The influence of ethnicity on symbol digit modalities test performance: An analysis of a multi-ethnic college and hepatitis C patient sample

Neuropsychologists routinely assess patients from racially, ethnically, and culturally diverse populations. Despite this fact, there remains a paucity of research investigating the influence of these variables on neuropsychological test performance. The Symbol Digit Modalities Test (SDMT) is a widely used measure of attention, visual scanning and tracking, and psychomotor speed. The purpose of the present study was to assess the relation between ethnicity and SDMT performance in ethnically diverse cognitively normal and cognitively impaired samples. Participants were 168 college students (81 Caucasian, 49 African American, 20 Asian American, and 18 Hispanic) and 24 patients (12 Caucasian and 12 Hispanic) chronically infected with hepatitis C. Results revealed no significant group differences in SDMT performance in either the student or patient sample. Furthermore ethnicity accounted for only 2 and 3 percent of the variance in SDMT scores for the patient and student samples, respectively. These findings provide preliminary support for the use of the SDMT across ethnically diverse populations in both clinical and normal samples though further analysis is warranted.