Alsalaheen B.1, Marchetti G.2
1University of Michigan, Flint, United States, 2Duquesne University, Pittsburgh, United States
Background: Over the last twenty years, computerized neurocognitive tests (CNTs) have been widely implemented to quantify the acute cognitive effects of mild traumatic brain injury (i.e. concussion). It is considered the cornerstone in the clinical management of concussion. From a clinical perspective, the benefit of CNT depends on its ability to document reliable cognitive declines beyond the resolution of symptoms. Yet, there is currently a gap in the literature evaluating athletes with concussion that are no longer reporting concussion related symptoms.
Purpose: To review the literature on the effects of concussion on construct-specific neurocognitive declines, and to compare it to self-reported symptoms before one week and between one to three weeks post-concussion.
Methods: Relevant literature in PubMed, CINAHL, and PsycINFO published up to November 2015 were reviewed. Studies were included if participants completed the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) prior to and following concussion, and if test performance and the Post-Concussion Symptom Scale (PCSS) scores were reported at both times. After reviewing abstracts and full texts, data from 17 studies consisting of 29 independent samples was extracted. Therefore, this meta-analysis included 1,777 unique participants. Hedges g effect size (ES) was estimated. A random or fixed effect model was used based on heterogeneity findings. In the presence of significant heterogeneity, meta-regression assessed unexplained between-study variance.
Results: Within the first week of injury, the ES for cognitive declines were moderate and ranged from -0.43 (-0.52,-0.35) to -0.67 (-0.77,-0.58) compared to a large ES for the PCSS [-0.81 (-0.91,-0.71)]. After
1 week, the ESs for cognitive declines [-0.25 (-0.35,-0.15)] to -0.37 (-0.55,-0.19)] and PCSS [-0.38 (-0.53,-0.22)] were moderate. Within one week of injury, PCSS and time since injury appear to weakly moderate the cognitive ESs.
Conclusion(s): When a neurocognitive test was administered within one week of injury, the ES for self-reported symptoms was larger than ImPACT scores generated at the same testing session. After 1 week of injury, the ESs for symptoms and ImPACT scores were comparable. Within the first week of injury, if the athlete is reporting symptoms, administration of a cognitive assessment does not appear to offer any additional information to the clinician. If however, the athlete is not reporting symptoms following injury, then cognitive testing may have an added benefit to the clinical management of the injury.
Implications: From a clinical perspective, clinicians utilizing ImPACT and similar neurocognitive tests in symptomatic patients should place a greater emphasis on the extent of cognitive declines as indicated by the number of composite scores with a decline greater than what is attributable to measurement error (i.e. reliable change index). When a clinician suspects that an athlete is under-reporting symptoms, the ImPACT test and similar tests may be helpful to quantify possible effects of concussion when used in conjunction with a multi-faceted performance assessment.
Funding acknowledgements: No sources of funding were used in the preparation of this review.
Topic: Sport & sports injuries
Ethics approval: This study was approved by the University of Michigans Institutional Review Board (IRB) as an exempt.
All authors, affiliations and abstracts have been published as submitted.
