Restless Legs Syndrome Severity and Cognitive Function in Adults With Multiple Sclerosis: An Exploratory Pilot Study.

BACKGROUND: Restless legs syndrome (RLS) is a sleep disorder present in as many as 26% of persons with multiple sclerosis (MS) and can be associated with cognitive function. The present study examined the relationships between RLS symptoms (severity, frequency, occurrence) and cognitive function in adults with MS who have RLS. METHODS: Twenty-two participants attended 1 laboratory session and completed the International Restless Legs Syndrome Study Group Rating Scale (IRLS), the Restless Legs Syndrome-6 Scale, and then the Brief International Cognitive Assessment for Multiple Sclerosis battery consisting of the Symbol Digit Modalities Test; California Verbal Learning Test, Second Edition; and Brief Visuospatial Memory Test-Revised. RESULTS: Nonparametric bivariate correlations indicated that worse IRLS total severity was associated with slower processing speed (ρ = -0.42), worse verbal memory (ρ = -0.63), and worse visual memory (ρ = -0.61); worse RLS severity at falling asleep was associated with worse verbal memory (ρ = -0.45) and worse visual memory (ρ = -0.55); and worse RLS severity during the day while active was associated with slower processing speed (ρ = -0.58), worse verbal memory (ρ = -0.52), and worse visual memory (ρ = -0.60). CONCLUSIONS: These results suggest that those with more severe RLS, including worse symptoms at falling asleep and during the day while active, might experience worse cognitive function, particularly processing speed and memory. Future research should evaluate whether treatment of RLS symptoms can offer new opportunities for managing cognitive dysfunction in adults with MS.

Restless legs syndrome severity associated with reduced physical function in adults with multiple sclerosis.

BACKGROUND: Restless legs syndrome (RLS) is a sleep disorder that occurs in approximately 26 % of adults with multiple sclerosis (MS) and may be associated with reduced physical function. RESEARCH QUESTION: The present study examined the relationship between RLS symptomology (i.e., overall severity, frequency, and occurrence) and physical function outcomes in adults with MS who had RLS. METHODS: Participants (N = 22) with MS who had RLS came into the laboratory for a single session wherein a rater performed a brief neurological examination for scoring the Expanded Disability Status Scale (EDSS) and completed a demographics questionnaire, the International Restless Legs Syndrome Study Group Scale (IRLS), and the Restless Legs Syndrome Scale-6 (RLS-6) followed by the Short Physical Performance Battery (SPPB) and the Six-minute Walk Test (6 MW). RESULTS: Bivariate Spearman's rho correlation analyses indicated total IRLS had a strong, negative association with total distance traveled during the 6 MW (ρ = -0.50) and a moderate association with SPPB scores (ρ = -0.43), but not EDSS scores (ρ = 0.28). RLS severity during the day while active had strong, negative associations with total distance traveled during the 6 MW (ρ = -0.61) and SPPB scores (ρ = -0.52), but not EDSS scores (ρ = 0.13). SIGNIFICANCE: We observed associations between worse overall RLS severity and RLS severity during the day while active with reduced performance during the 6 MW and lower SPPB scores. The management of RLS may offer an opportunity for mitigating reductions in physical function in adults with MS who have RLS.

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.

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.

Validity and reliability of the suggested immobilization test for measurement of restless legs syndrome severity in adults with multiple sclerosis.

OBJECTIVE/BACKGROUND: Adults with multiple sclerosis (MS) often present with conditions that mimic restless legs syndrome (RLS), thereby adding complexity into the assessment of RLS severity. The current gold-standard measures of RLS severity rely on a fixed seven-day time frame, which limits the ability of these measures for studying acute changes in RLS severity. The present study examined if subjective and objective scores from the suggested immobilization test (SIT) provide a valid and reliable acute measure of RLS severity in persons with MS. PATIENTS/METHODS: Participants with MS and RLS (n = 20) and MS without RLS (n = 20) were matched by age, gender, and disability. All participants completed validated questionnaires for RLS severity followed by the SIT, conducted at 18:00 (±15 min) on the same day of the week for two consecutive weeks. Participants wore accelerometer devices for seven nights to capture periodic limb movements (PLMs) during the night. RESULTS: Self-reported RLS severity during the SIT had excellent construct validity and convergent validity, but moderate test-retest reliability. Device-measured PLMs, while not themselves a direct measure of RLS severity, were significantly associated with PLMs during the night and had excellent test-retest reliability during the SIT in adults with MS. CONCLUSIONS: Our results suggest that the SIT represents a valid acute measure for capturing self-reported sensory aspects of RLS severity and should be considered in future research and clinical practice as a standardized acute measure of subjective RLS severity in adults with MS who present with RLS.