P2‐139: Central Auditory Processing and Imaging Biomarkers of Alzheimer's Dementia
Bibliographic record
Abstract
To find interventions that may prevent Alzheimer's disease (AD) dementia, one needs markers that can track the progression of the disease in its pre-symptomatic stages. Central Auditory Processing (CAP), i.e., the cognitive interpretation of auditory stimuli, is impaired in dementia and MCI, and has been shown in individuals at risk to predict later development of AD dementia (Gates, 2011). Recently, CAP deficits have also been shown to identify responders to donepezil treatment (Ouchi, 2015). Previously, we reported a relationship of CAP to age and genetic risk. We now report studies on the relationship between CAP and imaging markers of pre-symptomatic AD. Over 200 participants in the PREVENT-AD cohort of asymptomatic persons with a parental history of AD completed the Synthetic Sentence Identification with Ipsilateral Competing Message (SSI-ICM) task, a measure of speech comprehension with background noise. We explored whole brain cortical thickness in 148 of these subjects using CIVET 1.12 (Lerch, 2005). SurfStat was used to correct for multiple comparisons using Random Field Theory with p <0.05. We extracted temporal gyrus functional connectivity with regions of interest selected a priori using NIAK (Bellec, 2011). After controlling for age, cortical thickness analyses revealed association of SSI-ICM performance with thickness of rostral mid frontal cortex (rMFC) and the pars orbitalis (PO). In subjects who had a successful tone test (n= 43), we found decreased resting state connectivity between the temporal gyri (TG) and dorsomedial prefrontal cortex (dMPFC) in persons with reduced performance on the SSI-ICM (age-corrected partial correlations r= 0.345 for left and r= 0.313 for right, p <0.05 for both). We also found a correlation between decreased connectivity of the left TG and posterior cingulate cortex (PCC), and lower SSI-ICM scores (r= 0.328, p <0.05). Tests of central auditory processing appear to correlate with the thickness of several cortical structures, and with resting state connectivity between areas implicated in auditory scene analysis and speech processing. These areas are commonly affected by AD pathology, suggesting that CAP dysfunction may serve as an indicator of AD progression in pre-symptomatic disease. Analysis for whole brain cortical thickness shows positive correlations, after correction for age, between SSI-ICM scores and cortical thickness of the rostral mid frontal cortex and pars orbitalis (both indicated in blue). Random Field Theory was used to correct for multiple comparisons (at p< 0.05). Data are shown for the analysis of 148 participants. SSI-ICM scores correlate with connectivity between the left temporal gyrus and dorsomedial prefrontal cortex. Data are shown for 43 participants who passed a hearing screening. Adjusting for age, r= 0.345 and p= 0.025. SSI-ICM scores correlate with connectivity between the right temporal gyrus and dorsomedial prefrontal cortex. Data are shown for 43 participants who passed a hearing screening. Adjusting for age, r= 0.313 and p= 0.044. SSI-ICM scores correlate with connectivity between the left temporal gyrus and posterior cingulate cortex. Data are shown for 43 participants who passed a hearing screening. Adjusting for age, r= 0.328 and p= 0.034.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.007 | 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 teacher head, 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".