0. Twelve trials with 476 TBI patients were included. The included studies did not indicate a positive effect of CBT on pain. Significant improvements were shown for self-reported sleep quality, reported with the Pittsburgh Self-Reported Sleep Quality Index (MD, -2.30; 95% CI, -3.45 to -1.15; P < 0.001) and Insomnia Severity Index (MD, -5.12; 95% CI, -9.69 to -0.55; P = 0.028). No major adverse events related to CBT were reported. The underpowered evidence suggested that CBT is effective in the management of sleep quality and pain in TBI adults. Future studies with larger samples are recommended to determine significance. This trial is registered with PROSPERO registration number CRD42019147266.

Evaluation of rest-activity cycles in patients with severe acquired brain injury: an observational study

BACKGROUND

There is little knowledge about rest-activity cycles (RAC) in patients with severe-acquired brain injury (sABI) during early in-hospital rehabilitation. This study aimed to investigate if patients with sABI displayed unconsolidated RACs at the beginning of in-hospital rehabilitation, and how these changed over time.

METHODS

This study was a prospective observational study. All patients consecutively admitted to one ward were screened for eligibility. We recorded accelerometric activity for 20 days. The Daytime Activity Ratio (DAR) of activity between daytime (7-22) and the total activity during the entire day was calculated and used to estimate consolidation.

RESULTS

Fifty-five patients were screened and 20 patients were included. Complete day 1 & 2 data was obtained on 18 patients. Fifty-six percentage of these had a consolidated RAC at the beginning of rehabilitation. On day 19 & 20, complete data could be obtained from 15 patients, 80% of these had consolidation of RAC. When comparing these a significant mean increase of 5.8% 95%CI(0.52; 11.01) in DAR was found p < .05, and the model of all data also showed a significant increase in median DAR over time p < .01.

CONCLUSION

RAC consolidation improves over time in patients admitted for in-hospital early neurorehabilitation.

Pain Perception in Disorder of Consciousness: A Scoping Review on Current Knowledge, Clinical Applications, and Future Perspective

Pain perception in individuals with prolonged disorders of consciousness (PDOC) is still a matter of debate. Advanced neuroimaging studies suggest some cortical activations even in patients with unresponsive wakefulness syndrome (UWS) compared to those with a minimally conscious state (MCS). Therefore, pain perception has to be considered even in individuals with UWS. However, advanced neuroimaging assessment can be challenging to conduct, and its findings are sometimes difficult to be interpreted. Conversely, multichannel electroencephalography (EEG) and laser-evoked potentials (LEPs) can be carried out quickly and are more adaptable to the clinical needs. In this scoping review, we dealt with the neurophysiological basis underpinning pain in PDOC, pointing out how pain perception assessment in these individuals might help in reducing the misdiagnosis rate. The available literature data suggest that patients with UWS show a more severe functional connectivity breakdown among the pain-related brain areas compared to individuals in MCS, pointing out that pain perception increases with the level of consciousness. However, there are noteworthy exceptions, because some UWS patients show pain-related cortical activations that partially overlap those observed in MCS individuals. This suggests that some patients with UWS may have residual brain functional connectivity supporting the somatosensory, affective, and cognitive aspects of pain processing (i.e., a conscious experience of the unpleasantness of pain), rather than only being able to show autonomic responses to potentially harmful stimuli. Therefore, the significance of the neurophysiological approach to pain perception in PDOC seems to be clear, and despite some methodological caveats (including intensity of stimulation, multimodal paradigms, and active vs. passive stimulation protocols), remain to be solved. To summarize, an accurate clinical and neurophysiological assessment should always be performed for a better understanding of pain perception neurophysiological underpinnings, a more precise differential diagnosis at the level of individual cases as well as group comparisons, and patient-tailored management.

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.

Sleep after Traumatic Brain Injury

Sleep disturbances are common after traumatic brain injury of all levels of severity, interfere with acute and long-term recovery, and can persist for years after injury. There is increasing evidence of the importance of sleep in improving brain function and recovery. Noticing and addressing sleep disturbances are important aspects of nursing care, especially for the prevention or early recognition of delirium. Nonpharmacologic interventions can improve sleep. Teaching about the importance of sleep after traumatic brain injury, promoting sleep hygiene, and multidisciplinary approaches to addressing sleep problems and improving sleep are important for recovery from traumatic brain injury.

Slow wave activity moderates the association between new learning and traumatic brain injury severity

STUDY OBJECTIVES

Sleep-wake complaints and difficulties in making new learning are among the most persistent and challenging long-term sequelea following moderate to severe traumatic brain injury (TBI). Yet, it is unclear whether, and to what extent, sleep characteristics during the chronic stage of TBI contribute to sleep-wake and cognitive complaints. We aimed to characterize sleep architecture in chronic moderate to severe TBI adults and assess whether non-rapid eye movement slow wave activity (SWA) is associated to next day performance in episodic memory tasks according to TBI severity.

METHODS

Forty-two moderate to severe TBI participants, 12-47 months post-injury, and 38 healthy controls were tested with one night of in-laboratory polysomnography, followed the next morning by questionnaires (sleep quality, fatigue, and sleepiness) and neuropsychological assessment. We used multiple regression analyses to assess the moderator effect of SWA power on TBI severity and next-day memory performance.

RESULTS

We found that TBI participants reported worse sleep quality and fatigue, and had worse cognitive performance than controls. No between group differences were found on macro- and micro-architecture of sleep. However, SWA significantly interacted with TBI severity to explain next-day memory performance: higher SWA was more strongly associated to better memory performance in more severe TBI compared to milder TBI.

CONCLUSIONS

This study provides evidence that the injured brain is able to produce macro- and micro-architecture of sleep comparable to what is seen in healthy controls. However, with increasing TBI severity, lower non-rapid eye movement SWA power is associated with reduced ability to learn and memorise new information the following day.

The Bidirectional Relationship Between Sleep and Inflammation Links Traumatic Brain Injury and Alzheimer's Disease

Traumatic brain injury (TBI) and Alzheimer's disease (AD) are diseases during which the fine-tuned autoregulation of the brain is lost. Despite the stark contrast in their causal mechanisms, both TBI and AD are conditions which elicit a neuroinflammatory response that is coupled with physical, cognitive, and affective symptoms. One commonly reported symptom in both TBI and AD patients is disturbed sleep. Sleep is regulated by circadian and homeostatic processes such that pathological inflammation may disrupt the chemical signaling required to maintain a healthy sleep profile. In this way, immune system activation can influence sleep physiology. Conversely, sleep disturbances can exacerbate symptoms or increase the risk of inflammatory/neurodegenerative diseases. Both TBI and AD are worsened by a chronic pro-inflammatory microenvironment which exacerbates symptoms and worsens clinical outcome. Herein, a positive feedback loop of chronic inflammation and sleep disturbances is initiated. In this review, the bidirectional relationship between sleep disturbances and inflammation is discussed, where chronic inflammation associated with TBI and AD can lead to sleep disturbances and exacerbated neuropathology. The role of microglia and cytokines in sleep disturbances associated with these diseases is highlighted. The proposed sleep and inflammation-mediated link between TBI and AD presents an opportunity for a multifaceted approach to clinical intervention.

Sleep Supports Memory and Learning: Implications for Clinical Practice in Speech-Language Pathology

Purpose This tutorial aims to draw attention to the interactions among memory, sleep, and therapy potential and to increase awareness and knowledge in the field of speech-language pathology of the potential impact of sleep as a mediating or moderating factor in promoting therapeutic outcome. Method We highlight key findings from the literature on the cognitive neuroscience of memory, the neurophysiology of sleep, how sleep supports memory, and how sleep disruption affects memory and learning abilities in populations commonly served in speech-language pathology. Results Research increasingly points to the critical importance of sleep quality and quantity to memory and learning, and sleep disruption is linked to deficits in functional cognition that may limit our clients' ability to benefit from speech pathology interventions. Conclusions As a field dedicated to promoting memory, learning, and relearning through our interventions, any systemic factors that affect these abilities demand our attention. Although speech-language pathologists do not treat sleep disturbance, we play a critical role in recognizing the signs and symptoms of sleep disturbance and making appropriate referrals, as undiagnosed and untreated sleep disturbance can have serious impacts on success in therapeutic contexts. By considering how related factors affect memory and learning, we have the opportunity to take a whole client approach to maximizing our clients' therapy potential and functional progress.

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.

Validity of actigraphy for nighttime sleep monitoring in hospitalized patients with traumatic injuries

STUDY OBJECTIVES

Sleep-wake disturbances are frequent among patients hospitalized for traumatic injuries but remain poorly documented because of the lack of tools validated for hospitalized patients. This study aimed to validate actigraphy for nighttime sleep monitoring of hospitalized patients with severe traumatic injuries, using ambulatory polysomnography (PSG).

METHODS

We tested 17 patients (30.4 ± 14.7 years, 16.6 ± 8.2 days postinjury) who had severe orthopedic injuries and/or spinal cord injury, with or without traumatic brain injury. When medically stable, patients wore an actigraph on a nonparalyzed arm and underwent ambulatory PSG at the bedside. Data were converted to 1-minute epochs. The following parameters were calculated for the nighttime period: total sleep time, total wake time, sleep efficiency, and number of awakenings. Epoch-by-epoch concordance between actigraphy and PSG was analyzed to derive sensitivity, specificity, and accuracy. PSG sleep parameters were compared to those obtained from four actigraphy scoring algorithms by Bland-Altman plots.

RESULTS

Sensitivity to detect sleep was ≥ 92% and accuracy was > 85% for all four actigraphy algorithms used, whereas specificity varied from 48% to 60%. The low-activity wake threshold (20 activity counts per epoch) was most closely associated with PSG on all sleep parameters. This scoring algorithm also had the highest specificity (59.9%) and strong sensitivity (92.8%).

CONCLUSIONS

Actigraphy is valid for monitoring nighttime sleep and wakefulness in patients hospitalized with traumatic injuries, with sensitivity, specificity and accuracy comparable to actigraphic recordings in healthy individuals. A scoring algorithm using a low wake threshold is best suited for this population and setting.

Subacute sleep disturbance in moderate to severe traumatic brain injury: a systematic review

Objective: This systematic review evaluated subacute sleep disturbance following moderate to severe traumatic brain injury (TBI) and the impact of secondary factors such as mood or pain.Methods: A comprehensive search strategy was applied to nine databases. Inclusion criteria included: adults ≥18 years, moderate and severe TBI and within 3 months of injury. Eligible studies were critically appraised using the McMaster Quantitative Critical Review Form. Study characteristics, outcomes, and methodological quality were synthesized. This systematic review was registered with PROSPERO (Registration number: CRD42018087799).Results: Ten studies were included. Research identified early-onset sleep disturbances; characterized as fragmented sleep periods and difficulty initiating sleep. Alterations to sleep architecture (e.g. rapid eye movement sleep) were reported. Sleep disturbance appears to associate with alterations of consciousness. Sleep disturbance tended to be particularly increased during the phase of post-traumatic amnesia (PTA) (78.7%).Conclusions: There is a limited amount of research available, which has inherent measurement and sample size limitations. The gold standard for measuring sleep (polysomnography) was rarely utilized, which may affect the detection of sleep disturbance and sleep architecture. Secondary factors potentially influencing sleep were generally not reported. Further evaluation on associations between sleep and PTA is needed.

Injury, Sleep, and Functional Outcome in Hospital Patients With Traumatic Brain Injury

PROBLEM

Uninterrupted nighttime sleep is associated with better cognition and functional outcomes in healthy adults, but the relationship between sleep and functional outcome in individuals hospitalized with severe traumatic brain injury (TBI) remains to be clarified.

OBJECTIVE

The aims of this study were to (1) describe nighttime rest-activity variables-wake bouts (counts), total wake time (minutes), and sleep efficiency (SE) (percentage; time asleep/time in bed)-in people on a neuroscience step-down unit (NSDU) post-TBI and (2) describe the association between injury and nighttime rest-activity on post-TBI functional outcome (using Functional Independence Measure [FIM] at discharge from inpatient care).

METHODS

This study is a cross-sectional, descriptive pilot study. We recruited participants from the NSDU (n = 17 [age: mean (SD), 63.4 (17.9)]; 82% male, 94% white) who wore wrist actigraphy (source of nighttime rest-activity variables) for up to 5 nights. For injury variables, we used Glasgow Coma Scale (GCS) score and Injury Severity Score (ISS). We used Spearman ρ and regression to measure associations.

RESULTS

Glasgow Coma Scale mean (SD) score was 8.8 (4.9), ISS mean (SD) score was 23.6 (6.7), and FIM mean (SD) score was 48 (14.5). Averages of nighttime rest-activity variables (8 PM-7 AM) were as follows: SE, 73% (SD, 16); wake bouts, 41 counts (SD, 18); total wake time, 74 minutes (SD, 47). Correlations showed significance between FIM and GCS (P = .005) and between SE and GCS (P = .015). GCS was the only statistically significant variable associated with FIM (P = .013); we eliminated other variables from the model as nonsignificant (P > .10). Sleep efficiency and FIM association was nonsignificant (P = .40). In a separate model (ISS, GCS, and SE [dependent variable]), GCS was significant (P = .04), but ISS was not (P = .25).

CONCLUSION

Patients with severe TBI on the NSDU have poor actigraphic sleep at night. GCS has a stronger association to functional outcome than nighttime rest-activity variables.

Measures of CNS-Autonomic Interaction and Responsiveness in Disorder of Consciousness

Neuroimaging studies have demonstrated functional interactions between autonomic (ANS) and brain (CNS) structures involved in higher brain functions, including attention and conscious processes. These interactions have been described by the Central Autonomic Network (CAN), a concept model based on the brain-heart two-way integrated interaction. Heart rate variability (HRV) measures proved reliable as non-invasive descriptors of the ANS-CNS function setup and are thought to reflect higher brain functions. Autonomic function, ANS-mediated responsiveness and the ANS-CNS interaction qualify as possible independent indicators for clinical functional assessment and prognosis in Disorders of Consciousness (DoC). HRV has proved helpful to investigate residual responsiveness in DoC and predict clinical recovery. Variability due to internal (e.g., homeostatic and circadian processes) and environmental factors remains a key independent variable and systematic research with this regard is warranted. The interest in bidirectional ANS-CNS interactions in a variety of physiopathological conditions is growing, however, these interactions have not been extensively investigated in DoC. In this brief review we illustrate the potentiality of brain-heart investigation by means of HRV analysis in assessing patients with DoC. The authors' opinion is that this easy, inexpensive and non-invasive approach may provide useful information in the clinical assessment of this challenging patient population.

Persistent impairment based symptoms post mild traumatic brain injury: Does a standard symptom scale detect them?

AIM

To further explore symptoms in patients beyond the expected recovery period post mild Traumatic Brain Injury (mTBI) that are potentially indicative of impairment.

METHODS

Ninety-four individuals (62 diagnosed with mTBI within the previous 4-24 weeks and 32 healthy controls) participated in the study. Participants in the mTBI group were further grouped as symptomatic (n = 33) or asymptomatic (n = 29) based on their spontaneous report of symptoms at the time of screening. Measures included a demographic questionnaire, 8 impairment specific self-report clinical tools, and a standard post-mTBI self-report symptom scale (Head Injury Scale (HIS)).

RESULTS

Compared to the control group, scores for all instruments (including the HIS) were higher in the symptomatic mTBI group (P < 0.05), and higher for the neck disability and hyperarousal measures in the asymptomatic mTBI group (p < 0.035), but not the HIS (p > 0.093). Overall 94% of the symptomatic and 62% of the asymptomatic participants post-mTBI, recorded scores considered to be clinically relevant on at least one impairment screening tool. In contrast, only 28% of the asymptomatic mTBI group recorded a clinically relevant score for the HIS.

CONCLUSION

Symptoms indicative of persisting impairments beyond the expected recovery period were apparent in a substantial proportion of individuals post mTBI. Furthermore, a high percentage of individuals initially reporting as symptom free demonstrated clinically relevant scores on at least one impairment screening tool. Findings also suggest that a standard post-mTBI self-report symptom scale may often not detect the presence of persisting symptoms.

Clinical trials for pediatric traumatic brain injury: definition of insanity?

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in children both in the United States and throughout the world. Despite valiant efforts and multiple clinical trials completed over the last few decades, there are no high-level recommendations for pediatric TBI available in current guidelines. In this review, the authors explore key findings from the major pediatric clinical trials in children with TBI that have shaped present-day recommendations and the insights gained from them. The authors also offer a perspective on potential efforts to improve the efficacy of future clinical trials in children following TBI.

Sensorimotor and Physiological Indicators of Impairment in Mild Traumatic Brain Injury: A Meta-Analysis

OBJECTIVE

To systematically review the literature with meta-analysis to determine whether persistence of sensorimotor or physiological impairment exists between 4 weeks to 6 months post mild traumatic brain injury (mTBI), and assign level of evidence to findings.

METHOD

The databases PubMed, pscyINFO, SPORTdiscus, Medline, CINAHL and Embase were searched from inception to November 2016 using a priori inclusion criteria. Critical appraisal was performed, and an evidence matrix established level of evidence. Meta-analysis of pooled results identified standardized mean difference (SMD) and 95% confidence intervals (95% CI) between mTBI and healthy controls for a variety of physiological and sensorimotor indicators.

RESULTS

Eighteen eligible articles, with a mean quality score of 15.67 (SD = 2.33) were included in the final review. Meta-analysis of center of motion variable; maximal mediolateral center of motion/center of pressure separation distance SMD [95% CI] approached significance at (-0.42 [-0.84, -0.00], I² = 0%) for dual task, level walking indicating a potential reduction in maximal mediolateral excursion during gait in the mTBI group compared to healthy controls. Significantly reduced variability in the standard deviation of heart beat intervals was observed in the mTBI group (-0.51 [-0.74, -0.28], I² = 0%). Overall, significant group differences in 36 sensorimotor and physiological variables (eg, balance, gait velocity and motion analysis outcomes, various oculomotor tasks, as well as heart rate variability frequency domains) were identified.

CONCLUSION

Findings demonstrate that persistence of sensorimotor and physiological changes beyond expected recovery times following subacute mTBI in an adult population is possible. These findings have implications for post-injury assessment and management.