The myofascial trigger point region: correlation between the degree of irritability and the prevalence of endplate noise
Two articles on PainSci cite Kuan 2007: 1. The Complete Guide to Trigger Points & Myofascial Pain 2. The Trigger Point Identity Crisis
PainSci notes on Kuan 2007:
This study constitutes good replication of a 2002 study (see Simons) identifying an association between endplate noise or spontaneous electrical activity (SEA) and the clinical phenomenon of “trigger points.” In 32 patients with trapezius trigger points, they found endplate noise at the location of the putative trigger points, but not in adjacent muscle, concluding that “The irritability of an MTrP is highly correlated with the prevalence of endplate noise in the MTrP region of the upper trapezius muscle.”
original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
OBJECTIVE: This study was designed to investigate the correlation between the irritability of the myofascial trigger point (MTrP) and the prevalence of endplate noise (EPN) in the MTrP region of human skeletal muscle.
DESIGN: Twenty normal subjects with latent MTrPs and 12 patients with active MTrPs in the upper trapezius muscles were recruited for this study. The patients reported the subjective pain intensity of the active MTrP (0-10). The MTrP and an adjacent non-MTrP site were confirmed and marked for the measurement of pressure pain threshold (with a pressure algometer) and the prevalence of EPN (with electromyographic recordings).
RESULTS: The prevalence of EPN in the MTrP regions was significantly higher (P < 0.01) in the active MTrPs than in the latent ones. However, no EPN could be found in the non-MTrP region near either the active or the latent MTrPs. The pain intensity and the pressure pain threshold were highly correlated with the prevalence of EPN in the MTrP region (r = 0.742 and -0.716, respectively).
CONCLUSIONS: The irritability of an MTrP is highly correlated with the prevalence of EPN in the MTrP region of the upper trapezius muscle. The assessment of EPN prevalence in an MTrP region may be applied to evaluate the irritability of that MTrP.
related content
- “Endplate potentials are common to midfiber myofacial trigger points,” David G Simons, Chang-Zern Hong, and Lois Statham Simons, Am J Phys Med Rehabil, 2002.
- “Spinal cord mechanism involving the remote effects of dry needling on the irritability of myofascial trigger spots in rabbit skeletal muscle,” Yueh-Ling Hsieh, Li-Wei Chou, Yie-San Joe, and Chang-Zern Hong, Archives of Physical Medicine & Rehabilitation, 2011.
- “Myofascial trigger points: spontaneous electrical activity and its consequences for pain induction and propagation,” Hong-You Ge, César Fernández-de-Las-Peñas, and Shou-Wei Yue, Chin Med, 2011.
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- Relationships Between Sleep Quality and Pain-Related Factors for People with Chronic Low Back Pain: Tests of Reciprocal and Time of Day Effects. Gerhart 2017 Ann Behav Med.
- Modulation in the elastic properties of gastrocnemius muscle heads in individuals with plantar fasciitis and its relationship with pain. Zhou 2020 Sci Rep.