Characterizing olfaction, anxiety, and depression in subjective cognitive decline
Bibliographic record
Abstract
Background Olfactory dysfunction and neuropsychiatric symptoms are well-established hallmarks of Alzheimer's disease (AD) and serve as predictors of progression from mild cognitive impairment to AD. However, the literature remains unclear on whether olfactory dysfunction is already evident in the prodromal form of subjective cognitive decline (SCD). Objective This study aimed to characterize olfactory function and neuropsychiatric symptoms, including anxiety and depression, in individuals with SCD compared to healthy controls (HC). Methods A total of 110 community-dwelling participants aged 60 years and older were recruited, with 59 classified as SCD (42 women) and 51 as HC (35 women). Participants completed validated anxiety and depression questionnaires (Geriatric Anxiety Inventory and Geriatric Depression Scale) and underwent a comprehensive olfactory assessment using the complete Sniffin’ Sticks battery (odor threshold, discrimination, and identification). Results The SCD group exhibited lower global olfactory scores (small to moderate effect size; Cohen's d = 0.41), and higher depression (large effect size; Cohen's d = 1.07) and anxiety (moderate effect size; Cohen's d = 0.64 ) scores compared to HC. Notably, global olfactory performance enhanced group status prediction and classification (SCD versus HC) when combined with anxiety and depression measures. Conclusions These findings highlight subtle but significant lower olfactory performance in individuals with SCD. The neurophysiological underpinnings are unclear and may be unveiled with electrophysiological methods such as olfactory-evoked potentials.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".