Regional Brain Volume and Thickness in Mild Behavioral Impairment‐Apathy
Bibliographic record
Abstract
BACKGROUND: Mild Behavioral Impairment (MBI) is a pre-dementia syndrome defined by persistent late-life-onset behavioural changes and serves as a risk marker for cognitive decline and incident dementia. The apathy MBI domain is hypothesized to be associated with regional brain changes, but it is unclear if these are the same regions described for apathy in dementia. This study investigates volumetric differences between dementia-free individuals with MBI-apathy and those without neuropsychiatric symptoms (No NPS). METHOD: This study included 446 participants (mean age = 69.6 years; 79.8% cognitively normal; 62.8% female) from the National Alzheimer's Coordinating Center. Participants were grouped into No NPS (n = 387) and MBI-apathy (n = 59). Cross-sectional linear regression models examined the association between NPS status and regional brain measures. Outcomes included AD-related region composite measures of cortical thickness (entorhinal cortex, inferior temporal gyrus, middle temporal gyrus, inferior parietal lobule, fusiform gyrus, and precuneus) and volume (hippocampus, entorhinal cortex, amygdala, middle temporal gyrus, inferior parietal lobule, and precuneus). Additionally, cortical thickness and volume measures for four apathy-related regions (anterior cingulate cortex [ACC], orbitofrontal cortex [OFC], dorsolateral prefrontal cortex [dlPFC], and ventrolateral prefrontal cortex [vlPFC]) were included. Models adjusted for age, sex, education, APOE4 carrier status, and Mini-Mental State Examination score. RESULT: Compared to the No NPS group, MBI-apathy status was significantly associated with lower average AD composite thickness score (β = -0.40; 95% CI = -0.74-(-0.05); p = 0.024), total AD composite volume (β = -3.33; 95% CI = -4.66-(-2.00); p < 0.001), dlPFC thickness (β = -0.35; 95% CI = -0.69-(-0.004); p = 0.048), OFC volume (β = -0.34; 95% CI = -0.64-(-0.04); p = 0.028), and dlPFC volume (β = -0.27; 95% CI = -0.54-(-0.01); p = 0.040). CONCLUSION: MBI-apathy shows stronger stronger associations with atrophy in regions affected early in the course of AD. This finding suggests that at the CN and MCI stages, MBI-apathy may reflect brain changes characteristic of early AD. These findings suggest that MBI-apathy is associated with early-stage AD and that regions typically linked to apathy are likely affected later in the disease, with stronger associations emerging as AD progresses.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".