Autonomic Cardioregulatory Function Does Not Correlate With Symptom Improvement After Concussion in Children and Adolescents
Bibliographic record
Abstract
Although there is significant variability in the manifestations of persisting post-concussive symptoms (PPCS), autonomic dysfunction has been reported to contribute to PPCS and could serve as a biomarker of recovery. The objective of this study was to evaluate cardiac autonomic reflexes and autonomic function after concussion injury comparing those with prolonged concussion symptoms to those without. This is a case-control study where a non-referred population of concussed children or adolescent participants were enrolled from the Emergency Department (ED) of the Stollery Children's Hospital, a tertiary pediatric hospital in Edmonton, Alberta, Canada. Children and adolescents 8 through <18 years of age who presented with mild traumatic brain injury were diagnosed with concussion. Our study reported concussion symptoms and standardized clinical cardiac autonomic reflex testing at 4 and 12 weeks after injury. Our findings showed that 28 participants with concussion completed the 4-week follow-up questionnaires, and that 17 (61%) were diagnosed with PPCS. Difficulty concentrating, fatigue, noise sensitivity, light sensitivity, and headache were most commonly reported at baseline among those who were later diagnosed with PPCS. The mean change in heart rate (HR) with head-up tilt was 44.2 bpm (standard deviation [SD] 9.1) in the non-PPCS group and 46.6 bpm (SD 14.1) in the PPCS group at 4 weeks and was not significant in the unadjusted (p = 0.2) or adjusted analysis for age and female sex (p = 0.2). Overall, 70% (19/27) had significant orthostatic tachycardia >40 bpm, but PPCS and non-PPCS groups were similar. Similar results were observed among 23 participants at 12-week follow-up. The median maximum decrease in systolic blood pressure (SBP) with head-up tilt was -26.9 mm Hg (interquartile range [IQR] -32.6, -22.3) in the non-PPCS group and -25.1 mm Hg (IQR -32.2, -18.2) in the PPCS group, and was not significantly different in the unadjusted (p = 0.8) or adjusted (p = 0.8) analysis. Overall, 19 of 26 participants (73%) demonstrated orthostatic hypotension (SBP change >20 mm Hg) with no significant difference between the PPCS and non-PPCS groups. Similar results were observed at 12-week follow-up. In conclusion, cardiac autonomic reflex responses are abnormal in most children and adolescents with a concussion injury at 4- and 12-week follow-up and may reflect ongoing autonomic dysfunction. However, autonomic function did not differentiate PPCS, indicating that reported symptoms are not sensitive to autonomic abnormalities.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".