Normative Data for two Verbal Fluency Tests in a Spanish-Speaking Adult Population Living in the U.S./México Border Region

Abstract

Objective To investigate the impact of demographic factors and develop normative data for two verbal fluency tests in a sample of Spanish-Speakers living in the U.S./Mexico border region. Participants and Method The sample consisted of 252 adults (Age: M = 37.3, SD = 10.2, range 19-60; Education: M = 10.7, SD = 4.37, range 0-20, 59% female), living in the US-Mexico border region of Arizona and California. Participants completed the letter (letters P, M, and R) and semantic (Animal Naming) fluency tests as part of a larger neuropsychological test norming study. Normative T-scores were computed with fractional polynomial equations controlling for age, education, and sex. We also calculated the rates of impairment (T < 40) that would be obtained by applying the newly developed norms and available test norms for non-Hispanic English-speakers. Results Higher education was significantly associated with better raw scores on both verbal fluency tests (letter: r = 0.41, semantic: r = 0.36, ps < .001), and older age was significantly associated with higher raw scores on letter fluency (r = 0.14, p < .05). There were no other significant effects of demographic factors. The normalized distribution of T-scores with the new norms showed the expected impairment rate (16% letter and 15% semantic fluency). However, application of existing non-Hispanic White norms resulted in 23% impairment for letter fluency and 24% in semantic fluency. Using non-Hispanic Black norms resulted in 9% impairment in letter fluency and 2% in semantic fluency. Conclusions We provide norms for Spanish speakers living along the U.S-Mexico border region for two verbal fluency tests that are co-normed with a more extensive neuropsychological battery. We demonstrate that application of existing norms derived from English speaking samples yield inaccurate estimates of impairment. As such, these regional norms will improve the interpretation of verbal fluency performance in Spanish-speakers living in the US-Mexico borderland.