Heart Rate Variability in Young Adults with Persisting Post‐Concussion Symptoms
Bibliographic record
Abstract
Objective Recovery following a concussion generally occurs within 7 to 10 days. However, between 10 to 50% of adults experience persistent post‐concussion symptoms (PPCS). Alterations in cardiac autonomic function, which may lead to heart rate (HR) dysregulation, could explain some of those persisting symptoms . Our aim was to examine short‐term resting heart rate variability (HRV), commonly used as an indicator of cardiac autonomic balance, in a group of subjects with PPCS. Hypothesis HRV parameters associated with cardiac vagal tone will be lower, while parameters associated with cardiac sympathetic activity (SYMP) will be higher in subjects with PPCS when compared to controls. Methods HRV was quantified in individuals experiencing PPCS for more than 4 wks [n=9 (5M/4F); 25 ± 6 y; body mass index (BMI): 25 ± 4 kg/m 2 ] compared to matched healthy controls [n=18 (10M/8F); 27 ± 5 y; BMI: 23 ± 3 kg/m 2 ]. Electrical activity of the heart was recorded continuously for 5 min in resting supine position (3‐lead ECG). Signals were reviewed for artifacts and processed using Ensemble‐R software (Elucimed, Wellington, NZ). Time‐domain analysis of HRV provided the square root of the mean squared differences of successive NN intervals (RMSSD), and the number of interval differences, between successive intervals, greater than 50ms (pNN50). Using spectral power analysis, relative low frequency (LF) power, relative high frequency (HF) power and LF/HF ratio were obtained. RMSSD, pNN50 and relative HF power are generally associated with cardiac vagal tone, whilst relative LF power and LF/HF ratio reflect a mix of cardiac SYMP and vagal activity. Results Mean LF/HF ratio was elevated in PPCS compared to controls (2.4 ± 1.9 vs. 0.9 ± 0.5; p=0.020), owing mainly to a lower relative HF power (28.1 ± 15.8 % vs. 48.5 ± 15.8 %; p=0.004), whilst relative LF power did not differ between groups (p=0.053). There were no significant differences in RMSSD and PNN50 between groups. Conclusion As hypothesized, LF/HF ratio was increased. This shift in cardiac autonomic balance appears to result from a reduction in cardiac vagal tone in young adults with PPCS when assessed in the frequency domain.
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 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".