Objective
To describe the daily variability and patterns of pain, fatigue, depressed mood, and cognitive function in persons with multiple sclerosis (MS).
Design
Repeated-measures observational study of 7 consecutive days of home monitoring, including ecological momentary assessment (EMA) of symptoms. Multilevel mixed models were used to analyze data.
Setting
General community.
Participants
Ambulatory adults (N=107) with MS recruited through the University of Michigan and surrounding community.
Interventions
Not applicable.
Main Outcome Measure
EMA measures of pain, fatigue, depressed mood, and cognitive function rated on a 0 to 10 scale, collected 5 times a day for 7 days.
Results
Cognitive function and depressed mood exhibited more stable within-person patterns than pain and fatigue, which varied considerably within person. All symptoms increased in intensity across the day (all P<.02), with fatigue showing the most substantial increase. Notably, this diurnal increase varied by sex and age; women showed a continuous increase from wake to bedtime, whereas fatigue plateaued after 7 pm for men (wake–bed B=1.04, P=.004). For the oldest subgroup, diurnal increases were concentrated to the middle of the day compared with younger subgroups, which showed an earlier onset of fatigue increase and sustained increases until bed time (wake–3 pm B=.04, P=.01; wake–7 pm B=.03, P=.02). Diurnal patterns of cognitive function varied by education; those with advanced college degrees showed a more stable pattern across the day, with significant differences compared with those with bachelor-level degrees in the evening (wake–7 pm B=−.47, P=.02; wake–bed B=−.45, P=.04).
Conclusions
Findings suggest that chronic symptoms in MS are not static, even over a short time frame; rather, symptoms—fatigue and pain in particular—vary dynamically across and within days. Incorporation of EMA methods should be considered in the assessment of these chronic MS symptoms to enhance assessment and treatment strategies.