Dysphonia and its Correlation with Acoustic Voice Parameters

Abstract

Aim: To evaluate the laryngeal causes of dysphonia, correlation of acoustic voice analysis with Indirect laryngoscopic/ endoscopic findings in various voice disorders. Study design: Hospital based prospective observational study. Materials and methods: Forty patients attending the ear nose throat (ENT) outpatient department (OPD) at a Tertiary Care Government Hospital in one year, with dysphonia for more than 15 days were selected. History, examination, endoscopy, voice analysis was done. For consensus auditory-perceptual evaluation of voice (CAPE-V), the voice was analyzed under the following parameters: roughness, breathiness, strain, pitch, loudness, overall severity. Scores were given out of 100. For acoustic analysis, a computer-based software Praat was used based on jitter, shimmer, noise-harmonic ratio and mean pitch. Result: Benign lesions were most common in adults of age group 21 to 40 years, and malignancy in 41 to 50 years and 61 to 70 years; with male preponderance (4.7:1). Isolated vocal cord palsy (32.5%) was the most common lesion presenting with dysphonia, followed by malignancy (25%). Out of benign lesions, vocal polyp (10%) and nodule (10%) were the commonest, with equal incidence. On analyzing the voice, jitter and shimmer were found to be important parameters depicting the perturbation in frequency and amplitude, respectively. These parameters, indirectly, gave an idea about the vibratory motion of the vocal cords. On statistical analysis, jitter and shimmer showed significant direct correlation with the severity of dysphonia (jitter>shimmer). Noise to harmonic ratio (NHR) was raised in a significant number of dysphonic patients, with direct correlation with an increase in jitter. Although a significant relationship between the variation in mean pitch and CAPE V could not be established in this study; instrumental analysis was still useful in documentation and quantification of mean pitch in various dysphonic samples. Conclusion: Acoustic measurement of voice is a simple yet powerful tool to analyze the patients with dysphonic voice.