Effects of Transcutaneous Vagus Nerve Stimulation in Parkinson´s Disease

ConditionsTranscutaneous Vagal Nerve Stimulation (tVNS)Parkinson Disease (PD)

Trial statusRecruiting

Trial phaseNot applicable

Trial typeInterventional

Biological sexAll

AgeNot listed

SponsorUniversidade da Coruña

About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Being a member of the Association or be interested in joining;

Idiopathic PD diagnosis, stages 2-3 according to the Hoehn & Yahr scale; confirmed by neurologist

Ability to walk independently for at least 1 minute ant turn 180° without assistance;

Exhibiting symptoms of hypokinetic dysarthria;

Disqualifiers

Any contraindication for taVNS (e.g., ear lesions, pacemakers, defibrillators, or other electronic devices)

Previous vagotomy or previous application of electrical stimulation to the ear or brain, or treatment with high-intensity focused ultrasound (HIFU)

Voice or speech disorders caused by other medical conditions

MoCA score below 21

Trial design

Design model

Parallel

Treatments tested in this trial

Transcutaneous Electrical Nerve Stimulation (TENS) of Vagus Nerve
Device
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.
Conventional Physical therapy
Other intervention
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.
Conventional Speech Therapy
Other intervention
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.
Sham Transcutaneous Electrical Stimulation of Vagus Nerve
Device
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.

Treatment groups

46 Participants

are divided into 2 treatment groups

Group A: Active tVNS paired with conventional Speech Therapy and Physical TherapyActive comparator 3 interventions

Group B: Sham tVNS paired with Speech Therapy and Physical TherapySham comparator 3 interventions

Trial outcomes

Primary outcomes

Voice intensity

The PRAAT software will be used to test the voice twice, when sustaining till 10 seconds the vowel "a" and when reading a text at their usual volume. The intensity (voice volume, measured in decibels) will be recorded.

Time frame