Articulatory and bottleneck features for speaker-independent ASR of dysarthric speech

The rapid population aging has stimulated the development of assistive devices that provide personalized medical support to the needies suffering from various etiologies. One prominent clinical application is a computer-assisted speech training system which enables personalized speech therapy to patients impaired by communicative disorders in the patient's home environment. Such a system relies on the robust automatic speech recognition (ASR) technology to be able to provide accurate articulation feedback. With the long-term aim of developing off-the-shelf ASR systems that can be incorporated in clinical context without prior speaker information, we compare the ASR performance of speaker-independent bottleneck and articulatory features on dysarthric speech used in conjunction with dedicated neural network-based acoustic models that have been shown to be robust against spectrotemporal deviations. We report ASR performance of these systems on two dysarthric speech datasets of different characteristics to quantify the achieved performance gains. Despite the remaining performance gap between the dysarthric and normal speech, significant improvements have been reported on both datasets using speaker-independent ASR architectures.Comment: to appear in Computer Speech & Language - https://doi.org/10.1016/j.csl.2019.05.002 - arXiv admin note: substantial text overlap with arXiv:1807.1094

Improved status following behavioural intervention in a case of severe dysarthria with stroke aetiology

There is little published intervention outcome literature concerning dysarthria acquired from stroke. Single case studies have the potential to provide more detailed specification and interpretation than is generally possible with larger participant numbers and are thus informative for clinicians who may deal with similar cases. Such research also contributes to the future planning of larger scale investigations. Behavioural intervention is described which was carried out with a man with severe dysarthria following stroke, beginning at seven and ending at nine months after stroke. Pre-intervention stability between five and seven months contrasted with significant improvements post-intervention on listener-rated measures of word and reading intelligibility and communication effectiveness in conversation. A range of speech analyses were undertaken (comprising of rate, pause and intonation characteristics in connected speech and phonetic transcription of single word production), with the aim of identifying components of speech which might explain the listeners’ perceptions of improvement. Pre- and post intervention changes could be detected mainly in parameters related to utterance segmentation and intonation. The basis of improvement in dysarthria following intervention is complex, both in terms of the active therapeutic dimensions and also the specific speech alterations which account for changes to intelligibility and effectiveness. Single case results are not necessarily generalisable to other cases and outcomes may be affected by participant factors and therapeutic variables, which are not readily controllable

Articulatory Kinematics During Stop Closure in Speakers with Parkinson’s Disease

Purpose: The goal of this exploratory study was (a) to investigate the differences in articulatory movements during the closure phase of bilabial stop consonants with respect to distance, displacement, and timing of motion between individuals with Parkinson’s Disease (PD) and healthy controls; and (b) to investigate changes in articulatory movements of speakers with PD when they voluntarily vary the degree of speech intelligibility. Methods: Six participants, 4 PD and 2 healthy control (HC) speakers, participated in this study. The stimulus was a sentence containing several bilabial stop consonants (i.e., “Buy Bobby a puppy”). Movement data were collected using the Wave Speech Research System (NDI, Canada). Movement measures included duration, distance, and displacement and speed of the tongue front, tongue back, upper lip, lower lip, and jaw. Results: Speakers with PD and HC speakers produced observable articulatory differences during the stop closure of bilabial stops. Generally, the PD group produced smaller articulatory movement and had longer closure durations than the HC group. Regarding changes in speaking mode, the two groups made observable, but different articulatory changes during the stop closure. For more clear speech, both groups made greater articulatory movements and decreased the stop closure duration. For less clear speech, the HC group demonstrated reduced articulatory movements and longer closure durations whereas the PD group made greater articulatory movements and longer closure durations. Discussion: The findings of this study revealed several articulatory differences during the stop closure between the two speaking groups. For more clear speaking conditions, speakers in the PD group can successfully compensate for reduced articulatory movement by producing exaggerated lower lip and jaw movement. These findings support the use of more clear speaking modifications as a therapeutic technique to elicit better articulatory movement among speakers with PD. However, it also appears the PD group has difficulty producing fine motor articulatory changes (e.g., less clear speech)

Articulating: the neural mechanisms of speech production

Speech production is a highly complex sensorimotor task involving tightly coordinated processing across large expanses of the cerebral cortex. Historically, the study of the neural underpinnings of speech suffered from the lack of an animal model. The development of non-invasive structural and functional neuroimaging techniques in the late 20th century has dramatically improved our understanding of the speech network. Techniques for measuring regional cerebral blood flow have illuminated the neural regions involved in various aspects of speech, including feedforward and feedback control mechanisms. In parallel, we have designed, experimentally tested, and refined a neural network model detailing the neural computations performed by specific neuroanatomical regions during speech. Computer simulations of the model account for a wide range of experimental findings, including data on articulatory kinematics and brain activity during normal and perturbed speech. Furthermore, the model is being used to investigate a wide range of communication disorders.R01 DC002852 - NIDCD NIH HHS; R01 DC007683 - NIDCD NIH HHS; R01 DC016270 - NIDCD NIH HHSAccepted manuscrip

Vowel space in hypokinetic dysarthria: : Preliminary investigations.

The paper discusses acoustic and articulatory data on the use of vowel space by speaker affected by Parkinson’s Disease who developed hypokinetic dysarthria. Two experiments involving pathological subjects and matching controls are described, whose general aim is to better understand if the vowel space in Parkinson’s Disease dysarthric subjects is always and homogeneously reduced. In the first investigation, acoustic and kinematic data are collected and analyzed to test if pathological speakers always use a reduced vowel space compared to control subjects, and if they adopt different articulatory strategies depending on the axis of the speech gesture (vertical vs horizontal). In the second investigation, various articulatory metrics are used to better investigate the dimension and position of the acoustic vowel space, and if they change in Parkinson’s Disease subjects compared to controls. Results show that reduction takes place, but some subjects appear to compensate, widening their tongue gestures on the horizontal axis even though the lip gesture is not necessarily undershot. Nevertheless, metrics used in the second experiment do not allow to capture a reduction, even though, in line with results of the first experiment, they point to an asymmetry in the vowel space used depending on the axis considered

Speaking Rate Effects on Normal Aspects of Articulation: Outcomes and Issues

The articulatory effects of speaking rate have been a point of focus for a substantial literature in speech science. The normal aspects of speaking rate variation have influenced theories and models of speech production and perception in the literature pertaining to both normal and disordered speech. While the body of literature pertaining to the articulatory effects of speaking rate change is reasonably large, few speaker-general outcomes have emerged. The purpose of this paper is to review outcomes of the existing literature and address problems related to the study of speaking rate that may be germane to the recurring theme that speaking rate effects are largely idiosyncratic

Kinematic and correlational analyses on labial and lingual functions during syllable repetitions in Cantonese dysarthric speakers with Parkinson's disease of varying severity using electromagnetic articulography (EMA)

Articulatory imprecision in Parkinson patients with hypokinetic dysarthria has been attributed to articulatory undershooting. However, contradictory results in terms of acoustics and instrumental investigation has been reported in the literature throughout the years. The present study aimed to investigate labial and lingual kinematics in dysarthric Cantonese speakers with Parkinson’s disease (PD) of different severity (in terms of dysarthria) during rapid syllable repetitions and compared the measures with that of healthy age-matched controls using a 3-dimensional Electromagnetic Articulography (EMA). Dysarthria severity was also correlated with labial and lingual kinematics. Tongue tip, tongue back, upper and lower lips and jaw motion in five PD and six normal participants during repetitions of /pa/, /ta/ and /ka/ were recorded. Participants were also rated perceptually on their dysarthria severity. When compared to the normal group, the PD group showed reduced velocity in lingual movement and reduced distance travelled and velocity in labial movements. Correlational analysis between dysarthria severity and kinematic data revealed positive correlation for duration of lingual movement. Negative correlation was identified for the velocity and rate of lingual movement, and for distance travelled and velocity of labial movement. The present results supported the hypothesis of articulatory undershooting as a contributing factor of articulatory imprecision in hypokinetic dysarthria, while tongue and lip tremor might also cause such consonant imprecision. Possible differential effect of dopamine deficiency on the different cranial nerves has been hypothesized. Keywords:published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

The Phonetics of Speech Production and Medical Research

The production of speech requires the interplay of a number of cognitive and motoric activities, which make it an interesting object of study from both a linguistic and a medical point of view. In this paper, we discuss, first, the features and domain of application of the most used technologies in linguistic research on speech production, focusing on those that have been applied to medicine. Second, we offer an insight into the main results that have been obtained so far in studying dysarthria in Italian Parkinson's Disease, as an example of the interdisciplinary, experimental research at the border between linguistics and medicine

Deep Brain Stimulation of Caudal Zona Incerta and Subthalamic Nucleus in Patients with Parkinson's Disease: Effects on Diadochokinetic Rate

The hypokinetic dysarthria observed in Parkinson's disease (PD) affects the range, speed, and accuracy of articulatory gestures in patients, reducing the perceived quality of speech acoustic output in continuous speech. Deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) and of the caudal zona incerta (cZi-DBS) are current surgical treatment options for PD. This study aimed at investigating the outcome of STN-DBS (7 patients) and cZi-DBS (7 patients) in two articulatory diadochokinesis tasks (AMR and SMR) using measurements of articulation rate and quality of the plosive consonants (using the percent measurable VOT metric). The results indicate that patients receiving STN-DBS increased in articulation rate in the Stim-ON condition in the AMR task only, with no effect on production quality. Patients receiving cZi-DBS decreased in articulation rate in the Stim-ON condition and further showed a reduction in production quality. The data therefore suggest that cZi-DBS is more detrimental for extended articulatory movements than STN-DBS