Poor sleep quality in people with multiple sclerosis was associated with greater self-reported cognitive difficulties and poorer quality of life (symptoms and fatigue domains), but not with performance-based cognitive functioning.
Key Findings
Results
People with MS with poor sleep quality did not significantly differ from those with adequate sleep quality on performance-based cognitive functioning.
Performance-based cognition was measured using a composite of mean neuropsychological performance and two intraindividual variability (IIV) indices.
A multivariate analysis of variance found no significant group differences between poor (n=22) and adequate (n=72) sleep quality groups on the performance-based cognitive composite.
This null finding held even before accounting for covariates such as disease progression, depression, and fatigue.
Results
A significantly greater proportion of PwMS with poor sleep quality self-reported that sleep patterns affected their cognitive abilities compared to those with adequate sleep quality.
86.36% of PwMS with poor sleep quality reported sleep-affected cognitive abilities, compared to 40.28% of those with adequate sleep quality.
Chi-square test: χ2(1, N=94) = 14.32, p < .001, φ = -.39, indicating a medium-to-large effect size.
Self-reported cognitive difficulties were assessed via a dichotomous (yes/no) item on the Sleep Habits Questionnaire.
The sample included 97 PwMS in a cross-sectional design, with 22 in the poor sleep group and 72 in the adequate sleep group.
Results
After accounting for disease progression, depression, and fatigue, poor sleep quality significantly predicted Symptoms quality of life.
The incremental variance explained by sleep quality above covariates was small (R2 = .05).
This finding was derived from hierarchical linear regression controlling for disease progression, depression, and fatigue.
The result suggests sleep quality contributes uniquely to fatigue-related quality of life beyond the influence of fatigue itself as a covariate.
Methods
The study used a sleep quality composite to categorize participants into poor and adequate sleep quality groups.
The cross-sectional study included 97 people with multiple sclerosis (PwMS).
Two groups were created from a sleep quality composite: poor sleep quality (n=22) and adequate sleep quality (n=72).
Quality of life was measured across seven domains from the Functional Assessment of Multiple Sclerosis (FAMS).
Intraindividual variability (IIV) indices were included as part of the performance-based cognitive composite, capturing moment-to-moment fluctuations in cognitive performance.
What This Means
This research suggests that poor sleep quality in people with multiple sclerosis (MS) affects how they perceive their own cognitive functioning and their overall quality of life, even if it does not show up in formal cognitive test performance. In a study of 97 people with MS, those who slept poorly were far more likely to say that their sleep affected their thinking and memory — about 86% of poor sleepers reported this, compared to about 40% of adequate sleepers. However, when researchers measured cognitive ability directly through neuropsychological tests, they found no significant difference between the two groups.
The study also found that poor sleep quality predicted lower quality of life in the areas of physical symptoms and fatigue, even after taking into account how far the MS had progressed, how depressed participants were, and how fatigued they already felt. This means sleep quality appears to have a unique contribution to wellbeing in MS beyond these other well-known factors.
These findings matter because they highlight a potential disconnect between how people with MS experience their cognition and what standard tests can detect. This research suggests that clinicians working with MS patients should pay close attention to sleep quality, not only because poor sleep may worsen how patients feel day-to-day and their sense of cognitive functioning, but also because addressing sleep could be a practical avenue for improving quality of life in this population.
Riegler K, Román C, Guty E, Thomas G, Bradson M, Arnett P. (2026). Quality of Life, Self-Reported Cognitive Difficulties, and Performance-Based Cognitive Problems in Multiple Sclerosis: What's Sleep Got to Do With It?. Archives of clinical neuropsychology : the official journal of the National Academy of Neuropsychologists. https://doi.org/10.1093/arclin/acag001