Sleep disturbance and memory dysfunction in early multiple sclerosis

Abstract

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 = À0.617; 95% CI: À0.886, À0.348) than patients without disturbance (z = À0.171, À0.425, 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.

Resilience, Stress, Well-Being, and Sleep Quality in Multiple Sclerosis

“…This observed effect might have been caused by the challenge of adapting to a new diagnosis and the unknown that it brings, similarly to what has been observed in people shortly after a cancer diagnosis [ 88 ]. The observed association here between stress and sleep quality was recorded in various studies [ 89 ], and appears of utmost importance—poor sleep quality in MS may lead to greater impairment [ 24 , 25 , 90 ], and one’s stress levels remain a modifiable risk factor [ 91 , 92 , 93 ]. Fatigue, one of the most common and debilitating symptoms of MS [ 31 , 32 ], was also associated with stress, a finding that aligns with the previous studies on the subject [ 94 ].…”

“…The most recent studies on the subject reported lower rates, with poor sleep quality observed in about half of the study participants [ 110 , 111 ] and insomnia in 66.45% [ 112 ]. Sleep is especially important in PwMS because of its role in brain regeneration and regulation of inflammatory processes [ 25 ]. Poor sleep quality is related to cognitive decline, memory and attention problems, and lower processing speeds, all common and disturbing symptoms of MS as it progresses [ 24 , 25 , 113 ].…”

“…Sleep is especially important in PwMS because of its role in brain regeneration and regulation of inflammatory processes [ 25 ]. Poor sleep quality is related to cognitive decline, memory and attention problems, and lower processing speeds, all common and disturbing symptoms of MS as it progresses [ 24 , 25 , 113 ]. In the current study, poor sleep quality was observed across all the subcategories of PwMS examined, in all types of MS, both in the recently diagnosed and in those who have been diagnosed for over 20 years, in those who receive DMT and in those who do not.…”

“…Poor sleep quality is one of the major modifiable risk factors for cognitive decline [ 22 , 23 ]; in PwMS it has been specifically linked to diminished visual and verbal memory, executive function attention, and processing speed [ 24 , 25 ]. PwMS are very likely to suffer from sleep disturbances [ 26 , 27 ]: studies report that approximately half of PwMS may be suffering from poor sleep quality [ 28 , 29 ].…”

Mediterranean diet is linked to less objective disability in multiple sclerosis

“…Patient-reported frequency of moderate-to-vigorous physical activity ( MVPA ) was assessed with the health contribution score (HCS) from the Godin leisure time exercise questionnaire 14 (GLTEQ, continuous), which has convergent validity with accelerometer-measured MVPA in persons with MS. 15 Sleep disturbance is common in MS, and there is some evidence linking sleep to dietary patterns in other populations. Sleep disturbance was assessed with the insomnia severity index 16 ( SLEEP , dichotomous) using the validated cutoff (raw ⩾ 10), 16 which we have previously used in MS. 17 Medical history forms completed by patients documented dichotomous histories (ever vs never) of hypertension ( HTN ), diabetes mellitus ( DM ), hyperlipidemia ( HLD ), and smoking ( SMOKE ).…”