Comparison of Voice Improvement Effects from Semi-occluded Vocal Tract Exercises and Voice Rest between Treatment Sessions among Speech-Language Pathologists

Shin, Won Seok; Lee, Seung Jin

doi:2025.30.1.192

ORIGINAL ARTICLE

Commun Sci Disord. 2025;30(1): 192-205.
Published online March 31, 2025.
doi: https://doi.org/10.12963/csd.250092

Comparison of Voice Improvement Effects from Semi-occluded Vocal Tract Exercises and Voice Rest between Treatment Sessions among Speech-Language Pathologists

Won Seok Shin^a

, and Seung Jin Lee^b

^aDepartment of Speech Pathology and Audiology, Graduate School of Hallym University, Chuncheon, Korea
^bDivision of Speech Pathology and Audiology, Research Institute of Audiology and Speech Pathology, College of Natural Sciences, Hallym University, Chuncheon, Korea

Corresponding Author: Seung Jin Lee ,Tel: +82-33-248-2223, Fax: +82-33-256-3420, Email: sjl@hallym.ac.kr

Received January 5, 2025 Revised: February 16, 2025 Accepted February 24, 2025

ABSTRACT

Objectives
Speech-language pathologists (SLPs) are at high risk for voice disorders, and voice rest (VR) has commonly been used as a coping strategy. However, VR may lead to reduced income and service quality. Semi-occluded vocal tract exercises (SOVTEs), including voiced high-frequency oscillation (VHFO), provide immediate voice benefits without disrupting work routines. This study aimed to compare the efficacy of VHFO during rest periods between therapy sessions with VR in SLPs.
Methods
Twenty-two 1st and 2nd grade SLPs without existing voice issues participated in a two-week crossover study. In the first session, participants were randomly assigned to either the VR or SOVTE group, switching to the other group in the second session. Voice evaluations were conducted before the first and after the final therapy session of each day. Acoustic parameters, including F0, jitter (Jitt), shimmer (Shim), noise-to-harmonics ratio (NHR), and cepstral peak prominence (CPP), were analyzed using the MDVP, ADSV, and VOXplot. Multiparametric indices such as CIVF, AVQI, and APSID were calculated. Psychometric assessments measured vocal fatigue and perceived voice severity.
Results
The VHFO group showed significantly lower Jitt, Shim, and NHR values compared to the VR group. Within-group comparisons revealed that the VR group experienced increased Jitt, Shim, and APSID values, while the VHFO group exhibited improved F0 and CPP values and decreased Jitt and NHR values.
Conclusion
VHFO demonstrated superior efficacy in improving acoustic measures (CPP, Jitt, NHR) and maintaining vocal health compared to VR. These findings underscore the clinical value of VHFO as a practical voice management strategy for SLPs.

Keywords: Speech-language pathologists (SLPs) | Semi-occluded vocal tract exercises (SOVTE) | Voiced high-frequency oscillation (VHFO)