Verbal fluency in Alzheimer's disease and mild cognitive impairment in individuals with low educational level and its relationship with reading and writing habits.

Bruna Tessaro,Andressa Hermes-Pereira,Rochele Paz Fonseca,Renata Kochhann,Lucas Porcello Schilling,Lilian Cristine Hübner

doi:10.1590/1980-57642020dn14-030011

Abstract

ABSTRACT.Verbal fluency (VF) has contributed to building cognitive maps as well as differentiating healthy populations from those with dementia.Objectives: To compare the performance of healthy controls and patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) in two semantic VF tasks (animals/clothes) and a phonemic VF task (letter P). Also, to analyze the relationship between the frequency of reading and writing habits (FRWH) and VF in individuals with low educational level.Methods: Sixty-seven older adults aged 60-80 years and with 2-8 years of schooling were divided into three groups: controls (n=25), older adults with MCI (n=24), and older adults with AD (n=18). We analyzed the type, mean size, and number of clusters, switches, intersections, and returns. A post-hoc single-factor ANOVA analysis was conducted to verify differences between groups.Results: Total words in the phonemic VF and the animal category discriminated the three groups. Regarding the animal category, AD patients performed worse than controls in the total number of words, taxonomic clusters, returns, and number of words remembered. We found a moderate correlation between FRWH and total number of words in the phonemic fluency.Conclusions: Semantic (animate) and phonemic (total words) VF differentiated controls and clinical groups from each other - the phonemic component was more related to FRWH than the semantic one. The phonemic VF seems to be more related to cognitive reserve. VF tasks, considering total words and cluster analyses, are a valuable tool to test healthy and cognitively impaired older adults who have a low educational level.

Highlights

This study aimed at verifying whether healthy older adults and those with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) presented differences in semantic and phonemic verbal fluency (VF) tasks, as well as exploring the relationship between VF and frequency of reading and writing habits (FRWH), analyzing if lifelong cognitive stimulation through the individuals’ reading and writing habits affected their VF performance
The inclusion criteria were absence of cognitive decline or dementia, as evaluated by the Mini-Mental State Examination (MMSE), with cut-off points established by Kochhann et al.,[23] and socioeconomic classes B2, C1, and C2, following the guidelines for socioeconomic status assessment by Associação Brasileira de Empresas e Pesquisa (ABEP)
We identified statistical differences distinguishing the three groups in the total words generated in the phonemic fluency (PF)

Summary

Introduction

This study aimed at verifying whether healthy older adults and those with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) presented differences in semantic and phonemic verbal fluency (VF) tasks, as well as exploring the relationship between VF and frequency of reading and writing habits (FRWH), analyzing if lifelong cognitive stimulation through the individuals’ reading and writing habits affected their VF performance. Studies show that VF can be useful in differentiating MCI and AD.[3] VF measures two important cognitive components usually linked to cognitive decline: verbal and executive skills.[4] Uttering words during the task requires lexical access and retrieval, which, in turn, demand the recruitment of executive functions related to sub-constructs of inhibition and self-monitoring, as well as attention. Two types of VF tasks are typically administered: phonemic fluency (PF), or orthographic and letter fluency, and semantic fluency (SF), or category fluency

Objectives

Methods

Results