Browsing by Author "Guzman, Marco"

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    Bibliometric analysis, systematic review of literature, and meta-analysis on the effect of amplification on voice production among teachers
    (2025) Cantor-Cutiva, Lady Catherine ; Acevedo, Karol ; Guzman, Marco; Gonzalez, Juan Carlos ; Cerda Sandoval, Felipe Enrique; Smith, Catalina ; Behm, Isidora; Hunter, Eric
    Background: Teaching is identified as a high-risk profession for developing voice disorders due tothe significant vocal demands placed on educators. This can lead to symptoms such as vocalfatigue, adversely affecting their quality of life. One common intervention is the provision of voice amplification systems, which have been reported to reduce vocal strain by enabling teachers to speak at lower volumes, thereby potentially improving voice quality and minimizing vocal fold damage. Despite these benefits, various factors such as adoption rates, technical issues, and the need for proper use and training can influence the effectiveness of these systems. This study systematically reviews the literature and conducts a meta-analysis to determine the impact of voice amplification on teachers’ vocal function. Methods: The results reported in this manuscript are based on a bibliometric analysis and systematic literature review using seven databases, selecting 20 relevant publications from an initial pool of 462, and performing a meta-analysis to compare vocal metrics with and withoutamplification. Results: The meta-analysis indicated that voice amplification systems tend to positively affect fundamental frequency, sound pressure level (SPL), and phonation time percentage; however,these effects were not statistically significant. The analysis also suggests no significant publicationbias, though the quality of the included publications varied: 15 % were rated as strong, 25 % asmoderate, and 60 % as weak.Conclusion and Recommendations: The study concludes that voice amplification systems showpotential benefits for teachers’ vocal health. However, their implementation should be part of abroader strategy that includes education, training, and regular monitoring to maximize theireffectiveness
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    Validation of the Spanish Version of the Voice-Related Quality of Life Questionnaire: Psychometric Properties and Clinical Applications
    (2024) Contreras-Ruston, Francisco; Fuentes, Andres Rosenbaum; Velasquez, Lukas Salfate; Acevedo, Karol; Gonzalez, Nury; Meneses, Norma Leon; Napolitano, Carla; Guzman, Marco
    Introduction: The present study aimed to validate the Voice-Related Quality of Life (V-RQOL), vocal self-assessment questionnaire for Spanish. Methods: The validation and psychometric properties were developed according to the criteria of the Scientific Advisory Committee of Medical Outcomes Trust (SAC). The Spanish translation for linguistic and cultural adaptation of the V-RQOL was used. The study involved 193 participants, including 90 vocally healthy individuals and 103 patients with voice disorders, to establish validity. To evaluate reliability, the protocol was applied to 40 participants with dysphonia, who answered it twice before the treatment. Then to determine response changes, the responses of 13 dysphonic participants to the V-RQOL for Spanish were analyzed after intervention and then compared to the initial ones. Clinicians contrasted subjects' V-RQOL results with a perceptual analysis of voice quality using the GRBAS scale. In order to determine sensitivity and specificity cut-off values, tools results were subjected to the receiver operating characteristic curve analysis. The sensitivity was obtained from the experimental group (dysphonic group) and the specificity from the control group (non-dysphonic group). Results: This version of the V-RQOL questionnaire may be used as part of the standard assessment process of people with voice complaints and as an outcome of treatment efficacy in clinical trials. Conclusion: A validation of the V-RQOL for Spanish in Chilean population was achieved.