Voice Alterations in Multiple Sclerosis: A Systematic Review and Meta-analysis of Acoustic Parameters

This study aimed to compare acoustic voice parameters between individuals with multiple sclerosis (MS) and healthy controls through a systematic review and meta-analysis.

Systematic review and meta-analysis.

A comprehensive search of PubMed, Scopus, Web of Science, and Cochrane CENTRAL was conducted in July 2025. Studies assessing objective acoustic voice measures in MS were included. Risk of bias was evaluated using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Random-effects meta-analyses were performed for seven acoustic parameters.

Eleven cross-sectional studies involving 636 MS patients and 430 healthy controls met the eligibility criteria. Compared with controls, MS patients showed significantly lower fundamental frequency (F0) [MD (mean differences) = -9.48, 95% CI (confidence interval) (-17.89, -1.06)] and reduced maximum phonation time (MD = -4.71, 95% CI [-5.97, -3.44]). They also exhibited greater variability in F0 [standard deviation: MD = 0.82, 95% CI (0.44, 1.20)], higher jitter (MD = 0.17, 95% CI [0.12, 0.21]) and shimmer [MD = 0.93, 95% CI (0.59, 1.2)], elevated harmonics-to-noise ratio [MD = 0.04, 95% CI (0.02, 0.05)], and higher formant centralization ratio [MD = 0.09, 95% CI (0.03, 0.15)]. Heterogeneity was high across most analyses (I² > 80%).

MS is associated with measurable alterations in multiple acoustic domains, particularly reflecting vocal instability and reduced phonatory capacity. These parameters may serve as noninvasive and accessible markers for the early detection and monitoring of neuromotor dysfunction in MS. Standardized assessment protocols and integration with clinical voice evaluations are necessary to enhance the diagnostic value of these markers.