Contents lists available at ScienceDirect Brain and Language journal homepage: www.elsevier.com/locate/b&l Short communication Brain volumetric correlates of dysarthria in multiple sclerosis Jan Rusz a,b, ⁎ , Manuela Vaneckova c , Barbora Benova b , Tereza Tykalova a , Michal Novotny a , Hana Ruzickova b , Tomas Uher b , Michaela Andelova b , Klara Novotna b , Lucie Friedova b , Jiri Motyl b , Karolina Kucerova b , Jan Krasensky c , Dana Horakova b a Department of Circuit Theory, Faculty of Electrical Engineering, Czech Technical University in Prague, Czech Republic b Department of Neurology and Center of Clinical Neuroscience, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic c Department of Radiology, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic ARTICLE INFO Keywords: Multiple sclerosis Brain atrophy MRI Morphometry Dysarthria Speech Acoustic analyses ABSTRACT Although dysarthria is a common pattern in multiple sclerosis (MS), the contribution of specific brain areas to key factors of dysarthria remains unknown. Speech data were acquired from 123 MS patients with Expanded Disability Status Scale (EDSS) ranging from 1 to 6.5 and 60 matched healthy controls. Results of computerized acoustic analyses of subtests on spastic and ataxic aspects of dysarthria were correlated with MRI-based brain volume measurements. Slow articulation rate during reading was associated with bilateral white and grey matter loss whereas reduced maximum speed during oral diadochokinesis was related to greater cerebellar involve- ment. Articulation rate showed similar correlation to whole brain atrophy (r = 0.46, p < 0.001) as the standard clinical scales such as EDSS (r = -0.45, p < 0.001). Our results support the critical role of the pyramidal tract and cerebellum in the modification of motor speech timing in MS. 1. Introduction Speech is a fine motor skill that requires precise muscle coordina- tion and its various contributing factors are believed to be regulated at a neural level (Kent, Kent, Weismer, & Duffy, 2000). Spastic, ataxic or mixed spastic-ataxic dysarthria is a common clinical pattern in multiple sclerosis (MS) (Hartelius, Runmarker, & Andersen, 2000; Merson & Rolnick, 1998). These speech abnormalities have traditionally been attributed to either spastic weakness or ataxia of the articulatory muscles (Darley, Brown, & Goldstein, 1972). Darley, Aronson, and Brown (1969a) first observed that spastic dysarthria requires damage to the bilateral corticobulbar pathways while ataxic dysarthria is typically associated with lesions in the cere- bellum. Several subsequent neuroimaging studies have explored neural correlates of dysarthria and verified or extended the observations by Darley et al. (1969a). The critical role of the cerebellum has been widely established and linked to speech motor control and aspects of ataxic dysarthria (Spencer & Slocomb, 2007). To the best of our knowledge, only a few studies have explored neural correlates of spastic dysarthria. Previous research using voxel-based morphometry has re- vealed widespread grey matter reduction in subjects with predominant spastic dysarthria after childhood brain injury (Morgan, 2013). In ad- dition, further study has shown striking bilateral white matter volume loss in subjects with progressive spastic dysarthria (Clark et al., 2014). However, the contribution of specific brain areas to spastic and ataxic aspects of dysarthria in MS remains unknown. Darley et al. (1972) perceptually identified impaired loudness control, harshness, defective articulation, and impaired emphasis and pitch control as the most common signs of dysarthria in MS, which were manifested by more than one-third of 168 subjects investigated. A re- cent study sought to verify these perceptual findings using objective acoustic analyses and showed prosodic-articulatory speech disorder in MS presenting mainly with monopitch, articulatory decay, excess loudness variations and slow rate (Rusz et al., 2018). Importantly, five investigated spastic and ataxic elements of MS dysarthria including ir- regular pitch variability, slow oral diadochokinesis, irregular oral dia- dochokinesis, slow articulation rate and excess loudness variations were found to be related to the degree of neurological involvement (Rusz et al., 2018). As the severity of neurological involvement reflects structural brain damage in MS (Fisher et al., 2000; Uher et al., 2014), we hypothesized though, that these five dysarthric patterns might also reflect the extent of global brain atrophy and potentially serve as speech https://doi.org/10.1016/j.bandl.2019.04.009 Received 22 May 2018; Received in revised form 23 April 2019; Accepted 30 April 2019 ⁎ Corresponding author at: Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Circuit Theory, Technicka 2, 160 00 Prague 6, Czech Republic. Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine, Charles University, Kateřinská 30, 120 00, Prague 2, Czech Republic. E-mail address: rusz.mz@gmail.com (J. Rusz). Brain and Language 194 (2019) 58–64 0093-934X/ © 2019 Elsevier Inc. All rights reserved. T