Validity of ImPACT for measuring attention & processing speed following sports-related concussion

British Journal of Sports Medicine. 2004 Oct;

38(5):657-658.

Iverson, G. L., M. R. Lovell and M. W. Collins.

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Abstract:

Introduction: The purpose of this study was to examine the validity of ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing), a computerized neuropsychological test battery, for measuring attention and processing speed in athletes with concussions. This was accomplished by comparing the computerized testing to a traditional neuropsychological measure, the Symbol Digit Modalities Test (SDMT). Method: Participants were 72 amateur athletes who were seen within 21 days of sustaining a sports-related concussion (Mean = 9.4, Median = 9, SD = 5.4 days). The breakdown of athletes by concussion severity, based on the American Academy of Neurology guidelines, was as follows: Grade 1 = 33%, Grade 2 = 49%, and Grade 3 = 18%. Their average age was 17.1 years (SD = 1.9), and their average education was 10.5 years (SD = 1.8). Results: The SDMT correlated most highly with the Processing Speed (r = 0.70) and Reaction Time (r = −0.60) composites nom ImPACT. The composite scores from ImPACT and the SDMT were subjected to exploratory factor analysis. The subject to variable ratio was 12:1, and the communalities for the variables were high, ranging from 0.70 to 0.95. Three components were extracted accounting for 81.9% of the total variance (although one component was a single variable: Total Postconcussion Symptoms). Therefore, a two-factor solution was retained and interpreted as Speed/Reaction Time and Memory. Discussion: It appears as if the Processing Speed Composite, Reaction Time Composite, and SDMT are measuring a similar underlying construct in this sample of concussed amateur athletes.

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