Pathways between multiple sclerosis, sleep disorders, and cognitive function: Longitudinal findings from The Nurses'...

Area of Science:

• Neurology
• Sleep Medicine
• Cognitive Science

Background:

• The relationship between sleep disorders and cognitive outcomes in multiple sclerosis (MS) remains understudied.
• Investigating these effects is crucial for understanding the full impact of MS on daily functioning.

Purpose of the Study:

• To examine the direct and indirect longitudinal associations between sleep disorders and perceived cognitive dysfunction in women with MS.
• To determine how obstructive sleep apnea (OSA), sleepiness, and insomnia mediate and moderate the cognitive effects of MS.

Main Methods:

• Utilized data from the Nurses' Health Study (2013 and 2017 waves) including 524 women with MS.
• Assessed subjective cognitive function using memory composite scores and binary outcomes for specific difficulties.
• Employed the four-way decomposition method to estimate moderating and mediating effects of OSA, sleepiness, and insomnia.

Main Results:

• Women with MS reported higher prevalence of OSA, sleepiness, and insomnia.
• MS patients were more likely to experience cognitive difficulties.
• Insomnia mediated 5.4%-15.1% and sleepiness mediated 8.6%-12.3% of the total effect of MS on cognitive outcomes.
• OSA accounted for 34% of the total effect between MS and following instructions.

Conclusions:

• Obstructive sleep apnea, insomnia, and sleepiness differentially moderate or mediate the impact of MS on cognition in women.
• Addressing these sleep disorders may be important for managing cognitive function in MS patients.