Distal Electroacupuncture Modulates Maladaptive Brainstem and Motor Cortex Plasticity to Alleviate Hemifacial Spasm.
Distal Electroacupuncture Modulates Maladaptive Brainstem and Motor Cortex Plasticity to Alleviate Hemifacial Spasm.
Where did the research take place?
The study site has not been established. Author addresses may differ from where the research occurred.
Guangzhou, CN · Author affiliation
Acupuncture Research Team, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.Location evidence
Shenyang, CN · Author affiliation
Liaoning University of Traditional Chinese Medicine, Shenyang, China.Location evidence
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Original abstract
BACKGROUND: Hemifacial spasm (HFS) is characterized by maladaptive brain plasticity, yet whether modulating this plasticity can alleviate symptoms remains unclear. OBJECTIVE: To evaluate the efficacy of electroacupuncture (EA)-a form of peripheral nerve stimulation-for HFS and elucidate its underlying neuroplastic mechanisms. METHODS: In this randomized, double-blind, sham-controlled trial (conducted 2016-2023), 84 HFS patients and 84 healthy controls were enrolled. Patients received 30 sessions of distal (hand), local (facial), or sham EA over 15 weeks. Clinical outcomes included Jankovic and Global Rating Scales. Physiological markers, including lateral spread response (LSR), synkinetic response (SR), and blink reflex (BR) excitability, were measured by electromyography (EMG). Motor cortex (M1) excitability was quantified via motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS). Parameter-probing experiments in healthy controls identified optimal stimulation characteristics. RESULTS: At baseline, HFS patients exhibited profound brainstem (BR R1/R2: P < 0.001) and facial M1 hyperexcitability versus controls. Low-frequency, low-intensity hand EA (2 Hz, 0.5-1 mA) significantly reduced Jankovic scores by 3.32 points (95% CI -4.12 to -2.52; P < 0.001; Cohen's d = 1.86) versus sham EA. This clinical improvement was mechanistically linked to a significant suppression of LSR (P < 0.01) and BR amplitude (P < 0.001), a reduction in facial M1 excitability (P < 0.05), and a compensatory increase in hand M1 excitability (P < 0.001). Notably, these neurophysiological and clinical benefits were maintained for 6 months post-treatment. CONCLUSION: Distal low-frequency, low-intensity peripheral stimulation effectively alleviates HFS by modulating maladaptive brainstem and M1 plasticity. These findings highlight the potential of this approach as a promising neuromodulatory strategy for hyperkinetic movement disorders. © 2026 International Parkinson and Movement Disorder Society.