Connected speech profiles in mild cognitive impairment reflect global cognition

Abstract

Background: Mild cognitive impairment (MCI), a prodromal stage of Alzheimer’s disease (AD) for many individuals, is accompanied by widespread connected speech (CS) changes (e.g., shorter CS samples, mention of fewer semantic content units, lower syntactic complexity). Nevertheless, findings on CS in MCI are heterogeneous. This heterogeneity, combined with the heterogeneity in cognition in MCI suggests that there could exist more than one CS profile in this population.

Objective: We aimed to determine if there are multiple CS profiles in MCI and whether these potential CS profiles are characterized by distinct cognitive presentations.

Methods: CS characteristics were extracted from the samples of 109 controls and 210 individuals with MCI from the COMPASS-ND study database. A Two-Step Cluster Analysis was then carried out to identify potential CS profiles in MCI. These profiles were compared to one another and to controls in terms of their linguistic and cognitive characteristics.

Results: We identified two CS profiles in MCI, characterized by reduced syntactic complexity and semantic content and by dysfluencies, longer CS samples, and reduced semantic idea density and efficiency, respectively. The reduced semantic content/syntactic complexity profile was also characterized by various cognitive difficulties (e.g., visuospatial, episodic memory, executive functioning domains) in comparison with controls, whereas the increased production and reduced idea transmission effectiveness profile had relatively isolated episodic memory difficulties.

Conclusions: CS analysis could be a helpful screening tool to identify individuals with MCI who show greater cognitive difficulties and who would most benefit from more extensive cognitive and/or medical testing as well as from cognitive and/or psychological interventions.