Development and Validation of an Iranian Voice Quality of Life Profile (IVQLP) Based on a Classic and Rasch Rating Scale Model (RSM).

OBJECTIVES: No culture based instrument exists for the people of Iran to measure outcomes of voice disorders. The objective of this study was to develop a statistically and culturally robust tool for assessing voice disorder outcomes in the Iranian population. METHODS: A 65-item assessment tool called the Iranian Voice Quality of Life Profile (IVQLP) was developed after three stages of study. IVQLP measures voice disorder outcomes in four domains: physical, emotional, functional, and cultural. The questionnaire was given to 130 individuals with various voice disorders and 30 control subjects with no vocal pathology. The data obtained were subjected to measures of reliability (internal consistency and test-retest) and validity (content, construct, and concurrent) in the classic sense, as well as examined based on Rasch rating scale model analysis. RESULTS: Results showed that IVQLP had high internal consistency (α = 0.99) and test-retest reliability (r = 0/90). IVQLP differentiated the dysphonic group from the control group. Findings using the classic models suggested adequate construct validity for 43 items of the IVQLP fit the Rasch model. The high Rasch item separation reliability, separation index, and strata statistics for 43 items indicated that IVQLP provided further evidence that the items are reliable and comprehensive representations of quality of life concepts in Iranian people with voice disorders. CONCLUSIONS: This study concludes that IVQLP is a sufficiently reliable and valid tool to measure Iranian patients' perception of their quality of life in respect to their voice problem.

Correlation of VHI-30 to Acoustic Measurements Across Three Common Voice Disorders.

OBJECTIVES: Voice disorders that affect the quality of voice also result in varying degrees of psychological and social problems. The research question here is whether the correlations between Voice Handicap Index (VHI)-30 scores and objective acoustic measures differ in patients with different types of voice disorders. METHODS: The subjects were divided into three groups: muscle tension dysphonia (MTD), benign mid-membranous vocal fold lesions, and unilateral vocal fold paralysis (UVFP). All participants were male. The mean age for the groups were 32.85 ± 8.6 years in the MTD group, 33.24 ± 7.32 years in the benign lesions group, and 34.24 ± 7.51 years in the UVFP group. The participants completed the Persian VHI-30 questionnaire. PRAAT software was used to obtain acoustic analyses. RESULTS: There was a significant correlation between the physical subscale of the VHI-30 and the total score of the VHI-30 and maximum phonation time (MPT) in the MTD group. Also, there was a significant correlation between the total VHI-30 score and the MPT value. There were relatively strong and significant correlations between the physical subscale of the VHI-30 with jitter and shimmer, harmonics-to-noise ratio (HNR) for the group with benign lesions such as nodules and polyps. Also, in this group, there was a significant correlation between the total VHI-30 score and the jitter value. The physical scale had strong and significant correlations between jitter, shimmer, and HNR in the unilateral paralysis group. CONCLUSIONS: Findings suggest that although the VHI-30 and the acoustic measurements of voice provide independent information, they are associated to some extent.