Demographically-adjusted norms for selected tests of verbal fluency: Results from the Neuropsychological Norms for the US-Mexico Border Region in Spanish (NP-NUMBRS) project

Verbal fluency tests are sensitive to various disorders affecting the central nervous system and are commonly included in neuropsychological evaluations. We aimed to develop normative data for two verbal fluency tests in a sample of native Spanish-speakers living in the US-Mexico border region. Participants included 254 adults from the Neuropsychological Norms for the US-Mexico Border Region in Spanish (NP-NUMBRS) Project (Age: range = 19–60; Education: range = 0–20, 59% female). Participants completed two verbal fluency tests (i.e., letter [PMR] and semantic/category fluency [Animal Naming]) as part of a larger neuropsychological test battery. We examined linear and nonlinear effects of demographic factors (age, education, and gender) on verbal fluency raw scores, and developed T-scores using fractional polynomial equations controlling for demographics. We also calculated the rates of “impairment” (T-scores < 40) that would be obtained by applying the newly developed norms and available norms for non-Hispanic English-speakers on comparable tests. There were positive small effects of age and medium effects of education on verbal fluency raw scores. The normalized distribution of T-scores with the new norms showed expected psychometric properties. However, rates of impairment for both letter and semantic fluency were significantly higher when applying non-Hispanic White norms, and significantly lower when applying non-Hispanic Black norms. We provide norms for Spanish-speakers living along the US-Mexico border region for two verbal fluency tests that are co-normed with a more extensive neuropsychological battery. These regional norms will improve interpretation of verbal fluency test performance in Spanish-speakers living in the US-Mexico borderland.

言语流畅性测验对影响中枢神经系统的各类障碍具有敏感性，常被纳入神经心理学评估流程。本研究旨在为居住于美墨边境地区的西班牙语母语者群体中的两项言语流畅性测验制定常模数据。本研究的参与者共254名成年人，均来自「美墨边境地区西班牙语神经心理学常模（Neuropsychological Norms for the US-Mexico Border Region in Spanish, NP-NUMBRS）」项目，年龄跨度为19至60岁，受教育年限范围为0至20年，其中女性占比59%。作为大型神经心理测验组合的一部分，所有参与者完成了两项言语流畅性测验：即字母流畅性测验（字母组为PMR）与语义/类别流畅性测验（动物命名）。我们分析了人口统计学因素（年龄、受教育程度与性别）对言语流畅性原始得分的线性与非线性效应，并通过控制人口统计学变量的分数多项式模型推导了T得分。此外，我们分别使用本研究新制定的常模，以及针对非西班牙裔英语使用者的现有同类测验常模，计算了「功能受损」的发生率（定义为T得分＜40）。研究结果显示，年龄对言语流畅性原始得分存在微弱的正向效应，而受教育程度则存在中等程度的正向效应。基于新常模得到的T得分标准化分布符合预期的心理测量学特征。不过，若使用非西班牙裔白人常模，字母流畅性与语义流畅性的受损率均显著升高；而若使用非西班牙裔黑人常模，则受损率显著降低。本研究为居住于美墨边境地区的西班牙语使用者提供了两项言语流畅性测验的常模，该常模与一套更全面的神经心理测验组合进行了联合标准化。这类地区性常模将有助于更准确地解读居住于美墨边境地区的西班牙语使用者的言语流畅性测验结果。