21 Assessment of Semantic Memory Decline in aMCI : Naming and Semantic Knowledge of Unique and Non-Unique Entities
Bibliographic record
Abstract
Objective: Semantic memory deficits have been reported in both Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). However, the nature of this decline is still a matter of debate. The aim of this study was to explore the patterns of semantic memory impairment in aMCI by examining performance on naming tasks, and on tests assessing both general and specific semantic knowledge. Participants and Methods: Participants were divided in two groups matched for age and education, one comprising 33 aMCI individuals and the other 39 healthy controls. Three experimental tests assessing naming and semantic knowledge of unique items of famous persons (FACE) and places (PLACE), logos recognition (LOGO: brands and pictograms), and non-unique entities (Boston Naming Test: BNT) were administered, and the performance of the two groups was compared. Results: Lower scores were observed on all naming tests (PLACE, FACE, LOGO and BNT) in the aMCI group compared to controls. On the PLACE test, the general knowledge mean score (M=84.5, SD=12.9) was significantly higher than the specific knowledge mean score (M=54.2, SD=18.5) in aMCI participants (t(31)=11.9, p<.001), but not in controls (general: M=92.2, SD=11.1; specific: M=73.7, SD=15.8), and there was a significant Group X Type of knowledge interaction (F(1,1)=15.13, p <.001, n2 = 18). On the FACE test, in addition to significant group and condition (naming, semantic questions) main effects, a significant interaction was found (F(1,1)=7.19, p = .009, n2 = .09). On the LOGO task, controls were significantly better on brand items (M= 94.4, SD=10.5) than on pictograms (M=83.3, SD=12.2), while no significant difference was noted in aMCI (brands: M=81.5, SD=22.6; pictograms: M=77.5, SD=14.1). Lastly, on the BNT, aMCI participants benefited more from phonemic cues than controls (F(1,1)=16.56, p<.001, n2=19), suggesting a lexical access deficit, in addition to their semantic memory impairment. Conclusions: This study adds to the growing evidence confirming the presence of semantic memory deficits in aMCI. Specific semantic knowledge seems to be more affected than general semantic knowledge, a finding reported in previous studies. Lexical access deficits, in addition to semantic decline, were also observed in the aMCI group. These results allow for a better understanding of the pattern of semantic memory deficits in the prodromal stage of AD and could potentially facilitate diagnosis of aMCI.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".