Strength-duration curve: A measure for assessing pain in trapezius spasm

Abstract

Objective: To ascertain the normative values of Strength-duration curve parameters for motor and sensory nerves of trapezius muscle in asymptomatic subjects and compare them with subjects suffering from chronic bilateral trapezius spasm. Methods: A multi-centric cross-sectional study was conducted to compare the Strength-duration curve parameters derived from normal healthy group of subjects (n = 100) and with subjects presenting with bilateral trapezius spasm (n = 100). The subjects were recruited after explaining the procedure in the language best understood by them and a written consent was procured before starting the research. Results: Level of significance was set at P value < 0.05. Rheobase values were found to be lower, whereas, chronaxie, rise time and pulse ratio were increased for both sensory and motor nerve in subjects with trapezius spasm as compared to normal healthy subjects. Discussion: Strength-duration curve parameters can be an important addition to the objective measurement tools of pain assessment and prognosis in musculoskeletal painful conditions. Conclusion: SDC can be effectively used an objective measure of assessment of pain in patients suffering from trapezius spasm. Clinical Implications: On the same lines further studies can be conducted and applied in various neuromuscular conditions.

Keywords

• Motor chronaxie
• motor rheobase
• sensory chronaxie
• sensory rheobase
• strength-duration curve
• trapezius spasm