Trajectories of sleep changes during the acute phase of traumatic brain injury: a 7-day actigraphy study

Concussion and the Sleeping Brain

BACKGROUND

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

MAIN BODY

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

SHORT CONCLUSION

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

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.

Hospital Environmental Effects on Sleep in Adults With Traumatic Brain Injury in Rehabilitation

PURPOSE

The aim of this study was to describe sleep patterns of adults with traumatic brain injury and examine effects of environmental stressors (patient care activities and light) on patterns of sleep.

DESIGN

A descriptive, correlational, explanatory design was used for this study.

METHODS

Sixty-three subjects with traumatic brain injury (>18 years) on an acute traumatic brain injury rehabilitation unit wore an Actiwatch for 48 hours to collect light and sleep data. Patient care activity data were collected between 11 p.m. and 7 a.m.

FINDINGS

Patient care activities and light occurred between 11 p.m. and 7 a.m. Nighttime sleep duration and sleep efficiency were explained by patient care activities, whereas light explained wake time after sleep onset.

CONCLUSION

Patient care activities and light serve as environmental stressors that affect sleep.

CLINICAL RELEVANCE

Results necessitate examining the need and timing of nursing care activities and light during nighttime. Findings provide a basis for policy changes that optimize sleep.

Wearable Device-Independent Next Day Activity and Next Night Sleep Prediction for Rehabilitation Populations

Wearable sensor-based devices are increasingly applied in free-living and clinical settings to collect fine-grained, objective data about activity and sleep behavior. The manufacturers of these devices provide proprietary software that labels the sensor data at specified time intervals with activity and sleep information. If the device wearer has a health condition affecting their movement, such as a stroke, these labels and their values can vary greatly from manufacturer to manufacturer. Consequently, generating outcome predictions based on data collected from patients attending inpatient rehabilitation wearing different sensor devices can be challenging, which hampers usefulness of these data for patient care decisions. In this article, we present a data-driven approach to combining datasets collected from different device manufacturers. With the ability to combine datasets, we merge data from three different device manufacturers to form a larger dataset of time series data collected from 44 patients receiving inpatient therapy services. To gain insights into the recovery process, we use this dataset to build models that predict a patient's next day physical activity duration and next night sleep duration. Using our data-driven approach and the combined dataset, we obtained a normalized root mean square error prediction of 9.11% for daytime physical activity and 11.18% for nighttime sleep duration. Our sleep result is comparable to the accuracy we achieved using the manufacturer's sleep labels (12.26%). Our device-independent predictions are suitable for both point-of-care and remote monitoring applications to provide information to clinicians for customizing therapy services and potentially decreasing recovery time.

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.

Relationships between Post-Concussion Sleep and Symptom Recovery: A Preliminary Study

Post-concussion sleep disturbances can be debilitating and may influence days to symptom recovery; however, evidence is minimal. The purpose of this study was to explore relationships between days to symptom recovery and aspects of sleep, as measured by actigraphy and subjective sleep questionnaires in a concussed sample. Thirty-one college students were physician-diagnosed with a concussion and asked to complete a daily sleep symptom checklist. Participants (n = 14) were excluded based on lack of compliance/early termination (22.6%), recorded <5 nights of data (12.9%), and protracted recoveries (3.2%). Final concussed sample included 17 college-aged students (varsity student-athletes, n = 5; university students, n = 12). A wrist-worn ActiGraph GT9X Link was provided during initial evaluation (within 72 h post-injury) and worn continuously until symptom recovery (follow-up evaluation; 14.3 ± 5.9 days post-injury). The Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) also were completed at follow-up. Pearson's correlations were conducted to determine relationships between days to symptom recovery and actigraphy sleep outcomes (sleep onset latency, wake after sleep onset (WASO_norm), total sleep time, sleep efficiency (SE), and number of awakenings) across recovery stages (2-3 days post-injury, mid-point, and end). Spearman's rho correlations were used to determine relationships between subjective sleep (PSQI global), sleepiness (ESS total), and sleep cluster symptom severity and days to symptom recovery. At recovery mid-point, individuals who were awake longer throughout the night (24.1 ± 9.0%) and/or were less efficient at sleeping (73.7 ± 9.7%) took longer to recover (WASO_norm: r = 0.58, p = 0.015; SE: r = -0.51, p = 0.035). Poorer post-concussion sleep quality (based on PSQI) was correlated with longer recovery (r_s = 0.70, p = 0.001). Post-concussion sleep-wake disturbances at recovery mid-point and overall poorer sleep quality may be associated with longer symptom recovery. Our findings provide preliminary guidance on identifying those who may be at risk for longer recoveries based on poorer sleep post-injury.

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

Study Objectives

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

Methods

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

Results

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

Conclusions

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

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.

Hypocretin Mediates Sleep and Wake Disturbances in a Mouse Model of Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of disability worldwide. Post-TBI sleep and wake disturbances are extremely common and difficult for patients to manage. Sleep and wake disturbances contribute to poor functional and emotional outcomes from TBI, yet effective therapies remain elusive. A more comprehensive understanding of mechanisms underlying post-TBI sleep and wake disturbance will facilitate development of effective pharmacotherapies. Previous research in human patients and animal models indicates that altered hypocretinergic function may be a major contributor to sleep-wake disturbance after TBI. In this study, we further elucidate the role of hypocretin by determining the impact of TBI on sleep-wake behavior of hypocretin knockout (HCRT KO) mice. Adult male C57BL/6J and HCRT KO mice were implanted with electroencephalography recording electrodes, and pre-injury baseline recordings were obtained. Mice were then subjected to either moderate TBI or sham surgery. Additional recordings were obtained and sleep-wake behavior determined at 3, 7, 15, and 30 days after TBI or sham procedures. At baseline, HCRT KO mice had a significantly different sleep-wake phenotype than control C57BL/6J mice. Post-TBI sleep-wake behavior was altered in a genotype-dependent manner: sleep of HCRT KO mice was not altered by TBI, whereas C57BL/6J mice had more non-rapid eye movement sleep, less wakefulness, and more short wake bouts and fewer long wake bouts. Numbers of hypocretin-positive cells were reduced in C57BL/6J mice by TBI. Collectively, these data indicate that the hypocretinergic system is involved in the alterations in sleep-wake behavior that develop after TBI in this model, and suggest potential therapeutic interventions.

Weekly sleep trajectories and their associations with obesity and hypertension in the Hispanic/Latino population

Study Objectives

To identify weekly sleep trajectories (sleep pattern changing by day over a course of week) of specific characteristics and examine the associations between trajectory classes and obesity and hypertension.

Methods

A total of 2043 participants (mean age 46.9, 65.5% female) completed at least 7 days of actigraphy aged 18-64 from the Sueño ancillary study of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Weekly sleep trajectories for three daily level measures (wake after sleep onset [WASO], daytime napping duration, and intranight instability index) were identified using latent class growth models. The outcomes were obesity and hypertension.

Results

Using the trajectory with low-stable WASO as reference, the trajectory classes with increasing and high-concave patterns had significantly higher odds for obesity (OR 3.64 [1.23-10.84]) and hypertension (OR 5.25 [1.33, 20.82]), respectively. Compared with individuals with a low-stable napping duration trajectory, those with the high-concave pattern class were associated with hypertension (OR 2.27 [1.10-4.67]), and the association was mediated in part by obesity (OR 1.11 [1.00-1.22]). Individuals in the high intranight instability index trajectory had significantly larger likelihood for both obesity (OR 1.90 [1.26-2.86]) and hypertension (OR 1.86 [1.13-3.06]) compared with those in the low intranight instability index trajectory.

Conclusions

Weekly trajectories varied for WASO, daytime napping duration, and intranight instability index. The trajectories with relatively larger values for these three measures were associated with greater risk for obesity and hypertension. These findings suggest that a stable pattern with relatively small weekly and nightly variability may be beneficial for cardiovascular health.

A Qualitative Study of Sleep-Wake Disturbance Among Veterans With Post-Acute Moderate to Severe Traumatic Brain Injury

OBJECTIVE

Examine sleep-wake disturbance (SWD) characteristics, factors, consequences, and management strategies from the perspective of veterans with chronic stage, moderate/severe traumatic brain injury (TBI).

SETTING

VA Medical Center, Rocky Mountain.

US PARTICIPANTS

Nineteen male veterans with post-acute TBI and SWD in the VA Health Administration.

DESIGN

Qualitative descriptive.

MEASURES

Semistructured interviews, Ohio State University TBI-Identification Method, Insomnia Severity Index.

RESULTS

Two main dimensions emerged: "Messed up sleep" and Surviving and Managing SWD. Sleep-wake disturbance has long-term multidimensional features, etiology, consequences, and practice implications. Although SWD may not be consistently discussed with providers, the problem appears to be pervasive in many aspects of the lives of the informants. Difficulty falling asleep, frequent awakenings, and poor sleep quality were common symptoms that were described as intrusive, isolating, and difficult to self-manage. Veterans discussed a host of physical symptoms, mental health issues, environmental, and behavioral factors that contributed to SWD. Medications, sleep apnea treatment, and self-imposed isolation were frequent management strategies. Veterans expressed a willingness to try new approaches and work with providers.

CONCLUSION

Sleep-wake disturbance among veterans with chronic stage TBI is a multidimensional phenomenon with interplay between comorbidities, contributing factors, effects on functioning, and sleep management strategies. Implications for practice include early and routine evaluation, monitoring, and treatment of SWD. Research is needed to test interventions that address SWD and common TBI comorbidities.

Parallel recovery of consciousness and sleep in acute traumatic brain injury

OBJECTIVE

To investigate whether the progressive recuperation of consciousness was associated with the reconsolidation of sleep and wake states in hospitalized patients with acute traumatic brain injury (TBI).

METHODS

This study comprised 30 hospitalized patients (age 29.1 ± 13.5 years) in the acute phase of moderate or severe TBI. Testing started 21.0 ± 13.7 days postinjury. Consciousness level and cognitive functioning were assessed daily with the Rancho Los Amigos scale of cognitive functioning (RLA). Sleep and wake cycle characteristics were estimated with continuous wrist actigraphy. Mixed model analyses were performed on 233 days with the RLA (fixed effect) and sleep-wake variables (random effects). Linear contrast analyses were performed in order to verify if consolidation of the sleep and wake states improved linearly with increasing RLA score.

RESULTS

Associations were found between scores on the consciousness/cognitive functioning scale and measures of sleep-wake cycle consolidation (p < 0.001), nighttime sleep duration (p = 0.018), and nighttime fragmentation index (p < 0.001). These associations showed strong linear relationships (p < 0.01 for all), revealing that consciousness and cognition improved in parallel with sleep-wake quality. Consolidated 24-hour sleep-wake cycle occurred when patients were able to give context-appropriate, goal-directed responses.

CONCLUSIONS

Our results showed that when the brain has not sufficiently recovered a certain level of consciousness, it is also unable to generate a 24-hour sleep-wake cycle and consolidated nighttime sleep. This study contributes to elucidating the pathophysiology of severe sleep-wake cycle alterations in the acute phase of moderate to severe TBI.

Sleep Quantity and Quality during Acute Concussion: A Pilot Study

STUDY OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Trajectories of Sleep and Its Predictors in the First Year Following Traumatic Brain Injury

OBJECTIVES

To examine how sleep patterns change over the first year following traumatic brain injury (TBI) and to determine whether specific demographic and disease characteristics predict the trajectories of sleep.

DESIGN

Prospective study.

PARTICIPANTS

Fifty-three patients with first-ever mild to severe TBI.

MAIN MEASUREMENTS

Sleep measured by actigraphy for 7 consecutive days in the first, third, sixth, and twelfth months following TBI: Chinese versions of Beck Anxiety Inventory and Beck Depression Inventory-II (CBDI-II) measured at the same time points. Data were analyzed with a linear mixed model.

RESULTS

Sleep efficiency (the ratio of sleep time to the total time spent in bed) showed a significant upward trend during the study period. Scores on the Chinese version of the Beck Anxiety Inventory and the CBDI-II as well as the use of analgesics significantly predicted the slope of change in sleep efficiency over time.

CONCLUSIONS

Poor sleep efficiency is a common symptom in the first year among patients with first-ever TBI. Healthcare providers should consider both mental health and pain issues when dealing with sleep complaints in patients with TBI.

Alterations in Daytime and Nighttime Activity in Piglets after Focal and Diffuse Brain Injury

We have developed and implemented a noninvasive, objective neurofunctional assessment for evaluating the sustained effects of traumatic brain injury (TBI) in piglets with both diffuse and focal injury types. Derived from commercial actigraphy methods in humans, this assessment continuously monitors the day/night activity of piglets using close-fitting jackets equipped with tri-axial accelerometers to monitor movements of the thorax. Acceleration metrics were correlated (N = 7 naïve piglets) with video images to define values associated with a range of activities, from recumbancy (rest) to running. Both focal (N = 8) and diffuse brain injury (N = 9) produced alterations in activity that were significant 4 days post-TBI. Compared to shams (N = 6) who acclimated to the animal facility 4 days after an anesthesia experience by blurring the distinction between day and night activity, post-TBI time-matched animals had larger fractions of inactive periods during the daytime than nighttime, and larger fractions of active time in the night were spent in high activity (e.g., constant walking, intermittent running) than during the day. These persistent disturbances in rest and activity are similar to those observed in human adults and children post-TBI, establishing actigraphy as a translational metric, used in both humans and large animals, for assessment of injury severity, progressions, and intervention.

Increased Incidence of Herpes Zoster and Postherpetic Neuralgia in Adult Patients following Traumatic Brain Injury: A Nationwide Population-Based Study in Taiwan

The aims of this study were to estimate the incidences of herpes zoster (HZ) and postherpetic neuralgia (PHN) in patients after traumatic brain injury (TBI). Furthermore, we aimed to explore the risk factors of the development of HZ and PHN in patients after TBI. This population-based, longitudinal analysis was conducted using the Taiwan National Health Insurance Research Database (consisting of 1,000,000 beneficiaries) from 1996 to 2010. Using the longitudinal National Health Insurance Research Database, we conducted a retrospective population-based cohort study to evaluate the incidence of HZ and PHN in adult TBI patients and controls. Kaplan-Meier analysis and Cox regression were used to compare differences in the development of HZ and PHN. The effects of gender, comorbidity and surgery on the risk of HZ and PHN development were assessed by subgroup analyses. Over a 15-year follow-up, the cumulative incidence of HZ in 28,234 TBI patients (604.00/100,000 person-years) was significantly higher than 34,085 controls (322.21/100,000 person-years) (P<0.0001, by log-rank test). Females showed a significantly higher incidence of HZ than males (p for interaction = 0.0010). The time to HZ development in the follow-up period was 5.9 years in TBI patients compared to 9.9 years in the control set (p <0.0001). TBI patients were 2.93 and 2.11 times likely to develop HZ and PHN, respectively, than the general population. The incidences of HZ and PHN in TBI patients were also significantly greater than for controls in the CCI = 0 subgroup. To our knowledge, this is the first population-based cohort study to reveal that TBI is an independent risk factor for HZ and PHN in TBI patients, especially in females. Physician should pay attention to the possibility of HZ and PHN in TBI patients and be aware that HZ vaccination early after brain trauma may lower the incidence of HZ and PHN.

The effects of sleep on the relationship between brain injury severity and recovery of cognitive function: a prospective study

BACKGROUND

Disturbed sleep pattern is a common symptom after head trauma and its prevalence in acute traumatic brain injury (TBI) is less discussed. Sleep has a profound impact on cognitive function recovery and the mediating effect of disturbed sleep on cognitive function recovery has not been examined after acute TBI.

OBJECTIVES

To identify the prevalence of disturbed sleep in mild, moderate, and severe acute TBI patients, and to determine the mediating effects of sleep on the relationship between brain injury severity and the recovery of cognitive function.

DESIGN

A prospective study design.

SETTING

Neurosurgical wards in a medical center in northern Taiwan.

PARTICIPANTS

Fifty-two acute TBI patients between the ages of 18 and 65 years who had received a diagnosis of TBI for the first time, and were admitted to the neurosurgical ward.

METHOD

The severity of brain injury was initially determined using the Glasgow Coma Scale. Each patient wore an actigraphy instrument on a non-paralytic or non-dominated limb for 7 consecutive days. A 7-day sleep diary was used to facilitate data analysis. Cognitive function was assessed on the first and seventh day after admission based on the Rancho Los Amigos Levels of Cognitive Functioning.

RESULTS

The mild (n=35), moderate (n=7) and severe (n=10) TBI patients exhibited poorer sleep efficiency, and longer total sleep time (TST) and waking time after sleep onset, compared with the normative values for the sleep-related variables (P<.05 for all). The severe and moderate TBI patients had longer daytime TST than the mild TBI patients (P<.001), and the severe TBI patients had longer 24-h TST than the mild TBI patients (P=.001). The relationship between the severity of brain injury and the recovery of cognition function was mediated by daytime TST (t=-2.65, P=.004).

CONCLUSIONS

Poor sleep efficiency, prolonged periods of daytime sleep, and a high prevalence of hypersomnia are common symptoms in acute TBI patients. The duration of daytime sleep mediates the relationship between the severity of brain injury and the recovery of cognition function.