Clinical Stage-Specific Low-Frequency Naming Ability in Alzheimer’s Disease: Comparison according to Beta-Amyloid Deposition

Objectives: This study aimed to examine semantic knowledge impairment across the Alzheimer’s disease (AD) continuum by classifying cognitive impairment groups based on both clinical diagnosis and the presence of beta-amyloid (Aβ) deposition, and by employing a low-frequency word confrontation naming task. Methods: Participants included 64 individuals with Aβ negative subjective cognitive decline (SCD), 101 patients with Aβ negative amnestic mild cognitive impairment (aMCI), 68 patients with Aβ positive aMCI, and 105 patients with Aβ positive AD. All participants completed a low-frequency word confrontation naming task. Group differences were analyzed for the number of correct responses, number of errors by error type, and cueing response rates. Results: Naming performance declined progressively from SCD to aMCI and from aMCI to Aβ+ AD. Analysis of errors and cueing response rates revealed that, with disease progression, deficits in semantic knowledge became more pronounced, leading to increased unrelated or no response errors and reduced responsiveness to cues. Conclusion: The low-frequency word naming task efficiently discriminated among cognitive impairment groups using a small set of stimuli. Naming impairment at the aMCI stage primarily reflected difficulty accessing the semantic-lexical system, whereas impairment at the AD stage reflected structural damage within that system. These findings suggest that low-frequency word naming provides valuable information for assessing the degree of semantic degradation and may serve as a clinically useful tool for the early detection and monitoring of AD progression.