The Effect of High-Power Pain Threshold Ultrasound Therapy on the Electrical Activity of Trigger Points and Local Twitch Response on Electromyography: A Preliminary Study

Abstract

Objectives: We aimed to compare the effects of the high-power pain threshold ultrasound [HPPTUS] technique and needling on the spontaneous electrical activity [SEA] of trigger points [TrPs], local twitch response [LTR], and clinical improvement in myofascial pain syndrome.

Methods: Twenty female patients presenting with acute TrPs on their upper trapezius muscles were included in this study. The patients were randomly assigned into two groups. The cases in the study group underwent HPPTUS technique and active stretching of the muscle. The cases in the control group underwent dry needling done by five adjacent electromyography [EMG] needle penetrations on the TrP [dry needling and analysis done concurrently] and did active stretching. Number of points where SEA observed were recorded. Visual analog scale [VAS], range of motion [ROM] measurement during contralateral flexion of the cervical spine, and the number of LTR were recorded.

Results: Significant improvements were measured in both groups in terms of pain level and cervical ROM [P < 0.05]. There were no statistically significant changes in the number of recorded SEA of both groups at the end of the treatment. However, significant reduction in the number of LTR in the HPPTUS group was found [P = 0.015]. When the two groups were compared regarding level, patients in the study group reported significantly more reduction in pain [P = 0.009]. However, there was no difference in the cervical ROM improvement between two groups [P = 0.136].

Conclusions: The HPPTUS technique combined with exercise was found to be more effective in reducing the LTRs when compared with dry needling combined with exercise.

KEYWORDS:

• Myofascial pain syndrome
• ultrasound
• electromyography