The Soleus H-Reflex as a Biomarker of Post-Injury Spasticity in Spinal Cord Injury: A Conceptual Pilot Study
Bibliographic record
Abstract
BackgroundSpinal cord injury (SCI) disrupts neuronal pathways, alters spinal reflexes, and often leads to spasticity-a condition of increased muscle tone and involuntary contractions that interfere with daily function. Spasticity typically emerges progressively after injury; however, its mechanisms remain poorly understood, particularly regarding why it develops in some individuals but not in others. Increased spinal excitability has been implicated, but prospective evidence remains scarce.ObjectiveThis pilot, proof-of-concept study explored whether early electrophysiological markers of spinal excitability, specifically the soleus H-reflex and post-activation depression (PAD), could be linked to the subsequent development of spasticity during intensive functional rehabilitation (IFR).MethodsSeventeen individuals with traumatic SCI were assessed. The Hmax/Mmax ratio and PAD were measured prior to or shortly after IFR admission. At IFR admission and discharge, spasticity (Modified Ashworth Scale and clonus) and motor function (Lower Extremity Motor Score, LEMS) were evaluated. Each lower limb was analyzed separately to account for asymmetry. Correlations between early electrophysiological measures and clinical outcomes were examined.ResultsSpasticity measures tended to increase from IFR admission to discharge, but only LEMS improved significantly, reflecting motor recovery. Several participants did not present spasticity at admission or discharge. A higher Hmax/Mmax ratio and reduced PAD at early IFR were associated with greater clonus at both admission and discharge, whereas no significant associations were found with Ashworth scores. Across injury levels and AIS grades, AIS A participants displayed the lowest Hmax/Mmax ratios and minimal spasticity, while AIS B or D participants with H/M ratios exceeding 0.2 in early IFR developed clonus.ConclusionThese exploratory findings suggest that early signs of spinal hyperexcitability reflect spasticity development, but it does not show that they precedes spasticity development, which would be required to support its prognostic value. Assessment at earlier timepoints, such as in acute care, would be necessary to validate both the Hmax/Mmax ratio and the PAD as predictive measures of spasticity in SCI. While not clinically generalizable due to the small and heterogeneous sample, this proof-of-concept study highlights the feasibility and potential value of H-reflex as early markers of spasticity. Larger, adequately powered studies stratified by injury level and severity are needed to confirm utility and clinical applicability.
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 | 0.000 | 0.007 |
| 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 | 0.001 |
| 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".