Engaging in mentally and/or physically demanding activities post-injury may play a role in post-concussion symptom expression; however, the temporal effects of activity demand on post-concussion symptoms in adults with persistent post-concussion symptoms (PPCS) are unclear. The purpose of this study was to examine activity demand and time-of-day effects of post-concussion symptoms in individuals with PPCS using ecological momentary assessment (EMA). We enrolled 40 adults (60.5% female; mean age = 42.53 ± 11.36 years) with PPCS in our prospective observational study with repeated measures. Participants completed a 20-day EMA period in which they responded to a smartphone app five times per day to report PPCS symptoms and the activities they were currently engaged in. PPCS symptoms were reported using the Post-Concussion Symptom Scale (PCSS), a 22-item symptom inventory that includes total symptoms (possible range = 0-132) and symptom clusters: cognitive-migraine-fatigue (possible range = 0-66), affective (0-18), sleep (0-12), and somatic (0-12). For each activity reported by participants, they were asked to characterize it as mentally demanding, physically demanding, both, or neither. Descriptive statistics captured PCSS scores and characterizations of activity demand. Linear mixed-effects models (LMMs) examined the effects of time of day and activity demand on PCSS symptom scores. During the EMA period, PCSS scores were in the clinically significant range (mean = 24.68 ± 21.04; range = 0-106). Mean symptom domain scores were 16.53 ± 13.84 for cognitive-migraine-fatigue (range = 0-63), 3.25 ± 4.05 for affective (range = 0-18), 1.69 ± 2.59 for sleep (range = 0-12), and 1.05 ± 1.72 for somatic symptoms (range = 0-10). Across all observations (n = 2,984), among the four activity characterization options, activities were most frequently characterized as neither mentally nor physically demanding (n = 1,675, 44.3%), and most participants (n = 26, 68.4%) characterized activities in this category most frequently. Open-ended responses elaborating on activities in this category included "doing nothing," "sleeping/relaxing," "watching TV," and "eating." Linear mixed-effects model (LMM) results (based on 38 participants with >33% response rates) showed that activity demands were significantly associated with symptoms. Mentally demanding activities were associated with increases in total and cognitive-migraine-fatigue symptoms, whereas physically demanding activities were associated with decreases in these symptoms. Mentally demanding and combined mentally and physically demanding activities were also associated with increased affective symptoms. Additionally, time of day was significantly associated with cognitive-migraine-fatigue symptoms, with increases in symptoms later in the day compared with early in the morning. The present findings extend existing literature by demonstrating the utility of EMA for capturing real-time associations between contextual factors and symptom expression in traumatic brain injury populations. We also provide evidence that time-of-day and activity demands are associated with symptom expression in individuals with PPCS. Collectively, these findings have implications for informing symptom management strategies in PPCS.
Keywords: concussion; ecological momentary assessment; mental activity; mild traumatic brain injury; patient-reported outcomes; physical activity.