Abstract:
CONTEXT: Meta-analyses examining construct-specific cognitive impairment concurrently with self-reported symptoms post-concussion are sparse. OBJECTIVE: To review the literature on the effects of concussion on construct-specific neurocognitive declines and to compare them with self-reported symptoms before 1 week and between 1 and 3 weeks post-concussion. DATA SOURCES: Relevant studies in PubMed, CINAHL, and PsycINFO published from January 1, 1999 through November 30, 2015. STUDY SELECTION: Studies were included if participants completed the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) before and after concussion and if test performance and Post-Concussion Symptom Scale (PCSS) scores were reported at both times. DATA EXTRACTION: After reviewing the full texts, we extracted data from 17 studies consisting of 29 independent samples; therefore, this meta-analysis consisted of 1777 unique participants. DATA SYNTHESIS: The Hedges g effect size (ES) was estimated. A random-effects or fixed-effects model was used based on heterogeneity findings. When heterogeneity was present, we used meta-regression to assess unexplained between-studies variance. Within the first week of injury, the ESs were small to moderate for cognitive declines, ranging from -0.43 (95% confidence interval [CI] = -0.52, -0.35) to -0.67 (95% CI = -0.77, -0.58), and large for the PCSS score (Hedges g = -0.81; 95% CI = -0.91, -0.71). After 1 week, the ESs for cognitive declines (Hedges g range = -0.25 [95% CI = -0.35, -0.15] to -0.37 [95% CI = -0.55, -0.19]) and PCSS score (Hedges g = -0.38; 95% CI = -0.53, -0.22) were also small. Within 2 weeks of injury, PCSS score and time since injury weakly moderated the cognitive ES. CONCLUSIONS: When a neurocognitive test was administered within 1 week of injury, the ES was larger for self-reported symptoms than for ImPACT scores generated at the same session. After 1 week of injury, the ESs for ImPACT and PCSS scores were comparable. If the athlete reports symptoms within 1 week of injury, administering a cognitive test does not appear to offer additional information to the clinician. However, if the athlete does not report symptoms post-concussion, cognitive testing may inform the clinical management of the injury. KEYWORDS: ImPACT; effect size; mild traumatic brain injuries PMID: 28809606 PMCID: PMC5634232 DOI: 10.4085/1062-6050-52.7.05