Effects of Transcutaneous Vagus Nerve Stimulation in Parkinson´s Disease

Summary

This study aims to determine whether electrical stimulation of the ear, when combined with physical and speech therapy, can improve symptoms in subjects diagnosed with Parkinson´s disease, by comparing two different application sites.

Each subject will undergo an initial in-person screening and provide consent before participating in the study.

The main questions to answer are:

* Does transcutaneous electrical nerve stimulation (tVNS) in the ear paired with physical and speech therapy improve speech and voice-related problems, airway protection, salivation, and swallowing?
* Does tVNS paired with physical and speech therapy improve tremor, walking speed, and balance in people with PD?
* Does tVNS paired with physical and speech therapy improve heart rate and heart rate variability in people with PD?
* Do its effects persist at 8 weeks?

Participants will:

Attend 12 rehabilitation sessions over 4 weeks (three per week). During each session, participants received either active or sham tVNS, accompanied by speech therapy (once per week), physical therapy (once per week), or conducted alone (once per week).

Undergo speech, voice, swallowing, respiratory, gait, balance, tremor, heart rate variability, and cognitive testing, as well as questionnaires regarding the quality of life, before and after treatment.

Return for a follow-up visit eight weeks after therapy to check how long the effects last.

Conditions

• Transcutaneous Vagal Nerve Stimulation (tVNS)
• Parkinson Disease (PD)

Interventions

DEVICE

Transcutaneous Electrical Nerve Stimulation (TENS) of Vagus Nerve

The tVNS will be performed at 200 microseconds, with frequencies ranging from 20 to 200 Hz (30 seconds/30 seconds) for 30 minutes, in the area innervated by the auricular branch of the vagus nerve (cymba concha and concha). The individually titrated intensity will be set above the sensory threshold (intense tingling sensation) but below the level of discomfort.

OTHER

Conventional Physical therapy

Physical therapy delivered to both groups consists of exercises aimed at posture alignment and body coordination, static and dynamic balance improvement, and gait quality. It will be delivered once a week, during a session of electrical stimulation.

OTHER

Conventional Speech Therapy

It will focus on the orofacial muscles, the acquisition of a diaphragmatic-abdominal breathing pattern that integrates breathing with vocal production, voice training with exercises that enhance vocal quality and prosody, articulation exercises to improve speech clarity, and swallowing training. It will be administered once a week, during one of the three electrical stimulation sessions.

DEVICE

Sham Transcutaneous Electrical Stimulation of Vagus Nerve

The sham- tVNS will be performed at 200 microseconds, with frequencies ranging from 20 to 200 Hz (30 seconds/30 seconds) for 30 minutes, with electrodes placed on the earlobe, which lacks vagus nerve innervation. The individually titrated intensity will be set above the sensory threshold (intense tingling sensation) but below the level of discomfort.

Sponsors & Collaborators

• Parkinson´s Association Galicia-Coruña

  collaborator UNKNOWN

• Universidade da Coruña

  lead OTHER

Principal Investigators

• Alicia Martínez-Rodríguez, Lecrurer · Universidade da Coruña

• Olalla Bello, Lecurer · Universidade da Coruña

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-05-31

Primary Completion

2026-09-30

Completion

2026-11-30

Countries

• Spain

Study Locations