Dysarthria

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

Impaired corticolingual pathways in patients with or without dysarthria after acute monohemispheric stroke.

Abstract: The occurrence of dysarthria is not infrequent in stroke but little is known about its pathophysiology. The aims of the present study were to assess the central motor innervation of the tongue in normal adults using transcranial magnetic stimulation (TMS) and to compare this with that seen in stroke patients with or without dysarthria. The study included 46 patients with acute monohemispheric stroke due to occlusion of the territory of the middle cerebral artery as documented by CT brain scan (26 patients with dysarthria and 20 patients without dysarthria). Forty-five (age and sex matched) normal volunteers served as controls. Corticolingual pathways were assessed for each subject after TMS of each hemisphere. TMS over the motor cortex of healthy subjects elicited consistent ipsilateral and contralateral lingual responses. The ipsilateral response was usually smaller and approximately 73% of the amplitude of the contralateral response. The cross talk between the two halves of the tongue as estimated after unilateral electrical stimulation of hypoglossal nerve gave a contra/ipsi ratio of 36%, which was significantly smaller than the ratio seen after cortical stimulation (CL). For the patients, with or without dysarthria, motor evoked potential (MEP) latencies (ipsilateral and contralateral) were significantly prolonged after stimulation of affected hemisphere compared with the non-affected hemisphere or the control group (P< 0.001). MEP amplitudes were significantly smaller in hemiplegic patients with dysarthria compared to patients without dysarthria. In patients without dysarthria stimulation of the unaffected hemisphere tended to evoke responses that were of similar size on both sides. There were no significant associations between neurophysiological parameters and side of infarction. We conclude that interruption of the corticolingual pathways is frequent in stroke patients with or without dysarthria. The ability of unaffected hemisphere to evoke responses in the side contralateral to the lesion may relate to the absence or presence of dysarthria.

Dysarthria: Definition, clinical contexts, neurobiological profiles and clinical treatments

Abstract: Starting from the general concept of Dysarthria, the present work focuses on the clinical, neurobiological, and functional aspects of the morbid condition, suggesting a multidimensional treatment between physiotherapy, psychotherapy, and rehabilitation exercises for lost skills.

Robust Estimation of Hypernasality in Dysarthria with Acoustic Model Likelihood Features

Abstract: Hypernasality is a common characteristic symptom across many motor-speech disorders. For voiced sounds, hypernasality introduces an additional resonance in the lower frequencies and, for unvoiced sounds, there is reduced articulatory precision due to air escaping through the nasal cavity. However, the acoustic manifestation of these symptoms is highly variable, making hypernasality estimation very challenging, both for human specialists and automated systems. Previous work in this area relies on either engineered features based on statistical signal processing or machine learning models trained on clinical ratings. Engineered features often fail to capture the complex acoustic patterns associated with hypernasality, whereas metrics based on machine learning are prone to overfitting to the small disease-specific speech datasets on which they are trained. Here we propose a new set of acoustic features that capture these complementary dimensions. The features are based on two acoustic models trained on a large corpus of healthy speech. The first acoustic model aims to measure nasal resonance from voiced sounds, whereas the second acoustic model aims to measure articulatory imprecision from unvoiced sounds. To demonstrate that the features derived from these acoustic models are specific to hypernasal speech, we evaluate them across different dysarthria corpora. Our results show that the features generalize even when training on hypernasal speech from one disease and evaluating on hypernasal speech from another disease (e.g. training on Parkinson's disease, evaluation on Huntington's disease), and when training on neurologically disordered speech but evaluating on cleft palate speech.

Towards a noisy-channel model of dysarthria in speech recognition

Abstract: Modern automatic speech recognition is ineffective at understanding relatively unintelligible speech caused by neuro-motor disabilities collectively called dysarthria. Since dysarthria is primarily an articulatory phenomenon, we are collecting a database of vocal tract measurements during speech of individuals with cerebral palsy. In this paper, we demonstrate that articulatory knowledge can remove ambiguities in the acoustics of dysarthric speakers by reducing entropy relatively by 18.3%, on average. Furthermore, we demonstrate that dysarthric speech is more precisely portrayed as a noisy-channel distortion of an abstract representation of articulatory goals, rather than as a distortion of non-dysarthric speech. We discuss what implications these results have for our ongoing development of speech systems for dysarthric speakers.