Validation of alternative dot counting test E-score cutoffs based on degree of cognitive impairment in veteran and civilian clinical samples.

Objective: This study examined Dot Counting Test (DCT) performance among patient populations with no/minimal impairment and mild impairment in an attempt to cross-validate a more parsimonious interpretative strategy and to derive optimal E-Score cutoffs.

Method: Participants included clinically-referred patients from VA ( = 101) and academic medical center (AMC,  = 183) settings. Patients were separated by validity status (valid/invalid), and subsequently two comparison groups were formed from each sample's valid group. Namely, Group 1 included patients with no to minimal cognitive impairment, and Group 2 included those with mild neurocognitive disorder. Analysis of variance tested for differences between rounded and unrounded DCT E-Scores across both comparison groups and the invalid group. Receiver operating characteristic curve analyses identified optimal validity cut-scores for each sample and stratified by comparison groups.

Results: In the VA sample, cut scores of ≥13 (rounded) and ≥12.58 (unrounded) differentiated Group 1 from the invalid performers (87% sensitivity/88% specificity), and cut scores of ≥17 (rounded; 58% sensitivity/90% specificity) and ≥16.49 (unrounded; 61% sensitivity/90% specificity) differentiated Group 2 from the invalid group. Similarly, in the AMC group, a cut score of ≥13 (rounded and unrounded; 75% sensitivity/90% specificity) differentiated Group 1 from the invalid group, whereas cut scores of ≥18 (rounded; 43% sensitivity/94% specificity) and ≥16.94 (unrounded; 46% sensitivity/90% specificity) differentiated Group 2 from the invalid performers.

Conclusions: Different cut scores were indicated based on degree of cognitive impairment, and provide proof-of-concept for a more parsimonious interpretative paradigm than using individual cut scores derived for specific diagnostic groups.