Comparison of Methods for Classifying Persistent Post-Concussive Symptoms in Children

Abstract

Pediatric mild traumatic brain injury (pmTBI) has received increased public scrutiny over the past decade, especially for children who experience persistent post-concussive symptoms (PPCS). However, several methods for defining PPCS exist in clinical and scientific literature, and even healthy children frequently exhibit non-specific, concussive-like symptoms. Inter-method agreement (six PPCS methods), observed misclassification rates, and other psychometric properties were examined in large cohorts of consecutively recruited adolescent pmTBI (N=162) one week and four months post-injury and in age/sex matched healthy controls (HC; N=117) at equivalent time intervals. Six published PPCS methods were stratified into simple (e.g., ICD-10) and standardized (e.g., reliable change indices) change algorithms. Among HC, test-retest reliability was fair to good across the four-month assessment window, with evidence of bias (i.e., higher symptom ratings) during retrospective relative to other assessments. Misclassification rates among HC were higher (>30%) for simple change algorithms, with poor inter-rater reliability of symptom burden across HC and their parents. A 49% spread existed in terms of the proportion of pmTBI “diagnosed” with PPCS at 4 months, with superior inter-method agreement amongst standardized change algorithms. In conclusion, the self-reporting of symptom burden is only modestly reliable in typically developing adolescents over a 4 month period, with additional evidence for systematic bias in both adolescent and parental ratings. Significant variation existed for identifying pmTBI who had “recovered” (i.e., those who did not meet individual criteria for PPCS) from concussion across the six definitions, representing a considerable challenge for estimating the true incidence rate of PPCS in published literature. Although relatively straight-forward to obtain, current findings question the utility of the most commonly used simple change scores for diagnosis of PPCS in clinical settings.