Investigating semantic control in amnestic mild cognitive impairment and mild dementia

Abstract

Individuals in the preclinical stage of Alzheimer’s disease (amnestic mild cognitive impairment [aMCI] and mild dementia) primarily exhibit episodic memory deficits, while the presence of semantic control impairments remains understudied. To explore semantic control and white matter connectivity in individuals with aMCI and mild dementia, we assessed semantic control deficits, through a word-picture verification task, and integrity of language-relevant ventral pathways, utilizing fixel-based analysis, adhering to a preregistered protocol. We found that individuals with aMCI and mild dementia exhibited greater semantic interference compared to matched controls. No significant group differences were observed in fixel metrics of the white matter pathways. The extent to which reduced white matter integrity might lead to weakened semantic control remains unclear.