Objective: The diagnosis of myofascial pain syndrome (MPS) is commonly made by Simons' clinical diagnostic criteria which is mainly based on patients' complaints, so it is difficult to distinguish from malingering. The purpose of this study is to evaluate local twitch response by needling (LTR) as an objective diagnostic criterion of MPS.
Method: Forty four industrial designers complaining of regional pain in neck, shoulder, or upper arm were examined by a physiatrist. If trigger point was detected, local twitch response by needling was confirmed and than severity was measured by 4 grades. Sensitivity, specificity, and positive predictive value of local twitch response was calculated with diagnosis made by Simons' clinical diagnostic criteria. Correlation between grade of local twitch response and sum of clinical features in Simons' criteria was also evaluated.
Results: Local twitch response by needling was corresponding with the diagnosis of MPS by Simons' criteria (sensitivity 100%, specificity 96.7%, positive predictive value 93.3%), and the severity of local twitch response was significantly associated with sum of clinical features in Simons' criteria (Spearman correlation 0.950; p=0.048)
Conclusion: Local twitch response by needling is an important and objective diagnostic criterion of MPS.
