Immediate Effects of External Trigeminal Nerve Stimulation on Motor Dysfunction in Parkinson's Disease

Condition(s) studied

Investigational drug(s) / intervention(s)

external Trigeminal Nerve Stimulation, eTNS: The experiment will be conducted in the MED-ON state, consistently 1-2 h after administration of antiparkinsonian medication. Baseline gait and motor function assessments will first be performed, followed by three randomized eTNS stimulation sessions. Gait will be assessed after each stimulation session, and motor function scales will be reassessed after completion of all experimental conditions.

Study summary

Parkinson's disease (PD), the most common movement disorder, is characterized by motor symptoms including tremor, rigidity, bradykinesia, and postural instability. These symptoms substantially impair quality of life and increase the risk of falls, disability, and accidental injury, representing a major therapeutic challenge.

External trigeminal nerve stimulation (eTNS), a non-invasive neuromodulation technique, has shown promising potential in PD and other movement disorders. A clinical study published in 2017 suggested that trigeminal nerve stimulation may contribute to the alleviation of motor symptoms in patients with PD. In 2023, the U.S. Food and Drug Administration cleared the Portable Neuromodulation Stimulator (PoNS) as an adjunctive treatment for gait impairment caused by multiple sclerosis; the lingual nerve is a branch of the mandibular division of the trigeminal nerve. In the same year, experimental evidence showed that trigeminal nerve stimulation could activate intracranial dopaminergic neurons and modulate dopamine release in mice. These findings suggest substantial potential for eTNS in modulating motor dysfunction in PD, although high-level clinical evidence remains lacking.

This randomized, within-subject study will evaluate the immediate effects of eTNS at different stimulation frequencies on motor dysfunction in patients with PD. Gait parameters will be quantitatively assessed using the IDEEA gait system, together with the MDS-Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS Part III), Tinetti Gait Scale, and Hoehn and Yahr Scale.

This within-subject study comprises three 20-min stimulation conditions: 120-Hz eTNS, 40-Hz eTNS, and sham stimulation. Each patient with Parkinson's disease will complete all conditions in a single session in randomized order. Instrumented gait analysis, together with motor and gait rating scales, will be used to quantify immediate post-stimulation changes in gait and motor function relative to baseline.

Eligibility

Primary outcome measure(s)

• Dual-Task Cost (DTC) — DTC will be assessed at baseline and after each randomized eTNS condition during walking tasks, using the IDEEA inertial sensor based gait analysis system.
  This is a within-subject study. Instrumented gait parameters and clinical rating scales will be assessed at baseline, followed by eTNS stimulation in randomized order under the 120-Hz, 40-Hz, and sham conditions. After each eTNS condition, instrumented gait parameters will be collected during walking tasks. Clinical rating scales will be additionally assessed after the final stimulation condition.Dual-task cost will be calculated as: \[(single-task gait speed - dual-task gait speed) / single-task gait speed\] × 100%.DTC reflects the reduction in walking performance under dual-task conditions relative to single-task conditions. A decrease in DTC after eTNS indicates reduced dual-task interference during walking, suggesting that eTNS may reduce dual-task gait cost in patients with PD.
• Mean Gait Speed（m/s） — Mean gait speed will be assessed at baseline and after each randomized eTNS condition during walking tasks, using the IDEEA inertial sensor-based gait analysis system.
  This is a within-subject study. Instrumented gait parameters and clinical rating scales will be assessed at baseline, followed by eTNS stimulation in randomized order under the 120-Hz, 40-Hz, and sham conditions. After each eTNS condition, instrumented gait parameters will be collected during walking tasks. Clinical rating scales will be additionally assessed after the final stimulation condition. Mean gait speed will be directly obtained from the IDEEA system, which uses inertial sensors to quantitatively monitor gait during walking tasks in patients with PD.
• Mean Stride Length (m) — Mean stride length will be assessed at baseline and after each randomized eTNS condition during walking tasks, using the IDEEA inertial sensor-based gait analysis system.
  This is a within-subject study. Instrumented gait parameters and clinical rating scales will be assessed at baseline, followed by eTNS stimulation in randomized order under the 120-Hz, 40-Hz, and sham conditions. After each eTNS condition, instrumented gait parameters will be collected during walking tasks. Clinical rating scales will be additionally assessed after the final stimulation condition. Mean stride length will be directly obtained from the IDEEA system, which uses inertial sensors to quantitatively monitor gait during walking tasks in patients with PD.

Trial sites (1)

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