Comparison of the Results of Voice Handicap Index and Computer-Assisted Voice Analysis in Patients with Benign Vocal Cord Lesions before and after Microlaryngeal Surgery

Wang, Jong Hwan; Park, Soo Kyung; Lee, Suk Kee; Choi, Seung Ho; Kim, Sang Yoon; Nam, Soon Yuhl

Abstract

BACKGROUND AND OBJECTIVES
The Voice Handicap Index (VHI) subjectively evaluates the severity of voice disorders. On the other hand, computer-assisted voice analysis objectively evaluates the severity of voice disorders. The purpose of this study was to compare the results of these two different tests in patients with benign vocal cord lesions and to measure the correlation between parameters of these two tests. MATERIALS AND METHODS: From January 2002 to December 2003, 76 patients who underwent microlaryngeal surgery for benign vocal cord lesions in the Asan Medical Center were included in this study. They all filled out the VHI questionnaires, which were composed of 30 questions about before and after surgery. For 32 out of 76 patients, we also performed preoperative and postoperative acoustic analysis (jitter, shimmer, noise to harmonic ratio) and aerodynamic analysis (maximum phonation time, mean flow rate, mean subglottic pressure). All VHI and voice analysis parameters were entered into a statistical program and analyzed using a Pearson correlation. RESULTS: All the parameters of VHI showed significant improvement after surgery. The values of jitter, shimmer, noise to harmonic ratio, and maximal phonation time showed a significant change after surgery, but the mean flow rate and the mean subglottic pressure didn't. Each VHI parameter provided a significant level of reliability (p<0.01) when compared with other VHI parameters before and after the surgery. Three voice analysis parameters (jitter, shimmer, noise to harmonic ratio) also showed significant reliability (p<0.01) in comparison with other parameters except maximum phonation time, mean flow rate and mean subglottic pressure before and after the surgery. Reliability of VHI and voice analysis showed to be strong (p<0.01) for the maximum phonation time and the mean flow rate before surgery but poor (p>0.05) after surgery. CONCLUSION: The VHI provides a measure of self-perception on the severity of the voice disorders that cannot be assessed through objective acoustic and aerodynamic measures. No objective parameters show strong correlation with VHI parameters when compared across other testing methods after surgery. This discrepancy indicates that no objective parameters can yet be regarded as a prognostic factor to evaluate subjective perception.