Sleep and stroke

Do changes in beliefs and behaviours moderate improvement in insomnia after acquired brain injury?

Key mechanisms of change in cognitive behavioural therapy for insomnia in the general population encompass changing sleep-related beliefs and behaviours. In a population with acquired brain injury, cognitive behavioural therapy for insomnia is effective as well, but little is known about the mechanisms of change. The aim of this study was to evaluate how changing sleep-related beliefs and behaviours were associated with improvement in insomnia following blended cognitive behavioural therapy for insomnia in a population with acquired brain injury. A secondary analysis was performed on data of a randomized-controlled trial, including 24 participants that received blended cognitive behavioural therapy for insomnia, and 24 participants that received treatment as usual. Results showed that following blended cognitive behavioural therapy for insomnia, significantly more participants improved on dysfunctional beliefs and sleep-related behaviours and this was associated to improvement in insomnia severity. For sleep-related behaviours, the association between improvement on behaviour and improvement on insomnia was significantly moderated by blended cognitive behavioural therapy for insomnia. However, the relation between dysfunctional beliefs and insomnia was not moderated by type of treatment. Similar results were found for acquired brain injury-adapted versions of the questionnaires in which up to half of the items were excluded as they could be regarded as not dysfunctional for people with acquired brain injury. These results show that improvement on insomnia severity is related to improvement in dysfunctional beliefs and behaviours, and cognitive behavioural therapy for insomnia efficacy may be moderated by the improvement in behaviours in particular. A focus on these behaviours can enhance treatment efficacy, but caution is needed regarding the behaviours that may reflect adequate coping with the consequences of the acquired brain injury.

Are sleep-related beliefs and behaviours dysfunctional in people with insomnia after acquired brain injury? A cross-sectional study

Inappropriate sleep-related beliefs and behaviours are considered key maladaptive mechanisms in the development and maintenance of insomnia in the otherwise healthy population. The aim of this study was to evaluate critically the role of sleep-related beliefs and behaviours in insomnia after acquired brain injury. Cross-sectional data of 51 outpatients with insomnia disorder and acquired brain injury were used to evaluate associations of the insomnia severity index with the dysfunctional beliefs and attitudes about sleep scale and sleep-related behaviours questionnaire. Seven (44%) of the dysfunctional beliefs and attitudes about sleep scale items and 10 (31%) of the sleep-related behaviours questionnaire items correlated significantly with insomnia severity. Ten experts were consulted on whether they considered the questionnaire items maladaptive or accurately reflecting coping with conditions experienced by people with acquired brain injury. Although multiple linear regression showed that the total scores of the questionnaires explained a significant part of interindividual differences in insomnia severity (R2 = 0.27, F(2,48) = 8.72, p < 0.01), the experts unanimously rated only four (25%) of the dysfunctional beliefs and attitudes about sleep scale items as dysfunctional beliefs and three (9%) of the sleep-related behaviours questionnaire items as safety behaviours. In people with brain injury, sleep related beliefs and behaviours may also play a role in insomnia, especially a diminished perception of control and worry about sleep. However, more than half of the questionnaire items on sleep-related beliefs and behaviours may not be considered inappropriate and maladaptive for the acquired brain injury population, and may reflect adequate observations and efforts in coping with consequences of the brain damage.

Circadian Rhythm Disturbance in Acute Ischemic Stroke Patients and Its Effect on Prognosis

INTRODUCTION

Poststroke sleep disturbances are common and can affect stroke outcomes, but the clinical studies mainly focus on breathing-related sleep disorders, while the bidirectional impact of circadian rhythm dysfunction in ischemic stroke remains unknown. This study observed the characteristics of melatonin secretion in acute ischemic stroke patients and evaluated whether melatonin rhythm impacts the prognosis after stroke by assessing the neurological function, cognition, emotion, and quality of life 3 months after stroke.

METHODS

Acute ischemic stroke patients were selected from the Department of Neurology Inpatients of the Second Hospital affiliated with Soochow University from October 2019 to July 2021. Healthy control subjects were recruited at the same time. Demographic and clinical data were collected, and relevant scale scores (including neurological function, cognition, emotion, and sleep) were assessed within 2 weeks of onset and followed up 3 months later. All participants collected salivary melatonin samples on the 4th day of hospitalization and dim light melatonin onset (DLMO) was calculated according to melatonin concentration. Stroke patients were then divided into three groups based on their DLMO values.

RESULTS

A total of 74 stroke patients and 33 control subjects were included in this analysis. Compared with healthy controls, stroke patients exhibited a delayed melatonin rhythm during the acute phase of stroke (21:36 vs. 20:38, p = 0.004). Stroke patients were then divided into three groups, namely normal (n = 36), delayed (n = 28), or advanced DLMO (n = 10), based on their DLMO values. A χ2 test showed that there were significant differences in the rate of poor prognosis (p = 0.011) and depression tendency (p = 0.028) among the three groups. A further pairwise comparison revealed that stroke patients with delayed DLMO were more likely to experience poor short-term outcomes than normal DLMO group (p = 0.003). The average melatonin concentration of stroke patients at 5 time points was significantly lower than that of the control group (3.145 vs. 7.065 pg/mL, p < 0.001). Accordingly, we split stroke patients into three groups, namely low melatonin level (n = 14), normal melatonin level (n = 54), or high melatonin level (n = 6). Unfortunately, there were no great differences in the clinical characteristics, cognition, emotion, sleep quality, and short-term outcome among groups.

CONCLUSIONS

This is a preliminary study, and our results indicate that changes in melatonin secretion phase of stroke patients may have effect on their short-term prognosis.

A blended eHealth intervention for insomnia following acquired brain injury: a randomised controlled trial

The high prevalence and severe consequences of poor sleep following acquired brain injury emphasises the need for an effective treatment. However, treatment studies are scarce. The present study evaluates the efficacy of blended online cognitive behavioural therapy for insomnia (eCBT-I) developed specifically for people with acquired brain injury. In a multicentre prospective, open-label, blinded end-point randomised clinical trial, 52 participants with insomnia and a history of a stroke or traumatic brain injury were randomised to 6 weeks of guided eCBT-I or treatment as usual, with a 6-week follow-up. The primary outcome measure was the change in insomnia severity between baseline and after treatment, measured with the Insomnia Severity Index. Results showed that insomnia severity improved significantly more with eCBT-I than with treatment as usual compared to baseline, both at post-treatment (mean [SEM] 4.0 [1.3] insomnia severity index points stronger decrease, d = 0.96, p < 0.003) and at follow-up (mean [SEM] 3.2 [1.5] insomnia severity index points, d = -0.78, p < 0.03). In conclusion, our randomised clinical trial shows that blended CBT is an effective treatment for insomnia, and feasible for people with acquired brain injury, regardless of cognitive and psychiatric complaints. Online treatment has major advantages in terms of availability and cost and may contribute to the successful implementation of insomnia treatment for people with acquired brain injuries.

Validation Study of the Richards-Campbell Sleep Questionnaire in Patients with Acute Stroke

Sleep disorders are frequent in acute stroke. The Richards-Campbell Sleep Questionnaire (RCSQ) is a validated scale for the sleep assessment in intensive care unit. The aim of the present study is to validate RCSQ for use in patients with acute stroke. We performed a validation study by comparing the RCSQ with polysomnography (PSG), the standardized measure of sleep. Inclusion criteria were age ≥ 18 years and a radiologically confirmed diagnosis of stroke. Exclusion criteria were global aphasia, extreme severity of clinical conditions and inability to attend PSG. All patients underwent PSG in a stroke unit, the day after a subjective sleep assessment by means of the RCSQ. The RCSQ was compared with PSG parameters to assess the degree of concordance of the two measures. The cohort consisted of 36 patients. Mean RCSQ score was 61.5 ± 24.8. The total score of the RCSQ showed a good degree of concordance with the sleep efficiency index of PSG. Accuracy of the RCSQ was 70%, sensitivity 71% and specificity 68%. The RCSQ is a good tool for screening the sleep quality in the setting of a stroke unit. Therefore, it could be useful to select the patients who might beneficiate from an instrumental sleep evaluation.

Sleep Monitoring during Acute Stroke Rehabilitation: Toward Automated Measurement Using Multimodal Wireless Sensors

Sleep plays a critical role in stroke recovery. However, there are limited practices to measure sleep for individuals with stroke, thus inhibiting our ability to identify and treat poor sleep quality. Wireless, body-worn sensors offer a solution for continuous sleep monitoring. In this study, we explored the feasibility of (1) collecting overnight biophysical data from patients with subacute stroke using a simple sensor system and (2) constructing machine-learned algorithms to detect sleep stages. Ten individuals with stroke in an inpatient rehabilitation hospital wore two wireless sensors during a single night of sleep. Polysomnography served as ground truth to classify different sleep stages. A population model, trained on data from multiple patients and tested on data from a separate patient, performed poorly for this limited sample. Personal models trained on data from one patient and tested on separate data from the same patient demonstrated markedly improved performance over population models and research-grade wearable devices to detect sleep/wake. Ultimately, the heterogeneity of biophysical signals after stroke may present a challenge in building generalizable population models. Personal models offer a provisional method to capture high-resolution sleep metrics from simple wearable sensors by leveraging a single night of polysomnography data.

Images: polysomnographic findings of nystagmus caused by a midbrain hemorrhagic stroke

Brainstem strokes can present with an array of ophthalmologic findings depending on the location of the lesion. Eye movements are recorded on electrooculogram during polysomnography for sleep staging. We present the case of a patient with a dorsal midbrain hemorrhagic stroke and nystagmus with distinct findings on the electrooculogram during polysomnography. These eye movements from nystagmus differed in many aspects (frequency and amplitude) from the classic findings of other eye movements recorded during different stages of sleep. These polysomnography findings have not been reported in the setting of midbrain stroke. Future studies comparing nystagmus in multiple sleep stages in stroke patients would be of interest.

CITATION

Shoukat U, Glick DR, Chaturvedi S, Diaz-Abad M. Images: Polysomnographic findings of nystagmus caused by a midbrain hemorrhagic stroke. J Clin Sleep Med. 2022;18(5):1479-1482.

Measuring Sleep, Wakefulness, and Circadian Functions in Neurologic Disorders

Neurologic disorders impact the ability of the brain to regulate sleep, wake, and circadian functions, including state generation, components of state (such as rapid eye movement sleep muscle atonia, state transitions) and electroencephalographic microarchitecture. At its most extreme, extensive brain damage may even prevent differentiation of sleep stages from wakefulness (eg, status dissociatus). Given that comorbid sleep-wake-circadian disorders are common and can adversely impact the occurrence, evolution, and management of underlying neurologic conditions, new technologies for long-term monitoring of neurologic patients may potentially usher in new diagnostic strategies and optimization of clinical management.

Combination of Alprazolam and Bailemian Capsule Improves the Sleep Quality in Patients With Post-Stroke Insomnia: A Retrospective Study

Insomnia is often ignored in the diagnosis and treatment of patients of stroke. The present study aimed to evaluate the efficacy of alprazolam (ALP) combined with Bailemian capsule (BC, a traditional Chinese patent medicine) in the treatment of post-stroke insomnia (PSI). A total of 231 stroke patients involved in this retrospective study were treated with ALP, BC, or ALP + BC for 3 weeks. The quality of sleep was evaluated by the Pittsburgh Sleep Quality Index (PSQI) and polysomnography (PSG), while self-care ability was monitored by the modified Rankin Scale (mRS) before and after treatment. Compared with the baseline, the self-care ability of patients in each group was significantly improved after treatment (P < 0.01). The PSQI data showed a significant improvement in all patients in all of the subjective PSQI items and global score (P < 0.05). Notably, ALP + BC administration had a significantly greater effect on sleep latency, quality, disturbance, and efficiency, as well as daytime dysfunction and global PSQI than the use of ALP or BC alone (P < 0.05). The PSG data showed that ALP significantly improved the sleep efficiency and decreased the arousal times, rapid eye movement (REM) sleep, and sleep latency (P < 0.05), while BC significantly improved the sleep efficiency, total sleep time, and the duration of N3 (P < 0.05). Strikingly, ALP + BC achieved the effect of both ALP and BC (P < 0.05). Importantly, the effect of the combination of ALP and BC was greater than the use of ALP or BC alone, which was consistent with the result of PSQI. In conclusion, the sleep quality and self-care ability of patients with PSI were improved by ALP and BC, thereby supporting the potential advantages of ALP combined with BC in the treatment of patients with PSI.

Sleep Disturbances as a Risk Factor for Stroke

Sleep, a vital process of human being, is carefully orchestrated by the brain and consists of cyclic transitions between rapid eye movement (REM) and non-REM (NREM) sleep. Autonomic tranquility during NREM sleep is characterized by vagal dominance and stable breathing, providing an opportunity for the cardiovascular-neural axis to restore homeostasis, in response to use, distress or fatigue inflicted during wakefulness. Abrupt irregular swings in sympathovagal balance during REM sleep act as phasic loads on the resting cardiovascular system. Any causes of sleep curtailment or fragmentation such as sleep restriction, sleep apnea, insomnia, periodic limb movements during sleep, and shift work, not only impair cardiovascular restoration but also impose a stress on the cardiovascular system. Sleep disturbances have been reported to play a role in the development of stroke and other cardiovascular disorders. This review aims to provide updated information on the role of abnormal sleep in the development of stroke, to discuss the implications of recent research findings, and to help both stroke clinicians and researchers understand the importance of identification and management of sleep pathology for stroke prevention and care.

Nonmotor Symptoms in Vascular and Other Secondary Parkinsonism

Vascular parkinsonism (VP) is a relatively frequent variant of secondary parkinsonism caused by ischemic or hemorrhagic lesions of basal ganglia, midbrain, or their links with frontal cortex. According to different investigations, various forms of cerebrovascular disease cause 1%-15% of parkinsonism cases. Nonmotor symptoms are frequently found in VP and may negatively influence on quality of life. However, nonmotor symptoms such as hallucinations, orthostatic hypotension, REM-sleep behavior disorder, and anosmia are rarely revealed in VP, which may be noted to another diagnosis or mixed pathology. Clinical value of nonmotor symptoms in normal pressure hydrocephalus, toxic, and drug-induced parkinsonism is also discussed.

Role of REM Sleep, Melanin Concentrating Hormone and Orexin/Hypocretin Systems in the Sleep Deprivation Pre-Ischemia

STUDY OBJECTIVES

Sleep reduction after stroke is linked to poor recovery in patients. Conversely, a neuroprotective effect is observed in animals subjected to acute sleep deprivation (SD) before ischemia. This neuroprotection is associated with an increase of the sleep, melanin concentrating hormone (MCH) and orexin/hypocretin (OX) systems. This study aims to 1) assess the relationship between sleep and recovery; 2) test the association between MCH and OX systems with the pathological mechanisms of stroke.

METHODS

Sprague-Dawley rats were assigned to four experimental groups: (i) SD_IS: SD performed before ischemia; (ii) IS: ischemia; (iii) SD_Sham: SD performed before sham surgery; (iv) Sham: sham surgery. EEG and EMG were recorded. The time-course of the MCH and OX gene expression was measured at 4, 12, 24 hours and 3, 4, 7 days following ischemic surgery by qRT-PCR.

RESULTS

A reduction of infarct volume was observed in the SD_IS group, which correlated with an increase of REM sleep observed during the acute phase of stroke. Conversely, the IS group showed a reduction of REM sleep. Furthermore, ischemia induces an increase of MCH and OX systems during the acute phase of stroke, although, both systems were still increased for a long period of time only in the SD_IS group.

CONCLUSIONS

Our data indicates that REM sleep may be involved in the neuroprotective effect of SD pre-ischemia, and that both MCH and OX systems were increased during the acute phase of stroke. Future studies should assess the role of REM sleep as a prognostic marker, and test MCH and OXA agonists as new treatment options in the acute phase of stroke.

The role of sleep in recovery following ischemic stroke: A review of human and animal data

Despite advancements in understanding the pathophysiology of stroke and the state of the art in acute management of afflicted patients as well as in subsequent neurorehabilitation training, stroke remains the most common neurological cause of long-term disability in adulthood. To enhance stroke patients' independence and well-being it is necessary, therefore, to consider and develop new therapeutic strategies and approaches. We postulate that sleep might play a pivotal role in neurorehabilitation following stroke. Over the last two decades compelling evidence for a major function of sleep in neuroplasticity and neural network reorganization underlying learning and memory has evolved. Training and learning of new motor skills and knowledge can modulate the characteristics of subsequent sleep, which additionally can improve memory performance. While healthy sleep appears to support neuroplasticity resulting in improved learning and memory, disturbed sleep following stroke in animals and humans can impair stroke outcome. In addition, sleep disorders such as sleep disordered breathing, insomnia, and restless legs syndrome are frequent in stroke patients and associated with worse recovery outcomes. Studies investigating the evolution of post-stroke sleep changes suggest that these changes might also reflect neural network reorganization underlying functional recovery. Experimental and clinical studies provide evidence that pharmacological sleep promotion in rodents and treatment of sleep disorders in humans improves functional outcome following stroke. Taken together, there is accumulating evidence that sleep represents a "plasticity state" in the process of recovery following ischemic stroke. However, to test the key role of sleep and sleep disorders for stroke recovery and to better understand the underlying molecular mechanisms, experimental research and large-scale prospective studies in humans are necessary. The effects of hospital conditions, such as adjusting light conditions according to the patients' sleep-wake rhythms, or sleep promoting drugs and non-invasive brain stimulation to promote neuronal plasticity and recovery following stroke requires further investigation.

Sleep apnoea and stroke

Sleep disorders have been known to physicians for a long time. In his famous aphorisms, Hippocrates said “Sleep or watchfulness exceeding that which is customary, augurs unfavorably”. Modern medicine has been able to disentangle some of the phenomena that disturb sleep. Among the most notable offenders is sleep apnoea that has gained prominence in the past few decades. It is being proposed as one of the potentially modifiable risk factors for vascular diseases including stroke. The pathological mechanisms linking sleep apnoea to vascular risk factors include hypoxia, cardiac arrhythmias, dysautonomia, impaired glucose tolerance, hypertension, dyslipidaemia and inflammation. In this article, we review literature linking sleep apnoea and stroke, including sleep apnoea as a risk factor for primary prevention with the potential to improve outcome after acute stroke and as a secondary risk factor, amenable to modification and hence vascular risk reduction.

Semantic clustering and sleep in patients with amnestic mild cognitive impairment or with vascular cognitive impairment-no dementia

BACKGROUND

Cognition and sleep deficits occur in amnestic mild cognitive impairment (aMCI) and vascular cognitive impairment-no dementia (VCIND). However, how memory and sleep deficits differ between aMCI and VCIND remains unclear.

METHODS

Fifty aMCI and 50 VCIND patients and 38 sex- and age-matched healthy controls (HCs) were administered the Hopkins Verbal Learning Test-Revised (HVLT-R), Trail Making Test-A/B (TMT-A/B), Wisconsin Card Sorting Test (WCST), Paced Auditory Serial Addition Test (PASAT), Symbol Digit Modalities Test (SDMT), Benton Judgment of Line Orientation (JLO) test, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Insomnia Severity Index (ISI) to quantify cognitive deficits and subjective sleep disturbance.

RESULTS

Compared with VCIND patients, aMCI patients had lower HVLT-R scores for total recall (p < 0.001), delayed recall (p < 0.001) and recognition (p = 0.001), and for total-recall (p = 0.002) and delayed-recall (p < 0.001) semantic clustering ratios (SCRs). However, VCIND patients exhibited more obvious executive dysfunction (TMT-A, p < 0.001; TMT-B, p < 0.001; WCST, p < 0.001), lower information processing speed (PASAT, p = 0.003; SDMT, p < 0.001), and more severe sleep disturbance (PSQI, p < 0.001; ESS, p < 0.001; ISI, p < 0.001). Additionally, sleep quality and efficiency were related to total and delayed recall (all r values from -0.31 to -0.60, p < 0.05) in aMCI and VCIND.

CONCLUSIONS

aMCI and VCIND differ in cognitive function, memory strategy and sleep impairment; these characteristics are helpful to identify and distinguish patients with very early cognitive impairment. Our results also suggest that memory deficits are associated with sleep disturbance in aMCI and VCIND.

Application of Transcranial Direct Current Stimulation in Neurorehabilitation: The Modulatory Effect of Sleep

The relationship between sleep disorders and neurological disorders is often reciprocal, such that sleep disorders are worsened by neurological symptoms and that neurological disorders are aggravated by poor sleep. Animal and human studies further suggest that sleep disruption not only worsens single neurological symptoms but may also lead to long-term negative outcomes. This suggests that sleep may play a fundamental role in neurorehabilitation and recovery. We further propose that sleep may not only alter the efficacy of behavioral treatments but also plasticity-enhancing adjunctive neurostimulation methods, such as transcranial direct current stimulation (tDCS). At present, sleep receives little attention in the fields of neurorehabilitation and neurostimulation. In this review, we draw together the strands of evidence from both fields of research to highlight the proposition that sleep is an important parameter to consider in the application of tDCS as a primary or adjunct rehabilitation intervention.

Polysomnographic Characteristics of Sleep in Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

Research on sleep after stroke has focused mainly on sleep disordered breathing. However, the extend to which sleep physiology is altered in stroke survivors, how these alterations compare to healthy volunteers, and how sleep changes might affect recovery as well as physical and mental health has yet to be fully researched. Motivated by the view that a deeper understanding of sleep in stroke is needed to account for its role in health and well-being as well as its relevance for recovery and rehabilitation, we conducted a systematic review and meta-analysis of polysomnographic studies comparing stroke to control populations.

METHOD

Medline and PsycInfo databases were searched using "stroke" and words capturing polysomnographic parameters as search terms. This yielded 1692 abstracts for screening, with 15 meeting the criteria for systematic review and 9 for meta-analysis. Prisma best practice guidelines were followed for the systematic review; the Comprehensive Meta-Analysis software was used for random effects modelling.

RESULTS

The meta-analysis revealed that patients with stroke have poorer sleep than controls. Patients had lower sleep efficiency (mean 75% vs 84%), shorter total-sleep-time (309.4 vs 340.3 min) and more wake-after-sleep-onset (97.2 vs 53.8 min). Patients also spend more time in stage 1 (13% vs 10%) and less time in stage 2 sleep (36% vs 45%) and slow-wave-sleep (10% vs 12%). No group differences were identified for REM sleep. The systematic review revealed a strong bias towards studies in the early recovery phase of stroke, with no study reporting specifically on patients in the chronic state. Moreover, participants in the control groups included community samples as well as other patients groups.

CONCLUSIONS

These results indicate poorer sleep in patients with stroke than controls. While strongly suggestive in nature, the evidence base is limited and methodologically diverse, and hands a clear mandate for further research. A particular need regards polysomnographic studies in chronic community-dwelling patients compared to age-matched individuals.

Factors Associated with Poststroke Fatigue: A Systematic Review

Background. Poststroke fatigue (PSF) is a frequent, disabling symptom that lacks a consensual definition and a standardized evaluation method. The (multiple) causes of PSF have not been formally characterized. Objective. To identify factors associated with PSF. Method. A systematic review of articles referenced in MEDLINE. Only original studies having measured PSF and potentially associated factors were included. Data was extracted from articles using predefined data fields. Results. Although PSF tends to be more frequent in female patients and older patients, sociodemographic factors do not appear to have a major impact. There are strong associations between PSF and emotional disturbances (such as depression and anxiety). PSF may also be linked to attentional disturbances (mainly slowing in processing speed). The literature data have failed to demonstrate a clear impact of the type and severity of stroke. It has been suggested that PSF results from alterations in the frontothalamostriatal system and/or inflammatory processes. Pain, sleep disorders, and prestroke fatigue also appeared to be associated with PSF. Implications. A better understanding of PSF may improve stroke patient care and facilitate the development of effective treatments.

Baclofen and gamma-hydroxybutyrate differentially altered behavior, EEG activity and sleep in rats

OBJECTIVES

Animal and human studies have shown that sleep may have an impact on functional recovery after brain damage. Baclofen (Bac) and gamma-hydroxybutyrate (GHB) have been shown to induce physiological sleep in humans, however, their effects in rodents are unclear. The aim of this study is to characterize sleep and electroencelphalogram (EEG) after Bac and GHB administration in rats. We hypothesized that both drugs would induce physiological sleep.

METHODS

Adult male Sprague-Dawley rats were implanted with EEG/electromyogram (EMG) electrodes for sleep recordings. Bac (10 or 20 mg/kg), GHB (150 or 300 mg/kg) or saline were injected 1 h after light and dark onset to evaluate time of day effect of the drugs. Vigilance states and EEG spectra were quantified.

RESULTS

Bac and GHB induced a non-physiological state characterized by atypical behavior and an abnormal EEG pattern. After termination of this state, Bac was found to increase the duration of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep (∼90 and 10 min, respectively), reduce sleep fragmentation and affect NREM sleep episode frequency and duration (p<0.05). GHB had no major effect on vigilance states. Bac drastically increased EEG power density in NREM sleep in the frequencies 1.5-6.5 and 9.5-21.5 Hz compared to saline (p<0.05), while GHB enhanced power in the 1-5-Hz frequency band and reduced it in the 7-9-Hz band. Slow-wave activity in NREM sleep was enhanced 1.5-3-fold during the first 1-2 h following termination of the non-physiological state. The magnitude of drug effects was stronger during the dark phase.

CONCLUSION

While both Bac and GHB induced a non-physiological resting state, only Bac facilitated and consolidated sleep, and promoted EEG delta oscillations thereafter. Hence, Bac can be considered a sleep-promoting drug and its effects on functional recovery after stroke can be evaluated both in humans and rats.

Adaptive servo-ventilation as treatment of persistent central sleep apnea in post-acute ischemic stroke patients

BACKGROUND

Adaptive servo-ventilation (ASV) is a well-established treatment of central sleep apnea (CSA) related to congestive heart failure (CHF). Few studies have evaluated the effectiveness and adherence in patients with CSA of other etiologies, and even less is known about treatment of CSA in patients of post ischemic stroke.

METHODS

A single-centre retrospective analysis of ASV treatment for CSA in post-acute ischemic stroke patients without concomitant CHF was performed. Demographics, clinical data, sleep studies, ventilator settings, and adherence data were evaluated.

RESULTS

Out of 154 patients on ASV, 15 patients had CSA related to ischemic stroke and were started on ASV a median of 11 months after the acute cerebrovascular event. Thirteen out of the 15 patients were initially treated with continuous positive airway pressure (11/15) and bilevel positive airway pressure (2/15) therapy with unsatisfactory control of CSA. ASV significantly improved AHI (46.7 ± 24.3 vs 8.5 ± 12/h, P = 0.001) and reduced ESS (8.7 ± 5.7 vs 5.6 ± 2.5, P = 0.08) with a mean nightly use of ASV of 5.4 ± 2.4 h at 3 months after the initiation of treatment. Results were maintained at 6 months.

CONCLUSION

ASV was well tolerated and clinically effective in this group of patients with persistent CSA after ischemic stroke.

Post-stroke apathy and hypersomnia lead to worse outcomes from acute rehabilitation

Apathy and hypersomnia occur after stroke and, by definition, reduce participation in rehabilitation, but their effect on outcome from acute rehabilitation is not known. We performed a retrospective review of 213 patients admitted to a stroke-specialized acute rehabilitation unit in the United States. All patients had ischemic or hemorrhagic stroke, and no dementia or dependence on others pre-stroke. We diagnosed apathy and hypersomnia using standardized documentation by treating therapists. We used multiple regression analysis to control for overall impairment (combination of strength, cognitive and sensory measures), age, time since stroke, and stroke type (ischemic or hemorrhagic). Forty-four (21%) of the patients had persistent apathy, and 12 (5.6%) had persistent hypersomnia. Both groups were more impaired in cognition, sustained attention, and more likely to be treated for depression. Patients with apathy were 2.4 times more likely to go to a nursing home, and had discharge FIM scores 12 points below the mean. Patients with hypersomnia were ten times more likely to go to a nursing home, and had discharge FIM scores 16 points below the mean. These findings indicate that studies to prospectively define these clinical factors and potential confounds using standardized tools are indicated, and if confirmed, justify studies to identify these patients early and develop targeted interventions.

Polysomnographic abnormalities in patients with vascular cognitive impairment-no dementia

OBJECTIVES

We aimed to investigate subjective sleep quality and polysomnographic sleep structure features in patients with vascular cognitive impairment-no dementia (VCIND).

METHODS

Fifty-six patients with VCIND, 48 patients with simple stroke (without cognitive impairment), and 48 control subjects were included. The Pittsburgh Sleep Quality Index (PSQI) and polysomnography (PSG) were used to analyze their sleep characteristics. The Montreal Cognitive Assessment (MoCA) was conducted to assess mental state.

RESULTS

Patients with VCIND had higher PSQI scores compared with control subjects and simple stroke patients (P<.01). PSG revealed that patients with VCIND or stroke were more likely to experience prolonged sleep latency (SL), decreased sleep efficiency (SE), increased arousal, and reduced deep sleep and rapid eye movement (REM) sleep than controls. Patients with VCIND had significantly longer SL, increased periodic leg movements in sleep (PLMS), decreased SE, and increased arousal and sleep fragmentation compared to patients with simple stroke (P<.05). In VCIND patients, a significant positive correlation was found between SE and MoCA scores (r=0.632; P<.001), though PSQI, SL, and arousal index were significantly negatively associated with MoCA scores (r=-0.787, -0.740, -0.772, respectively; P<.001 for all).

CONCLUSIONS

VCIND patients had different abnormal sleep features, including decreased SE, increased PLMS, and prolonged SL and sleep fragmentation. Abnormal sleep in VCIND may be associated with cognitive impairment.

Sleep deprivation before stroke is neuroprotective: a pre-ischemic conditioning related to sleep rebound

BACKGROUND AND AIM

We have previously shown in a rat model of focal cerebral ischemia that sleep deprivation after stroke onset aggravates brain damage. Others reported that sleep deprivation prior to stroke is neuroprotective. The main aim of this study was to test the hypothesis that the neuroprotection may be related to an increase in sleep (sleep rebound) during the acute phase of stroke.

METHODS

Male Sprague Dawley rats (n=36) were subjected to continuous polygraphic recordings for baseline, total sleep deprivation (TSD), and 24h after ischemia. TSD for 6h was performed by gentle handling and immediately followed by ischemia. Focal cerebral ischemia was induced by permanent occlusion of distal branches of the middle cerebral artery. Control experiments included ischemia without SD (nSD) and sham surgery with TSD (n=6/group).

RESULTS

Shortly after stroke, the amount of slow wave sleep (SWS) and paradoxical sleep (PS) increased significantly (p<0.05) in the TSD/ischemia, resulting in an increase in the total sleep time by 30% compared to baseline, or by 20% compared with the nSD/ischemia group. The infarct volume decreased significantly by 50% in the TSD/ischemia compared to nSD group (p<0.02). Removal of sleep rebound by allowing TSD-rats sleep for 24h before ischemia eliminated the reduction in the infarct size.

CONCLUSION PRESTROKE

Sleep deprivation results in sleep rebound and reduces brain damage. Sleep rebound may be causally related to the neuroprotection.

Sleep disturbance impairs stroke recovery in the rat

STUDY OBJECTIVES

There is a lack of experimental evidence to support the hypothesis that sleep may modulate stroke outcome as suggested by clinical observations. We have previously shown that sleep disturbance (SDis) over 3 days aggravates brain damage in a rat model of focal cerebral ischemia. The aim of this study is to further investigate effects of SDis on long-term stroke recovery and neuroplasticity as assessed by axonal sprouting, neurogenesis, and angiogenesis.

DESIGN

Focal cerebral ischemia was induced by permanent occlusion of the distal branches of middle cerebral artery. Twelve hours after initiation of ischemia, SDis was performed over 3 consecutive days (deprivation of 80% sleep during the 12-h light phase). Weekly assessments on sensorimotor function by the single pellet reaching test (SPR) were performed for 5 weeks after surgery. Axonal sprouting was evaluated by anterograde tracing with biotinylated dextran amine (BDA) and neurogenesis/angiogenesis by bromodeoxyuridine (BrdU) labelling along with cell-type markers. Control groups included ischemia without SDis, sham with SDis, and sham without SDis.

SETTING

Basic sleep research laboratory.

MEASUREMENTS AND RESULTS

Rats subjected to SDis after ischemia showed significantly less recovery of forearm motor skills during the post-stroke period of 5 weeks. This effect was accompanied by a substantial reduction in axonal sprouting, expression of synaptophysin, and the ischemia-stimulated neural and vascular cell proliferation.

CONCLUSION

SDis has detrimental effects on functional and morphological/structural outcomes after stroke, suggesting a role of sleep in the modulation of recovery processes and neuroplasticity.