Comparison of Dysphonia Severity Index and its Parameters Among Individuals with Multiple Sclerosis and Healthy Subjects

Abstract

Background: Concerning demyelination’s process in multiple sclerosis (MS), speech changes often occur earlier than other symptoms; thus early diagnosis of these changes is necessary. According to recent studies, phonation subsystem appears with the most symptoms compared with other subsystems, especially in the initial stages. In this study, the researchers aimed at comparing these symptoms in MS patients with healthy people using dysphonia severity index (DSI) and its parameters. Methods: This study was conducted on 40 MS patients and 20 healthy individuals in Ahvaz city. The subjects were asked to phonate vowel /a/ for calculating maximum phonation time (MPT), maximum F0, jitter, minimum intensity, and DSI score with the Praat software. For statistical analysis of data, Kolmogorov-Smirnov and independent t-test were used. Results: The mean scores of DSI in MS patients (1.07 ± 1.51) was significantly lower than the control group (3.603 ± 1.13) (P value < 0.001). Maximum phonation time and maximum frequency values in MS patients were lower than the control group (MPT, P value = 0.005; maxF0, P value = 0.003). Jitter and minimum intensity values in MS patients were higher than the control group (jitterppq5, P value < 0.001; min intensity, P value = 0.040). Conclusions: The findings of this study indicated that the MS group had worse vocal quality than the healthy group, which means they were at risk of voice and speech problems; therefore, acoustic assessments can determine the vocal impairments of the disease at the early stages and prevent progression of vocal impairments with an appropriate treatment plan. Also, dysphonia severity index, as a reliable tool, can detect vocal quality impairments in multiple sclerosis and can be a supplementary assessment tool for early detection of degenerative diseases.