Analysis of Speech Fundamental Frequencies for Different Tasks in Japanese.

PURPOSE: Speech fundamental frequency (SFF) assessment is essential for all dysphonia patients to effectively evaluate the therapeutic effects of voice therapy, especially in patients with disturbances in their voice pitch due to mutational dysphonia, Reinke's edema, or as side effects of hormone therapy. A standard method of SFF measurement remains unknown. Speech tasks such as sustained vowel phonation, counting, reading passage, and spontaneous speech have generally been used for SFF measurements. Ideally, spontaneous speech best reflects SFF; however, this task has not yet been clearly defined and is limited with regard to its adaptation to a clinical setting. A reliable task for SFF measurement in Japanese, which corresponds to a speech task that most closely reflects the value that would be observed with typical spontaneous speech, has not been investigated. This study aimed to identify a reliable speech task by measuring the SFF values elicited by different widely used speech tasks in Japanese, and assess its reliability and coefficient of determination (R2). METHODS: Sixty healthy volunteers (30 men and 30 women; aged 19-30 years; mean age 22.5 years) were enrolled. All experimental procedures were performed in Japanese. The SFF values for the speech tasks were determined through the voice samples recorded using a Pulse Code Modulation (PCM) recorder. Each task, except spontaneous speech, was repeated five times, and the average fundamental frequency in each task was determined as the SFF. To assess the reliability of the SFF values across daily variations within individual speakers, the SFF measurements were repeated on two different days, separated by at least 1 week. RESULTS: The SFF values of sustained /a/ phonation, sustained vowel-average, counting, reading passage, and spontaneous speech had excellent reliability, in terms of their reproduction based on intraclass correlation. Significantly high SFF values were observed, in decreasing order, for sustained vowels-average, counting, reading passage, and spontaneous speech in both males and females. The highest R2 for spontaneous speech was that of reading passage in both males (R2 = 0.771) and females (R2 = 0.806) (P < 0.01). CONCLUSION: When spontaneous speech was presented as a task most reflective of daily conversation, reading passage was determined to be the reliable task to assess the therapeutic effect of voice therapy in Japanese.

Assessment of Dysphonia Using the Japanese Version of the Voice Handicap Index and Determination of Cutoff Points for Screening.

INTRODUCTION: The Voice Handicap Index (VHI) is recognized as a useful subjective assessment method for dysphonia. The original VHI has been translated into numerous other languages, including Japanese (J-VHI). Although the reliability and validity of the J-VHI have already been established, the cutoff point has not been determined. The aims of this study were to investigate the relationship between the J-VHI and other voice laboratory measurements, and determine the cutoff point. METHOD: This study included 167 dysphonic patients and 55 healthy volunteers. All patients and volunteers completed the J-VHI at the initial visit, and the following outcomes were determined: VHI scores of patients with dysphonia and healthy volunteers, VHI scores according to disease, cutoff point, and correlations between VHI scores and other voice laboratory measurements. RESULTS: Both the total VHI (VHI-T) and individual domain (functional domain [VHI-F], emotional domain [VHI-E], physical domain [VHI-P]) scores were significantly higher in the dysphonia group compared to the healthy volunteer group. VHI-T, VHI-F, and VHI-E scores were significantly lower in the benign mucosal lesion subgroup, compared to the other disease subgroups. The G scale and B scale of the grade-roughness-breathiness-asthenia-strain scale showed a significant association with VHI-T, VHI-F, and VHI-P scores. Similarly, the A scale showed a significant association with VHI-T, VHI-F, and VHI-E scores. The cutoff point (12) for VHI-T was chosen from the receiver operating characteristic curve to maximize sensitivity and specificity. Similarly, the cutoff points for VHI-F (5), VHI-P (5), and VHI-E (3) were also obtained. Significant differences in maximum phonation time, pitch range, G scale, and B scale were observed between the VHI-T negative (VHI ≤ 12) and positive (VHI-T > 13) groups. CONCLUSION: These findings suggest that self-evaluation using the VHI could serve as an independent assessment and screening tool for patients with dysphonia.