Abstract
Objective
To evaluate the role of time since injury on the factor structure of the Post-Concussion Symptom Scale (PCSS) for athletes after sustaining a sport-related concussion (SRC).
Methods
Adolescent athletes (n = 782) were dichotomized based on time since injury: 0–7 (EARLY; n = 321, age: 15.4 ± 1.9 years, 51.7% female), 8–14 (MIDDLE; n = 281, age: 15.8 ± 2.2 years, 54.8% female) and 15–30 days (LATE; n = 180, age: 15.6 ± 1.8 years, 52.8% female). An EFA was performed on the 22 variables of the PCSS for each of the three cohorts (primary factor loading of 0.6 to retain each item).
Results
EARLY had a five-component model (64% of total variance): 1) GLOBAL (18.0%; headache/dizziness/photosensitivity/phonosensitivity/difficulty concentrating), 2) FATIGUE/HYPERSOMNIA (16.4%; fatigue/drowsiness/mental fogginess/slowed down/hypersomnia), 3) AFFECTIVE (12.6%; more emotional/sadness), 4) INSOMNIA (9.0%; insomnia/trouble falling asleep), 5) SOMATIC (8.0%; vomiting/numbness). MIDDLE had a four-component model (63.1% of variance): 1) GLOBAL (19.4%; photosensitivity/headache/phonosensitivity/nausea/dizziness), 2) INSOMNIA/AFFECTIVE (14.4%; insomnia/more emotional/nervousness/trouble falling asleep), 3) SOMATIC/MEMORY (12.2%; difficulty remembering/numbness), and 4) HYPERSOMNIA (12.0%; drowsiness/hypersomnia). LATE had a four-component model (65.7% of variance): 1) VESTIBULAR/OCULAR (18.2%; vision/difficulty remembering/balance/fogginess/dizziness), 2) MIGRAINE (16.6%; photosensitivity/phonosensitivity/fatigue/headache), 3) AFFECTIVE (16.1%; sadness/nervousness/more emotional), and 4) INSOMNIA (7.6%; insomnia/trouble falling asleep).
Conclusions
The results of this study suggest greater time since injury modifies symptom factor structure in adolescent athletes with SRC. Specifically, symptom factors become more distinct with longer time since injury before first clinical visit. A GLOBAL symptom factor was observed for both EARLY and MIDDLE, but not in LATE. SOMATIC (i.e., numbness) was observed in EARLY/MIDDLE, but not LATE. Symptom factors in LATE seem to mirror concussion clinical sub-types from previous research (e.g., vestibular/ocular, migraine, affective, sleep).