External validation of symptom severity classification levels for the PostConcussion Symptom Inventory (PCSI).

Two distinct samples of parents and children, ages 8-18, participated from a: (1) prospective multicenter cohort study (Predicting Persistent Post-concussive Problems in Pediatrics, 5P) (Zemek et al., 2016), including parents (n=2,852), adolescents (n=1,087; mean age=15.13; 54% male), and children (n=1,271; mean age=10.70; 65% male) and (2) published clinic sample at Children’s National Hospital (CN) including parents (n=1,197; adolescents, n=835; children, n=326) (Gioia et al., 2019). Participants completed the age-specific Post-Concussion Symptom Inventory (PCSI): Mean time postinjury = 8 hours (5P), 6 days (PCSI2), generating a post-pre-injury difference (RAPID) score. The distribution of the RAPID scores for the Total Symptom and 4 subscales (physical, emotional, cognitive, sleep/fatigue) were examined to define 4 symptom severity classification levels (minimal - within the CI for recovered, low <20th %tile, moderate 21-79th %tile, high >80th %tile) for the respective samples. These severity distributions were compared between the two distinct datasets.

ANOVAs were performed to examine group differences in the mean scores for each of the 4 classification levels. No significant differences were found for all the RAPID score distributions with minimal effect sizes (<.1% variance) for the parents, adolescents and children. PCSI RAPID Total Score ranges for the severity classifications were as follows: Minimal-Parent and adolescent groups 5P<=5, Clinic <=5; Children: 5P<=3, Clinic<=3; Low- Parents 5P 6-15, Clinic 6-13; Adolescents 5P 6-19, Clinic 6-16; Children: 5P 4-7, Clinic: 4-7; Moderate-Parents 5P 16-49, Clinic 14-47; Adolescents 5P 20-56, Clinic 17-51; Children 5P 8-17, Clinic: 818; High- Parents: 5P>=50, Clinic >=48; Adolescents 5P >=57, Clinic >=52; Children 5P >=18, Clinic >=19).

Our findings reveal a parallel distribution of RAPID scores in the two distinct 5P and Clinic patient populations, yielding nearly identical severity classification level parameters across all five PCSI symptom domains (total score, physical, cognitive, emotional, and sleep/fatigue). The present investigation provides evidence of validity for the use of these severity classification levels across the ED and specialty clinic settings.