Search Abstracts | Symposia | Slide Sessions | Poster Sessions | Lightning Talks

Basal ganglia-thalamocortical loop involvement in the speech deficits of Parkinson’s Disease

There is a Poster PDF for this presentation, but you must be a current member or registered to attend SNL 2023 to view it. Please go to your Account Home page to register.

Poster B57 in Poster Session B, Tuesday, October 24, 3:30 - 5:15 pm CEST, Espace Vieux-Port
This poster is part of the Sandbox Series.

Fatemeh Mollaei1,2, Mohammed Asif Basha Chinoor1,2; 1University of Reading, 2Centre for Integrative Neuroscience and Neurodynamics

Introduction Parkinson’s disease (PD) is a neurodegenerative disorder often associated with laryngeal and articulatory related motor speech deficits. Previous studies investigating the neural correlates for laryngeal and articulatory functioning have found ventral pre-central gyrus, ventromedial putamen, and ventrolateral thalamus to be involved in speech production. These areas have cortical-cortical and cortical-subcortical white-matter connections forming the basal ganglia-thalamo-cortical loop (BGTC-loop), which is involved in the control and coordination of feedforward motor signals for speech production (Alexander et al., 1986; Chang & Guenther, 2020; Kearney & Guenther, 2019). Recent studies have shown increased resting-state functional connectivity between dorsal laryngeal motor area and globus pallidus in PD with speech deficits (Manes et al., 2018). However, there is relatively little understanding about the structural properties of the white-matter tracts connecting these regions in the BGTC-loop in PD. Hence, our study aimed to investigate the properties of white-matter tracts concerning these speech related (laryngeal and articulatory) areas in the BGTC-loop. Material and Methods We used pre-collected diffusion-weighted and T1-weighted MRI data of 20 PD with speech deficits, 20 PD without speech deficits, and 20 healthy controls from the Parkinson’s Progressive Markers Initiative database. Participants were assigned to PD with and without speech deficits based on the Movement Disorders Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS; Goetz, 2009), Part III speech item scores (scale of 0-4; 0= no speech problems, 4=most speech is difficult to understand or unintelligible) with the score of 2 and above in the speech deficits group. We performed probabilistic tractography between articulatory and laryngeal motor related areas and inner subcortical structures such as ventrolateral thalamus and ventromedial putamen to reconstruct white-matter tracts connecting these areas in the BGTC-loop. White matter metrics of Fractional Anisotropy (FA), Mean Diffusivity (MD), Axial Diffusivity (AD), and Radial Diffusivity (RD) were extracted from each of the laryngeal and articulatory motor tracts and compared using repeated-measures ANOVA with post-hoc analysis. Results Our main findings were observed in MD and AD metrics – i) MD value for left-laryngeal pathway was significantly increased in PD individuals with speech deficits compared to PD individuals without speech deficits, and ii) AD value for left-articulatory pathway was significantly decreased in PD individuals with speech deficits compared to PD individuals without speech deficits. However, there were no significant differences for FA and RD metrics. Conclusion Increased MD and decreased AD values in PD with speech deficits can be an indicative of progressive degeneration and axonal injury of neurons forming the laryngeal and articulatory related white-matter tracts in the BGTC-loop (Basser & Jones, 2002; Pierpaoli et al., 1996; Zhang & Burock, 2020). These aberrant properties of white-matter tracts might be a contributing factor causing imbalance in the excitation and inhibition mechanisms in the BGTC-loop, resulting in reduction of feedforward flow of motor signals from the laryngeal and articulatory related motor areas to the basal-ganglia structures. Hence, these findings support the notion that there might be deficits in the laryngeal and articulatory white-matter tract properties contributing to the speech deficit seen in PD.

Topic Areas: Disorders: Acquired, Speech Motor Control

SNL Account Login

Forgot Password?
Create an Account