Performance validity of the Dot Counting Test in a dementia clinic setting

Abstract

Objective

This study examined the utility of a performance validity test (PVT), the Dot Counting Test (DCT), in individuals undergoing neuropsychological evaluations for dementia. We investigated specificity rates of the DCT Effort Index score (E-Score) and various individual DCT scores (based on completion time/errors) to further establish appropriate cutoff scores.

Method

This cross-sectional study included 56 non-litigating, validly performing older adults with no/minimal, mild, or major cognitive impairment. Cutoffs associated with ≥90% specificity were established for 7 DCT scoring methods across impairment severity subgroups.

Results

Performance on 5 of 7 DCT scoring methods significantly differed based on impairment severity. Overall, more severely impaired participants had significantly higher E-Scores and longer completion times but demonstrated comparable errors to their less impaired counterparts. Contrary to the previously established E-Score cutoff of ≥17, a cutoff of ≥22 was required to maintain adequate specificity in our total sample, with significantly higher adjustments required in the Mild and Major Neurocognitive Disorder subgroups (≥27 and ≥40, respectively). A cutoff of >3 errors achieved adequate specificity in our sample, suggesting that error scores may produce lower false positive rates than E-Scores and completion time scores, both of which overemphasize speed and could inadvertently penalize more severely impaired individuals.

Conclusions

In a dementia clinic setting, error scores on the DCT may have greater utility in detecting non-credible performance than E-Scores and completion time scores, particularly among more severely impaired individuals. Future research should establish and cross-validate the sensitivity and specificity of the DCT for assessing performance validity.

Keywords:

• Dementia
• Dot Counting Test
• invalidity
• malingering
• performance validity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.