Validation of a modified-composite autonomic symptom score (COMPASS-31) as an outcome measure for persistent autonomic symptoms post-concussion: an observational pilot study.

Objective: Persistent symptoms post-mild traumatic brain injury (mTBI) includes autonomic dysregulation (AD). The composite autonomic symptoms score, (COMPASS-31), was developed to quantify AD symptom severity in the last year, which limits clinical utility. The primary aim was to determine validity of a modified-COMPASS-31 measuring symptoms in the last month compared to the original, secondarily to compare both original and modified versions to the Neurobehavioral Symptom Inventory (NSI), and tertiarily to detect change post-treatment of the modified-COMPASS-31 compared to NSI and headache intensity (HI).

Participants: Thirty-three military personnel with persistent headache post-mTBI.

Main outcome measures: Total and domain scores for COMPASS-31 (original vs. modified) NSI and HI at baseline. Change in modified-COMPASS-31. NSI, and HI.

Results: Baseline COMPASS-31 versions were comparable and highly correlated (r = 0.72, p < 0.001), they were moderately correlated at best to the NSI (r < 0.6), which may suggest differences in measurement metrics. The mean change in modified-COMPASS-31 scores (15.4/100, effect size 0.8) was mild to moderately correlated to the change in HI (r = 0.39) score, but not to NSI (r = 0.28).

Conclusion: The modified-COMPASS-31 appears to be valid, can measure change of AD symptom severity, and is recommended as an outcome measure.