Characteristics of Voice in Individuals with Multiple Sclerosis

Background: Individuals who suffer from multiple sclerosis, aside from other symptoms, usually have voice changes such as poor control of pitch, variations in voice intensity, altered voice quality and resonance disorders. Purpose: The purpose of this study was to determine voice acoustic characteristics in individuals with multiple sclerosis and to compare those results with control group. Methods: This study was conducted on 17 subjects, both males and females, of chronological age between 27 and 55 years. All subjects were diagnosed with multiple sclerosis by professional neurologist. Control group consisted of 17 subjects who matched with experimental group of the same age and sex. The study was conducted at the Clinic for Neurology, University Clinical Centre Tuzla. Sustained phonation of vowel /A/ was analyzed by computer programme for voice analysis MDVP (Multi Dimensional Voice Program). Results: Results of our study exhibited statistically significant differences between subjects with multiple sclerosis and control subjects in variables standard deviation of fundamental frequency and phonatory F0 range. We also found statistically significant differences between variable related to pitch perturbation (jitter) and peak-to-peak amplitude variation. Statistically significant differences were also determined between subjects with multiple sclerosis and control subjects in variables related to degree of irregular vocalization, noise to harmonic ratio and variable related to amplitude tremor intensity index. Conclusion: Results of this study showed that subjects with multiple sclerosis exhibited significant variation in voice acoustic characteristics compared to control group. MDVP can be a useful tool for further monitoring of voice characteristics alterations in patients with multiple sclerosis during diagnostic and treatment processes.