Prevalence of low scores on language tests as a potential factor in misdiagnosis of cognitive impairment in a Spanish-speaking adult population.

Objective: In this study, the prevalence of low scores for two neuropsychological tests of language has been determined.Methods: In total, N = 5218 healthy adults from 11 countries in Latin America (LA) were administered the Boston Naming Test (BNT) and the Verbal Fluency Test (VFT) as part of a comprehensive neuropsychological evaluation. Z-scores were calculated for BNT Total score, and phonological (letters F, A, S, M) and semantic (Animals, Fruits). Scores were adjusted for age, age2, sex, education, and interaction variables if significant for the given country. Each Z-score was converted to a percentile for each of the seven test-scores. Each participant was categorized based on his/her number of low scoring tests in specific percentile cutoff groups (25th, 16th, 10th, 5th, and 2nd).Results: Between 53% (Paraguay) and 71% (Mexico) of the sample had at least 1-score below the 25th percentile, and between 41% (Paraguay) and 55% (Cuba) scored below the 16th percentile. Between 27% (Paraguay) and 39% (Peru) scored below the 10th percentile on at least 1-score, and between 17% (Chile) and 23% (Argentina) scored below the 5th percentile.Conclusions: Clinicians should use these data to reduce false-positive diagnoses and to improve the neuropsychological assessments in Spanish-speaking individuals from LA countries.