Dysarthria

About: Dysarthria is a research topic. Over the lifetime, 2402 publications have been published within this topic receiving 56554 citations.

Anatomy and lateralization of the human corticobulbar tracts: an fMRI-guided tractography study

Abstract: The left hemisphere lateralization bias for language functions, such as syntactic processing and semantic retrieval, is well known. Although several theories and clinical data indicate a link between speech motor execution and language, the functional and structural brain lateralization for these functions has never been examined concomitantly in the same individuals. Here, we used functional MRI during rapid silent syllable repetition (/lalala/, /papapa/ and /pataka/, known as oral diadochokinesis or DDK) to map the cortical representation of the articulators in 17 healthy adults. In these same participants, functional lateralization for language production was assessed using the well-established verb generation task. We then used DDK-related fMRI activation clusters to guide tractography of the corticobulbar tract from diffusion-weighted MRI. Functional MRI revealed a wide inter-individual variability of hemispheric asymmetry patterns (left and right dominant, as well as bilateral) for DDK in the motor cortex, despite predominantly left hemisphere dominance for language-related activity in Broca's area. Tractography revealed no evidence for structural asymmetry (based on fractional anisotropy) within the corticobulbar tract. To our knowledge, this study is the first to reveal that motor brain activation for syllable repetition is unrelated to functional asymmetry for language production in adult humans. In addition, we found no evidence that the human corticobulbar tract is an asymmetric white matter pathway. We suggest that the predominance of dysarthria following left hemisphere infarct is probably a consequence of disrupted feedback or input from left hemisphere language and speech planning regions, rather than structural asymmetry of the corticobulbar tract itself.

Automatic Discrimination of Apraxia of Speech and Dysarthria Using a Minimalistic Set of Handcrafted Features.

Abstract: To assist clinicians in the differential diagnosis and treatment of motor speech disorders, it is imperative to establish objective tools which can reliably characterize different subtypes of disorders such as apraxia of speech (AoS) and dysarthria. Objective tools in the context of speech disorders typically rely on thousands of acoustic features, which raises the risk of difficulties in the interpretation of the underlying mechanisms, overadaptation to training data, and weak generalization capabilities to test data. Seeking to use a small number of acoustic features and motivated by the clinical-perceptual signs used for the differential diagnosis of AoS and dysarthria, we propose to characterize differences between AoS and dysarthria using only six handcrafted acoustic features, with three features reflecting segmental distortions, two features reflecting loudness and hypernasality, and one feature reflecting syllabification. These three different sets of features are used to separately train three classifiers. At test time, the decisions of the three classifiers are combined through a simple majority voting scheme. Preliminary results show that the proposed approach achieves a discrimination accuracy of 90%, outperforming using state-of-the-art features such as openSMILE which yield a discrimination accuracy of 65%.

The Impact of Stimulated Vocal Loudness on Nasalance in Dysarthria

Abstract: This study was designed to determine the effect of stimulated vocal loudness on nasalance in individuals with various dysarthria subtypes. Thirty participants produced three stimulated levels of vocal loudness while reading a nonnasal passage. Data included dysarthria classification, vocal sound pressure level, nasalance, and listener perception of nasality. There was not a predictable relationship between a change in vocal sound pressure level (SPL) and a change in nasalance, nor did these changes result in consistent perceptual results. There were, however, dysarthria-specific effects of stimulated vocal loudness on nasality. Further, the study highlighted the importance of corroborating objective data with perceptual findings.

The effect of rate reduction on signaling prosodic contrasts in dysarthria.

Abstract: Background/Aims: To understand how reducing speaking rate alters prosodic contrasts in speakers with dysarthria (DYS) and healthy controls (HC).

Use of Listening Strategies for the Speech of Individuals with Dysarthria and Cerebral Palsy

Abstract: This study examined listeners' endorsement of cognitive, linguistic, segmental, and suprasegmental strategies employed when listening to speakers with dysarthria. The study also examined whether strategy endorsement differed between listeners who earned the highest and lowest intelligibility scores. Speakers were eight individuals with dysarthria and cerebral palsy. Listeners were 80 individuals who transcribed speech stimuli and rated their use of each of 24 listening strategies on a 4-point scale. Results showed that cognitive and linguistic strategies were most highly endorsed. Use of listening strategies did not differ between listeners with the highest and lowest intelligibility scores. Results suggest that there may be a core of strategies common to listeners of speakers with dysarthria that may be supplemented by additional strategies, based on characteristics of the speaker and speech signal.