Deficits in narrative discourse elicited by visual stimuli are already present in patients with mild cognitive impairment

Abstract

Language batteries used to assess the skills of elderly individuals, such as naming and semantic verbal fluency, present some limitations in differentiating healthy controls from patients with amnestic mild cognitive impairment (a-MCI). Deficits in narrative discourse occur early in dementia caused by Alzheimer's disease (AD), and the narrative discourse abilities of a-MCI patients are poorly documented. The present study sought to propose and evaluate parameters for investigating narrative discourse in these populations. After a pilot study of 30 healthy subjects who served as a preliminary investigation of macro- and micro-linguistic aspects, 77 individuals (patients with AD and a-MCI and a control group) were evaluated. The experimental task required the participants to narrate a story based on a sequence of actions visually presented. The Control and AD groups differed in all parameters except narrative time and the total number of words recalled. The a-MCI group displayed mild discursive difficulties that were characterized as an intermediate stage between the Control and AD groups' performances. The a-MCI and Control groups differed from the AD group with respect to global coherence, discourse type and referential cohesion. The a-MCI and AD groups were similar to one another but differed from the Control group with respect to the type of words recalled, the repetition of words in the same sentence, the narrative structure and the inclusion of irrelevant propositions in the narrative. The narrative parameter that best distinguished the three groups was the speech effectiveness index. The proposed task was able to reveal differences between healthy controls and groups with cognitive decline. According to our findings, patients with a-MCI already present narrative deficits that are characterized by mild discursive difficulties that are less severe than those found in patients with AD.

Discourse macrolinguistic impairment as a marker of linguistic and extralinguistic functions decline in early Alzheimer's disease

“…Another study compared healthy controls (HC) with mild cognitive impairment (MCI) and AD participants (Drummond et al . ). It indicated that MCI participants had a level of performance intermediate between those of the two other groups.…”

Language in Amnestic Mild Cognitive Impairment and Dementia of Alzheimer’s Type: Quantitatively or Qualitatively Different?

“…Individuals with MCI produced fewer core elements of the narrative elicited and showed word-retrieving deficits which were not always reflected in standard naming tasks, leading to the conclusion that the discourse production task was more challenging than the naming task [43]. In a study comparing discourse production between healthy controls, MCI patients and DAT patients, Drummond et al [44] found that the MCI group’s performance would at times resemble controls’ (similar type of discourse, use of macropropositions and cohesion) and at times resemble the DAT group’s performance (similar amount of irrelevant propositions).…”

Análise de aspectos micro e macrolinguísticos da narrativa de indivíduos com doença de Alzheimer, comprometimento cognitivo leve e sem comprometimentos cognitivos

“…O desempenho nas tarefas de função executiva mostrou-se correlacionado à habilidade discursiva. Drummond et al (2015) analisaram a narrativa de brasileiros com diagnóstico de DA, CCL e grupo controle. Para eliciar a narrativa foram utilizadas sequências de figuras.…”

“…A introdução de informações / conteúdos irrelevantes e elementos fora do tópico pode ocorrer devido à presença de problemas no componente semântico-pragmático da linguagem (Drummond et al, 2015).…”

“…O discurso é uma atividade complexa que inclui diferentes níveis do sistema linguístico (fonologia, morfologia, sintaxe, pragmática) em conjunto com memória e funções executivas (Drummond et al, 2015).…”