Investigating covert awareness in individuals with Alzheimer’s Disease using functional near‐infrared spectroscopy (fNIRS)
Bibliographic record
Abstract
Abstract Background Alzheimer’s disease (AD) is a form of dementia that impairs memory, language, and daily functioning. With disease progression, AD patients reportedly experience disturbances in their awareness of self, others, and their environment. These disturbances are associated with unfavourable clinical outcomes, which prompts critical questions about how AD patients experience the world around them. The present study utilizes a validated neuroimaging paradigm to ‘map’ conscious experiences through changes in brain activity. The premise is that similarity (i.e., synchrony) in conscious experiences of different people can be detected by investigating activity in fronto‐parietal areas linked with higher‐order processing essential for plot‐following. This paradigm was previously used to assess conscious states of behaviorally non‐responsive brain‐injured patients, showing that the internal mental experience of some patients was similar to that of healthy controls. Methods In this study, patients with mild‐moderate AD (n = 9) and age‐matched healthy controls (n = 29) underwent a 40‐minute functional near‐infrared spectroscopy (fNIRS) scan. During the scan, participants watched two short movies, each with an intact‐ and scrambled‐plot version. Scrambled versions were included to demonstrate that synchrony was associated with higher‐order processing rather than the mere presentation of audio‐visual stimuli. Inter‐subject correlations (i.e., Pearson correlation coefficients between the hemodynamic activity of one or more AD patients and the remaining participants, including healthy controls) were used as the metric for synchrony. Results Compared to the scrambled plot conditions, healthy controls showed robust synchronization in the frontal and parietal regions in the intact‐plot conditions. AD patients, in contrast, did not demonstrate a consistent pattern of synchronization in these regions during the intact‐plot conditions. Single‐subject analyses (i.e., comparing individual patients to the control group) further revealed that only one AD patient exhibited some degree of synchronization with the healthy controls during the audio‐visual stimuli. Conclusion These preliminary findings indicate that AD patients may be experiencing the world differently from healthy individuals. The variability noted in synchronization across AD patients may be reflective of the heterogeneity in disease‐related impairments. Understanding deficits and patient needs from the lens of impaired conscious processing could support disease prognosis and promote improvements in person‐centered care.
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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 | 0.000 |
| 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) | 0.001 | 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".