Effect of Transcranial Direct Current Stimulation on Singers' Voice
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 45
- Locations
- 2
- Primary Endpoint
- Vocal Range Profile
Study Overview
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.
Detailed Description
Data collection was conducted at the Applied Neuroscience Laboratory (LANA) of the Federal University of Pernambuco (UFPE).
This study includes vocally healthy individuals who are singers without formal music or singing training. Residents of the city of Recife and the Metropolitan Region, aged 18 to 45 years. The age range was chosen considering the period of maximum vocal efficiency To determine the sample size, a pilot study was conducted with 15 participants using the G*Power 3.1 program, considering a statistical power (β) of 80% and a significance level (α) of 5%. For this analysis, the primary vocal outcome variables (vocal range profile) was considered, and the sample size considered was 45, the largest value among the selected outcomes.
Singers without formal music training and without vocal complaints were included.
Individuals who were smokers or who presented signs and symptoms of laryngeal, pharyngeal or respiratory diseases at the time of data collection were excluded from the sample. Volunteers who were using neuroactive medications regularly, have metal implants in the cervical region or above, and had any history of seizures or epilepsy were also excluded.
The sample of singers was constituted by convenience through individuals who were singers without vocal complaints of both sexes, recruited through advertisements in electronic media. The first contact with the volunteers was through a screening to verify the eligibility criteria.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to 45 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Vocally healthy singers without formal singing education
Exclusion Criteria
- •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
Arms & Interventions
M1 and vocal exercise
anodal tDCS over primary motor cortex associated with the vocal exercise using the flexible tube in water.
Intervention: tDCS (Device)
M1 and vocal exercise
anodal tDCS over primary motor cortex associated with the vocal exercise using the flexible tube in water.
Intervention: Flexible tube in water (Device)
Cerebellum and vocal exercise
anodal tDCS over cerebellum associated with the vocal exercise using the flexible tube in water.
Intervention: tDCS (Device)
Cerebellum and vocal exercise
anodal tDCS over cerebellum associated with the vocal exercise using the flexible tube in water.
Intervention: Flexible tube in water (Device)
Sham and vocal exercise
tDCS sham associated with the vocal exercise using the flexible tube in water.
Intervention: tDCS (Device)
Sham and vocal exercise
tDCS sham associated with the vocal exercise using the flexible tube in water.
Intervention: Flexible tube in water (Device)
Outcomes
Primary Outcomes
Vocal Range Profile
Time Frame: From enrollment to the end of evaluation at 6 weeks
Minimum fundamental frequency - f0; Maximum f0; Extension f0; Extension in Semitone; Minimum intensity; Maximum intensity and Area
Secondary Outcomes
- Vocal quality(From enrollment to the end of evaluation at 6 weeks)
Investigators
Kátia Monte-Silva
Principal investigator
Universidade Federal de Pernambuco