Characteristics of motor speech phenotypes in multiple sclerosis

Area of Science:

• Neurology
• Speech-Language Pathology
• Biomarkers

Background:

• Motor speech disorders in multiple sclerosis (MS) are not well understood.
• Quantitative acoustic characterization of MS speech disorders is limited.
• Data on the relationship between MS speech disorders, neurological involvement, and specific functional systems (pyramidal, cerebellar) is scarce.

Purpose of the Study:

• To objectively characterize motor speech disorders in MS using acoustic analysis.
• To investigate the relationship between speech disorder severity and neurological impairment in MS.
• To determine the contribution of pyramidal and cerebellar systems to MS speech phenotypes.

Main Methods:

• Acoustic speech data collected from 141 MS patients (EDSS 1-6.5) and 70 healthy controls.
• Objective acoustic assessment included subtests for phonation, oral diadochokinesis, articulation, and prosody.
• Correlation and discrimination analyses were performed to link speech features with neurological status.

Main Results:

• 56% of MS patients had dysarthria, generally mild with spastic-ataxic components.
• Prosodic-articulatory disorder (monopitch, decay, loudness variations, slow rate) was most prominent.
• Speech analysis accurately (78%) distinguished asymptomatic MS patients from controls, indicating subclinical motor impairment.
• Speech disorder severity correlated with neurological involvement (EDSS, MS Functional Composite).
• Irregular oral diadochokinesis strongly correlated with the 9-Hole Peg Test (r = -0.65).
• Specific speech features differentiated pyramidal and mixed pyramidal-cerebellar MS subgroups.

Conclusions:

• Automated speech analysis offers valuable biomarkers for MS progression.
• Dysarthria is a common and early sign in MS, reflecting disease disability.
• Speech analysis can reveal underlying pyramidal-cerebellar pathophysiology in MS.