THE RELIABILITY OF HEART RATE VARIABILITY MEASURES IN INDIVIDUALS WITH SPINAL CORD INJURY
Bibliographic record
Abstract
PURPOSE The purpose of this study was to examine the reliability of resting heart rate variability (HRV) measures in individuals with spinal cord injury (SCI). METHODS Ten individuals (6 male, 4 female; age 35.9±13.2 yrs) with chronic (5.4±7.7 yrs post injury) SCI (C4-T12; ASIA A-C) participated. On two separate occasions, 10-minute resting supine electrocardiogram (ECG) recordings were obtained from each participant during spontaneous breathing in a dark, quiet room. Participants abstained from caffeine and smoking for 12 hours prior to each ECG recording, and recordings were taken at the same time of day on each occasion. Customized computer software identified successive RR-intervals and calculated frequency domain variables of HRV (LF:HF, LF, HF) as well as mean heart rate (HR). One-way analyses of variance (ANOVA) determined if means differed between testing days and intraclass correlations were calculated to determine the test-retest reliability of the HRV measures. Statistical analyses were performed for i) all participants (n = 10), and ii) only those with tetraplegia (n = 6) as this group would be expected to have substantial cardiac sympathetic disruption. RESULTS When considering all participants (n = 10), there were no significant differences between days for any variable tested (p > 0.05). The intraclass correlations between days for the HRV measures showed good reliability for LF:HF (r = 0.82), LF (r = 0.84), and HR (r = 0.88). When considering only those participants with tetraplegia (n = 6), there were no significant differences between days for any variable tested (p > 0.05), and intraclass correlations between days for the HRV measures showed good reliability for LF:HF (r = 0.82), and HR (r = 0.88). HF measures were found to be less reliable (all participants, r = 0.53; tetraplegics r = 0.66). CONCLUSION Despite the compromised sympathetic function that follows SCI, the high reliability found for LF:HF suggests that this HRV measure may still be used as a reliable index of resting sympathovagal balance in this population.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".