The Contributions of Pitch, Loudness, and Rate Control to Speech Naturalness in Cerebellar Ataxia.

PURPOSE: The goal of this study was to determine the relationship between the perceptual measure of speech naturalness and objective measures of pitch, loudness, and rate control as a potential tool for assessment of ataxic dysarthria. METHOD: Twenty-seven participants with ataxia and 29 age- and sex-matched control participants completed the pitch glide and loudness step tasks drawn from the Frenchay Dysarthria Assessment-Second Edition (FDA-2) in addition to speech diadochokinetic (DDK) tasks. First, group differences were compared for pitch variability in the pitch glide task, loudness variability in the loudness step task, and syllable duration and speech rate in the DDK task. Then, these acoustic measures were compared with previously collected ratings of speech naturalness by speech-language pathology graduate students. RESULTS: Robust group differences were measured for pitch variability and both DDK syllable duration and speech rate, indicating that the ataxia group had greater pitch variability, longer DDK syllable duration, and slower DDK speech rate than the control group. No group differences were measured for loudness variability. There were robust relationships between speech naturalness and pitch variability, DDK syllable duration, and DDK speech rate, but not for loudness variability. CONCLUSIONS: Objective acoustic measures of pitch variability in the FDA-2 pitch glide task and syllable duration and speech rate in the DDK task can be used to validate perceptual measures of speech naturalness. Overall, speech-language pathologists can incorporate both perceptual measures of speech naturalness and acoustic measures of pitch variability and DDK performance for a comprehensive evaluation of ataxic dysarthria.

Contributions of Speech Timing and Articulatory Precision to Listener Perceptions of Intelligibility and Naturalness in Parkinson's Disease.

PURPOSE: Parkinson's disease (PD) results in hypokinetic dysarthria in as many as 90% of cases. Among the most distinctive features of hypokinetic dysarthria are atypical timing and articulatory imprecision in speech production. Here, we examined the contributions of perceived speech timing typicality and articulatory precision, both on their own and while controlling for the other, on intelligibility and naturalness in speakers with PD. METHOD: Twenty speakers with PD and four healthy older adults read aloud the first paragraph of the Rainbow Passage. Twenty inexperienced listeners with typical hearing listened to these recordings and rated intelligibility, naturalness, timing typicality, and articulatory precision using separate visual analog scales. Ratings were averaged across listeners and entered into linear regression models with intelligibility and naturalness as dependent variables and timing typicality and articulatory precision as independent variables in each. RESULTS: Articulatory precision, but not timing typicality, was positively correlated with intelligibility on its own, but neither was associated with intelligibility after accounting for the other. Both timing typicality and articulatory precision were positively correlated with naturalness on their own as well as after controlling for the other variable. CONCLUSION: These results contribute to the overall understanding of speech factors associated with intelligibility and naturalness in speakers with PD and indicate that considering the unique contributions of related perceptual constructs may provide more information than bivariate relationships alone.

Prosody matters: Preserved prominence marking strategies in people with Parkinson's disease independent of motor status.

While many studies focus on segmental variation in Parkinsonian speech, little is known about prosodic modulations reflecting the ability to adapt to communicative demands in people with Parkinson's disease (PwPD). This type of prosodic modulation is important for social interaction, and it involves modifications in speech melody (intonational level) and articulation of consonants and vowels (segmental level). The present study investigates phonetic cues of prosodic modulations with respect to different focus structures in mild dysarthric PwPD as a function of levodopa. Acoustic and kinematic speech parameters of 25 PwPD were assessed in two motor conditions. Speech production data from PwPD were collected before (medication-OFF) and after levodopa intake (medication-ON) by means of 3-D electromagnetic articulography. On the acoustic level, intensity, pitch, and syllable durations were analyzed. On the kinematic level, movement duration and amplitude were investigated. Spatio-temporal modulations of speech parameters were examined and compared across three different prosodic focus structures (out-of-focus, broad focus, contrastive focus) to display varying speech demands. Overall, levodopa had beneficial effects on motor performance, speech loudness, and pitch modulation. Acoustic syllable durations and kinematic movement durations did not change, revealing no systematic effects of motor status on the temporal domain. In contrast, there were spatial modulations of the oral articulators: tongue tip movements were smaller and lower lip movements were larger in amplitude under levodopa, reflecting a more agile and efficient articulatory movement under levodopa. Thus, respiratory-phonatory functions and consonant production improved, while syllable duration and tongue body kinematics did not change. Interestingly, prominence marking strategies were comparable between the medication conditions under investigation, and in fact, appear to be preserved in mild dysarthric PwPD.

Voice signals database of ALS patients with different dysarthria severity and healthy controls.

This paper describes a new publicly-available database of VOiCe signals acquired in Amyotrophic Lateral Sclerosis (ALS) patients (VOC-ALS) and healthy controls performing different speech tasks. This dataset consists of 1224 voice signals recorded from 153 participants: 51 healthy controls (32 males and 19 females) and 102 ALS patients (65 males and 37 females) with different severity of dysarthria. Each subject's voice was recorded using a smartphone application (Vox4Health) while performing several vocal tasks, including a sustained phonation of the vowels /a/, /e/, /i/, /o/, /u/ and /pa/, /ta/, /ka/ syllable repetition. Basic derived speech metrics such as harmonics-to-noise ratio, mean and standard deviation of fundamental frequency (F0), jitter and shimmer were calculated. The F0 standard deviation of vowels and syllables showed an excellent ability to identify people with ALS and to discriminate the different severity of dysarthria. These data represent the most comprehensive database of voice signals in ALS and form a solid basis for research on the recognition of voice impairment in ALS patients for use in clinical applications.

Dysarthria and dysphagia in patients with mitochondrial diseases.

BACKGROUND: Information about dysarthria and dysphagia in mitochondrial diseases (MD) is scarce. However, this knowledge is needed to identify speech and swallowing problems early, to monitor the disease course, and to develop and offer optimal treatment and support. This study therefore aims to examine the prevalence and severity of dysarthria and dysphagia in patients with MD and its relation to clinical phenotype and disease severity. Secondary aim is to determine clinically relevant outcome measures for natural history studies and clinical trials. METHODS: This retrospective cross-sectional medical record study includes adults (age ≥ 18 years) diagnosed with genetically confirmed MD who participated in a multidisciplinary admission within the Radboud center for mitochondrial medicine between January 2015 and April 2023. Dysarthria and dysphagia were examined by administering the Radboud dysarthria assessment, swallowing speed, dysphagia limit, test of mastication and swallowing solids (TOMASS), and 6-min mastication test (6MMT). The disease severity was assessed using the Newcastle mitochondrial disease scale for adults (NMDAS). RESULTS: The study included 224 patients with MD with a median age of 42 years of whom 37.5% were male. The pooled prevalence of dysarthria was 33.8% and of dysphagia 35%. Patients with MD showed a negative deviation from the norm on swallowing speed, TOMASS (total time) and the 6MMT. Furthermore, a significant moderate relation was found between the presence of dysarthria and the clinical phenotypes. There was a statistically significant difference in total time on the TOMASS between the clinical phenotypes. Finally, disease severity showed a significant moderate relation with the severity of dysarthria and a significant weak relation with the severity of dysphagia. CONCLUSION: Dysarthria and dysphagia occur in about one-third of patients with MD. It is important for treating physicians to pay attention to this subject because of the influence of both disorders on social participation and wellbeing. Referral to a speech and language therapist should therefore be considered, especially in patients with a more severe clinical phenotype. The swallowing speed, TOMASS and 6MMT are the most clinically relevant tests to administer.

Do Acoustic Characteristics of Dysarthria in People With Parkinson's Disease Differ Across Languages?

PURPOSE: Cross-language studies suggest more similarities than differences in how dysarthria affects the speech of people with Parkinson's disease (PwPD) who speak different languages. In this study, we aimed to identify the relative contribution of acoustic variables to distinguish PwPD from controls who spoke varieties of two Romance languages, French and Portuguese. METHOD: This bi-national, cross-sectional, and case-controlled study included 129 PwPD and 124 healthy controls who spoke French or Portuguese. All participants underwent the same clinical examinations, voice/speech recordings, and self-assessment questionnaires. PwPD were evaluated off and on optimal medication. Inferential analyses included Disease (controls vs. PwPD) and Language (French vs. Portuguese) as factors, and random decision forest algorithms identified relevant acoustic variables able to distinguish participants: (a) by language (French vs. Portuguese) and (b) by clinical status (PwPD on and off medication vs. controls). RESULTS: French-speaking and Portuguese-speaking individuals were distinguished from each other with over 90% accuracy by five acoustic variables (the mean fundamental frequency and the shimmer of the sustained vowel /a/ production, the oral diadochokinesis performance index, the relative sound level pressure and the relative sound pressure level standard deviation of the text reading). A distinct set of parameters discriminated between controls and PwPD: for men, maximum phonation time and the oral diadochokinesis speech proportion were the most significant variables; for women, variables calculated from the oral diadochokinesis were the most discriminative. CONCLUSIONS: Acoustic variables related to phonation and voice quality distinguished between speakers of the two languages. Variables related to pneumophonic coordination and articulation rate were the more effective in distinguishing PwPD from controls. Thus, our research findings support that respiration and diadochokinesis tasks appear to be the most appropriate to pinpoint signs of dysarthria, which are largely homogeneous and language-universal. In contrast, identifying language-specific variables with the speech tasks and acoustic variables studied was less conclusive.

Differential spectral characteristics of the Spanish fricative /s/ in the articulation of individuals with dysarthria and apraxia of speech.

PURPOSE: This study examines whether there are differences in the speech of speakers with dysarthria, speakers with apraxia and healthy speakers in spectral acoustic measures during production of the central-peninsular Spanish alveolar sibilant fricative /s/. METHOD: To this end, production of the sibilant was analyzed in 20 subjects with dysarthria, 8 with apraxia of speech and 28 healthy speakers. Participants produced 12 sV(C) words. The variables compared across groups were the fricative's spectral amplitude difference (AmpD) and spectral moments in the temporal midpoint of fricative execution. RESULTS: The results indicate that individuals with dysarthria can be distinguished from healthy speakers in terms of the spectral characteristics AmpD, standard deviation (SD), center of gravity (CoG) and skewness, the last two in context with unrounded vowel, while no differences in kurtosis were detected. Participants with AoS group differ significantly from healthy speaker group in AmpD, SD and CoG and Kurtosis, the first one followed unrounded vowel and the latter two followed by rounded vowels. In addition, speakers with apraxia of speech group returned significant differences with respect to speakers with dysarthria group in AmpD, CoG and skewness. CONCLUSIONS: The differences found between the groups in the measures studied as a function of the type of vowel context could provide insights into the distinctive manifestations of motor speech disorders, contributing to the differential diagnosis between apraxia and dysarthria in motor control processes.

The Effects of Interactive Context on Acoustic Characteristics of Speech in People With Dysarthria: A Preliminary Study.

PURPOSE: The current study compared temporal and spectral acoustic contrast between vowel segments produced by speakers with dysarthria across three speech tasks-interactive, solo habitual, and solo clear. METHOD: Nine speakers with dysarthria secondary to amyotrophic lateral sclerosis participated in the study. Each speaker was paired with a typical interlocutor over videoconferencing software. The speakers produced the vowels /i, ɪ, ɛ, æ/ in /h/-vowel-/d/ words. For the solo tasks, speakers read the stimuli aloud in both their habitual and clear speaking styles. For the interactive task, speakers produced a target stimulus for their interlocutor to select among the four possibilities. We measured the duration difference between long and short vowels, as well as the F1/F2 Euclidean distance between adjacent vowels, and also determined how well the vowels could be classified based on their acoustic characteristics. RESULTS: Temporal contrast between long and short vowels was higher in the interactive task than in both solo tasks. Spectral distance between adjacent vowel pairs was also higher for some pairs in the interactive task than the habitual speech task. Finally, vowel classification accuracy was highest in the interactive task. CONCLUSIONS: Overall, we found evidence that individuals with dysarthria produced vowels with greater acoustic contrast in structured interactions than they did in solo tasks. Furthermore, the speech adjustments they made to the vowel segments differed from those observed in solo speech.

Does Native Language Matter in Perceptual Ratings of Dysarthria?

PURPOSE: Despite the general agreement that dysarthria characteristics are largely language-independent, few efforts have attempted a systematic comparison across languages. To examine the role of native languages in the perception of speech characteristics of dysarthria secondary to Parkinson's disease (PD), auditory-perceptual ratings of dysarthria, and confidence level of the judgments were compared between two listener groups: language-matched and language-crossed. METHOD: A total of 60 listeners (35 native speakers of Korean and 25 native speakers of American English) estimated speech abnormality for 20 speech dimensions using a visual analog scale method for both language-matched and language-crossed speech stimuli. Speech stimuli were passage readings of the respective languages obtained from individuals with and without PD. RESULTS: For speech dimension ratings, eight of 20 speech dimensions revealed significant differences in response to PD speech between the two listener groups, for most of which, language-crossed listeners' estimation was lower (i.e., more impaired) than language-matched listeners. For confidence-level ratings, language-matched listeners were less confident in the ratings of speakers with PD compared to the language-crossed listeners. CONCLUSIONS: The data support both language-universal and language-specific aspects in perceiving dysarthria characteristics, such that native language plays a role, especially when rating articulatory- and rhythmic-related characteristics. The findings are discussed with respect to the role of linguistic information, such as phonetic inventories and prosodic structures, in perceiving dysarthria characteristics.

Effects of Speech Cues on Acoustics and Intelligibility of Korean-Speaking Children With Cerebral Palsy.

PURPOSE: Reduced speech intelligibility is often a hallmark of children with dysarthria secondary to cerebral palsy (CP), but effects of speech strategies for increasing intelligibility are understudied, especially in children who speak languages other than English. This study examined the effects of (the Korean translation of) two cues, "speak with your big mouth" and "speak with your strong voice," on speech acoustics and intelligibility of Korean-speaking children with CP. METHOD: Fifteen Korean-speaking children with CP repeated words and sentences in habitual, big mouth, and strong voice conditions. Acoustic analyses were performed and intelligibility was assessed by means of 90 blinded listeners' ease-of-understanding (EoU) ratings and percentage of words correctly transcribed (PWC). RESULTS: In response to both cues, children's vocal intensity and utterance duration increased significantly and differentially, whereas their vowel space area gains did not reach statistical significance. EoU increased significantly in the big mouth condition at word, but not sentence, level, whereas in the strong voice condition, EoU increased significantly at both levels. PWC increases were not statistically significant. Considerable variability in children's responses to cues was noted overall. CONCLUSIONS: Korean-speaking children with CP modify their speech styles differentially when provided with cues aimed to increase their articulatory working space and vocal intensity. The results provide preliminary support for the use of the strong voice cue, in particular, to increase EoU. While the findings do not offer conclusive evidence of the intelligibility benefits of these cues, investigation with a larger sample size should provide further insight into optimal cueing strategies for increasing intelligibility in this population. Implications for language-specific versus language-independent treatment approaches are discussed. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25521052.

Short-term effects of transcranial direct current stimulation on motor speech in Parkinson's disease: a pilot study.

INTRODUCTION: Hypokinetic dysarthria (HD) is a common motor speech symptom of Parkinson's disease (PD) which does not respond well to PD treatments. We investigated short-term effects of transcranial direct current stimulation (tDCS) on HD in PD using acoustic analysis of speech. Based on our previous studies we focused on stimulation of the right superior temporal gyrus (STG) - an auditory feedback area. METHODS: In 14 PD patients with HD, we applied anodal, cathodal and sham tDCS to the right STG using a cross-over design. A protocol consisting of speech tasks was performed prior to and immediately after each stimulation session. Linear mixed models were used for the evaluation of the effects of each stimulation condition on the relative change of acoustic parameters. We also performed a simulation of the mean electric field induced by tDCS. RESULTS: Linear mixed model showed a statistically significant effect of the stimulation condition on the relative change of median duration of silences longer than 50 ms (p = 0.015). The relative change after the anodal stimulation (mean = -5.9) was significantly lower as compared to the relative change after the sham stimulation (mean = 12.8), p = 0.014. We also found a correlation between the mean electric field magnitude in the right STG and improvement of articulation precision after anodal tDCS (R = 0.637; p = 0.019). CONCLUSIONS: The exploratory study showed that anodal tDCS applied over the auditory feedback area may lead to shorter pauses in a speech of PD patients.

Exploring the Impact of Fine-Tuning the Wav2vec2 Model in Database-Independent Detection of Dysarthric Speech.

Many acoustic features and machine learning models have been studied to build automatic detection systems to distinguish dysarthric speech from healthy speech. These systems can help to improve the reliability of diagnosis. However, speech recorded for diagnosis in real-life clinical conditions can differ from the training data of the detection system in terms of, for example, recording conditions, speaker identity, and language. These mismatches may lead to a reduction in detection performance in practical applications. In this study, we investigate the use of the wav2vec2 model as a feature extractor together with a support vector machine (SVM) classifier to build automatic detection systems for dysarthric speech. The performance of the wav2vec2 features is evaluated in two cross-database scenarios, language-dependent and language-independent, to study their generalizability to unseen speakers, recording conditions, and languages before and after fine-tuning the wav2vec2 model. The results revealed that the fine-tuned wav2vec2 features showed better generalization in both scenarios and gave an absolute accuracy improvement of 1.46%-8.65% compared to the non-fine-tuned wav2vec2 features.

Language-Independent Acoustic Biomarkers for Quantifying Speech Impairment in Huntington's Disease.

PURPOSE: Changes in voice and speech are characteristic symptoms of Huntington's disease (HD). Objective methods for quantifying speech impairment that can be used across languages could facilitate assessment of disease progression and intervention strategies. The aim of this study was to analyze acoustic features to identify language-independent features that could be used to quantify speech dysfunction in English-, Spanish-, and Polish-speaking participants with HD. METHOD: Ninety participants with HD and 83 control participants performed sustained vowel, syllable repetition, and reading passage tasks recorded with previously validated methods using mobile devices. Language-independent features that differed between HD and controls were identified. Principal component analysis (PCA) and unsupervised clustering were applied to the language-independent features of the HD data set to identify subgroups within the HD data. RESULTS: Forty-six language-independent acoustic features that were significantly different between control participants and participants with HD were identified. Following dimensionality reduction using PCA, four speech clusters were identified in the HD data set. Unified Huntington's Disease Rating Scale (UHDRS) total motor score, total functional capacity, and composite UHDRS were significantly different for pairwise comparisons of subgroups. The percentage of HD participants with higher dysarthria score and disease stage also increased across clusters. CONCLUSION: The results support the application of acoustic features to objectively quantify speech impairment and disease severity in HD in multilanguage studies. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25447171.

Isolated dysarthria due to hypoglossal palsy caused by supratentorial ischemic stroke: Radiological and electropsyological analysis.

OBJECTIVES: Isolated dysarthria caused by stroke is a rare condition and generally seen in infratentorial lesions, especially in cerebellar lesions. Isolated dysarthria associated with supratentorial ischemic lesions are also very rare and, these conditions were shown in only a few cases. In this study, six patients characterized by IHP due to supratentorial ischemic lesions are presented. PATIENTS AND METHODS: Physical examinations of patients were done by two different neurologists. The risk factors for stroke were determined. Localisations of lesions were identified by using magnetic resonance images(MRI). Corticolingual tract affection without sensorial and other corticospinal tract involvement was confirmed using Somatosensory evoked potentials(SEPs) and Transcranial Magnetic Stimulation(TMS). RESULTS: Unilateral lingual paresis was detected in all of the patients. The lesions were demonstrated on MRI slices. All lesions were on the same localization. The affection of the corticolingual tract without any other motor and sensory tract involvement was proven electrophysiologically. CONCLUSION: Corticospinal and corticobulbar fibers are very close to each other. Therefore common involvement is expected in cerebrovascular diseases. However, six patients with IHP caused by supratentorial ischemic lesions were reported in this study. Thus, a possible map of the corticolingual tract was drawn.

Progressive midbrain clefts after head trauma and decompressive surgery: a report of two patients.

This report describes two patients with acute-onset ptosis, oculomotor dysfunction, ataxia and drowsiness, referable to the midbrain tegmentum. Both patients had previously suffered severe closed head injuries requiring craniotomy for cerebral decompression. Serial brain scans in both cases revealed a newly developing cleft in the midbrain, with features suggestive of abnormal cerebrospinal fluid (CSF) flow across the aqueduct. A trial of acetazolamide was initiated to reduce CSF production, followed by a third ventriculostomy for CSF diversion in one patient, which resulted in arrested disease progression and partial recovery. There are only two previous reports in the literature of midbrain clefts that developed as remote sequelae of head trauma. We postulate that altered CSF flow dynamics in the aqueduct, possibly related to changes in brain compliance, may be contributory. Early recognition and treatment may prevent irreversible structural injury and possible death.

Metronidazole-induced reversible cerebellar dysfunction.

A 73-year-old man who presented with fever and abdominal discomfort was diagnosed to have a liver abscess. He was treated with antimicrobials which included metronidazole. One month into treatment, he developed neurological symptoms and signs that were suggestive of cerebellar pathology. MRI of the brain showed T2/fluid attenuated inversion recovery hyperintensities involving bilateral dentate, fastigial and interpositus nuclei. After excluding common aetiologies, the possibility of metronidazole-induced neurotoxicity was considered. After stopping metronidazole, his symptoms and signs resolved. A subsequent MRI scan of the brain showed reversal of changes. Neurotoxicity caused by metronidazole is an uncommon adverse effect of a commonly used antimicrobial drug and should be considered in the appropriate clinical scenario.

Articulatory network reorganization in Parkinson's disease as assessed by multimodal MRI and acoustic measures.

INTRODUCTION: Hypokinetic dysarthria (HD) is common in Parkinson's disease (PD). Our objective was to evaluate articulatory networks and their reorganization due to PD pathology in individuals without overt speech impairment using a multimodal MRI protocol and acoustic analysis of speech. METHODS: A total of 34 PD patients with no subjective HD complaints and 25 age-matched healthy controls (HC) underwent speech task recordings, structural MRI, and reading task-induced and resting-state fMRI. Grey matter probability maps, task-induced activations, and resting-state functional connectivity within the regions engaged in speech production (ROIs) were assessed and compared between groups. Correlation with acoustic parameters was also performed. RESULTS: PD patients as compared Tto HC displayed temporal decreases in speech loudness which were related to BOLD signal increases in the right-sided regions of the dorsal language pathway/articulatory network. Among those regions, activation of the right anterior cingulate was increased in PD as compared to HC. We also found bilateral posterior superior temporal gyrus (STG) GM loss in PD as compared to HC that was strongly associated with diadochokinetic (DDK) irregularity in the PD group. Task-induced activations of the left STG were increased in PD as compared to HC and were related to the DDK rate control. CONCLUSIONS: The results provide insight into the neural correlates of speech production control and distinct articulatory network reorganization in PD apparent already in patients without subjective speech impairment.

Dysarthria syndromes in children with cerebral palsy.

AIM: To investigate whether dysarthria syndromes acquired in adulthood can also be observed in children with cerebral palsy (CP) and, if so, whether they align with children's CP subtypes. METHOD: Twenty-six children with CP participated (mean age 7y 8mo [SD 1y 2mo], 5y 1mo-9y 10mo; 16 males and 10 females). Speech samples were elicited in a computer-based game and were analysed using the auditory perceptual criteria of the Bogenhausen Dysarthria Scales (BoDyS). For statistical classification, three comparison groups of adults with standard dysarthria syndromes (i.e. spastic, hyperkinetic, and ataxic) were used. Their BoDyS data were entered into a mixture discriminant analysis, with data from the comparison groups as the training sample and those from the children with CP as the test sample. Results were related to findings in a group of adults with CP. RESULTS: Among the children with CP, most had spastic (n=14), while fewer had ataxic (n=9) or hyperkinetic (n=3), dysarthria. However, syndrome allocations were significantly more ambiguous than in adults with CP. For 11 children, their dysarthria syndromes did not align with their CP subtype. INTERPRETATION: Dysarthria syndromes are less clear cut in children than in adults with CP because of a number of developmental factors. WHAT THIS PAPER ADDS: Children with cerebral palsy (CP) show diverse patterns of dysarthric symptoms. Dysarthria syndromes do not seem to manifest fully during childhood. Dysarthria syndrome and CP subtype may not align in children with CP.