Ecological Momentary Assessment of Pain, Fatigue, Depressive, and Cognitive Symptoms Reveals Significant Daily Variability in Multiple Sclerosis

Abstract

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.

Keywords: Ecological momentary assessment; Fatigue; Multiple sclerosis; Pain; Rehabilitation.

Figure 1

Diurnal patterns of symptom ratings across the day represented by sample averages for symptoms at each time point, showing a steady increase in all symptoms from wake to bedtime across the sample. Note. error bars = standard error of the mean

Figure 2

Single case example (25 year old female with relapsing-remitting MS) of variability in momentary symptoms across 7 days Note. Fatigue (red line) shows the most obvious within-person fluctuations, with peak values around bed time (corresponding to every fifth tick mark, marked with “B” on horizontal axis). In comparison, pain (blue line) shows slightly less variation across the days, but more variation than cognitive function (purple line) and depressed mood (green line), which shows almost no variability across the entire study period. This single-case example demonstrates both the differences between the symptoms in degree of within-person variability as well as the diurnal effects (evidenced by symptom peaks at bedtime (“B”) and symptom valleys at wake (“W”).

Figure 3

Difference by age categories (youngest = 23–38 years; middle = 39–52 years; oldest = 53–67 years) in the diurnal pattern (change across the day) of fatigue ratings. Lines depict average fatigue ratings at each time point for the different age groups. Note. error bars = standard error of the mean: * = time point at which change in fatigue from wake time point is significantly different by sex.

Figure 4

Differences between men and women in the diurnal pattern (change across the day) of fatigue ratings. Lines depict average fatigue ratings at each time point for men and women. Note. error bars = standard error of the mean; * = time points at which change in fatigue from wake time point is significantly different by age.

Figure 5

Differences by education categories (Note. error bars = standard error of the mean; * = time points at which change in cognitive function from wake time point is significantly different by education.