Validation of the Five Digit Test in a clinical sample: An alternative to the Stroop Color-Word Task with possible cultural implications

This study investigated the discriminant neurological and construct validity of the Five Digit Test (FDT), an experimental instrument derived from the Stroop paradigm. The FDT is thought to require less language processing than the traditional Stroop task and may fill a role in the neuropsychological assessment of individuals who cannot take the Stroop Color-Word Task (SCWT) because of difficulty perceiving color information, reduced reading skills, or unfamiliarity with the language of the dominant culture. The theoretical underpinnings of the FDT rest both on the Stroop paradigm as well as cognitive neuropsychological models of attention, particularly the distinction between automatic and controlled, purposeful attentional processing.; Forty adult participants aged 55 and older with subacute or chronic cerebrovascular accidents (CVAs), localized in either anterior (ACVA, n = 20) or posterior (PCVA, n = 20) brain regions, participated as a neurologically impaired sample; their performance on a brief neuropsychological battery (including the FDT and the SCWT) was compared to a normal comparison group (NCOM, n = 39) equated on gender, age, education, and premorbid intelligence. Neurologically impaired participants were recruited from the resident populations of local convalescent and rehabilitation care centers and time post stroke ranged between 4 week and 1 year.; Discriminant function analyses revealed the FDT correctly classified 98.7% of cases dichotomously into either normative or neurologically impaired groups, and the SCWT was able to correctly classify 100% of cases in this sample. No significant difference in the classification rates based on the FDT subtests and those based on the SCWT were observed and combination of FDT and SCWT subtests did not increase incremental validity beyond that already found with the SCWT alone. Performance across ACVA and PCVA groups indicated parallel and coincident profiles with a trend for both groups to perform worse than normal comparison participants over the FDT subtests. A similar finding was observed when comparing these groups on the SCWT subtests. Performance on both the FDT and the SCWT was not necessarily specific to CVA location along a posterior-anterior dimension. Thus neither instrument was useful for differential classification of anterior and posterior CVA in this study, calling into question the use of an automatic versus controlled processing model for interpreting FDT subtest scores. Exploratory Principal Components Analysis showed that the FDT and SCWT subtests did not load on factors with one another. However, the subtests from both measures tended to load on factors requiring controlled processing, suggesting that they may be assessing different attributes of attention, response inhibition, and mental flexibility in this sample.; Overall, the findings suggest that the FDT may be useful as a brief neuropsychological screening alternative to the SCWT, with minimal reduction in screening accuracy. Further, stimulus attributes of the FDT (i.e., achromatic stimuli, possibly more culture fair than SCWT, reduced word reading, etc.) suggest that the FDT may be most useful in special clinical needs contexts.