Brief iPad-Based Assessment of Cognitive Functioning with ImPACT® Quick Test: Prevalence of Low Scores Using Multivariate Base Rates.

Objective: The ImPACT® Quick Test is a brief iPad-based battery of neurocognitive tests that has been standardized on a sample of children, adolescents, and adults (ages 12-70). This study provides information on the prevalence of ImPACT® Quick Test scores falling below specific percentiles in the normative sample to aid in clinical interpretation and reduce the risk of over-interpreting, or misinterpreting, a single low score.

Method: Participants were 683 individuals ranging in age from 12 to 70, who were assessed individually. The ImPACT® Quick Test includes five subtests, contributing to three factor scores: motor speed, memory, and attention tracker. The prevalence of low factor scores, stratified by age and sex, were calculated using multivariate base rates.

Results: In the total sample, obtaining 1 or more scores below the 25th percentile was common (base rate, BR = 47.2%), but obtaining 2 or more scores in this range was uncommon (BR = 15.3%). Similarly, obtaining 1 or more scores below the 16th percentile was common (BR = 31.4%), but obtaining two or more scores in this range was uncommon (BR = 6.9%). There were small differences in BRs between sexes and the number of low scores was fairly similar across the age groups.

Conclusion: Results from this study parallel previous work illustrating that a substantial percentage of healthy individuals will obtain one or more low test scores when administered a brief battery of cognitive tests. Given that some healthy individuals will obtain a single score below expected cut-offs, clinicians should caution against overinterpreting a single low test score.