Pathways between multiple sclerosis, sleep disorders, and cognitive function: Longitudinal findings from The Nurses’ Health Study

Abstract

Background: The potential mediating and moderating effects of sleep disorders on cognitive outcomes in multiple sclerosis (MS) have been insufficiently studied. Objectives: To determine direct and indirect longitudinal associations between sleep disorders and perceived cognitive dysfunction in women with MS. Methods: The 2013 and 2017 waves of the Nurses’ Health Study ( n = 63,866) were utilized. All diagnoses and symptoms including MS ( n = 524) were self-reported. Subjective cognitive function was measured using a composite score of four memory items and three binary outcomes that assessed difficulty following instructions, conversations/plots, and street navigation. Moderating and mediating effects of diagnosed/suspected obstructive sleep apnea (OSA), sleepiness, and insomnia between MS and cognition were estimated using the four-way decomposition method. Results: Prevalence of diagnosed/suspected OSA, sleepiness, and insomnia in 2013 were higher for nurses with MS (NwMS). NwMS were more likely to report cognitive difficulties in 2017. Insomnia mediated 5.4%–15.1% of the total effect between MS and following instructions, conversations/plots, and memory impairment, while sleepiness mediated 8.6%–12.3% of the total effect for these outcomes. In interaction analyses, OSA significantly accounted for 34% of the total effect between MS and following instructions. Conclusion: Prevalent OSA, insomnia, and sleepiness could differentially moderate or mediate the effect of MS on cognition in women with MS.

Sleep-disordered breathing and neurocognitive function in multiple sclerosis: Differential associations across cognitive domains

“…In that study, the interaction between OSA and MS was associated with future perceived cognitive difficulty with verbal comprehension, whereas insomnia and sleepiness mediated relationships between verbal comprehension and memory. 37 Nonetheless, even if similar sleep-cognition relationships do exist in MS and non-MS populations, our findings still hold clinical relevance for PwMS—a population that may escape sleep evaluations. 13 Finally, the cross-sectional design of this study precludes assessment of cause-and-effect relationships.…”

“…We cannot rule out the possibility that both cognitive dysfunction and sleep apnea could be independent, unrelated consequences of MS. However, given preliminary short-term temporal associations between MS-related cognitive impairment and sleep disturbances, 37,38 and published data from non-MS populations that suggest sleep disturbances increase risk for future cognitive dysfunction, 39 our data allow speculation that disturbed sleep could cause cognitive dysfunction in PwMS.…”

Resilience, mental health, sleep, and smoking mediate pathways between lifetime stressors and Multiple Sclerosis severity

“…PwMS have a higher lifetime prevalence of mental health challenges including depression, anxiety, bipolar disorder, adjustment disorders, and psychotic disorders 19-21 . The prevalence and severity of sleep disturbances, including poor sleep quality, sleep fragmentation, sleep apnea, insomnia, and restless legs syndrome (RLS), are increased in PwMS 22-24 . Despite their high prevalence and impact, sleep disturbances often go unrecognized and untreated 25 , contributing to other symptoms as well as diminishing quality of life in PwMS 24,26,27 .…”

“…The prevalence and severity of sleep disturbances, including poor sleep quality, sleep fragmentation, sleep apnea, insomnia, and restless legs syndrome (RLS), are increased in PwMS 22-24 . Despite their high prevalence and impact, sleep disturbances often go unrecognized and untreated 25 , contributing to other symptoms as well as diminishing quality of life in PwMS 24,26,27 . Lastly, tobacco smoking is particularly harmful in the context of MS 28 .…”

Well-being at midlife: Correlates of mental health in ambulatory menopausal women with multiple sclerosis

“…Furthermore, "overlap symptoms" common to both MS and the menopausal transition, such as worsening mood, fatigue, and bladder control, could cumulatively worsen symptoms in MS. [4][5][6][7] Finally, in the general population, the perimenopausal period is associated with worse sleep quality, including sleep onset and sleep maintenance. Menopause could therefore also exacerbate MS symptoms through worsening in sleep quality, which disproportionately affects people with MS. [8][9][10][11] Because of this, it was hypothesized that poor sleep quality and worse VMSs would impact general mental health in this patient population.…”