Clinical effects of passive cable theory applied via subthreshold electrical stimulation in chronic neck pain: A randomized trial

PM R. 2026 Mar 28. doi: 10.1002/pmrj.70098. Online ahead of print.

ABSTRACT

BACKGROUND: Neck pain is considered a common problem in adults. Chronic neck pain usually causes hypersensitivity of nociceptors. Current pain therapies have not targeted this hypersensitivity. Recently, a novel theory used in rehabilitation called the passive cable theory was developed. This theory helps in treating hypersensitive areas like nociceptors.

OBJECTIVE: To investigate the passive cable theory applied via subthreshold stimulation on electromyographical activity (EMG) of neck muscles, myofascial trigger point sensitivity, pain, and disability in patients with chronic neck pain.

DESIGN: A randomized double-blinded controlled trial.

SETTING: Outpatient clinic.

PARTICIPANTS: Forty patients with chronic neck pain were randomly distributed to the study and control groups.

INTERVENTION: The study group received subthreshold electrical stimulation for 8 weeks, and the control group received sham treatment.

MAIN OUTCOME MEASURES: The main outcome measurements were EMG activity of the upper trapezius muscle, neck pain intensity, myofascial trigger point sensitivity, neck flexion, neck lateral flexion to both sides, and neck lateral rotation to both sides. All outcomes were measured at preintervention, postintervention (8 weeks), and follow-up (8 weeks).

RESULTS: At preintervention, there were nonsignificant differences in resting EMG, maximum EMG, pain intensity, pressure threshold, neck flexion, neck right flexion, neck left flexion, neck right rotation, and neck left rotation (p > .05). Post intervention (8 weeks), there were significant differences between study and control groups for all outcomes (p < .05).

CONCLUSION: Eight weeks of subthreshold stimulation is an effective intervention for reducing resting EMG activity in neck muscles while increasing their maximum contraction. It also decreases myofascial trigger point sensitivity, pain, and disability in patients with chronic neck pain. These improvements are maintained for at least 8 weeks following treatment.

PMID:41902500 | DOI:10.1002/pmrj.70098