Effects of Finger Kazoo Exercise With and Without Oropharyngeal Enlargement in the Operatic Singing Voice

NCT07129668 | Completed

• 2 other identifiers: 10-CE/2025doi.org/10.54499/2023.0361.BD
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

This clinical trial aimed to evaluate the effects of the semi-occluded vocal tract exercise Finger Kazoo (FK), with and without oropharyngeal expansion, on the singing voice. Fifteen classically trained singers, screened using the Singing Voice Handicap Index-10 (SVHI-10), participated in a randomized, single-blind, crossover trial with two experimental sessions separated by 48 hours. Participants were randomized via Sealed Envelope to start in Condition A (without oropharyngeal expansion) or Condition B (with oropharyngeal expansion). In each session, standardized recordings were obtained before and after the intervention, including maximum phonation time for the vowels /a/ and /i/, and an operatic aria excerpt. Acoustic analysis (PRAAT) extracted fundamental frequency (F0), jitter, and shimmer. Comparisons between baseline and experimental conditions were performed using paired-samples t-tests, Wilcoxon tests, robust paired t-tests, and Friedman ANOVA with Durbin-Conover, Tukey, Bonferroni, and Holm post hoc corrections, with a 95% confidence interval. Auditory-perceptual evaluation was conducted by 15 blinded experts using the EAI Scale Form, with balanced sample distribution among raters. Self-perceptual evaluation was also performed by participants using the same scale.

Conditions

Voice Alteration

Keywords

Singing Voice; Finger Kazoo; SOVTE; Operatic Voice

Outcome Measures

Primary Outcomes (1)

• Maximum Phonation Time (MPT) variation between conditions without and with oropharyngeal enlargement.

  Assessment of the difference in maximum phonation time (in seconds) between two experimental conditions: without oropharyngeal enlargement (Condition A) and with oropharyngeal enlargement (Condition B), during sustained vowel phonation. Data Collection Method: Acoustic recordings obtained using Praat software. The MPT was measured from the onset of phonation to cessation, with participants instructed to sustain the vowel at comfortable pitch and loudness. Analysis Method: Robust Paired Samples T-Test comparing MPT between Condition A and Condition B. Effect sizes calculated using Cohen's d. Results Summary: Mean MPT was significantly higher in Condition B (+7.9 s; p \< .001; d = 0.46), indicating improved phonatory efficiency.

  Baseline and 48 hours after first session (allowing return to baseline before second session).

Secondary Outcomes (1)

• Change in Fundamental Frequency Stability (ΔF0) between conditions without and with oropharyngeal enlargement.

  Baseline and 48 hours after first session (allowing return to baseline before second session).

Other Outcomes (2)

• Change in Jitter between conditions without and with oropharyngeal enlargement.

  Baseline and 48 hours after first session (allowing return to baseline before second session).

• Change in Shimmer between conditions without and with oropharyngeal enlargement.

  Baseline and 48 hours after first session (allowing return to baseline before second session).

Study Arms (3)

Condition A

ACTIVE COMPARATOR

Without Oropharyngeal Enlargement

Behavioral: Condition A; Behavioral: Condition B

Condition B

ACTIVE COMPARATOR

With Oropharyngeal Enlargement

Behavioral: Condition A; Behavioral: Condition B

Condition 0 or Baseline

ACTIVE COMPARATOR

Condition 0 (Baseline) consists of producing the target vocal tasks without any semi-occlusion or intentional oropharyngeal modification just a pre vocal warmup.

Behavioral: Condition A; Behavioral: Condition B

Interventions

Condition A BEHAVIORAL

Condition A consists of performing the Finger Kazoo exercise without inducing oropharyngeal enlargement. In this condition, participants place the index finger vertically in front of the lips to partially occlude the vocal tract, producing a semi-occluded vocal tract configuration, but without modifying tongue position, soft palate height, or pharyngeal wall expansion to increase the oropharyngeal space.

Also known as: Whitout Oropharyngeal Enlargement

Condition 0 or Baseline; Condition A; Condition B

Condition B BEHAVIORAL

Condition B consists of performing the Finger Kazoo exercise with intentional oropharyngeal enlargement. In this condition, participants place the index finger vertically in front of the lips to partially occlude the vocal tract, producing a semi-occluded vocal tract configuration, while simultaneously modifying tongue position, elevating the soft palate, and expanding the pharyngeal walls to increase the oropharyngeal space.

Also known as: With Oropharyngeal Enlargement

Condition 0 or Baseline; Condition A; Condition B

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Classically trained singers aged 18 to 45 years.
• Scoring below the cutoff for vocal handicap on the Singing Voice Handicap Index-10 (SVHI-10 ≤ 6 )\*.
• No history of recently vocal fold pathology or laryngeal surgery.
• Non-smokers and no current upper respiratory infection.
• Willingness and ability to attend two experimental sessions spaced 48 hours apart.

You may not qualify if:

• Presence of any current voice disorder or history of chronic laryngeal disease.
• Recent respiratory infection within 2 weeks prior to enrollment.
• Use of medications affecting voice or respiratory function.
• Inability or unwillingness to comply with study protocol.

Sponsors & Collaborators

• Aveiro University: lead
• School of Health Sciences, University of Aveiro (ESSUA): collaborator

Study Sites (1)

Essua - University of Aveiro

Aveiro, Aveiro District, 3810-193, Portugal

Location

MeSH Terms

Conditions

Dysphonia

Condition Hierarchy (Ancestors)

Voice Disorders; Laryngeal Diseases; Respiratory Tract Diseases; Otorhinolaryngologic Diseases; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Fifteen classically trained singers participated in a randomized, single-blind, crossover trial with two experimental sessions separated by 48 hours. Participants were allocated via Sealed Envelope randomization to start in Condition A (without oropharyngeal expansion) or Condition B (with oropharyngeal expansion). In each session, standardised recordings were obtained before and after the intervention, including maximum phonation time for the vowels /a/ and /i/, and an operatic aria excerpt.

Study Record Dates

• First Submitted: August 11, 2025
• First Posted: August 19, 2025
• Study Start: May 30, 2025
• Primary Completion: July 24, 2025
• Study Completion: July 26, 2025
• Last Updated: August 19, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

PT (1)