Impaired generation of new subcategories and switching in a semantic verbal fluency test in older adults with mild cognitive impairment

Abstract

The semantic verbal fluency task is broadly used in the neuropsychological assessment of elderly subjects. Even some studies have identified differences in verbal fluency clustering and switching measures between subjects with normal aging and a clinical condition such as mild cognitive impairment (MCI) and Alzheimer's disease, the results are not always consistent. This study aimed to compare clustering and switching measures of an animal's semantic verbal fluency task among normal controls (NC, n = 25), amnestic mild cognitive impairment (aMCI; n = 25), amnestic multiple domain Mild Cognitive Impairment (a+mdMCI; n = 25) and Alzheimer's disease (AD; n = 25) Brazilian subjects. The analyses were executed considering three (unifying the MCI subtypes) and four groups. As the data were not normally distributed, we carried out non-parametric tests (Kruskal-Wallis and Mann-Whitney tests) to evaluate the differences in performance in the measures of the verbal fluency test among the groups. The comparison demonstrated that the groups differed in the total of correct words produced, number of clusters and switching but the measure of new subcategories was the only with significant difference among the NC and all the clinical groups. The measure of new subcategories is the number of original subcategories inside the higher category of animals that the subject produced, such as farm, domestic, African animals. Our results indicate that semantic memory impairment is a visible and recent deficit that occurs even in non-demented subjects with very MCI and the implications of these findings are discussed.

Methodological Criteria for Scoring Clustering and Switching in Verbal Fluency Tasks

“…We attempted to contribute to the analysis of the cognitive components underlying VF performance to assist in refining the diagnosis and prognosis of neuropsychological performances. Up to date, the Brazilian studies using this method (Becker et al, 2014;Bertola et al, 2014;Brucki & Rocha, 2004;Lopes et al, 2009;Silva et al, 2011;Toazza et al, 2014) to answer the research questions did not describe the scoring rules in detail so as to enable accurate replication.…”

“…We could find studies of adults (Brucki & Rocha, 2004) and healthy elderly , elderly with mild cognitive decline (Bertola et al, 2014), patients with Alzheimer's disease (Lopes et al, 2009), patients with lesion in the right hemisphere (Becker, Muller, Rodrigues, Villavicencio, & Salles, 2014), and children with anxiety disorders (Toazza et al, 2014). However, we could not find specific studies discussing the criteria used to make up clusters and switching analysis between them.…”

Clustering e switching em deficientes auditivos usuários do português brasileiro: fluência verbal semântica e fonológica

“…However, some studies of young adults [11][12][13][14][15] , elderly and neurological diseases 16,17 , provided data regarding the abilities of clustering and switching of these populations, arguing that this analysis provides aditional information in regard to the cognitive flexibility, executive function and lexical organization. There is no normative data for these parameters for Brazilian Portuguese.…”

“…Some studies found in young adults without conditions, total words recalled that varied between 14.0 and 26.2 on average in the semantic test, and 9.5 and 15.1 in phonological test; already for the average cluster size, the values range between 0.75 and 1.7 for semantics, and phonological between 0.24 and 1.4. The number of switches varies in studies between 7.0 and 11.6 for the group "animals" and between 7.9 and 10.55 for letters 12,[14][15][16][17][18] . Regarding the comparative performance of the two tests and the factors determining the results, there is greater agreement in the literature, and in this study has obtained similar data to studies cited, even analysing itself a different population.…”

Neuropsychologiczna ocena funkcji wykonawczych – przegląd

“…Z drugiej strony pojawiają się doniesienia o obniżeniu fluencji w następstwie uszkodzeń prawopółkulowych i podkorowych. Niższe wyniki w Teście Fluencji obserwuje się w następstwie udarów, urazów mózgu, zespołów otępiennych, łagodnych zaburzeń poznawczych, padaczki oraz chorób psychicznych [5,6,[32][33][34][35].…”