Speech motor deficits in developmental stuttering and Parkinson's Disease: from cellular and circuit to network-level disruptions

Turk, A. Z., Millwater, M., Sheikh-Bahaei, S., Mollaei, F. ORCID: https://orcid.org/0000-0003-2916-9750, Riessland, M. and SheikhBahaei, S. (2026) Speech motor deficits in developmental stuttering and Parkinson's Disease: from cellular and circuit to network-level disruptions. European Journal of Neuroscience, 63 (3). e70393. ISSN 0953-816X doi: 10.1111/ejn.70393

Abstract/Summary

Speech dysfluency occurs across multiple motor disorders to varying degrees, yet the underlying mechanisms remain incom-pletely understood. Like locomotion, speech production is relies on basal ganglia circuits, and disruptions in these pathwayscan lead to varied symptomatic presentations. In this perspective, we discuss evidence from cellular, circuit and network-levelstudies to highlight shared and disorder-specific mechanisms of speech dysfluency in Parkinson's disease and developmentalstuttering. Basal ganglia function and dopaminergic modulation are central to both disorders, while cortical and brainstemmicrocircuits remain crucial; emerging evidence also implicates astrocytes and inflammatory processes in these conditions. Byintegrating these multiscale insights, we aim to provide a conceptual framework that explains the mechanistic basis of speechdysfluency in Parkinson's disease and developmental stuttering and identifies avenues for future research and possible therapeu-tic interventions.