The reliability of finding myofascial trigger points with infrared imaging

updated Jan 18, 2018

Tags: muscle pain, etiology, muscle, pain problems, pro

PainSci summary of Dibai-Filho 2015?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★★★☆☆?3-star ratings are for typical studies with no more (or less) than the usual common problems. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.

Thermography is infrared scanning of the human body for signs of trouble. Do trigger points cause hot spots on the skin overlying them? Will they light up on a thermograph? A scientific review by the same authors looked at four studies, finding mixed results (see Dibai-Filho). The authors tested their own method to try to resolve the uncertainty.

Twenty-four adults with neck pain and a suspected active trigger point in the trapezius were assessed by two trained examiners each, twice in a week. Each examiner detected similar thermography results, suggesting that “the methods of infrared image analyses of myofascial trigger points in the upper trapezius muscle employed in the present study are suitable for clinical and research practices.”

The fact that they concluded that their own method was effective is promising if you’re an optimist, and bit fishy if you’re not. Replication is definitely needed before the method can be trusted.

~ Paul Ingraham

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.

BACKGROUND: Infrared thermography is recognized as a viable method for evaluation of subjects with myofascial pain.

OBJECTIVE: The aim of the present study was to assess the intra- and inter-rater reliability of infrared image analysis of myofascial trigger points in the upper trapezius muscle.

METHOD: A reliability study was conducted with 24 volunteers of both genders (23 females) between 18 and 30 years of age (22.12 ± 2.54), all having cervical pain and presence of active myofascial trigger point in the upper trapezius muscle. Two trained examiners performed analysis of point, line, and area of the infrared images at two different periods with a 1-week interval. The intra-class correlation coefficient (ICC(2,1)) was used to assess the intra- and inter-rater reliability.

RESULTS: With regard to the intra-rater reliability, ICC values were between 0.591 and 0.993, with temperatures between 0.13 and 1.57 °C for values of standard error of measurement (SEM) and between 0.36 and 4.35 °C for the minimal detectable change (MDC). For the inter-rater reliability, ICC ranged from 0.615 to 0.918, with temperatures between 0.43 and 1.22 °C for the SEM and between 1.19 and 3.38 °C for the MDC.

CONCLUSION: The methods of infrared image analyses of myofascial trigger points in the upper trapezius muscle employed in the present study are suitable for clinical and research practices.

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.

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