Voice Quality in Multiple Sclerosis: Insights from Acoustic and Cepstral Analyses

Voice Quality in Multiple Sclerosis: Insights from Acoustic and Cepstral Analyses Gamze Yesilli Puzella, Ayşe Şehidhamza Cappadocia University, Speech and Language Therapy Department Background: Multiple sclerosis (MS), a chronic demyelinating disease that can affect voice quality, can affect the neuromuscular regulation of breathing, phonation, and articulation. Knowing how MS impacts the acoustic and cepstral aspects of the voice may help with the early detection of vocal dysfunction. Objective: This study compared acoustic and cepstral parameters between MS patients and normophonic controls to assess the impact of MS on voice quality and determine whether these effects varied by gender. Methods: A total of 126 participants were included: 63 patients with MS (mean age 36.19±10.79 years) and 63 age- and sex-matched healthy controls, all nonsmokers. Sustained /a/ phonation and the standardized reading text were recorded in a sound-treated room using a Samson Go Mic (10 cm distance). F0, Jitter, Shimmer, NHR, HNR, AVQIv2 and cepstral parameters (CPPS, Cepstral Median) were analyzed using Praat (version 6.2.01). SPSS 22.0 was used to perform statistical analyses using parametric and nonparametric tests (p<0.05). Results: MS patients had significantly higher Jitter (0.50±0.32 vs. 0.30±0.18; p<0.001), shimmer (4.56±1.94 vs. 2.57±0.49; p<0.001), and AVQIv2 scores (4.12±1.00 vs. 2.82±0.34; p<0.001) than controls. HNR was lower in MS (18.95±4.11) compared to controls (20.55±4.26; p<0.05). Cepstral analysis revealed significantly reduced CPPS during both sustained phonation (14.12±2.14 vs. 16.05±1.84; p<0.001) and continuous speech (8.59±1.07 vs. 9.04±1.17; p<0.05). The cepstral median was also lower in the MS group (13.60±2.42 vs. 14.70±2.37; p<0.05). According to a gender-based analysis, female MS patients had significantly lower CPPS and higher AVQIv2, whereas male MS patients had higher F0 and AVQIv2 but lower CPPS and HNR than male controls. Conclusion: MS indicates a decline in vocal fold stability and harmonic organization, which deteriorates voice quality by increasing perturbation measures and decreasing cepstral energy. Acoustic and cepstral analyses are helpful methods for detecting early vocal changes in multiple sclerosis. Keywords: Multiple Sclerosis, Neurogenic Voice Disorders, Acoustic Analysis, Cepstral Analysis, Voice Quality