Background: Although electromyography (EMG) has been used extensively in dentistry to assess masticatory muscle impairments in several conditions, especially temporomandibular disorders (TMDs), many investigators have questioned its psychometric properties and accuracy in diagnosing TMD.
Types of studies reviewed: The authors conducted a systematic review to analyze the literature critically and determine the accuracy of EMG in diagnosing TMDs. They conducted an electronic search of MEDLINE, Embase, all Evidence-Based Medicine Reviews, Allied and Complementary Medicine, Ovid HealthSTAR and SciVerse Scopus. The authors selected abstracts that fulfilled the inclusion criteria, retrieved the original articles, verified the inclusion criteria and hand searched the articles' references. They used a methodological tool (Quality Assessment of Diagnostic Accuracy Studies [QUADAS]) to evaluate the quality of the selected articles.
Results: The electronic database search resulted in a total of 130 articles. The authors selected eight articles as potentially meeting eligibility for the review. Of these eight articles, only two fulfilled the study inclusion criteria, and the authors analyzed them. Investigators in both studies reported low sensitivity (values ranged from 0.15 to 0.40 in one study and a mean of 0.69 in the second study). In addition, investigators in the two studies reported contradictory levels of specificity (values ranged from 0.95 to 0.98 in one study, and the mean value in the second study was 0.67). The likelihood ratios and predictive values were not helpful in diagnosing TMD by means of EMG. The quality of the two studies was poor on the basis of the QUADAS checklist.
Clinical implications: The authors of this systematic review found no evidence to support the use of EMG for the diagnosis of TMD.