Transcranial Direct Current Stimulation on Singers Voice

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

Interventions

DEVICE

tDCS

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.

DEVICE

Flexible tube in water

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.

Sponsors & Collaborators

• Coordination for the Improvement of Higher Education Personnel

  collaborator OTHER

• Universidade Federal de Pernambuco

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

45 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-03-11

Primary Completion

2025-10-10

Completion

2025-12-20

Countries

• Brazil

Study Locations