Fatigue and sleep-disordered breathing in multiple sclerosis: a clinically relevant association?

The relationship between sleep quality and gait in people with multiple sclerosis: A pilot study

Background

Gait deficits are common among people with multiple sclerosis (PwMS). Therefore, investigating factors that may influence walking in PwMS is important. Previous studies in older adults and other neurological populations demonstrated the relationship between sleep quality and gait performance. Despite the fact that the prevalence of poor sleep quality is very high among PwMS, little is known about the effect of sleep quality on gait among PwMS.

Objective

This study aimed to explore the relationship between sleep quality and gait performance in PwMS.

Methods

Forty-one PwMS participated in the study between February 2019 and December 2019. Participants were asked to walk at a self-selected speed over 10 m with an inertial measurement unit (IMU) attached over the back. Walking speed, step length (left and right), and step time were calculated. Sleep was estimated objectively using a wrist-worn triaxle-accelerometer; the derived parameters were sleep efficiency (SE) and the number of awakening after sleep onset (NASO).

Results

SE significantly correlated with step length (p = 0 . 02 ). Furthermore, the NASO significantly correlated with gait speed (p = 0 . 03 ), and step-time (p = 0 . 02 ). These correlations remained significant even after adjusting for age and disease duration.

Conclusion

We observed that when corrected for disease duration and age there were relationships between NASO and SE to gait parameters; these observations warrant further investigations.

Sleep disturbance and fatigue in multiple sclerosis: A systematic review and meta-analysis

Sleep disturbance is common in people with multiple sclerosis and may worsen fatigue; however, the assessment of sleep-fatigue relationships varies across studies. To better understand sleep-fatigue relationships in this population, we conducted a systematic review and random effects meta-analyses for the associations between fatigue and 10 sleep variables: Sleep-disordered breathing, daytime sleepiness, sleep quality, insomnia, restless legs, number of awakenings, sleep efficiency, sleep latency, sleep duration, and wake after sleep onset. Of the 1062 studies screened, 46 met inclusion criteria and provided sufficient data for calculating Hedges' g. Study quality was assessed using the Newcastle-Ottawa Scale. Sample characteristics did not differ between the 10 analyses. Results indicated that sleep quality and insomnia (assessed via self-report or diagnostic criteria) were strongly associated with fatigue (all gs ≥ 0.80 and all ps < .001). In contrast, the number of awakenings and sleep duration (assessed objectively) were not significantly associated with fatigue. Remaining sleep variables yielded moderate, significant effects. Most effects did not vary based on study quality or sample demographics. Results highlight that insomnia and perceptions of poor sleep have a stronger link than objective sleep duration to fatigue in multiple sclerosis and may represent a more effective target for intervention.

The Relationship Between Sleep Quality, Sleep-Related Biomarkers, and Motor Skill Acquisition in People With Multiple Sclerosis: A Pilot Study

OBJECTIVE

Neurorehabilitation that involves learning new motor skills is one of the promising clinical methods for motor recovery in people with multiple sclerosis (PwMS); therefore, factors that influence the acquisition of motor skills in PwMS need to be investigated. Sleep disturbances are common in PwMS; however, no study has investigated the effect of sleep and sleep-related biomarkers on skill acquisition in PwMS. This study aimed to examine the effect of sleep and sleep-related biomarkers on motor acquisition in PwMS.

METHODS

Forty participants with MS and 40 controls were recruited in this study. To assess motor acquisition, each participant was asked to perform a novel game through a virtual reality (VR) system 5 times (blocks). The main outcome measures for each block were the required time to complete the VR game and the recorded errors. The difference in scores between Block 5 and Block 1 for both outcomes were considered to represent motor skill acquisition. Sleep was assessed by self-report using the Pittsburgh Sleep Quality Index (PSQI) and objectively using sleep monitor technology. Serotonin level was assessed using means of enzyme-linked immunosorbent assay using plasma samples.

RESULTS

There were significant positive correlations in both groups between motor skill acquisition and PSQI score. In PwMS, significant negative correlation between motor skill acquisition and sleep efficiency and significant positive correlation between motor skill acquisition and sleep latency were also observed. Interestingly, a significant negative correlation was observed between motor skill acquisition and the plasma serotonin level in both groups. Most of these correlations remained significant after controlling for disease severity, fatigue, baseline performance, and cognitive status.

CONCLUSION

Sleep quality may influence motor skill acquisition in PwMS. Circulatory serotonin level might explain this relationship.

IMPACT

Physical therapists are encouraged to be aware of sleep quality and sleep assessment. Sleep management strategies should be considered when treating PwMS.

Patients with obstructive sleep apnea have suppressed levels of soluble cytokine receptors involved in neurodegenerative disease, but normal levels with airways therapy

Purpose

Obstructive sleep apnea (OSA) results in systemic intermittent hypoxia. By one model, hypoxic stress signaling in OSA patients alters the levels of inflammatory soluble cytokines TNF and IL6, damages the blood brain barrier, and activates microglial targeting of neuronal cell death to increase the risk of neurodegenerative disorders and other diseases. However, it is not yet clear if OSA significantly alters the levels of the soluble isoforms of TNF receptors TNFR1 and TNFR2 and IL6 receptor (IL6R) and co-receptor gp130, which have the potential to modulate TNF and IL6 signaling.

Methods

Picogram per milliliter levels of the soluble isoforms of these four cytokine receptors were estimated in OSA patients, in OSA patients receiving airways therapy, and in healthy control subjects. Triplicate samples were examined using Bio-Plex fluorescent bead microfluidic technology. The statistical significance of cytokine data was estimated using the nonparametric Wilcoxon rank-sum test. The clustering of these high-dimensional data was visualized using t-distributed stochastic neighbor embedding (t-SNE).

Results

OSA patients had significant twofold to sevenfold reductions in the soluble serum isoforms of all four cytokine receptors, gp130, IL6R, TNFR1, and TNFR2, as compared with control individuals (p = 1.8 × 10⁻¹³ to 4 × 10⁻⁸). Relative to untreated OSA patients, airways therapy of OSA patients had significantly higher levels of gp130 (p = 2.8 × 10⁻¹³), IL6R (p = 1.1 × 10⁻⁹), TNFR1 (p = 2.5 × 10⁻¹⁰), and TNFR2 (p = 5.7 × 10⁻⁹), levels indistinguishable from controls (p = 0.29 to 0.95). The data for most airway-treated patients clustered with healthy controls, but the data for a few airway-treated patients clustered with apneic patients.

Conclusions

Patients with OSA have aberrantly low levels of four soluble cytokine receptors associated with neurodegenerative disease, gp130, IL6R, TNFR1, and TNFR2. Most OSA patients receiving airways therapy have receptor levels indistinguishable from healthy controls, suggesting a chronic intermittent hypoxia may be one of the factors contributing to low receptor levels in untreated OSA patients.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02205-y) contains supplementary material, which is available to authorized users.

Evaluation of sleep-related respiratory disorders in patients with multiple sclerosis

Patients with multiple sclerosis (MS) often report fatigue, poor sleep and complaint of sleep disorders. Neurofilament light chain (NF-L) has been identified as a potential biomarker for disease progression in MS patients. In this study, we aimed to evaluate sleep characteristics in MS patients and its relationship with the level of serum NF-L. In the present study carried out as a prospective and cross-sectional study, 32 relapsing-remitting MS (RRMS) patients and 32 control subjects were included. Epworth Sleepiness Scale and Fatigue Severity Scale tests were applied to the groups and the full night polysomnography was performed. Serum samples were obtained for NF-L analysis. Apnea-hypopnea index (AHI), AHI in rapid eye movement sleep (AHI REM), percentage of NonREM stage 1 (N1) and NonREM stage 3 (N3) values were significantly different in RRMS patients (p < 0.05). There was correlation between AHI and Expanded Disability Status Scale indicating a negative directed moderate relationship (r = - 0.343 p = 0.055). Serum NF-L correlations with sleep efficiency and percentage of NonREM stage 2 (N2) were showed mild significant correlation (r = - 0.342 as - 0.535, p < 0.05). We found that sleep disorders are prevalent in RRMS patients and it has a negative effect on the clinical outcome of disease. In clinical practice, the association of these two diseases should be taken into consideration because sleep disturbances increase the disability of MS disease especially presenting with fatigue.

Better Objective Sleep Was Associated with Better Subjective Sleep and Physical Activity; Results from an Exploratory Study under Naturalistic Conditions among Persons with Multiple Sclerosis

Persons with multiple sclerosis (PwMS) often complain about sleep problems. There is less known about objective sleep-electroencephalography (EEG) dimensions within naturalistic conditions (i.e., home and/or familiar setting). The present cross-sectional study examined the associations between objective and subjective sleep, depression, physical activity scores, and MS-related information among PwMS in their familiar setting. The sample consisted of 16 PwMS (mean age: 50.3 years; median Expanded Disability Status Scale (EDSS): 5.5) who completed questionnaires covering subjective sleep (symptoms of insomnia, restless legs syndrome (RLS) and sleep-disordered breathing), as well as daytime sleepiness, subjective physical activity, depression, and MS-related information (fatigue, EDSS; disease-modifying treatments). Objective sleep was assessed with a mobile sleep-EEG device under naturalist conditions within the home. Descriptively, better objective sleep patterns were associated with lower sleep complaints (r_s = −0.51) and daytime sleepiness (r_s = −0.43), and with lower symptoms of RLS (r_s = −0.35), but not with sleep-disordered breathing (r_s = −0.17). More deep sleep was associated with higher moderate physical activity levels (r_s = 0.56). Objective sleep parameters were not associated with vigorous physical activity levels (r_s < 0.25). Descriptively, moderate and vigorous physical activity scores were associated with lower symptoms of RLS (r_s = −0.43 to −0.47). Results from this small study carried out under naturalistic conditions suggest that among PwMS, better objective sleep correlated with better subjective sleep and higher moderate physical activity levels.

The effects of aerobic exercise on sleep quality measures and sleep-related biomarkers in individuals with Multiple Sclerosis: A pilot randomised controlled trial

BACKGROUND

Sleep disturbances are highly prevalent in people with multiple sclerosis(MS), and are associated with pain, fatigue, depression, and reduced quality of life (QoL). Importantly, sleep has been considered a critical brain state for motor learning and memory consolidation. Therefore, interventions that target sleep managementin people with MS are needed.

OBJECTIVES

To explore the effects of a six weeks moderate-intensity aerobic exercise intervention on sleep characteristics and sleep-related biomarkers specifically serotonin, melatoninand cortisol in people with MS using a pilot randomized controlled trial.

METHODS

Participants were randomly allocated to either a moderate-intensity aerobic exercise program (MAE, n = 20) or a home exercise program (HEP, n = 20). Participants were assessed at baseline and follow-up. Subjective and objective measures were used to assess sleep quality. The Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI) were used to subjectively assess sleep. While Actigraphy was used to objectivelyassess sleep. Blood samples were collected for measurement of cortisol, melatonin and serotonin from MS participants in both groups at 8:00 am±1 hour.

RESULTS

Seventeen participants in the MAE and 13 in the HEP group completed the study. Compared to the HEP group, people with MS who participated in a moderate-intensity aerobic exercise experienced significant improvements (P < 0.05) on the PSQI, ISI, and several objective sleep parameters measured using actigraphy. Only the serotonin levels increased significantly over the six-week period in the MAE group compared to the HEP group. The change score in serotonin (from baseline to follow up assessment) was significantly correlatedwith the change score in PSQI (r = -0.97, p < 001) and the change score in ISI (r = -0. 56, p = 0.015) only in the MAE group but not the HEP group.

CONCLUSIONS

Exercise may be a non-pharmacological, inexpensive, safe method to improve sleep quality in people with MS. The improvement in the serotonin level due to aerobic exercisemight explain one of the physiologic mechanisms driving these improvements.

In Patients With Multiple Sclerosis, Both Objective and Subjective Sleep, Depression, Fatigue, and Paresthesia Improved After 3 Weeks of Regular Exercise

Background: Multiple sclerosis (MS) patients suffer from various difficulties including sleep complaints, symptoms of depression and fatigue, paresthesia, and cognitive impairments. There is growing evidence that regular physical activity has a positive effect on both sleep and psychological functioning, though there is limited evidence of this kind for MS patients. The aim of the present study was therefore to investigate the impact on this patient group of a regular exercise program with respect to subjective and objective sleep, depression, paresthesia, fatigue, and cognitive performance. Methods: A total of 46 patients [mean age: 50.74 years; Expanded Disability Status Scale (EDSS): mean: 5.3, 78.4% females] completed this 3-week intervention study. At baseline and 3 weeks later, they answered questionnaires covering sociodemographic information, subjective sleep, depression, fatigue, paresthesia, and subjective physical activity. Objective sleep [sleep electroencephalogram (EEG) recordings] and cognitive performance were also assessed at both time points. Patients participated in a regular exercise activity every weekday for about 60 min. Results: Compared to the baseline, by the end of the study, objective sleep had significantly improved (sleep efficiency, sleep onset latency, and wake time after sleep onset), and symptoms of sleep complaints, depression, fatigue, and paresthesia were significantly reduced. Subjective physical activity (moderate and vigorous) and cognitive performance also increased over the course of the intervention. Conclusions: In patients with MS, participation in regular exercise impacted positively on their objective and subjective sleep, depression, paresthesia, fatigue, and cognitive performance.

Sleep-Disordered Breathing in People with Multiple Sclerosis: Prevalence, Pathophysiological Mechanisms, and Disease Consequences

Sleep problems are common in people with multiple sclerosis (MS). Reported prevalence rates of sleep-disordered breathing (SDB) vary between 0 and 87%. Differences in recruitment procedures and study designs likely contribute to the wide variance in reported prevalence rates of SBD in MS. This can make attempts to compare SDB rates in people with MS to the general population challenging. Little is known about the pathophysiological mechanisms that contribute to SDB in people with MS or whether MS contributes to SDB disease progression. However, compared to the general obstructive sleep apnea (OSA) population, there are clear differences in the clinical phenotypes of SDB in the MS population. For instance they are typically not obese and rates of SDB are often comparable or higher to the general population, despite the high female predominance of MS. Thus, the risk factors and pathophysiological causes of SDB in people with MS are likely to be different compared to people with OSA who do not have MS. There may be important bidirectional relationships between SDB and MS. Demyelinating lesions of MS in the brain stem and spinal cord could influence breathing control and upper airway muscle activity to cause SDB. Intermittent hypoxia caused by apneas during the night can increase oxidative stress and may worsen neurodegeneration in people with MS. In addition, inflammation and changes in cytokine levels may play a key role in the relationship between SDB and MS and their shared consequences. Indeed, fatigue, neurocognitive dysfunction, and depression may worsen considerably if both disorders coexist. Recent studies indicate that treatment of SDB in people with MS with conventional first-line therapy, continuous positive airway pressure therapy, can reduce fatigue and cognitive impairment. However, if the causes of SDB differ in people with MS, so too may the optimal therapy. Thus, many questions remain concerning the relationship between these two disorders and the underlying mechanisms and shared consequences. Improved understanding of these factors has the potential to unlock new therapeutic targets.

[Sleep disturbances - an important factor in combination 'minor' symptoms of multiple sclerosis]

AIM

To investigate the clinical and neurophysiological features of sleep disorders in patients with different forms of multiple sclerosis (MS) and their impact on life quality, dynamic and prognosis of the disease. Identify the impact of sleep disorders on the formation and maintenance of chronic fatigue syndrome in patients with MS.

MATERIAL AND METHODS

General clinical methods of examination like neuropsychological testing (definition of anxiety and depression), the scales of the subjective determination of the quality of sleep, the severity of daytime sleepiness, quality of life, severity of chronic fatigue syndrome) and their subsequent correlation with neuroimaging and neurophysiological data were studied. 54 patients with different forms of MS and 54 healthy volunteers in the control group were selected.

RESULTS AND CONCLUSION

Data analysis showed a high level of sleep disorders associated with anxiety disorders, comorbid pathologies, which is significantly higher in the study group.

Central sleep apnea in multiple sclerosis: a pilot study

PURPOSE

The purpose of the present study is to investigate sleep-disordered breathing and symptoms of sleepiness in a consecutive clinical cohort of multiple sclerosis (MS) patients.

METHODS

Twenty-one (16 females) community-dwelling adults aged 18-75 years with MS and an Expanded Disability Status Scale score between 2 and 6 were recruited consecutively from an academic teaching hospital MS clinic. Participants performed a home sleep study (ResMed ApneaLink Plus) to objectively quantify sleep-disordered breathing. Subjective sleepiness and its impact were assessed using the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and Functional Outcomes of Sleep Questionnaire.

RESULTS

Three (one female) of the 19 participants who completed home overnight testing had central sleep apnea (median apnea-hypopnea index = 15 [range = 8-36] events/h sleep, median nadir SaO₂ = 88 % [range = 81-88]). There were no cases of obstructive sleep apnea. Thirty-three percent of participants reported excessive daytime sleepiness, and 71% reported poor sleep quality.

CONCLUSIONS

Home sleep testing was well tolerated, and a high proportion of central rather than obstructive sleep apnea was observed in a clinical MS sample. Possible reasons include brainstem or spinal cord lesions from MS affecting the control of breathing. Poor sleep quality and daytime sleepiness were common in this group.

Randomized controlled trial of exercise interventions to improve sleep quality and daytime sleepiness in individuals with multiple sclerosis: A pilot study

BACKGROUND

Nearly 70% of individuals with multiple sclerosis (MS) experience sleep disturbances. Increasing physical activity in people with MS has been shown to produce a moderate improvement in sleep quality, and exercise has been shown to improve sleep quality in non-neurologically impaired adults.

OBJECTIVE

The purpose of this pilot randomized controlled trial study was to examine the effect of two exercise interventions on sleep quality and daytime sleepiness in individuals with MS.

METHODS

Twenty-eight individuals with relapsing-remitting or secondary progressive MS were randomized into one of two 12-week exercise interventions: a supervised, moderate-intensity aerobic exercise (AE) program or an unsupervised, low-intensity walking and stretching (WS) program. Only individuals who were ≥ 70% compliant with the programs were included in analysis (n = 12 AE; n = 10 WS).

RESULTS

Both groups demonstrated a moderate improvement in sleep quality, although only the improvement by the WS group was statistically significant. Only the AE group demonstrated a significant improvement in daytime sleepiness. Change in sleep quality and daytime sleepiness was not correlated with disease severity or with change in cardiovascular fitness, depression, or fatigue.

CONCLUSION

The mechanisms for improvement in sleep quality and daytime sleepiness need further investigation, but may be due to introduction of zeitgebers to improve circadian rhythm.

The Neurological Sleep Index: A suite of new sleep scales for multiple sclerosis

Objective

The objective of this study was to develop patient-reported outcome measures for sleep dysfunction and sleepiness in multiple sclerosis (MS), since there are currently no MS-specific measurement tools for these clinically important entities.

Methods

Items were generated from semi-structured interviews followed by cognitive debrief. A 42-item pool was administered to patients with MS at three neuroscience centres in the UK. Comparator scales were co-administered. Constructs were validated by Rasch analysis, guided by initial exploratory factor analysis.

Results

There were two supraordinate qualitative themes of diurnal sleepiness and non-restorative nocturnal sleep. Rasch analysis on 722 records produced three scales, which corresponded to diurnal sleepiness, non-restorative nocturnal sleep and fragmented nocturnal sleep. All had excellent fit parameters, were unidimensional and were free from differential item functioning. A summed raw score cut-point of 31/48 in the Diurnal Sleepiness Scale equated to the standard cut-point of 10 on the Epworth Sleepiness Scale (ESS).

Conclusion

Three high-quality measurement scales were developed, and together they compose the Neurological Sleep Index for MS (NSI-MS). The Diurnal Sleepiness Scale might provide an alternative to the ESS. The Non-Restorative Nocturnal Sleep Scale and the Fragmented Nocturnal Sleep Scale appear to be the only such measures for use in MS.

Sleep disorders in patients with multiple sclerosis

OBJECTIVE

Poor sleep is a frequent symptom in patients with multiple sclerosis (MS). The objective of the study was to assess the relationship between nocturnal polysomnographic (PSG) findings and quality of sleep, fatigue, and increased daytime sleepiness among patients with MS.

METHODS

Clinical characteristics were collected. Pittsburgh Sleep Quality Index (PSQI), Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), and International Restless Legs Syndrome Rating Scale were used to assess quality of sleep, fatigue, excessive daytime sleepiness, and the presence of restless legs syndrome (RLS). All patients underwent nocturnal diagnostic PSG examination.

RESULTS

Fifty patients with MS were enrolled into the study. Age was the only independent variable significantly determining apnea-hypopnea index and desaturation index (DI) (beta = 0.369, p = 0.010, beta 0.301, p = 0.040). PSQI and ESS score were significantly higher in a population with RLS (p = 0.004, p = 0.011). FSS significantly correlated with DI (r = 0.400, p = 0.048). Presence of RLS was the only independent variable significantly determining PSQI and ESS (p = 0.005, p = 0.025). DI and presence of RLS were independent variables determining FSS (p = 0.015, p = 0.024).

CONCLUSION

Presence of RLS seems to be the main factor determining poor sleep, fatigue, and daytime somnolence. Sleep disordered breathing and its severity influences only fatigue in patients with MS.

Fatigue in multiple sclerosis: a look at the role of poor sleep

Fatigue is a frequent and debilitating symptom of multiple sclerosis (MS) with rates ranging anywhere from 53 to 90%. Despite its high prevalence and grave impact on overall functioning and quality of life, the accurate definition, quantification, and etiology of fatigue have plagued the MS literature and clinical care for decades. With regard to its etiology, MS-related fatigue has been construed as being either primary or secondary. Primary fatigue is purported to be related to centrally mediated processes of the disease whereas secondary fatigue is thought to be a result of the host of factors that may accompany MS (e.g., depression, sleep disturbance). The present paper focuses on secondary fatigue and the role of sleep disturbance, in particular. Despite the intuitive assumption that sleep problems could contribute to fatigue, sleep problems in MS have gone fairly unrecognized until recently. The present paper provides a brief review of the literature pertaining to the prevalence and nature of sleep problems in MS as well as their association with fatigue. A replication of this author’s and others work is presented further demonstrating that sleep disturbance is a significant contributor to fatigue in MS when taking into account disease variables, depression, and sleep disturbance.