Acoustic characteristics of patients with vocal fold polyp and paralysis

Unilateral Vocal Fold Paralysis (UVFP) and vocal fold Polyps lead to some vocal fold asymmetry and consequently, changing the acoustic characteristics. In this study, we aimed reporting these acoustic changes due to the mentioned disorders. Method & Materials: This study was a cross sectional, descriptive and analytical. Subjects were 5 patients with UVFP, 5 with polyps and 5 normal persons who were selected in an easy access mode. Normal subjects in the control group were selected among available people with considerations of their gender and age. For each subject, samples of sustaining vowel of /a/ and /i/ were obtained and then analyzed by the Praat software. The results were analysed statistically by SPSS version 17 via using Mann-Whitney and Kruskal-Wallis tests. In vowel /a/: Harmony to Noise Ratio (HNR) in UVFP (p=0.006) and in polyp subjects (p=0.047) was significantly different with normal group. Noise to Harmony Ratio (NHR) and jitter in UVFP had significant differences (p = 0.006) with normal group. In vowel /i/: Jitter in UVFP (P= 0.006) and in Polyp (P= 0.047) was significantly different with normal data. Also, the jitter was the only variable which had significant differences between two groups of patients (p=0.04). HNR, NHR, Jitter in vowel /a/ and jitter in vowel /i/ seem possibly more reliable for initial assessment and improvement monitoring of the patients.