Objective: To determine clinically meaningful subgroups of persons with traumatic brain injury (TBI) who have failed performance validity testing.
Method: Study participants were selected from a cohort of 674 participants with definitive medical evidence of TBI. Participants were those who failed performance validity testing (the Word Memory Test, using the standard cutoffs). Participants were administered cognitive tests and self-report questionnaires. Test and questionnaire results were summarized as 12 dimension scores. Cluster analysis using the k-means method was performed.
Results: Cluster analysis for the 143 retained participants indicated three subgroups. These subgroups differed on patterns of scores. Subgroup 1 was impaired for memory and had no excessive complaints. Subgroup 2 had impaired memory and processing speed as well as concern regarding cognition function. Subgroup 3 showed impairment on all cognitive tests and excess complaints in multiple areas.
Conclusions: These results provide a preliminary basis for improved understanding of poor performance validity.
Keywords: Cognitive tests; Performance validity; Self-report questionnaires; Subgroups; Traumatic brain injury.