Nociceptor hypostimulation shows superior long-term benefit for chronic cervical pain in small RCT

BACKGROUND AND PURPOSE: Chronic cervical pain is a common disorder and is difficult to manage. Therefore, this study was conducted to investigate the effects of nociceptor hypostimulation versus hyperstimulation on electromyographic (EMG) activity of cervical muscles, myofascial trigger point (MTP) sensitivity, pain intensity, and disability in patients with chronic cervical pain. METHODS: Sixty patients with chronic cervical pain were randomly assigned to hypostimulation, hyperstimulation, or control groups. The hypostimulation group received subthreshold stimulation, the hyperstimulation group received suprathreshold stimulation, and the control group received sham treatment. Stimulation was applied for 20 min, three times per week, for 8 weeks. Outcome measures included upper trapezius EMG activity (resting and maximal contraction), pain intensity, MTP pressure pain threshold, and cervical range of motion (flexion, lateral flexion, and rotation bilaterally). Outcomes were assessed at baseline, post-treatment (8 weeks), and follow-up (8 weeks). RESULTS: At baseline, no significant differences were observed among groups for any outcome (p > 0.05). Post-treatment, the hypostimulation group demonstrated significantly greater improvements than both the hyperstimulation and control groups across all outcomes (p < 0.05). These improvements were maintained at follow-up. Hyperstimulation resulted in short-term improvements in pain and cervical range of motion but not in EMG activity; these effects were not sustained at follow-up. DISCUSSION: Eight weeks of nociceptor hypostimulation produced significant and sustained improvements in cervical muscle EMG activity, MTP sensitivity, pain, and disability in adults aged 40-65 years with chronic cervical pain. Hypostimulation was superior to hyperstimulation for the long-term management of chronic cervical pain involving upper trapezius MTPs. TRIAL REGISTRATION: NCT06559358.