Alterations in brain structure and functional connectivity associated with hearing loss and olfactory loss
Bibliographic record
Abstract
BACKGROUND: Sensory loss in hearing, vision, and olfaction are highly prevalent in older adults and are each associated with a higher risk of developing dementia. This study sought to identify the extent to which these sensory factors are associated with alterations in brain function and structure older adults with or at risk for dementia. We examined groups who range from relatively low risk (those with normal cognition and no cognitive complaints (NC)), to those with higher risk, namely individuals with subjective reports of cognitive decline (SCD) but normal cognition and those with mild cognitive impairment (MCI). METHOD: We used data from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) study (Release 7). Hearing loss was assessed with a pure-tone screening protocol, vision was assessed with the MARS test for contrast sensitivity, and olfaction was assessed with the Brief Smell Identification Test (BSIT). We examined the frequency of sensory deficits in 128 NC (mean age = 69 years; mean education = 16 years), 135 participants with SCD (age = 70; education = 17), 241 with MCI (age = 72; education = 16), and 93 with Alzheimer's disease (AD, age = 75; education = 15). Participants were matched on age and education, except for AD participants who were older. RESULTS: As shown in Figure 1, normal sensory performance in all three modalities was observed in the minority of participants and decreased in prevalence across the dementia risk spectrum groups (e.g., NC: 29%; SCD: 29%; MCI: 11%; AD: 2%). Olfactory deficits (hyposmia or anosmia) were the most frequent (ranging from 45% in NC to 61% in AD), followed by hearing impairment, and then deficits in visual contrast sensitivity. Deficits in multiple sensory domains were highly prevalent, with 37% of participants with AD having deficits in two or more domains. Preliminary analyses indicate that hearing loss is associated with altered connectivity in the default mode network in MCI participants and olfactory loss is associated with reduced hippocampal volumes in SCD. CONCLUSION: These analyses indicate that sensory loss is highly frequent and co-morbid in persons with or at risk for dementia. These findings have implications for cognition, brain function, functional activities, and care delivery for persons with or at risk for dementia.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".