Demographically-adjusted norms for the WAIS-R Block Design and Arithmetic subtests: Results from the Neuropsychological Norms for the US-Mexico Border Region in Spanish (NP-NUMBRS) project

Abstract

Objective Wechsler Adult Intelligence Scale (WAIS) Block Design and Arithmetic subtests are frequently used as measures of visuospatial construction and verbal working memory, respectively. As part of a larger test adaptation and norming effort for this population, we generated and investigated demographically-adjusted interpretive norms for WAIS-R Block Design and Arithmetic in Spanish-speaking adults living in the US-Mexico border region. Method Participants included 183 community-dwelling adults ages 20-55 (education range: 0–20 years; 58% women) from the NeuroPsychological-Norms for the US-Mexico Border Region in Spanish (NP-NUMBRS) Project. They completed the WAIS-R Block Design and Arithmetic subtests in Spanish. Demographically-adjusted T-scores were calculated for these subtests using fractional polynomial equations adjusting for linear and non-linear effects of age, education (continuous), and sex. We compared our rates of impairment (i.e. T < 40) against rates calculated using published English-speaking WAIS-R standardization sample norms adjusted for age, education, and sex. Results Education was positively associated with performance on Block Design and Arithmetic subtests, and men outperformed women on both subtests. The present Spanish-speaker norms for these subtests yielded expected rates of “impairment” (i.e. 15–16% impaired, a 1 SD cutoff), while existing norms for English-speakers underestimated impairment (i.e. 5–6% impaired) when applied to our Spanish-speaking sample. Conclusions Regional normative data will improve interpretation of test performance on Block Design and Arithmetic subtests for Spanish-speakers living in the US-Mexico border region and may aid in bolstering the overall analysis of neuropsychological profile patterns in this population. Cross-validation with Spanish-speakers in other regions and/or with other national origins is needed.