CEREBROVASCULAR HEMODYNAMICS, POSTURAL STABILITY AND FALLS IN OLDER ADULTS
Bibliographic record
Abstract
Impaired blood pressure (BP) recovery upon standing occurs in 21% of older adults (OA) and is an independent risk factor for falls. The present investigation sought to determine if reductions in BP and cerebral tissue oxygenation (tSO2) after posture transition increased postural instability and increased risk for a future fall. Seventy-seven OA (87 ± 7yrs) performed i) supine-stand, ii) supine-sit-stand, iii) sit-stand with continuous measurements of BP and tSO2. Delta-tSO2 was the difference between baseline and nadir defined as the lowest three-beat tSO2. Stability was determined from total path-length of the center of pressure (COP) sway. Twenty-second averages at initial-standing, 1-min, 2-min and 3-min were calculated for tSO2 and TPL. K-cluster-analysis grouped participants (clustering variables: delta-tSO2 and tSO2 1-min) into groups (regulators n=66, impaired-regulators n=18). A mixed model 2-way-repeated-measures-ANOVA compared group by condition effects. A Chi-square test compared number of fallers between groups. Significance was set to p≤0.05. Impaired-regulators had lower tSO2 and higher TPL at all time points (initial, 1-min, 2-min, 3-min, p<0.05) of the standing protocol compared to regulators (initial standing, tSO2: regulators 62.3 ± 0.6%, impaired-regulators 54.9 ± 1.3%, TPL: regulators 40.9 ± 2.3cm, impaired-regulators: 59.6 ± 4.8cm) A brief 10-s sitting-pause time minimized the tSO2 reduction and improved stability for the impaired-regulators (p<0.05). Impaired-regulators had an increased risk (p=0.091) of fall in 6-month follow-up. This is the first study to show an association between posture-related cerebral hypoperfusion and quantitatively assessed instability. Importantly, this study revealed differences among OA and suggested that those with lower tSO2 and greater instability might be at risk for a fall.
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 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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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".