Sleep disturbance and cognitive impairment in multiple sclerosis: Clinical and imaging correlates

Cognitive impairment is a frequent complication in MS and has been shown to have an adverse effect on the lives of MS patients nearly equal to that caused by their physical impairments. Proper sleep is important for memory consolidation and sleep deprivation has been related to impaired functioning in various cognitive domains.

To evaluate the relationship between sleep quality and cognitive performance in MS and to explore clinical and radiological correlates.

This cross-sectional comparative study included 122 non -severely depressed MS patients and 122 age, sex and BMI matched control volunteers who underwent assessment of their cognitive performance using the Arabic version of the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS). Sleep health was assessed using Epworth sleepiness scale and Pittsburgh sleep quality index (PSQI). Multivariable logistic regression models were used to identify independent predictors of cognitive impairment.

Patients had significantly poorer sleep quality and worse cognitive performance across all domains than controls (all p < 0.001). Sleep disturbance was associated with cognitive impairment, particularly slower processing speed. In multivariable analyses, expanded disability status scale (EDSS) and PSQI were independently associated with SDMT impairment, whereas global cognitive impairment was more strongly linked to disability and educational level. The association between sleep quality and global cognition was attenuated after adjustment for psychological factors.

Sleep disturbance was associated with cognitive dysfunction in MS, particularly slower processing speed, and may represent a clinically relevant and potentially modifiable factor within the broader multidimensional framework of cognitive dysfunction. Routine assessment of sleep symptoms may therefore merit consideration in comprehensive MS care.