Usefulness of S/Z Ratio and Maximum Phonation Time in Unilateral Vocal Fold Paralysis with Decreased Pulmonary Function

Park, Joon Pyo; Jeong, Go-Eun; Kang, Byung Chul; Kim, Seong-Tae; Nam, Soon Yuhl; Kim, Sang-Yoon; Roh, Jong-Lyel; Choi, Seung-Ho

J Korean Soc Laryngol Phoniatr Logop > Volume 23(2); 2012 > Article

Journal of The Korean Society of Laryngology, Phoniatrics and Logopedics 2012;23(2): 129-132.

최장발성폐기능저하를 동반한 일측성 성대마비 환자에서의 S/Z Ratio와 최장 발성시간(Maximum Phonation Time)의 유용성 비교

박준표, 정고은, 강병철, 김성태, 남순열, 김상윤, 노종렬, 최승호

울산대학교 의과대학 서울아산병원 이비인후과학교실

Usefulness of S/Z Ratio and Maximum Phonation Time in Unilateral Vocal Fold Paralysis with Decreased Pulmonary Function

Joon Pyo Park, Go-Eun Jeong, Byung Chul Kang, Seong-Tae Kim, Soon Yuhl Nam, Sang-Yoon Kim, Jong-Lyel Roh, Seung-Ho Choi

Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine

ABSTRACT

Background and Objectives
: MPT is directly related to degree of glottal closure. So it is widely used in the assessment of glottal closure with unilateral vocal fold paralysis. But MPT could be influenced not only by glottal closure but also by pulmonary function. So MPT might not reflect glottal closure in UVFP with decreased pulmonary function. The purpose of the study is to evaluate usefulness of MPT and ratio of /s/ time to /z/ time before and after injection laryngoplasty in UVCP with decreased pulmonary function.
Materials and Method
s : This study involved 34 patients with unilateral vocal fold paralysis : with decreased pulmonary function in group A (n=15) : with normal pulmonary function in group B (n=19). All patients underwent injection laryngoplasty. Paramters of perceptual analysis, acoustic analysis, aerodynamic analysis, videostroboscopy were compared between two groups.
Results
: Breathness and asthenic scale, G scale of perceptual analysis were significantly improved in both groups. Glottal gap index were significantly decreased after injection in both groups. In aerodynamic analysis, MPT was improved after injection laryngoplasty in both groups, but S/Z ratio was improved only in group B. In correlation analysis, /s/ time was not correlated with pulmonary function.
Conclusion
: S/Z ratio reflects neither the pulmonary function nor the glottal clousure properly. MPT is more useful indicator than S/Z ratio to evaluate vocal fold paralysis even with decreased pulmonary function.

KEY WORDS： S/Z ratio;MPT;Unilateral vocal fold paralysis;Injection laryngoplasty;

중심 단어： S/Z 비율;최장 발성 시간;일측성 성대마비;성대 주입술;