Neuropsychological Norms for the U.S.-Mexico Border Region in Spanish (NP-NUMBRS) Project: Methodology and sample characteristics

The present paper describes the methodology and sample characteristics of the Neuropsychological Norms for the U.S.-Mexico Border Region in Spanish (NP-NUMBRS) Project, which aimed to generate demographically-adjusted norms for a battery of neuropsychological tests in this population.

The sample consisted of 254 healthy Spanish-speakers, ages 19-60 years, recruited from the U.S.-Mexico border regions of Arizona (n = 102) and California (n = 152). Participants completed a comprehensive neuropsychological test battery assessing multiple domains (verbal fluency, speed of information processing, attention/working memory, executive function, learning and memory, visual-spatial skills and fine motor skills). Fluency in both Spanish and English was assessed with performance-based measures. Other culturally-relevant data on educational, social, and language background were obtained via self-report. Demographic influences on test performances were modeled using fractional polynomial equations that allow consideration of linear and non-linear effects.

There were no significant demographic differences between participants tested in Arizona and California. Age and gender were similar across education ranges. Two thirds of the sample were Spanish dominant and the remainder were considered bilingual. Individual articles in this Special Issue detail the generation of demographically adjusted T-scores for the various tests in the battery as well as an exploration of bilingualism effects.

Norms developed through the NP-NUMBRS project stand to improve the diagnostic accuracy of neuropsychological assessment in Spanish-speaking young-to-middle-aged adults living in the U.S.-Mexico border region. Application of the present norms to other groups should be done with caution.