Sleep Abnormalities in Multiple Sclerosis

Exploring Sleep Architecture in Polish Patients with Multiple Sclerosis: A Polysomnography Study

BACKGROUND

Sleep disturbances are a prevalent phenomenon in patients with multiple sclerosis (PwMS). The present study employs polysomnography (PSG) to quantify sleep efficiency and architecture in PwMS, aiming to elucidate the relationships between PSG parameters and factors including gender, disability level, brain lesion location, and subjective measures of insomnia, excessive daytime sleepiness (EDS), fatigue, pain, and mood disorders.

METHODS

The study cohort comprised 51 adult PwMS, of whom 31 underwent overnight PSG. The demographic and clinical characteristics, including age, gender, and Expanded Disability Status Scale (EDSS), were collated. The Athens Insomnia Scale, the Epworth Sleepiness Scale, the Fatigue Severity Scale, the Modified Fatigue Impact Scale (MFIS), the Numerical Pain Rating Scale, and the Hospital Anxiety and Depression Scale were employed for the assessment of insomnia, EDS, fatigue, pain, and mood disorders. The brain and spinal cord magnetic resonance imaging (MRI) were evaluated.

RESULTS

A reduced sleep efficiency was observed among 30 PwMS (aged 38.9 ± 12.9), with a mean of 80 ± 12%, especially in those with brainstem demyelinating lesions. In those PwMS aberrant sleep onset latency (SOL) and wake after sleep onset were also noted (p < 0.05). The prevalence of sleep fragmentation, as measured by the total arousal index, was greater in male PwMS than in female (p < 0.05). Higher disability according to the EDSS correlated with longer SOL (ρ = 0.48, p < 0.05), and reduced N2 sleep stage correlated with cognitive fatigue according to MFIS (ρ = -0.46, p < 0.05). Age, disease duration, insomnia, EDS, physical fatigue, and mood disorders did not impact PSG parameters.

CONCLUSIONS

The study demonstrated the disruption of sleep architecture in PwMS, and highlighted the importance of a comprehensive PSG assessment of sleep disturbances in this population.

Can a six-week Swedish massage reduce mood disorders and enhance the quality of life in individuals with Multiple Sclerosis? A randomized control clinical trial

INTRODUCTION

There is a limited amount of research specifically focusing on the effects of Swedish massage on mood disorders and the quality of life (QOL) among individuals with MS, emphasizing the need for further investigation. Therefore, this study aimed to assess the effects of a 6-week Swedish massage on the quality of life, stress, anxiety, depression, pain, fatigue, spasticity, and sleep quality in MS patients.

METHODS

This randomized controlled trial involved 70 MS patients who were divided into two groups. The massage group underwent two 50-minute sessions of whole-body Swedish massage per week for six weeks, while the usual treatment group maintained their regular medical care routine. Outcomes were Short Form-36 (SF-36) and the Depression, Anxiety, and Stress Scale (DASS), Visual Analog Scale (VAS), Fatigue Severity Scale (FSS), Pittsburgh Sleep Quality Index (PSQI-P), and Modified Ashworth Scale (MAS). These measurements were taken before and after the massage intervention.

RESULTS

The massage group demonstrated significant improvements in QOL and its components compared to the usual treatment group (Hedge's g = 0.53 for QOL, ranging from 0.31 to 0.58 for QOL components; p < 0.001). Participants in the massage group also reported significantly lower levels of stress (Hedge's g = 0. 80), anxiety (Hedge's g = 0.47), and depression (Hedge's g = 0.70) than those in the usual treatment group (p < 0.001). Additionally, the massage group had lower levels of pain, fatigue, and spasticity, and better sleep quality compared to the usual treatment group (p < 0.05).

CONCLUSION

Swedish massage can be considered a valuable complementary and alternative treatment alongside conventional medicine for individuals with MS.

12-week melatonin supplementation improved dynamic postural stability and walking performance in persons living with multiple sclerosis: A randomized controlled trial

BACKGROUND

Persons with multiple sclerosis (PwMS) suffer from sleep disturbances, fatigue and pain, which can be due, at least in part, to decreased levels of endogenous melatonin. These alterations could exacerbate postural instability, gait disorders and fall risk. Acute effects of exogenous melatonin on physical disorders have been studied in PwMS but its long-term effects on these parameters have not been explored yet in this population. This study aimed to determine the impact of chronic melatonin intake on dynamic postural stability, walking performance and fall risk in PwMS.

METHODS

This randomized placebo-controlled study included 27 PwMS who were assigned to either melatonin group (MG, n=15) or placebo group (PG, n=12) (3 mg/night for 12 weeks). Dynamic postural balance (force platform), walking performance (locometer) and fall risk (Four Square Step Test) were evaluated pre (T0)- and post (T1)-intervention. Sleep quality (Pittsburgh Sleep Quality Index (PSQI)), fatigue perception (Fatigue Severity Scale (FSS)), neuropathic pain (Neuropathic Pain Questionnaire 4 (DN4)) and quality of life (International Multiple Sclerosis (MS) Quality of Life Questionnaire) were also assessed at T0 and T1.

RESULTS

The center of pressure mean velocity decreased in MG compared with PG in the frontal plane (22.98 %, p=0.028). Stride length and walking speed increased in MG comparatively with PG (18.09 %, p=0.036; 9.65 %, p=0.025, respectively). The PSQI (55.89 %, p<0.001), FSS (32.38 %, p=0.003) and DN4 (32.41 %, p=0.035) scores decreased in MG compared with PG.

CONCLUSION

12-week melatonin supplementation can be recommended for managing MS-related gait disorders and dynamic postural imbalance. This therapy may also be prescribed for PwMS due to its anti-fatigue and analgesic effects as well as its benefits on sleep quality.

CLINICAL REGISTRATION

This study was prospectively recorded in the Pan African Clinical Trial Registry database (PACTR202007465309582) (https://pactr.samrc.ac.za/.).

The multidimensional sleep health of individuals with multiple sclerosis and Huntington's disease and healthy controls

STUDY OBJECTIVES

Sleep issues are common for people with neurodegenerative conditions, yet research has focused on specific aspects of sleep. While important, a more holistic approach to investigating sleep, termed "sleep health," considers sleep's positive and negative aspects. Current studies exploring sleep health have lacked a control group for reference. For the first time, this study investigated the sleep health of people living with multiple sclerosis and Huntington's disease (HD) and compared it with a community sample.

METHODS

111 people, including 43 with multiple sclerosis, 19 with HD, and 49 from a community sample, participated in this study. The data, including actigraphy, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale, were collected as part of ongoing research studies. Seven sleep health domains were determined from the collected data, and a composite sleep health score was developed. Analysis of variance and independent t tests were performed to identify population and sex differences.

RESULTS

The HD group had higher sleep regularity and lower sleep rhythmicity than the multiple sclerosis and community sample groups. The HD group had significantly less sleep duration than the multiple sclerosis group. No significant differences between the groups were observed in the sleep health composite score. Males had significantly higher sleep regularity within the HD group but significantly lower sleepiness scores in the community sample.

CONCLUSIONS

These findings indicate that people with HD may experience greater variance in their wake times, therefore decreasing the consistency of being awake or asleep 24 hours apart. Understanding the mechanisms for this should be explored in people with HD.

CITATION

Turner M, Griffiths M, Laws M, Vial S, Bartlett D, Cruickshank T. The multidimensional sleep health of individuals with multiple sclerosis and Huntington's disease and healthy controls. J Clin Sleep Med. 2024;20(6):967-972.

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.

The glymphatic system and multiple sclerosis: An evolving connection

Multiple sclerosis (MS) is a complex autoimmune disorder that affects the central nervous system, resulting in demyelination and an array of neurological manifestations. Recently, there has been significant scientific interest in the glymphatic system, which operates as a waste-clearance system for the brain. This article reviews the existing literature, and explores potential links between the glymphatic system and MS, shedding light on its evolving significance in the context of MS pathogenesis. The authors consider the pathophysiological implications of glymphatic dysfunction in MS, the impact of disrupted sleep on glymphatic function, and the bidirectional relationship between MS and sleep disturbances. By offering an understanding of the intricate interplay between the glymphatic system and MS, this review provides valuable insights which may lead to improved diagnostic techniques and more effective therapeutic interventions.

Sleep Disorders and Fatigue among Patients with MS: The Role of Depression, Stress, and Anxiety

Sleep disorders and fatigue represent prominent symptoms frequently experienced by individuals with multiple sclerosis (MS). Some psychological factors such as depression, stress, and anxiety seem to have a relationship with such problems. This study aimed to examine the role of depression, stress, and anxiety in predicting sleep disorders and fatigue among patients with MS. Employing a cross-sectional descriptive-correlational design, the study involved a sample size of 252 participants selected through purposive sampling based on inclusion and exclusion criteria. We utilized a demographic information questionnaire along with the Mini-Sleep Questionnaire (MSQ), Fatigue Severity Scale (FSS), and Depression, Anxiety, and Stress Scale (DASS-21) to collect data and analyzed them applying SPSS22, incorporating statistical measures including Pearson correlation and regression. The results of the Pearson correlation coefficient showed that sleep disorders had a positive and significant relationship with depression (r = 0.56; P < 0.001), stress (r = 0.40; P < 0.001), and anxiety (r = 0.52; P < 0.001). There was no significant relationship between age and the development of sleep disorders in total score (r = -0.001; P < 0.985), but age had a relationship with insomnia (r = -0.146; P < 0.021) and oversleeping (r = 0.153; P < 0.015). Age and fatigue did not have a significant relationship as well (r = -0.044; P < 0.941). In addition, fatigue had a positive and significant relationship with depression (r = 0.52; P < 0.001), stress (r = 0.48; P < 0.001), and anxiety (r = 0.54; P < 0.001). The results of the regression analysis also showed that depression, stress, and anxiety predict 0.37% of the total variance of sleep disorders (F = 48.34; P < 0.001) and 0.35% of the total variance of fatigue (F = 44.64; P < 0.001). Our findings suggest that depression, stress, and anxiety play a significant role in predicting sleep disorders and fatigue among patients with MS. This study has been reported in accordance with the TREND checklist for nonrandomized trials.

BMAL1 loss in oligodendroglia contributes to abnormal myelination and sleep

Myelination depends on the maintenance of oligodendrocytes that arise from oligodendrocyte precursor cells (OPCs). We show that OPC-specific proliferation, morphology, and BMAL1 are time-of-day dependent. Knockout of Bmal1 in mouse OPCs during development disrupts the expression of genes associated with circadian rhythms, proliferation, density, morphology, and migration, leading to changes in OPC dynamics in a spatiotemporal manner. Furthermore, these deficits translate into thinner myelin, dysregulated cognitive and motor functions, and sleep fragmentation. OPC-specific Bmal1 loss in adulthood does not alter OPC density at baseline but impairs the remyelination of a demyelinated lesion driven by changes in OPC morphology and migration. Lastly, we show that sleep fragmentation is associated with increased prevalence of the demyelinating disorder multiple sclerosis (MS), suggesting a link between MS and sleep that requires further investigation. These findings have broad mechanistic and therapeutic implications for brain disorders that include both myelin and sleep phenotypes.

Effect of effleurage massage therapy on sleep disturbance, fatigue, pain, and anxiety in patients with multiple sclerosis: A quasi-experimental study

BACKGROUND

Fatigue, pain, sleep disturbance, and anxiety are prevalent symptoms of multiple sclerosis (MS) and frequent complaints in MS patients, which reduce their quality of life. Many studies have shown that massage therapy improves MS patients' symptoms. However, the effect of effleurage massage on sleep disturbance, fatigue, pain, and anxiety in patients with MS is not studied in Egypt.

AIM

To examine the effect of Effleurage massage therapy on sleep disturbance, fatigue, pain, and anxiety in patients with multiple sclerosis (MS).

METHODS

This research study has a quasi-experimental design, with control and intervention groups, and pre and post-tests conducted at the multiple sclerosis in-patient clinic at one Egyptian hospital between May 2019 and January 2020. Sixty adult female patients with MS were recruited, with 30 patients in the control group and 30 in the intervention group. The intervention group received Effleurage massage therapy intervention three times a week for two weeks, and each session lasted about 20 min. Patients in the control group received routine hospital care. Data were collected using the patient's demographic and medical data sheet, Insomnia Severity Index, Modified Fatigue Impact Scale, Numeric Pain Rating Scale, and Beck Anxiety Inventory before and after the intervention.

RESULTS

Significant improvement was observed in pain, sleep, fatigue, and anxiety in the massage group (P < 0.001).

CONCLUSION

Based on the current study, Effleurage massage intervention for MS patients could have possible clinical value for improving sleep disturbance, palliating pain, fatigue, and reducing anxiety. Egyptian nurses can integrate massage therapy into the routine nursing care of patients with MS. Effleurage massage could be an adjunct treatment modality for MS patients; however, more significant studies are needed.

Sleep Disturbances in Autoimmune Neurological Diseases

PURPOSE OF REVIEW

To summarize the current evidence on the associations between autoimmune neurological diseases (e.g., multiple sclerosis, myasthenia gravis) and sleep disturbances (e.g., insomnia, parasomnias), as well as to review the main characteristics of sleep disorders with an immune-related pathophysiology (e.g., narcolepsy, anti-IgLON5 disease).

RECENT FINDINGS

An immune-mediated damage of the areas in the central nervous system that control sleep and wake functions (e.g., hypothalamus, brainstem) can lead to sleep disorders and sleep symptoms. Sleep disturbances are the reason to seek for medical attention in certain neuroimmunological conditions (e.g., narcolepsy, anti-IgLON5 disease) where sleep-related alterations are the main clinical feature. The assessment of sleep-related symptomatology and disorders should be included in the routine evaluation of patients with autoimmune neurological diseases. Clinicians should be aware of the typical clinical presentation of certain neuroimmunological disorders mainly affecting sleep.

Monitoring and Predicting Health Status in Neurological Patients: The ALAMEDA Data Collection Protocol

(1) Objective: We explore the predictive power of a novel stream of patient data, combining wearable devices and patient reported outcomes (PROs), using an AI-first approach to classify the health status of Parkinson's disease (PD), multiple sclerosis (MS) and stroke patients (collectively named PMSS). (2) Background: Recent studies acknowledge the burden of neurological disorders on patients and on the healthcare systems managing them. To address this, effort is invested in the digital transformation of health provisioning for PMSS patients. (3) Methods: We introduce the data collection journey within the ALAMEDA project, which continuously collects PRO data for a year through mobile applications and supplements them with data from minimally intrusive wearable devices (accelerometer bracelet, IMU sensor belt, ground force measuring insoles, and sleep mattress) worn for 1-2 weeks at each milestone. We present the data collection schedule and its feasibility, the mapping of medical predictor variables to wearable device capabilities and mobile application functionality. (4) Results: A novel combination of wearable devices and smartphone applications required for the desired analysis of motor, sleep, emotional and quality-of-life outcomes is introduced. AI-first analysis methods are presented that aim to uncover the prediction capability of diverse longitudinal and cross-sectional setups (in terms of standard medical test targets). Mobile application development and usage schedule facilitates the retention of patient engagement and compliance with the study protocol.

Rest-Activity Rhythm, Pain, and Motor Activity in Multiple Sclerosis

BACKGROUND

Although the relationships among physical disability, mood disorders, and pain are well described in multiple sclerosis (MS), little is known about whether those symptoms are associated with sleep disturbances.

METHODS

Forty-six patients with MS experiencing pain participated. Sleep was indirectly measured by assessing rest-activity rhythm via actigraphy: interdaily stability, intradaily variability, and relative amplitude. Pain was assessed using visual and verbal analog scales, mood by the Beck Depression Inventory and Symptom Checklist-90, and physical disability by the Expanded Disability Status Scale.

RESULTS

Incorporating mood, pain, and physical disability into 1 regression model resulted in a significant association with interdaily stability.

CONCLUSIONS

Compared with intradaily variability and relative amplitude, interdaily stability seems to be the most vulnerable actigraphy variable for mood disturbances, pain, and physical disabilities.

Upper-lower limb and breathing exercise program for improving sleep quality and psychological status in multiple sclerosis: a pilot randomized controlled trial

PURPOSE

To examine the feasibility and possible effect of an 8-week exercise program on sleep quality, insomnia and psychological distress in individuals with multiple sclerosis (MS).

METHODS

Twenty-four individuals with MS were recruited into a controlled pre-post feasibility study and divided into 2 groups: exercise (n = 13; Expanded Disability Status Scale (EDSS): 1.0-7.5) and a related control group with no exercise (n = 11; EDSS: 1.0-7.0). The exercise group performed combined upper limb, lower limb and breathing exercises in a controlled group (2d/week, 60 min/session) for 8 weeks. Participants were administered measures to evaluate sleep quality (Pittsburgh Sleep Quality Index, PSQI), insomnia severity (Insomnia Severity Index, ISI), psychological distress (Clinical Outcomes in Routine Evaluation-Outcome Measure, CORE-OM) and additionally impact of fatigue (Modified Fatigue Impact Scale, MFIS) after 8-weeks.

RESULTS

Insomnia severity measured with ISI (F(1;22)=5.95, p = 0.023, η p 2 = 0.213, 90% CI = 0.02-0.42) and psychological distress measured with the CORE-OM (F(1;22)=4.82, p = 0.039, η p 2 = 0.179, 90% CI = 0.01-0.40) showed statistically significant group-by-time interaction. Sleep quality measured with the PSQI showed statistically significant group-by-time interaction only in an aspect of daytime sleep dysfunction (F(1;22)=5.33, p = 0.031, η p 2 = 0.195, 90% CI = 0.01-0.40). The fatigue impact measured with the MFIS showed statistically significant group-by-time interaction in physical (F(1;22)=6.80, p = 0.016, η p 2 = 0.236, 90% CI = 0.02-0.44) and cognitive aspects (F(1;22)=9.12, p = 0.006, η p 2 = 0.293, 90% CI = 0.05-0.49), and total score (F(1;22)=11.29, p = 0.003, η p 2 = 0.339, 90% CI = 0.08-0.52).

CONCLUSIONS

Our 8-week program reduced insomnia severity, psychological distress and some aspects of fatigue (physical; cognitive; total), and improved sleep quality in an aspect of daytime sleep dysfunction in a small group of individuals with MS. Good feasibility and significant positive changes from baseline warrant further exploratory work.

A mobile app (IDoThis) for multiple sclerosis self-management: development and initial evaluation

BACKGROUND

Multiple sclerosis (MS) is one of the most common neurological disorders worldwide, and self-management is considered an essential dimension in its control. This study aimed to develop an evidence-based mobile application for MS self-management and evaluate it.

METHODS

This study was undertaken in three phases: content preparation, design, and evaluation. In the content preparation phase, the researchers extracted MS self-management needs based on related guidelines and guides, existing apps on the self-management of MS, and the field experts' views and confirmation. The design phase was conducted in five steps: defining app functionalities, depicting the wireframe, preparing the media, coding the app, and testing the app's performance. The app was developed using the Android Studio environment and Java programming language for the Android operating system. The performance of the developed app was tested separately in several turns, and existing defects were corrected in each turn. Finally, after using the app for three weeks, the app was evaluated for its short-term impact on MS management and user-friendliness using a researcher-constructed questionnaire from participants' (N = 20) perspectives.

RESULTS

The IDoThis app is an offline app for people with MS that includes five main modules: three modules for training or informing users about different aspects of MS, one module for monitoring the user's MS condition, and a reporting module. In the initial evaluation of the app, 75% (n = 15) of participants mentioned that using this app improved MS self-management status at intermediate and higher levels, but 25% (n = 5) of the participants mentioned that the effect of using the app on the self-management tasks was low or was very low. The majority of users rated the user-friendliness of the app as high. The users found the sections "exercises in MS" and "monitoring of MS status" beneficial to their self-management. Still, the fatigue and sleep management sections are needed to meet users' expectations.

CONCLUSION

Using IDoThis app as a self-management tool for individuals with MS appears feasible, that can meet the need for a free and accessible self-management tool for individuals with MS. Future directions should consider the users' fatigue and sleep management expectations.

Does physical activity timing differentially correlate with symptoms of restless legs syndrome in adults with multiple sclerosis?

OBJECTIVE/BACKGROUND

The present study examined the associations among physical activity during different times of the day(i.e., morning, midday,evening) and days of the week(i.e., weekdays, weekend days) with restless legs syndrome(RLS) severity and sleep quality in adults with multiple sclerosis(MS).

PATIENTS/METHODS

Participants(N = 39) completed the International Restless Legs Syndrome Study Group Scale and the Pittsburgh Sleep Quality Index as measures of RLS severity and global sleep quality, respectively, and wore an ActiGraph GT3X + on the non-dominant hip for seven days for measuring physical activity(i.e., light physical activity[LPA], moderate-to-vigorous physical activity[MVPA], and steps).

RESULTS

There was a significant effect of time of day wherein participants had more midday activity compared with morning or evening for LPA, MVPA, and steps; there was no effect of day of the week. Spearman's rho correlations across the week indicated higher evening LPA, evening steps, and overall daily steps (ρ = -0.42,ρ = -0.51,ρ = -0.40,respectively) were associated with lower RLS severity. Similar associations were demonstrated for weekdays(ρ = -0.39,ρ = -0.50,ρ = -0.41,respectively) and weekend days(ρ = -0.44,ρ = -0.51,ρ = -0.39,respectively). Higher evening MVPA on weekend days(ρ = -0.42) was associated with lower RLS severity. Higher morning and overall daily LPA(ρ = 0.34,ρ = 0.33,respecitvely) were associated with worse sleep quality. Similar associations were demonstrated on weekdays(ρ = 0.33,ρ = 0.37,respectively) and more evening MVPA(ρ = 0.32) was associated with worse sleep quality. On weekend days, more morning MVPA(ρ = 0.42) was associated with worse sleep quality.

CONCLUSIONS

Our results suggest that undertaking physical activity, particularly LPA and steps, in evenings may be important for managing symptoms of RLS without worsening sleep quality.

Menopausal symptoms and hormone therapy in women with multiple sclerosis: A baseline-controlled study

BACKGROUND

Depression, sleep disturbances, and cognitive difficulties impair the quality of life in people with multiple sclerosis (MS). Similar symptoms are also frequent during the menopausal transition. In clinical practice, it is important to consider the multifactorial causes of these overlapping symptoms and the potential benefits of menopausal hormone therapy (MHT). The objective of this study was to evaluate vasomotor symptoms (VMS), mood, sleep, and cognition of menopausal women with and without MS at baseline and during one year of MHT.

METHODS

In this prospective baseline-controlled study, peri- and early postmenopausal participants with (n=14) and without (n=13) MS received MHT containing 1 or 2 mg of estradiol and cyclical 10 mg dydrogesterone for one year. VMS frequency, depressive symptoms (measured by Beck Depression Inventory), insomnia severity (Insomnia Severity Index), and cognitive performance (Paced Auditory Serial Addition Test; PASAT, Symbol Digit Modalities Test; SDMT) were evaluated at baseline and at 3 and 12 months of treatment. Differences in the outcome measures between groups at baseline were assessed using the Mann-Whitney U test. Changes during follow-up compared to baseline within groups were evaluated by Wilcoxon Signed Ranks Test. P < 0.05 was considered for statistical significance. MS activity was monitored by clinical assessment and brain MRI at baseline and at 12 months.

RESULTS

Depressive symptoms were more common in MS group, while vasomotor and insomnia symptoms were equally common. During follow-up with MHT, VMS frequency decreased in both groups. Depressive symptoms decreased at 3 months (p = 0.031 with MS; p = 0.024 without MS) and the reduction was sustained at 12 months (p = 0.017; p = 0.042, respectively). Alleviation in insomnia symptoms was seen in participants without MS at 3 months (p = 0.029) and in those participants with MS suffering insomnia at baseline (p = 0.016 at 3 months; p = 0.047 at 12 months). Both groups improved their performance in PASAT, but no significant change was observed in SDMT. MS activity at baseline was mainly stable, and no increase in activity was detected during MHT.

CONCLUSION

Improvements in vasomotor, depressive, and insomnia symptoms observed during one year of MHT are encouraging and suggest that larger placebo-controlled studies of MHT in women with MS are warranted. Cognitive implications were inconclusive because the findings in PASAT likely result from practice effect. MHT did not show any adverse effect on MS activity and increasing safety data will hopefully facilitate patient recruitment for future studies.

Approach to Symptom Management in Multiple Sclerosis With a Focus on Wellness

PURPOSE OF REVIEW

This article describes an approach to symptom management in people with multiple sclerosis (MS), emphasizing healthy lifestyles and evidence-based treatments.

RECENT FINDINGS

Growing evidence supports healthy nutrition, exercise, and emotional well-being (wellness) as foundational for MS symptom management. A stepped approach starts with healthy lifestyle practices and adds nonpharmacologic, pharmacologic, and procedural-based therapies balancing levels of evidence, risks, and potential benefits. The growing availability of cannabis and widespread use of dietary supplements in self-management of MS symptoms raise both therapeutic promises and challenges.

SUMMARY

Wellness approaches for MS symptom management foster self-reliance and should be reinforced early and often. Recognition of symptom clusters and medical comorbidities helps limit polypharmacy.

Neural distinctiveness of fatigue and low sleep quality in multiple sclerosis

BACKGROUND AND PURPOSE

Fatigue and low sleep quality in multiple sclerosis (MS) are closely related symptoms. Here, the associations between the brain's functional connectivity (FC) and fatigue and low sleep quality were investigated to determine the degree of neural distinctiveness of these symptoms.

METHOD

A hundred and four patients with relapsing-remitting MS (age 38.9 ± 10.2 years, 66 females) completed the Modified Fatigue Impact Scale and the Pittsburgh Sleep Quality Index and underwent resting-state functional magnetic resonance imaging. FC was analyzed using independent-component analysis in sensorimotor, default-mode, fronto-parietal and basal-ganglia networks. Multiple linear regression models allowed us to test the association between FC and fatigue and sleep quality whilst controlling for one another as well as for demographic, disease-related and imaging variables.

RESULTS

Higher fatigue correlated with lower sleep quality (r = 0.54, p < 0.0001). Higher fatigue was associated with lower FC of the precentral gyrus in the sensorimotor network, the precuneus in the posterior default-mode network and the superior frontal gyrus in the left fronto-parietal network, independently of sleep quality. Lower sleep quality was associated with lower FC of the left intraparietal sulcus in the left fronto-parietal network, independently of fatigue. Specific associations were found between fatigue and the sensorimotor network's global FC and between low sleep quality and the left fronto-parietal network's global FC.

CONCLUSION

Despite the high correlation between fatigue and low sleep quality in the clinical picture, our findings clearly indicate that, on the neural level, fatigue and low sleep quality in MS are associated with decreased FC in distinct functional brain networks.

Melatonin and multiple sclerosis: antioxidant, anti-inflammatory and immunomodulator mechanism of action

BACKGROUND

Melatonin is an indole hormone secreted primarily by the pineal gland that showing anti-oxidant, anti-inflammatory and anti-apoptotic capacity. It can play an important role in the pathophysiological mechanisms of various diseases. In this regard, different studies have shown that there is a relationship between Melatonin and Multiple Sclerosis (MS). MS is a chronic immune-mediated disease of the Central Nervous System.

AIM

The objective of this review was to evaluate the mechanisms of action of melatonin on oxidative stress, inflammation and intestinal dysbiosis caused by MS, as well as its interaction with different hormones and factors that can influence the pathophysiology of the disease.

RESULTS

Melatonin causes a significant increase in the levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione and can counteract and inhibit the effects of the NLRP3 inflammasome, which would also be beneficial during SARS-CoV-2 infection. In addition, melatonin increases antimicrobial peptides, especially Reg3β, which could be useful in controlling the microbiota.

CONCLUSION

Melatonin could exert a beneficial effect in people suffering from MS, running as a promising candidate for the treatment of this disease. However, more research in human is needed to help understand the possible interaction between melatonin and certain sex hormones, such as estrogens, to know the potential therapeutic efficacy in both men and women.

Discrepancies between self-reported and device-measured sleep parameters in adults with multiple sclerosis

STUDY OBJECTIVES

Sleep problems are a common consequence of multiple sclerosis; however, there is limited evidence regarding the agreement between device-measured and self-reported sleep parameters in adults with multiple sclerosis. The present study examined the agreement between self-reported and device-measured parameters of sleep quality in a sample of adults with multiple sclerosis.

METHODS

Participants (n = 49) completed a 7-day sleep diary and wore a wrist-worn ActiGraph GT3×+ (ActiGraph Corp., Pensecola, FL) for seven consecutive nights to quantify self-reported and device-measured sleep parameters, respectively.

RESULTS

There was a significant discrepancy between self-reported and device-measured parameters of total time in bed (mean difference = 19.8 [51.3] min), sleep onset latency (mean difference = 22.2 [19.5] min), and frequency of awakenings during the night (mean difference = 12.8 [6.8]). Intraclass correlation estimates indicated poor agreement between methods on most parameters, except for total time in bed (intraclass correlation = 0.80). Bland-Altman plots suggested that total time in bed and total sleep time had acceptable levels of agreement and linear regression analyses indicated that sleep onset latency (F = 113.91, B = -1.34, P < .001), number of awakenings (F = 543.34, B = 1.85, P < .001), and sleep efficiency (F = 18.39, B = -0.77, P < .001) had significant proportional bias.

CONCLUSIONS

Our results draw attention to the discrepancies between sleep parameter measurements and highlight the importance of including both self-report and device-measured outcomes for a complete and accurate representation of sleep in adults with multiple sclerosis.

CITATION

Cederberg KLJ, Mathison BG, Schuetz ML, Motl RW. Discrepancies between self-reported and device-measured sleep parameters in adults with multiple sclerosis. J Clin Sleep Med. 2022;18(2):415-421.

Do physical activity and social cognitive theory variable scores differ across symptom cluster severity groups in multiple sclerosis?

BACKGROUND

Persons with multiple sclerosis (MS) experience co-occurring symptoms termed "symptom clusters" that can be distinguished based on mild, moderate, or severe symptom severity termed "symptom cluster severity." Physical activity (PA) may be an approach for improving co-occurring symptoms.

OBJECTIVE

To examined if PA and social cognitive theory (SCT) variables differed by symptom cluster groups, and if associations between SCT variables and PA were moderated by symptom cluster groups.

METHODS

Secondary analysis of participants with MS (N = 205) enrolled in a cross-sectional study. Trend analyses were conducted to determine if device-measured and self-reported PA and SCT variables (i.e., social support, self-efficacy, outcome expectations, goal setting, planning, and impediments) decreased with increased symptom cluster severity. Spearman rho rank-order correlations were conducted between PA measures and SCT variables within each symptom cluster group.

RESULTS

Linear trend analyses indicated that self-reported PA declined with increased symptom cluster severity groups (F = 4.90,p = 0.03). Linear trend analyses indicated significant differences among symptom cluster severity groups in social support (F = 31.43,p = 0.001), exercise self-efficacy (F = 22.55,p = 0.001), barrier self-efficacy (F = 11.48,p = 0.001), outcome expectations (F = 6.98,p = 0.009), and impediments (F = 34.41,p = 0.001). There were differential associations of moderate magnitude in correlations, such that three SCT variables were associated with PA in the mild group (i.e., self-efficacy, goal setting and planning), two in the moderate group (i.e., social support and goal setting), and four in the severe group (i.e., self-efficacy, outcome expectations, planning, and social support).

CONCLUSIONS

Further research is warranted examining the use of SCT-based behavior change techniques for promoting PA and improving symptom clusters in persons with MS.

Demographic, clinical, and symptomatic correlates of subjective sleep quality in adults with multiple sclerosis

BACKGROUND

This study examined a comprehensive set of demographic, clinical, and symptomatic variables as correlates of subjective sleep quality in adults with multiple sclerosis (MS).

METHODS

Participants with MS(N=485) completed the Pittsburgh Sleep Quality Index(PSQI), a demographics and clinical characteristics questionnaire, the Patient Determined Disease Steps Scale(PDDS), the Fatigue Severity Scale, and the Hospital Anxiety and Depression Scale. We conducted bivariate Spearman's rho (ρ) correlation analyses and multiple linear regression analysis for identifying variables associated with PSQI scores.

RESULTS

Participants had a mean (standard deviation) age of 55.4 (12.6) years and were mostly female (78%) with a median [interquartile range] PDDS of 2.0[3.0]. Higher levels of fatigue (ρ=0.32), more symptoms of anxiety (ρ=0.39) and depression (ρ=0.36), younger age (ρ=-0.12), lower income status (ρ=-0.13), shorter MS disease duration (ρ=-0.11), being in a minority group (ρ=0.09), and being unemployed (ρ=-0.10) were associated with worse sleep quality. There were no significant associations between gender, marital status, parental status, education level, disability status, or MS disease type and sleep quality. The overall regression model accounted for 26.3% of variance in sleep quality (F[8,229.8]=20.25) and there were significant coefficients for anxiety(β=0.25), fatigue(β=0.18), depression(β=0.16), and employment status(β=-0.12), but not disease duration, age, race, or income level.

DISCUSSION

Participants with higher levels of anxiety, fatigue, and depression and who were unemployed reported worse sleep quality in our sample of adults with MS. These results may identify specific subgroups of the MS population that experience more sleep problems, and therefore are in greatest need for interventions designed to improve sleep impairment.

Physical activity and self-reported sleep quality in adults with multiple sclerosis

BACKGROUND

There is a fourfold higher prevalence of sleep problems in multiple sclerosis (MS) than the general population.

OBJECTIVE

This study examined cross-sectional associations among device-measured sedentary and physical activity behavior with perceived sleep quality in adults with MS.

METHODS

Adults with MS (N = 290) completed the Pittsburgh Sleep Quality Index (PSQI) and wore an accelerometer for seven days providing a measure of time spent in sedentary behavior, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) using MS-specific cut-points. We conducted multiple linear regression analysis to identify the independent contributions of variables for explaining PSQI scores.

RESULTS

The overall model accounted for 2% of the variance in global PSQI scores, and MVPA was significantly and independently associated with global PSQI scores (β = ─0.123; p = 0.045; partial r = ─0.118) when accounting for average wear time, sedentary behavior, and time spent in LPA. There were no other significant associations with PSQI global score.

CONCLUSIONS

Our results suggest that time spent in MVPA may be associated with better sleep quality in adults with MS, but adults with MS do not spend sufficient time in physical activity. Researchers should evaluate these relationships in longitudinal study designs and behavior change interventions, as physical activity may provide a unique opportunity to improve sleep quality outcomes.

Distinguishing the Diagnosis and Management of Sleep Disturbance and Sleep Disorders in Multiple Sclerosis

Sleep is a critical issue for quality of life, cognition, and safety among patients with MS. Sleep disturbances from poor sleep hygiene, and multiple sclerosis symptomology, sleep disorders are prevalent; yet evaluation of sleep and screening of sleep disorders are inconsistent. This article presents commonly observed sleep disturbances and disorders, appropriate screening and diagnostic considerations, and management options. Nurses providing care for patients with MS must recognize sleep as an important component in care planning. A comprehensive sleep history and appropriate screening instruments should be incorporated into initial and ongoing assessments, with referral to sleep medicine providers as indicated.

Sleep disturbance and memory dysfunction in early multiple sclerosis

OBJECTIVE

Sleep-dependent memory processing occurs in animals including humans, and disturbed sleep negatively affects memory. Sleep disturbance and memory dysfunction are common in multiple sclerosis (MS), but little is known about the contributions of sleep disturbance to memory in MS. We investigated whether subjective sleep disturbance is linked to worse memory in early MS independently of potential confounders.

METHODS

Persons with early MS (n = 185; ≤5.0 years diagnosed) and demographically matched healthy controls (n = 50) completed four memory tests to derive a memory composite, and four speeded tests to derive a cognitive efficiency composite. Z-scores were calculated relative to healthy controls. Sleep disturbance was defined by the Insomnia Severity Index score ≥ 10. ANCOVAs examined differences in memory and cognitive efficiency between patients with and without sleep disturbance controlling for potential confounds (e.g., mood, fatigue, disability, T2 lesion volume, gray matter volume). Comparisons were made to healthy controls.

RESULTS

Seventy-four (40%) patients reported sleep disturbance. Controlling for all covariates, patients with sleep disturbance had worse memory (z = -0.617; 95% CI: -0.886, -0.348) than patients without disturbance (z = -0.171, -0.425, 0.082, P = .003). Cognitive efficiency did not differ between groups. Relative to healthy controls, memory was worse among patients with sleep disturbance, but not among patients without sleep disturbance.

INTERPRETATION

Sleep disturbance contributes to MS memory dysfunction, which may help explain differential risk for memory dysfunction in persons with MS, especially since sleep disturbance is common in MS. Potential mechanisms linking sleep disturbance and memory are discussed, as well as recommendations for further mechanistic and interventional research.

Vigilanz und Fahreignung

Störungen der Vigilanz können die Fahreignung relevant beeinträchtigen. Sie können vielfältige Ursachen haben und stellen eine der Hauptursachen für Verkehrsunfälle dar. Dieser Artikel benennt die rechtlichen Grundlagen für die Beurteilung der Fahreignung, stellt Testverfahren zur Einschätzung von Vigilanzstörungen vor und erläutert ein praktisches Vorgehen unter Berücksichtigung der gesetzlichen Bestimmungen.

Symptom clusters and quality of life in persons with multiple sclerosis across the lifespan

PURPOSE

To describe symptom clusters based on severity of co-occurring symptoms among adults with multiple sclerosis (MS) by age groups and to further examine symptom clusters as a correlate of quality of life (QOL) by age groups.

METHODS

This cross-sectional study enrolled persons with MS between 20 and 79 years of age who completed measures of fatigue, depression, anxiety, sleep quality, and QOL using the 36-Item Short Form Health Survey. Bivariate correlation and partial correlation analyses examined associations among symptoms, QOL, and MS characteristics. K-means cluster analyses determined symptom clusters among the full sample and pre-determined age groups (i.e., 20-39, 40-59, and 60-79). One-way ANOVAs examined differences in QOL among clusters for the overall sample and by age groups.

RESULTS

Among the overall sample of 205 participants, symptoms were significantly correlated with QOL and three distinct clusters were identified and differentiated by the magnitude of symptom experience (i.e., mild, moderate, and severe). Results were consistent among young and middle-aged adults; however, among older adults two severe sleep problem clusters were identified that were distinguished by moderate versus severe fatigue, depression, and anxiety. ANOVAs among the overall sample indicated that the three symptom clusters varied significantly for both physical component scores, F(2, 202) = 12.03, p < .001, η2 = .10, and mental component scores, F(2, 202) = 137.92, p < .001, η2 = .58; severe symptom cluster was associated with worse QOL. Patterns in the age subgroup ANOVAs were consistent.

CONCLUSIONS

Given the strong association between severity of symptom clusters and QOL, approaches for targeting co-occurring symptoms are critically needed.

Therapeutic Approaches to Insomnia and Fatigue in Patients with Multiple Sclerosis

The prevalence of sleep disorders in individuals with multiple sclerosis (MS) is 3-5 times higher compared to the general population. Insomnia Disorder, defined as difficulty falling asleep, maintaining sleep or waking up too early, can lead to significant fatigue, the most common and disabling symptom of MS. In addition, fatigue and insomnia in patients with MS also can overlap with and exacerbate other psychological and physical symptoms. Cognitive behavioral therapy for insomnia (CBT-I) has been shown as an effective treatment for chronic insomnia and burgeoning research has demonstrated the effectiveness of this treatment for insomnia in individuals with a variety of comorbid medical conditions including MS. The purpose of the current review will explore the literature surrounding the prevalence and impact of sleep disorders and fatigue in MS. Additionally, this review will address practical ways to help individuals with MS manage fatigue as well as how to modify typical standard behavioral treatments for insomnia to take into account special considerations for individuals with MS based on the level of disability and other comorbid issues that impact sleep.

Sleep Disturbances Associated with Neurological Autoimmunity

Associations between sleep disorders and neurological autoimmunity have been notably expanding recently. Potential immune-mediated etiopathogenesis has been proposed for various sleep disorders including narcolepsy, Kleine-Levin syndrome, and Morvan syndrome. Sleep manifestations are also common in various autoimmune neurological syndromes, but may be underestimated as overriding presenting (and potentially dangerous) neurological symptoms often require more urgent attention. Even so, sleep dysfunction has been described with various neural-specific antibody biomarkers, including IgLON5; leucine-rich, glioma-inactivated protein 1 (LGI1); contactin-associated protein 2 (CASPR2); N-methyl-D-aspartate (NMDA)-receptor; Ma2; dipeptidyl-peptidase-like protein-6 (DPPX); alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R); anti-neuronal nuclear antibody type-1 (ANNA-1, i.e., Hu); anti-neuronal nuclear antibody type-2 (ANNA-2, i.e., Ri); gamma-aminobutyric acid (GABA)-B-receptor (GABA-B-R); metabotropic glutamate receptor 5 (mGluR5); and aquaporin-4 (AQP-4). Given potentially distinctive findings, it is possible that sleep testing could potentially provide objective biomarkers (polysomnography, quantitative muscle activity during REM sleep, cerebrospinal fluid hypocretin-1) to support an autoimmune diagnosis, monitor therapeutic response, or disease progression/relapse. However, more comprehensive characterization of sleep manifestations is needed to better understand the underlying sleep disruption with neurological autoimmunity.

Sleep in multiple sclerosis patients treated with interferon beta: an actigraphic study

OBJECTIVE

Sleep disorders in multiple sclerosis (MS) patients are common and complex. Some evidences suggest that interferon beta (IFN-β), a first line disease modifying therapy can be involved in the induction of sleep architecture changes. The aim of this study was to evaluate and characterize actigraphic patterns in MS patients treated with IFN-β.

METHODS

Ten relapsing remitting MS patients with low to mild disability (Expanded Disability Status Scale<2.5), aged 20-50y treated with IFN-β for more than 6 months were enrolled. Actigraphy was used to study sleep pattern. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI). Ten sex-and age-matched healthy subjects served as controls. In patients, a comparison between drug free nights and nights following drug administration was made.

RESULTS

Patients had significantly higher PSQI (p = 0.006), sleep onset latency (p = 0.029), sleep efficiency percentage (p = 0.001) and number of wake episodes (p = 0,0001) values, when compared with controls. When comparing the actigraphic results acquired in the nights after treatment with those acquired in the free-drug nights, the only significant difference (p = 0.038) was detected for time in bed that was higher after IFN-β administration.

CONCLUSIONS

Our results, besides confirming the presence of alterations in sleep patterns in MS patients, suggest that IFN-β may contribute to promote alteration in sleep architecture. Actigraphy is a simple diagnostic tool, able to support an objective measure of sleep parameters. The relative simplicity of application and low costs may allow considering its use for an adequate screening of sleep disorders in MS patients.

The Effectiveness of Occupational Therapy-Based Sleep Interventions on Quality of Life and Fatigue in Patients with Multiple Sclerosis: A Pilot Randomized Clinical Trial Study

PURPOSE

Sleep difficulties are common in patients with multiple sclerosis (MS), which may increase feelings of fatigue, negatively interfere with daily activities, and consequently reduce their quality of life. Studies examining the effects of sleep-targeted interventions in MS are currently limited in the literature. Therefore, we aim to assess the effects of occupational therapy interventions on sleep quality, fatigue, and quality of life in patients with MS.

PATIENTS AND METHODS

In a single-blind, randomized, controlled trial, which occurred between April 2018 and March 2019 in Tehran, Iran, 20 eligible patients with MS were assessed using the Pittsburgh Sleep Quality Index (PSQI), Fatigue Impact Scale (FIS), Fatigue Severity Scale (FSS), and Short-Form Health Survey (SF-36). Patients were allocated randomly into the two following groups: patients receiving care-as-usual for MS (CAU) and patients receiving care-as-usual plus intervention (CAU + intervention). Both intervention groups underwent 2-3 sessions per week lasting 30-45 minutes for 8 weeks and received follow-up assessments. Data were analyzed using independent sample t-tests and Mann-Whitney U tests using SPSS (16 ver.) statistical software.

RESULTS

In the intervention group, sleep quality improved significantly across all items (p<0.001, effect size = 0.60) except for sleep efficiency and the use of sleep medications. FSS and FIS in the sleep intervention group were significantly reduced (p<0.001, effect size = 0.76 and p<0.001, effect size = 0.82, respectively). The quality of life in the intervention group improved significantly (p<0.004, effect size = 0.51-0.76) with the exception of the social functioning subgroup.

CONCLUSION

Although this is the result of a pilot study and more patients should be added, this intervention program demonstrates improvement in sleep quality and quality of life while decreasing fatigue in patients with MS. Adjunction of this program, if results are similar with more patients, to routine occupational therapy (OT) interventions can help improve the rehabilitation program of MS patients.

Sleep and neurological autoimmune diseases

Neurological autoimmune diseases are characterized by an inappropriate immune response that by mistake targets the nervous system. As a result, patients experiment a number of neurological manifestations that may include insomnia, excessive daytime sleepiness, cataplexy, central hypoventilation, and REM sleep behavior disorder. Polysomnographic evaluation may reveal disorganized sleep architecture involving both NREM and REM sleep, and REM sleep intrusions into wakefulness. The study of sleep disorders in the setting of autoimmune diseases (e.g., narcolepsy, anti-IgLON5 disease, paraneoplastic neurological syndromes) shows that an abnormal immune-mediated (humoral or cellular) response target the neuronal structures (e.g., brainstem, hypothalamus) and neurotransmitters systems (e.g., hypocretin) that regulate sleep resulting in sleep impairment. It is a window to examine the link between the autoimmune system and the sleep regulation at the molecular, cellular, and anatomic level.

The role of sleep and wakefulness in myelin plasticity

Myelin plasticity is gaining increasing recognition as an essential partner to synaptic plasticity, which mediates experience-dependent brain structure and function. However, how neural activity induces adaptive myelination and which mechanisms are involved remain open questions. More than two decades of transcriptomic studies in rodents have revealed that hundreds of brain transcripts change their expression in relation to the sleep-wake cycle. These studies consistently report upregulation of myelin-related genes during sleep, suggesting that sleep represents a window of opportunity during which myelination occurs. In this review, we summarize recent molecular and morphological studies detailing the dependence of myelin dynamics after sleep, wake, and chronic sleep loss, a condition that can affect myelin substantially. We present novel data about the effects of sleep loss on the node of Ranvier length and provide a hypothetical mechanism through which myelin changes in response to sleep loss. Finally, we discuss the current findings in humans, which appear to confirm the important role of sleep in promoting white matter integrity.

Sleep disturbance and cognitive decline in multiple sclerosis patients with isolated optic neuritis as the first demyelinating event

PURPOSE

Multiple sclerosis (MS) patients whose first demyelinating event is optic neuritis have been claimed to display a milder disease course and reduced physical disability. Our aim was to investigate the impact of the clinical features of the first clinical episode on cognitive disability and sleep dysfunction in MS.

METHODS

A total of 26 (10 with optic neuritis as the first clinical event) MS patients were recruited. A comprehensive sleep study was performed, and a panel of tests were administered to examine cognitive and motor performance. Serum levels of sleep-related mediators orexin-A and melatonin were measured by enzyme-linked immunosorbent assay. Subjective sleep quality was evaluated by Pittsburgh sleep quality test, and daytime excessive sleepiness was tested by Epworth sleepiness scale.

RESULTS

MS patients with the first clinical episode of optic neuritis and patients with at least one optic neuritis attack exhibited increased daytime sleepiness, higher sleep efficiency and NREM duration and lower total wake time. Patients with a history of optic neuritis obtained more favorable scores in neuropsychological tests measuring executive functions and complex attention as compared to those who had never experienced optic neuritis. Melatonin and orexin-A levels were lower in patients with optic neuritis onset. The higher no. of optic neuritis attacks was associated with reduced wake time and higher symbol digit modalities test scores.

CONCLUSIONS

Having a history of optic neuritis is associated with improved sleep quality and executive functions but increased daytime sleepiness. Reduction of orexin-A and melatonin levels might be one of the underlying mechanisms.