Validity of Cross-friction Algometry Procedure in Referred Muscle Pain Syndromes
Bibliographic record
Abstract
OBJECTIVES: Deep cross-friction pressure with a finger or an elbow in the proximal gluteal region causes a sciaticlike pain along the side of the thigh and the leg as a clinical presence of referred pain (RP) in patients with nonspecific low back pain (LBP). This study investigated the reliability and discriminative ability of experimentally provoked RP as a result of deep cross-friction with the aid of a Fischer algometer. The new clinical examination method measures the provoked RP threshold resulting in an outcome, expressed in kg/cm2. METHODS: Forty two patients with subacute LBP (3 to 12 wk) participated in a prospective clinical trial. The outcome was assessed by means of the standard (perpendicular) pressure pain thresholds (PPT) measured with the aid of a Fischer algometer on both sides of the gluteus medius, the provoked RP pain thresholds (PPT-RP) at the location of the medial superior cluneal nerve, the Oswestry Disability Index , and the McGill Pain Questionnaire. The diagnostic criteria for the clinical presence of RP were determined by the patient on the pain chart drawings of the McGill Pain Questionnaire. The criteria for provoked RP were determined by means of PPT-RP with the aid of a Fischer algometer until the patient pointed out the RP zone in the thigh and/or the leg. RESULTS: The interobserver reliability was sufficient for both sides with and without RP (intraclass correlation coefficient>0.97). The test-retest performed independently of the observers ranking, showed a perfect reliability of the PPT-RP measurements (intraclass correlation coefficient>0.98). The PPT-RP at the level of the medial superior cluneal nerve in the subgroup with a clinical presence of RP (N=20) was significantly higher (3.5 kg/cm2) than in the subgroup patients without RP (N=22). The correlation between the factor RP and the PPT-RP was high (R=0.91, P<0.001). The clinically important difference between provoked and clinical presence of RP was found to be higher or lower than 5.6 kg/cm2. The standard PPT measurement of the gluteus medius revealed no significant differences between the subgroups with and without RP. CONCLUSIONS: This clinical study support the reliability and discriminative ability of a new method of experimentally provoked RP, using deep cross-friction pressure with the aid of a Fischer algometer in patients with LBP. The experimentally "provoked referred pain threshold" (PPT-RP) values lower than 6 kg/cm correspond clinically with the presence of a referred muscle pain area in the thigh and/or the leg. Further studies of a similar kind are nevertheless needed to confirm those conclusions and to assess the responsiveness of the provoked RP measurements in different treatment follow-up periods.
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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 | 0.003 | 0.023 |
| 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 | 0.001 |
| Research integrity | 0.001 | 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".