Speech Impairment in Cerebellar Ataxia Affects Naturalness More Than Intelligibility.

The purpose of this analysis was to document intelligibility and naturalness in ataxia, a neurological condition that results from cerebellar damage. The cerebellum is important for normal speech production to scale and coordinate articulatory and laryngeal movements. The disruption of these cerebellar mechanisms has unique implications for how intelligibility and naturalness are affected in ataxia. The results of research on speech in ataxia have important clinical implications for assessment and treatment of individuals with ataxic dysarthria. Speech samples from 27 participants with ataxia and 28 age- and sex-matched control participants were assessed by nine speech-language pathology graduate students for intelligibility and naturalness. Intelligibility was measured as the percentage of words transcribed correctly, and naturalness was assessed as a subjective rating on a seven-point interval scale. Both intra- and inter-rater reliability were moderate to high for both intelligibility and naturalness. Speech intelligibility and naturalness were robustly decreased in the ataxia group compared to the control group; however, the difference was greater for measures of speech naturalness. There were robust relationships among dysarthria severity, length of diagnosis, and speech naturalness in speakers with ataxia, but there were no other robust effects for age, sex, or impact on quality of life for intelligibility or naturalness. Speech naturalness was more impaired than intelligibility in speakers with ataxia. Impaired naturalness can have debilitating consequences for communicative participation, effectiveness, and quality of life. Assessment and treatment for ataxic dysarthria should include aspects of prosodic control for speech naturalness.

Sensitivity and specificity of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised to detect dysarthria in individuals with amyotrophic lateral sclerosis.

INTRODUCTION/AIMS: Given the widespread use of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) to measure disease progression in ALS and recent reports demonstrating its poor sensitivity, we aimed to determine the sensitivity and specificity of the ALSFRS-R bulbar subscale and speech item to detect validated clinical ratings of dysarthria in individuals with ALS. METHODS: Paired ALSFRS-R and validated Speech Intelligibility Test (SIT) data from individuals with ALS were analyzed. Trained raters completed duplicate, independent, and blinded ratings of audio recordings to obtain speech intelligibility (%) and speaking rate (words per minute, WPM). Binary dysarthria profiles were derived (dysarthria ≤96% intelligible and/or <150 WPM). Data were obtained using the Kruskal-Wallis test, receiver-operating characteristic (ROC) curve, area under the curve (AUC), sensitivity and specificity percentages, and positive/negative predictive values (PPV/NPV). RESULTS: A total of 250 paired SIT and ALSFRS-R data points were analyzed. Dysarthria was confirmed in 72.4% (n = 181). Dysarthric speakers demonstrated lower ALSFRS-R bulbar subscale (8.9 vs. 11.2) and speech item (2.7 vs. 3.7) scores (P < .0001). The ALSFRS-R bulbar subscale score had an AUC of 0.81 (95% confidence interval [CI] 0.75 to 0.86). A subscale score of ≤11 yielded a sensitivity of 86%, specificity of 57%, PPV of 84%, and NPV of 60% to correctly identify dysarthria status. The ALSFRS-R speech item score demonstrated an AUC of 0.81 to detect dysarthria (95% CI 0.76 to 0.85), with sensitivity of 79%, specificity of 75%, PPV of 89%, and NPV of 58% for a speech item cutpoint of ≤3. DISCUSSION: The ALSFRS-R bulbar and speech item subscale scores may be useful, inexpensive, and quick tools for monitoring dysarthria status in ALS.

An Efficacy Study of Voice Quality Using Cepstral Analyses of Phonation in Parkinson's Disease before and after SPEAK-OUT!®.

INTRODUCTION: SPEAK-OUT!® is a behavioral treatment for hypokinetic dysarthria in persons with Parkinson's disease (PD) that has become an alternative to the gold-standard Lee Silverman Voice Treatment (LSVT) in recent years. Acoustic evaluation of the efficacy of SPEAK-OUT!® therapy has focused on prosody. The purpose of this study was to investigate SPEAK-OUT!® efficacy in terms of vocal quality and its impact on quality of life. Vocal quality was measured acoustically using cepstral peak prominence (CPP) analysis and the Acoustic Voice Quality Index (AVQI) and perceptually using clinical ratings of speech performance. Impact on quality of life was measured with the Voice Handicap Index (VHI) and Voice-Related Quality of Life (V-RQOL). An additional goal of this study was to investigate whether dysarthria severity and disease duration were predictive of changes in voice quality due to SPEAK-OUT!®. METHODS: Pre- and post-therapy data included PD participants' acoustic and perceptual ratings of audio recordings. Demographic data included age, sex, diagnosis, duration of PD, and severity of dysarthria. RESULTS: Participants achieved significant improvement in the vowel and sentence CPP smoothed (CPPS) mean score as well as in their AVQI score post SPEAK-OUT!® treatment. Improvements in AVQI correlated negatively with disease duration and positively with dysarthria severity. DISCUSSION/CONCLUSION: SPEAK-OUT!® is effective in improving voice quality in patients with hypokinetic dysarthria due to idiopathic PD. Patients with more severe dysarthria and with a shorter disease duration may benefit the most, supporting earlier intervention. As for the type of measurement, AVQI combines acoustics from both vowel and sentence contexts and may therefore be the measure of choice over CPPS (vowel) or CPPS (sentence).

Assessing speech intelligibility of pathological speech: test types, ratings and transcription measures.

Speech intelligibility is an essential though complex construct in speech pathology. In this paper, we investigated the interrater reliability and validity of two types of intelligibility measures: a rating-based measure, through Visual Analogue Scales (VAS), and a transcription-based measure called Accuracy of Words (AcW), through two forms of orthographic transcriptions, one containing only existing words (EWTrans) and one allowing all sorts of words, including both existing words and pseudowords (AWTrans). Both VAS and AcW scores were collected from five expert raters. We selected speakers with various severity levels of dysarthria (SevL) and employed two types of speech materials, i.e. meaningful sentences and word lists. To measure reliability, we applied Generalizability Theory, which is relatively unknown in the field of pathological speech and language research but enables more comprehensive analyses than traditional methods, e.g., the intraclass correlation coefficient. The results convincingly indicate that five expert raters were sufficient to provide reliable rating-based (VAS) and transcription-based (AcW) measures, and that reliability increased as the number of raters or utterances increased. Generalizability Theory has proved effective in systematically dealing with reliability issues in our experimental design. We also investigated construct and concurrent validity. Construct validity was addressed by exploring the correlations between VAS and AcW within and across speech materials. Concurrent validity was addressed by exploring the correlations between our measures, i.e. VAS and AcW, and two external measures, i.e. phoneme intelligibility and SevL. The correlations corroborate the validity of VAS and AcW to assess speech intelligibility, both in sentences and word lists.

Consonant articulation acoustics and intelligibility in Swedish speakers with Parkinson's disease: a pilot study.

Imprecise consonant articulation is common in speakers with Parkinson's disease and can affect intelligibility. The research on the relationship between acoustic speech measures and intelligibility in Parkinson's disease is limited, and most of the research has been conducted on English. This pilot study investigated aspects of consonant articulation acoustics in eleven Swedish speakers with Parkinson's disease and six neurologically healthy persons. The focus of the study was on consonant cluster production, articulatory motion rate and variation, and voice onset time, and how these acoustic features correlate with speech intelligibility. Among the measures in the present study, typicality ratings of heterorganic consonant clusters /spr/ and /skr/ had the strongest correlations with intelligibility. Measures based on syllable repetition, such as repetition rate and voice onset time, showed varying results with weak to moderate correlations with intelligibility. One conclusion is that some acoustic measures may be more sensitive than others to the impact of the underlying sensory-motor impairment and dysarthria on speech production and intelligibility in speakers with Parkinson's disease. Some aspects of articulation appear to be equally demanding in terms of acoustic realisation for elderly healthy speakers and for speakers with Parkinson's disease, such as sequential motion rate measures. Clinically, this would imply that for the purpose of detecting signs of disordered speech motor control, choosing measures with less variation among older speakers without articulation impairment would lead to more robust results.

[A multiscale feature extraction algorithm for dysarthric speech recognition].

In this paper, we propose a multi-scale mel domain feature map extraction algorithm to solve the problem that the speech recognition rate of dysarthria is difficult to improve. We used the empirical mode decomposition method to decompose speech signals and extracted Fbank features and their first-order differences for each of the three effective components to construct a new feature map, which could capture details in the frequency domain. Secondly, due to the problems of effective feature loss and high computational complexity in the training process of single channel neural network, we proposed a speech recognition network model in this paper. Finally, training and decoding were performed on the public UA-Speech dataset. The experimental results showed that the accuracy of the speech recognition model of this method reached 92.77%. Therefore, the algorithm proposed in this paper can effectively improve the speech recognition rate of dysarthria.

Correlates of vowel clarity in the spectrotemporal modulation domain: Application to speech impairment evaluation.

This article reports on vowel clarity metrics based on spectrotemporal modulations of speech signals. Motivated by previous findings on the relevance of modulation-based metrics for speech intelligibility assessment and pathology classification, the current study used factor analysis to identify regions within a bi-dimensional modulation space, the magnitude power spectrum, as in Elliott and Theunissen [(2009). PLoS Comput. Biol. 5(3), e1000302] by relating them to a set of conventional acoustic metrics of vowel space area and vowel distinctiveness. Two indices based on the energy ratio between high and low modulation rates across temporal and spectral dimensions of the modulation space emerged from the analyses. These indices served as input for measurements of central tendency and classification analyses that aimed to identify vowel-related speech impairments in French native speakers with head and neck cancer (HNC) and Parkinson dysarthria (PD). Following the analysis, vowel-related speech impairment was identified in HNC speakers, but not in PD. These results were consistent with findings based on subjective evaluations of speech intelligibility. The findings reported are consistent with previous studies indicating that impaired speech is associated with attenuation in energy in higher spectrotemporal modulation bands.

Picture Description in the Assessment of Connected Speech Intelligibility in Parkinson's Disease: A Pilot Study.

INTRODUCTION: Assessment of intelligibility in dysarthria tends to rely on oral reading of sentences or words. However, self-generated utterances are closer to a client's natural speech. This study investigated how transcription of utterances elicited by picture description can be used in the assessment of intelligibility in speakers with Parkinson's disease. METHODS: Speech samples from eleven speakers with Parkinson's disease and six neurologically healthy persons were audio-recorded. Forty-two naive listeners completed transcriptions of self-generated sentences from a picture description task and orally read sentences from the Swedish Test of Intelligibility, as well as scaled ratings of narrative speech samples. RESULTS: Intelligibility was higher in orally read than self-generated sentences and higher for content words than for the whole sentence in self-generated sentences for most of the speakers, although these within-group differences were not statistically significant at the group level. Adding contextual leads for the listeners increased intelligibility in self-generated utterances significantly but with individual variation. Although correlations between the intelligibility measures were at least moderate or strong, there was a considerable inter- and intra-speaker variability in intelligibility scores between tasks for the speakers with Parkinson's disease, indicating individual variation of factors that impact intelligibility. Intelligibility scores from neurologically healthy speakers were generally high across tasks with no significant differences between the conditions. CONCLUSION: Within-speaker variability supports literature recommendations to use multiple methods and tasks when assessing intelligibility. The inclusion of transcription of self-generated utterances elicited by picture description to the intelligibility assessment has the potential to provide additional information to assessment methods based on oral reading of pre-scripted sentences and to inform the planning of interventions.

The Screening Test for Aphasia and Dysarthria (STAD) for Patients with Neurological Communicative Disorders: A Large-Scale, Multicenter Validation Study in Japan.

INTRODUCTION: Evaluation of multiple domains, such as language, articulation, and cognitive function, is frequently required in neurological communicative disorders. The purpose of this study was to investigate the performance of a 10-min screening scale for estimating aphasia, dysarthria, and cognitive dysfunction using a multicenter, large-sized consecutive series. METHODS: We conducted a multicenter validation study that included 314 patients with brain injury between February 1 and June 31, 2018, from 20 medical centers across Japan. The Screening Test for Aphasia and Dysarthria (STAD) was developed in Japan in 2009, and a previous smaller-scale retrospective study established its high to moderate validity. All patients had undergone the STAD, and 212 of them underwent the Western Aphasia Battery or Assessment of Motor Speech for Dysarthria. The effect size on all 29 items and receiver operating curves of 3 sections of the STAD were analyzed based on external criteria, which were decided considering the clinical diagnosis of aphasia, dysarthria, and cognitive dysfunction. Correlations between the STAD and reference tests were calculated. RESULTS: The phi coefficients of 23 out of 29 items exceeded the moderate effect size of 0.3 toward the targeted disorder. Overall, there was a good balance between sensitivity (82-92%) and specificity (77-78%), with moderate to large positive and negative likelihood ratios (3.7-4.19 and 0.1-0.23). The Pearson's r between the verbal section and Western Aphasia Battery Aphasia Quotient, the articulation section and Assessment of Motor Speech for Dysarthria, and the nonverbal section and Western Aphasia Battery Nonlinguistic Skills were 0.89, 0.70, and 0.79, respectively. CONCLUSION: We demonstrated that the STAD has acceptable content and concurrent validity for the assessment of communicative function in patients with brain injury. This short screening tool can be useful in specific contexts, such as in early bedside investigations, to obtain a quick summary of communicative function prior to the administration of other tests, and in cases where more in-depth testing is not feasible.

Web-based assessment of communication-related parameters in dysarthria: development and implementation of the KommPaS web app.

This article describes the design of KommPaS, a web-based tool for the clinical assessment of communication impairment in persons with dysarthria. KommPaS (the German acronym for Communication-related Parameters in Speech Disorders) allows clinicians to recruit laypersons via crowdsourcing for the evaluation of samples of dysarthric speech with regard to communication relevant parameters, that is, intelligibility, naturalness, perceived listener effort, and efficiency (intelligible speech units per unit time). Moreover, a communication total score describing the KommPaS profile elevation, i.e., the arithmetic mean of the normalized KommPaS scores, is provided. Based on considerations regarding the theoretical underpinnings and methodological constraints of a clinical tool for the assessment of these parameters, the article describes how each theoretically and methodologically motivated feature is translated into design principles and how these principles are implemented in a web application. The paper reports efficiency data and details the data privacy and data security provisions that are essential in such an approach.

Clinical measures of communication limitations in dysarthria assessed through crowdsourcing: specificity, sensitivity, and retest-reliability.

Assessing the impact of dysarthria on a patient's ability to communicate should be an integral part of patient management. However, due to the high demands on reliable quantification of communication limitations, hardly any formal clinical tests with approved psychometric properties have been developed so far. This study investigates a web-based assessment of communication impairment in dysarthria, named KommPaS. The test comprises measures of intelligibility, naturalness, perceived listener effort and communication efficiency, as well as a total score that integrates these parameters. The approach is characterized by a quasi-random access to a large inventory of test materials and to a large group of naïve listeners, recruited via crowdsourcing. As part of a larger research program to establish the clinical applicability of this new approach, the present paper focuses on two psychometric issues, namely specificity and sensitivity (study 1) and retest-reliability (study 2). Study 1: KommPaS was administered to 54 healthy adults and 100 adult persons with dysarthria (PWD). Non-parametric criterion-based norms (specificity: 0.95) were used to derive a standard metric for each of the four component variables, and corresponding sensitivity values for the presence of dysarthria were identified. Overall classification accuracy of the total score was determined using a ROC analysis. The resulting cutscores showed a high accuracy in the separation of PWD from healthy speakers for the naturalness and the total score. Study 2: A sub-group of 20 PWD enrolled in study 1 were administered a second KommPaS examination. ICC analyses revealed good to excellent retest reliabilities for all parameters.

How expertise and language familiarity influence perception of speech of people with Parkinson's disease.

Parkinson's disease (PD) is a progressive neurological disorder characterized by several motor and non-motor manifestations. PD frequently leads to hypokinetic dysarthria, which affects speech production and often has a detrimental impact on everyday communication. Among the typical manifestations of hypokinetic dysarthria, speech and language therapists (SLTs) identify prosody as the most affected cluster of speech characteristics. However, less is known about how untrained listeners perceive PD speech and how affected prosody influences their assessments of speech. This study explores the perception of sentence type intonation and healthiness of PD speech by listeners with different levels of familiarity with speech disorders in Dutch. We investigated assessments and classification accuracy differences between Dutch-speaking SLTs (n = 18) and Dutch/non-Dutch speaking untrained listeners (n = 27 and n = 124, respectively). We collected speech data from 30 Dutch speakers diagnosed with PD and 30 Dutch healthy controls. The stimuli set consisted of short phrases from spontaneous and read speech and of phrases produced with different sentence type intonation. Listeners participated in an online experiment targeting classification of sentence type intonation and perceived healthiness of speech. Results indicate that both familiarity with speech disorders and with speakers' language are significant and have different effects depending on the task type, as different listener groups demonstrate different classification accuracy. There is evidence that untrained Dutch listeners classify PD speech as unhealthy more accurately than both trained Dutch and untrained non-Dutch listeners, while trained Dutch listeners outperform the other two groups in sentence type classification.

Guidelines for Speech Recording and Acoustic Analyses in Dysarthrias of Movement Disorders.

Most patients with movement disorders have speech impairments resulting from sensorimotor abnormalities that affect phonatory, articulatory, and prosodic speech subsystems. There is widespread cross-discipline use of speech recordings for diagnostic and research purposes, despite which there are no specific guidelines for a standardized method. This review aims to combine the specific clinical presentations of patients with movement disorders, existing acoustic assessment protocols, and technological advances in capturing speech to provide a basis for future research in this field and to improve the consistency of clinical assessments. We considered 3 areas: the recording environment (room, seating, background noise), the recording process (instrumentation, vocal tasks, elicitation of speech samples), and the acoustic outcome data. Four vocal tasks, namely, sustained vowel, sequential and alternating motion rates, reading passage, and monologues, are integral aspects of motor speech assessment. Fourteen acoustic vocal speech features, including their hypothesized pathomechanisms with regard to typical occurrences in hypokinetic or hyperkinetic dysarthria, are hereby recommended for quantitative exploratory analysis. Using these acoustic features and experimental speech data, we demonstrated that the hyperkinetic dysarthria group had more affected speech dimensions compared with the healthy controls than had the hypokinetic speakers. Several contrasting speech patterns between both dysarthrias were also found. This article is the first attempt to provide initial recommendations for a standardized way of recording the voice and speech of patients with hypokinetic or hyperkinetic dysarthria; thus allowing clinicians and researchers to reliably collect, acoustically analyze, and compare vocal data across different centers and patient cohorts. © 2020 International Parkinson and Movement Disorder Society.

Cognitive Determinants of Dysarthria in Parkinson's Disease: An Automated Machine Learning Approach.

BACKGROUND: Dysarthric symptoms in Parkinson's disease (PD) vary greatly across cohorts. Abundant research suggests that such heterogeneity could reflect subject-level and task-related cognitive factors. However, the interplay of these variables during motor speech remains underexplored, let alone by administering validated materials to carefully matched samples with varying cognitive profiles and combining automated tools with machine learning methods. OBJECTIVE: We aimed to identify which speech dimensions best identify patients with PD in cognitively heterogeneous, cognitively preserved, and cognitively impaired groups through tasks with low (reading) and high (retelling) processing demands. METHODS: We used support vector machines to analyze prosodic, articulatory, and phonemic identifiability features. Patient groups were compared with healthy control subjects and against each other in both tasks, using each measure separately and in combination. RESULTS: Relative to control subjects, patients in cognitively heterogeneous and cognitively preserved groups were best discriminated by combined dysarthric signs during reading (accuracy = 84% and 80.2%). Conversely, patients with cognitive impairment were maximally discriminated from control subjects when considering phonemic identifiability during retelling (accuracy = 86.9%). This same pattern maximally distinguished between cognitively spared and impaired patients (accuracy = 72.1%). Also, cognitive (executive) symptom severity was predicted by prosody in cognitively preserved patients and by phonemic identifiability in cognitively heterogeneous and impaired groups. No measure predicted overall motor dysfunction in any group. CONCLUSIONS: Predominant dysarthric symptoms appear to be best captured through undemanding tasks in cognitively heterogeneous and preserved cohorts and through cognitively loaded tasks in patients with cognitive impairment. Further applications of this framework could enhance dysarthria assessments in PD. © 2021 International Parkinson and Movement Disorder Society.

Assessment of dysarthria and dysphagia in patients with amyotrophic lateral sclerosis: Review of the current evidence.

Bulbar dysfunction is a common presentation of amyotrophic lateral sclerosis (ALS) and significantly impacts quality of life of people with ALS (PALS). The current paper reviews measurements of dysarthria and dysphagia specific to ALS to identify efficient and valid assessment measures. Using such assessment measures will lead to improved management of bulbar dysfunction in ALS. Measures reviewed for dysarthria in PALS are organized into three categories: acoustic, kinematic, and strength. A set of criteria are used to evaluate the effectiveness of the measures' identification of speech impairments, measurement of functional verbal communication, and clinical applicability. Assessments reviewed for dysphagia in PALS are organized into six categories: patient reported outcomes, dietary intake, pulmonary function and airway defense capacity, bulbar function, dysphagia/aspiration screens, and instrumental evaluations. Measurements that have good potential for clinical use are highlighted in both topic areas. Additionally, areas of improvement for clinical practice and research are identified and discussed. In general, no single speech measure fulfilled all the criteria, although a few measures were identified as potential diagnostic tools. Similarly, few objective measures that were validated and replicated with large sample sizes were found for diagnosis of dysphagia in PALS. Importantly, clinical applicability was found to be limited; thus, a collaborative team focused on implementation science would be helpful to improve the clinical uptake of assessments. Overall, the review highlights the need for further development of clinically viable and efficient measurements that use a multidisciplinary approach.

Assessment of non-progressive dysarthria: practice and attitude of speech and language therapists in Lebanon.

BACKGROUND: Non-progressive dysarthria is an acquired motor speech disorder resulting from neurological diseases such as stroke and traumatic brain injury. The evidence base for the assessment of non-progressive dysarthria remains limited with professional practices relying mainly on therapists' clinical experience. Limited information on the assessment practices of Lebanese speech and language therapists (SLTs) is available. Such information is crucial for the development of adequate therapy services for clients with non-progressive dysarthria. This study aims to explore the assessment practices and attitudes of Lebanese SLTs working with adults with non-progressive dysarthria and to investigate their adherence to the framework of the World Health Organization's International Classification of Functioning, Disability and Health (ICF). METHODS: A cross-sectional study was conducted in Lebanon between March and May 2021. Data was collected through an online survey that included information on socio-demographic characteristics, practices, and attitudes of SLTs who assess adults with non-progressive dysarthria. RESULTS: A total of 50 Lebanese SLTs responded to the survey. The majority of SLTs (78%) assessed clients with non-progressive dysarthria across all ICF domains. SLTs reported dissatisfaction with the available assessment tools (64%) and reliance on informal tools (84%). In addition, 68% of the SLTs suggested the crucial need for the development of Arabic formal assessments that can quantitatively evaluate dysarthria and determine severity. The survey also showed that the respondents demonstrated a preference for the use of impairment-based tools. CONCLUSION: It can be concluded that the assessment practices of Lebanese SLTs, generally, follow the international trend and the recommended professional guidelines. Further research initiatives should be held to develop Arabic formal assessment tools for non-progressive dysarthria.

Acoustic, perceptual and clinical correlates of speech and voice in isolated dystonia: Preliminary findings.

BACKGROUND: Hyperkinetic dysarthria is often present in isolated dystonia (ID) and is still understudied. Four main clusters of deviant speech dimensions in dystonia hyperkinetic dysarthria were initially provided: articulatory inaccuracy, phonatory stenosis, prosodic excess and prosodic insufficiency. AIM: The aim of our exploratory study was to provide preliminary data on both perceptual and acoustic analyses in relation to three out of these four main clusters. METHODS & PROCEDURES: Eleven patients with ID and 11 healthy controls (HC) participated in this study. Clinical/perceptual assessments and acoustic analyses of speech recordings were performed, the latter allowing for the analysis of parameters referring to aerophonatory control, voice quality, prosodic features and speech intelligibility estimated by nine listeners. Between-group statistical comparisons were performed (Wilcoxon tests, p < 0.05). Single-case differences between each patient and the control group were also carried out (effect size index and t < 0.05). OUTCOMES & RESULTS: Between-group comparisons confirmed the presence of a 'phonatory stenosis'; in addition, deficit in aerophonatory control and hypophonia was also displayed. 'Prosodic insufficiency' was confirmed, but not at the individual level. 'Prosodic excess' manifested only in patients with marked and severe dysarthria. Correlations between altered maximum phonation time, loudness variation, speech and articulatory rates on the one hand, and several clinical speech assessments on the other hand, were also found. CONCLUSIONS & IMPLICATIONS: From these findings, altogether, perceptual characteristics of hyperkinetic dysarthria, as suggested by Darley et al., were quantified by the acoustic parameters we measured. As regards to our data obtained in a small participant sample, we would suggest that Darley et al.'s clusters of excess and insufficiency prosody should be questioned in future studies involving larger numbers of dystonic patients. Our study provides novel and preliminary results that demonstrate the relevance of using quantitative measures to further characterise speech/voice deficits in patients with ID.

Effect of boost articulation therapy (BArT) on intelligibility in adults with dysarthria.

BACKGROUND: The articulatory accuracy of patients with dysarthria is one of the most affected speech dimensions with a high impact on speech intelligibility. Behavioural treatments of articulation can either involve direct or indirect approaches. The latter have been thoroughly investigated and are generally appreciated for their almost immediate effects on articulation and intelligibility. The number of studies on (short-term) direct articulation therapy is limited. AIMS: To investigate the effects of short-term, boost articulation therapy (BArT) on speech intelligibility in patients with chronic or progressive dysarthria and the effect of severity of dysarthria on the outcome. METHODS & PROCEDURES: The study consists of a two-group pre-/post-test design to assess speech intelligibility at phoneme and sentence level and during spontaneous speech, automatic speech and reading a phonetically balanced text. A total of 17 subjects with mild to severe dysarthria participated in the study and were randomly assigned to either a patient-tailored, intensive articulatory drill programme or an intensive minimal pair training. Both training programmes were based on the principles of motor learning. Each training programme consisted of five sessions of 45 min completed within one week. OUTCOMES & RESULTS: Following treatment, a statistically significant increase of mean group intelligibility was shown at phoneme and sentence level, and in automatic sequences. This was supported by an acoustic analysis that revealed a reduction in formant centralization ratio. Within specific groups of severity, large and moderate positive effect sizes with Cohen's d were demonstrated. CONCLUSIONS & IMPLICATIONS: BArT successfully improves speech intelligibility in patients with chronic or progressive dysarthria at different levels of the impairment. What this paper adds What is already known on the subject Behavioural treatment of articulation in patients with dysarthria mainly involves indirect strategies, which have shown positive effects on speech intelligibility. However, there is limited evidence on the short-term effects of direct articulation therapy at the segmental level of speech. This study investigates the effectiveness of BArT on speech intelligibility in patients with chronic or progressive dysarthria at all severity levels. What this paper adds to existing knowledge The intensive and direct articulatory therapy programmes developed and applied in this study intend to reduce the impairment instead of compensating it. This approach results in a significant improvement of speech intelligibility at different dysarthria severity levels in a short period of time while contributing to exploit and develop all available residual motor skills in persons with dysarthria. What are the potential or actual clinical implications of this work? The improvements in intelligibility demonstrate the effectiveness of a BArT at the segmental level of speech. This makes it to be considered a suitable approach in the treatment of patients with chronic or progressive dysarthria.

Intelligibility in Down syndrome: Effect of measurement method and listener experience.

BACKGROUND: Speech intelligibility is a global indicator of the severity of a speech problem. It is a measure that has been used frequently in research and clinical assessment of speech. Previous studies have shown that factors, such as measurement method and listener experience, can influence speech intelligibility scores. However, these factors of speech intelligibility assessment have not yet been investigated in people with Down syndrome (DS). AIMS: To compare the speech intelligibility scores in speakers with DS measured using two methods: orthographic transcription and visual analogue scale (VAS), by two groups of listeners, experienced listeners and naïve listeners. Also, to examine the relationship across the four sets of speech intelligibility scores by means of correlational analysis. METHODS & PROCEDURES: A total of 30 adolescents and adults with DS read or repeated 12 sentences from a standardized test of intelligibility for adults with dysarthria. Each sentence was saved as a separate sound file and the 360 sentences were divided to form eight sets of stimuli. A total of 32 adults (16 experienced and 16 naïve) served as listeners of speech intelligibility. Each listener heard a single set of sentences and independently estimated the level of intelligibility for each sentence using a VAS in one task and wrote down the words perceived (i.e., orthographic transcription) in another task. The order of the two tasks was counterbalanced across listeners and the tasks were completed at least 1 week apart. OUTCOMES & RESULTS: Repeated-measures analysis of variance (ANOVA), confirmed by mixed-methods analysis, showed that the scores obtained using orthographic transcription were significantly higher than those obtained using VAS; and the experienced listeners' scores were significantly higher than the naïve listeners' scores. Spearman rank correlation analysis showed that the four sets of scores across all conditions were strongly positively correlated with each other. CONCLUSIONS & IMPLICATIONS: Listeners, both experienced and naïve, may udge speech in DS differently when using orthographic transcription versus VAS as the method of measurement. In addition, experienced listeners can judge speech intelligibility differently compared with listeners who are less exposed to unclear speech, which may not represent 'real-world' functional communicative ability. Speech and language therapists should be aware of the effect of these factors when measuring intelligibility scores and direct comparison of scores obtained using different procedures and by different groups of listeners is not recommended. What this paper adds What is already known on the subject Previous research on other clinical groups (e.g., Parkinson's disease) has shown that speech intelligibility scores can vary across different measurement methods and when judged by listeners with different experience. However, these factors have not yet been investigated in people with DS. What this paper adds to existing knowledge Similar to the findings reported for other clinical groups, using an impressionistic measurement method, such as VAS, can result in different speech intelligibility scores compared with scores obtained from orthographic transcription in speakers with DS. Furthermore, experienced listeners can perceive intelligibility as better compared with naïve (untrained) listeners for this group. What are the potential or actual clinical implications of this work? When measuring speech intelligibility, speech and language therapists should be aware that scores obtained using orthographic transcription can be higher than those obtained using VAS. They should also be aware that their increased exposure to hearing atypical speech may cause them to judge the speech difficulty as less severe and lead to an inaccurate representation of speech performance. Speech and language therapists should consider these factors when interpreting assessment results and especially when using intelligibility measures for treatment outcomes.

Acoustic vowel analysis and speech intelligibility in young adult Hebrew speakers: Developmental dysarthria versus typical development.

BACKGROUND: Developmental dysarthria is a motor speech impairment commonly characterized by varying levels of reduced speech intelligibility. The relationship between intelligibility deficits and acoustic vowel space among these individuals has long been noted in the literature, with evidence of vowel centralization (e.g., in English and Mandarin). However, the degree to which this centralization occurs and the intelligibility-acoustic relationship is maintained in different vowel systems has yet to be studied thoroughly. In comparison with American English, the Hebrew vowel system is significantly smaller, with a potentially smaller vowel space area, a factor that may impact upon the comparisons of the acoustic vowel space and its correlation with speech intelligibility. Data on vowel space and speech intelligibility are particularly limited for Hebrew speakers with motor speech disorders. AIMS: To determine the nature and degree of vowel space centralization in Hebrew-speaking adolescents and young adults with dysarthria, in comparison with typically developing (TD) peers, and to correlate these findings with speech intelligibility scores. METHODS & PROCEDURES: Adolescents and young adults with developmental dysarthria (secondary to cerebral palsy (CP) and other motor deficits, n = 17) and their TD peers (n = 17) were recorded producing Hebrew corner vowels within single words. For intelligibility assessments, naïve listeners transcribed those words produced by speakers with CP, and intelligibility scores were calculated. OUTCOMES & RESULTS: Acoustic analysis of vowel formants (F1, F2) revealed a centralization of vowel space among speakers with CP for all acoustic metrics of vowel formants, and mainly for the formant centralization ratio (FCR), in comparison with TD peers. Intelligibility scores were correlated strongly with the FCR metric for speakers with CP. CONCLUSIONS & IMPLICATIONS: The main results, vowel space centralization for speakers with CP in comparison with TD peers, echo previous cross-linguistic results. The correlation of acoustic results with speech intelligibility carries clinical implications. Taken together, the results contribute to better characterization of the speech production deficit in Hebrew speakers with motor speech disorders. Furthermore, they may guide clinical decision-making and intervention planning to improve speech intelligibility. What this paper adds What is already known on the subject Speech production and intelligibility deficits among individuals with developmental dysarthria (e.g., secondary to CP) are well documented. These deficits have also been correlated with centralization of the acoustic vowel space, although primarily in English speakers. Little is known about the acoustic characteristics of vowels in Hebrew speakers with motor speech disorders, and whether correlations with speech intelligibility are maintained. What this paper adds to existing knowledge This study is the first to describe the acoustic characteristics of vowel space in Hebrew-speaking adolescents and young adults with developmental dysarthria. The results demonstrate a centralization of the acoustic vowel space in comparison with TD peers for all measures, as found in other languages. Correlation between acoustic measures and speech intelligibility scores were also documented. We discuss these results within the context of cross-linguistic comparisons. What are the potential or actual clinical implications of this work? The results confirm the use of objective acoustic measures in the assessment of individuals with motor speech disorders, providing such data for Hebrew-speaking adolescents and young adults. These measures can be used to determine the nature and severity of the speech deficit across languages, may guide intervention planning, as well as measure the effectiveness of intelligibility-based treatment programmes.