Transcranial Direct Current Stimulation on Singers Voice

NCT06612528 | Completed

• 1 other identifier: 5.758.856
• Study Type: interventional
• Target: 45
• Locations: 1 country
• Sites: 1

Brief Summary

Transcranial direct current stimulation (tDCS) can be used to temporarily and reversibly modulate brain functions and is an increasingly utilized tool to investigate the relationships between brain and behavior. This study aimed to identify the effects of tDCS on vocal quality, vocal range, neuromotor functioning of the larynx and self-reported vocal effort in vocally healthy singers. This is a triple-blinded, sham-controlled, randomized clinical trial. The participants were randomized to one of the three tDCS groups (primary motor cortex, cerebellum or sham). In each group a voice training was applied at the same tDCS time. The three groups are: (i) cerebellum; (ii) primary motor cortex (M1); (iii) sham. The tDCS parameters in the active groups are anodal - 2mA for 20 minutes, at the sham group the stimuli are finished 30 secondes before starting. Volunteers passed for 10 intervention days and they were evaluated for vocal performance before the sessions, in the day 5 of intervention, the last day of intervention (day 10) and 1 month later for follow up evaluation. Voice recordings was taken to assess the following vocal parameters: vocal range profile (VRP) at weak and strong intensities; vocal quality (jitter, shimmer, irregularity, glottal-to-noise excitation ratio, CPPS,HNR, and dysphonia acoustic index) at weak, habitual, and strong intensities; laryngeal diadochokinesis, and self-reported vocal effort using the adapted Borg CR10 scale.

Conditions

Voice; Voice Range Profile; Voice Quality

Keywords

transcranial direct current stimulation; tDCS; Flexible tube; voice; singers

Outcome Measures

Primary Outcomes (1)

• Vocal Range Profile

  Minimum fundamental frequency - f0; Maximum f0; Extension f0; Extension in Semitone; Minimum intensity; Maximum intensity and Area

  From enrollment to the end of evaluation at 6 weeks

Secondary Outcomes (1)

• Vocal quality

  From enrollment to the end of evaluation at 6 weeks

Other Outcomes (2)

• Larynx neuromuscular control and coordination

  From enrollment to the end of evaluation at 6 weeks

• Self-reported vocal effort

  From enrollment to the end of evaluation at 6 weeks

Study Arms (3)

M1 and vocal exercise

EXPERIMENTAL

anodal tDCS over primary motor cortex associated with the vocal exercise using the flexible tube in water.

Device: tDCS; Device: Flexible tube in water

Cerebellum and vocal exercise

ACTIVE COMPARATOR

anodal tDCS over cerebellum associated with the vocal exercise using the flexible tube in water.

Device: tDCS; Device: Flexible tube in water

Sham and vocal exercise

PLACEBO COMPARATOR

tDCS sham associated with the vocal exercise using the flexible tube in water.

Device: tDCS; Device: Flexible tube in water

Interventions

tDCS DEVICE

The tDCS is a non-invasive brain stimulation technique. In this study, we used an intensity of 2mA for 20 minutes in two different areas. M1 group: the anode was over C5 (10-10 EEG system) and the cathode was placed over Fp2. For the Cerebellum group stimulation, the targeted anode area was 2 cm below the inion and the cathode over the deltoid muscle.

Also known as: transcranial direct current stimulation

Cerebellum and vocal exercise; M1 and vocal exercise; Sham and vocal exercise

Flexible tube in water DEVICE

The exercise involved producing sustained /u/ vowels in ascending and descending scales, tailored to each participants vocal range. The flexible tube was 35 cm long, 1 cm in diameter, and 2 mm thick. One end of the tube was submerged 3 cm into a 500 ml bottle filled with water. Participants produced four sets of vocal exercises, each lasting 3 minutes, with 2-minute rests between sets, totaling 20 minutes of vocal therapy.

Also known as: Lax vox, Flexible tube

Cerebellum and vocal exercise; M1 and vocal exercise; Sham and vocal exercise

Eligibility Criteria

• Age: 18 Years - 45 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Vocally healthy singers without formal singing education

You may not qualify if:

• Smokers
• Abnormalities in previous screening for voice symptoms
• Exhibited signs and symptoms of laryngeal, pharyngeal, or respiratory diseases at the time of collection
• Used neuroactive medications
• Had metallic implants in the cervical region or above
• Had any history of seizures or epilepsy

Sponsors & Collaborators

• Universidade Federal de Pernambuco: lead
• Coordination for the Improvement of Higher Education Personnel: collaborator

Study Sites (1)

Universidade Federal de Pernambuco

Recife, Pernambuco, 50740-560, Brazil

Location

MeSH Terms

Interventions

Transcranial Direct Current Stimulation; Hydrotherapy

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques; Physical Therapy Modalities; Rehabilitation

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal investigator

Model Details: Participants were randomly assigned to one of three groups (M1, Cerebellum, or sham) using a computer-generated randomization list. All participants received 10 consecutive sessions of anodal tDCS combined with vocal exercises, except on weekends. Stimulation parameters and electrode placement varied by group: M1 - C5 (anode) and contralateral supraorbital (cathode); Cerebellum - cerebellar cortex (anode) and right deltoid (cathode); sham - identical electrode placement to the Cerebellum group, but with stimulation ceasing 30 seconds after onset. Vocal exercises consisted of four 3-minute bouts with a 2-minute rest between bouts. To maintain blinding, a towel was placed over the participants head during the procedure.

Study Record Dates

• First Submitted: September 21, 2024
• First Posted: September 25, 2024
• Study Start: March 11, 2024
• Primary Completion: October 10, 2025
• Study Completion: December 20, 2025
• Last Updated: May 7, 2026

Record last verified: 2026-05

Locations

BR (1)