Assessment of Voice and Speech Attributes in Adult Patients with Myasthenia Gravis: A Case-Control Study.

INTRODUCTION

Myasthenia gravis (MG) is a chronic autoimmune disorder that affects neuromuscular junction, resulting in fluctuating muscle weakness. Speech and voice can be affected by MG due to the involvement of bulbar muscles and muscular weakness, resulting in dysarthria. This work aimed to assess speech and voice attributes in adult patients with MG in comparison to normal individuals to highlight the effect of MG on speech and voice and its impact on quality of life.

METHODS

This study involved 40 participants (over 18 years old), who were divided into two groups matched for age and sex. Group 1 included 25 patients with MG, and group 2 included 15 normal subjects as a control group. All patients were subjected to detailed medical history and general and neurological examinations. Speech and voice assessment was performed in the form of auditory perceptual assessment, Voice Handicap Index, and acoustic analysis via the Multi-Dimensional Voice Program (MDVP), Computerized Speech Lab (CSL), Real-Time Pitch, and Nasometer II (NMII). The patients' results were compared to those of normal subjects.

RESULTS

The present study revealed statistically significant differences between the two groups across multiple speech and voice parameters. The Voice Handicap Index revealed that 76% of patients experienced mild handicap, whereas 8% reported severe handicap. Regarding MDVP findings, group 1 presented significantly greater absolute jitter, jitter percent, shimmer (dB), shimmer percent, and noise-to-harmonic ratio values. Regarding CSL findings, group 1 had a greater voice-onset time than did the control group, with significant differences. The Real-Time Pitch results revealed significant differences in the energy and duration parameters. NMII was associated with higher nasalance scores for some sounds, with significant differences between the two groups.

CONCLUSIONS

MG can lead to many speech and voice issues with changes in acoustic parameters that can affect patients' quality of life.