P4‐251: SIMILARITIES BETWEEN THE COGNITIVE PROFILE OF INDIVIDUALS WITH SUBJECTIVE COGNITIVE DECLINE+ AND THAT OF PERSONS WITH MILD COGNITIVE IMPAIRMENT: A STUDY FROM THE CIMA‐Q COHORT
Bibliographic record
Abstract
Persons with Subjective Cognitive Decline (SCD) complain about their memory, but perform within normal ranges on standard neuropsychological tests. It has been proposed that these individuals might be in a very early phase of Alzheimer's disease (AD). However, SCD is a recent classification and it represents a heterogeneous group of individuals. We have used established AD biomarkers to assess whether we could identify an SCD subgroup (SCD+) with a cognitive performance similar to that of persons with Mild Cognitive Impairment (MCI). One hundred and twenty-six older adults were recruited by the Quebec Consortium for the Early Identification of Alzheimer's disease (CIMA-Q): 67 with SCD, 29 with MCI, and 30 cognitively healthy controls (CH). All participants were genotyped for ApoE4 and received clinical, cognitive, and neuroimaging examinations. The SCD group was divided into two subgroups, SCD- (n = 41) and SCD+ (n = 26), where SCD+ subjects were differentiated by hippocampal volume one standard deviation below controls and/or presence of an ApoE4 allele. Performance of the four groups was compared on tests of memory (Memoria word recall; Face-name association) and executive functions (Hayling; Semantic fluency; Trail). As expected, the SCD- group did not differ from CH, while MCI showed lower performance than CH and SCD-. However, persons in the SCD+ group showed lower performance than CH and SCD- on the Face-name association task. Furthermore, there were no differences when comparing SCD+ and MCI cognitive results. Persons with an SCD+ profile are comparable to MCI on sensitive cognitive tasks and differ from CH on a face-name association task. Using AD biomarkers to parse out heterogeneity in SCD allows identification of a subgroup with a cognitive profile that seems to reflect prodromal AD. A longitudinal follow-up of this independent cohort could confirm whether the SCD+ subcategory is a valid predictor of a possible progression to AD.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".