Neuropsychiatric symptoms of Alzheimer’s dementia and their association with dorsolateral prefrontal cortex TMS evoked potentials
Bibliographic record
Abstract
Abstract Background Alzheimer’s Dementia (AD) is characterized by cognitive and neuropsychiatric symptoms (NPS). Recently, cognitive decline in AD has been linked to increased cortical excitability. However, the relationship between NPS and cortical excitability remains unclear. This study investigated the relationship between NPS and cortical excitability in the dorsolateral prefrontal cortex (DLPFC). Method 24 participants with probable AD diagnosed using National Institute of Aging‐Alzheimer’s Association criteria (Mage (SD) = 74.1 (7.2) years) were recruited and followed for up to 6 months. Global cognition was assessed with the Montreal Cognitive Assessment (MoCA). NPS were assessed using the Neuropsychiatric Inventory Questionnaire (NPI‐Q) total score and subdomain scores. Single pulse transcranial magnetic stimulation (TMS) was applied at the DLPFC (localized using MRI‐based neuronavigation) at a frequency of 0.1 Hz, at sufficient intensity; and collected using 62 channel electroencephalography (EEG) recorded from the scalp. TMS‐evoked potential (TEP) peak amplitudes for individual TEP peaks (P30, N45 and P60) were calculated. Result NPI‐Q severity score was positively correlated with DLPFC TEP peak P30 (r (19) = .64, p = .003) and negatively correlated with DLPFC TEP peak N45 (r (22) = ‐.46, p = .033). These associations remained significant after controlling for age, sex and cognition (DLPFC TEP peak P30 (ß = .93, p = .001) and N45 (ß = ‐.47, p = .031)). Further, NPI‐Q severity score at 6 month follow up negatively correlated with baseline DLPFC TEP peak N45 (r (16) = ‐.56, p = .025). Among NPI‐Q subdomains, apathy was positively correlated with DLPFC TEP peak P30 (r (19) = .64, p = .003) and negatively correlated with DLPFC TEP peak N45 (r (22) = ‐.42, p = .049). Conclusion NPS burden in AD was positively associated with excitatory activity (i.e., P30) and negatively associated with inhibitory activity (i.e., N45) using combined TMS‐EEG over the DLPFC. These associations were largely driven by the apathy domain. These findings may have implications for developing neurophysiological biomarkers and targeted treatment interventions for NPS in 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 | 0.001 |
| 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) | 0.001 | 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".