Objective acoustic quantification of phonatory dysfunction in Huntington's disease

Exploring the Relationships Between Antipsychotic Dosage and Voice Characteristics in Relation to Extrapyramidal Symptoms

OBJECTIVE

Extrapyramidal symptoms (EPS) are common side effects of antipsychotic drugs. Despite the growing interest in exploring objective biomarkers for EPS prevention and the potential use of voice in detecting clinical disorders, no studies have demonstrated the relationships between vocal changes and EPS. Therefore, we aimed to determine the associations between voice changes and antipsychotic dosage, and further investigated whether speech characteristics could be used as predictors of EPS.

METHODS

Forty-two patients receiving or expected to receive antipsychotic drugs were recruited. Drug-induced parkinsonism of EPS was evaluated using the Simpson-Angus Scale (SAS). Participants' voice data consisted of 16 neutral sentences and 2 second-long /Ah/utterances. Thirteen voice features were extracted from the obtained voice data. Each voice feature was compared between groups categorized based on SAS total score of below and above "0.6." The associations between antipsychotic dosage and voice characteristics were examined, and vocal trait variations according to the presence of EPS were explored.

RESULTS

Significant associations were observed between specific vocal characteristics and antipsychotic dosage across both datasets of 1-16 sentences and /Ah/utterances. Notably, Mel-Frequency Cepstral Coefficients (MFCC) exhibited noteworthy variations in response to the presence of EPS. Specifically, among the 13 MFCC coefficients, MFCC1 (t=-4.47, p<0.001), MFCC8 (t=-4.49, p<0.001), and MFCC12 (t=-2.21, p=0.029) showed significant group differences in the overall statistical values.

CONCLUSION

Our results suggest that MFCC may serve as a predictor of detecting drug-induced parkinsonism of EPS. Further research should address potential confounding factors impacting the relationship between MFCC and antipsychotic dosage, possibly improving EPS detection and reducing antipsychotic medication side effects.

Disease Delineation for Multiple Sclerosis, Friedreich Ataxia, and Healthy Controls Using Supervised Machine Learning on Speech Acoustics

Neurodegenerative disease often affects speech. Speech acoustics can be used as objective clinical markers of pathology. Previous investigations of pathological speech have primarily compared controls with one specific condition and excluded comorbidities. We broaden the utility of speech markers by examining how multiple acoustic features can delineate diseases. We used supervised machine learning with gradient boosting (CatBoost) to delineate healthy speech from speech of people with multiple sclerosis or Friedreich ataxia. Participants performed a diadochokinetic task where they repeated alternating syllables. We subjected 74 spectral and temporal prosodic features from the speech recordings to machine learning. Results showed that Friedreich ataxia, multiple sclerosis and healthy controls were all identified with high accuracy (over 82%). Twenty-one acoustic features were strong markers of neurodegenerative diseases, falling under the categories of spectral qualia, spectral power, and speech rate. We demonstrated that speech markers can delineate neurodegenerative diseases and distinguish healthy speech from pathological speech with high accuracy. Findings emphasize the importance of examining speech outcomes when assessing indicators of neurodegenerative disease. We propose large-scale initiatives to broaden the scope for differentiating other neurological diseases and affective disorders.

Speech biomarkers in Huntington's disease: A cross-sectional study in pre-symptomatic, prodromal and early manifest stages

BACKGROUND AND PURPOSE

Motor speech alterations are a prominent feature of clinically manifest Huntington's disease (HD). Objective acoustic analysis of speech can quantify speech alterations. It is currently unknown, however, at what stage of HD speech alterations can be reliably detected. We aimed to explore the patterns and extent of speech alterations using objective acoustic analysis in HD and to assess correlations with both rater-assessed phenotypical features and biological determinants of HD.

METHODS

Speech samples were acquired from 44 premanifest (29 pre-symptomatic and 15 prodromal) and 25 manifest HD gene expansion carriers, and 25 matched healthy controls. A quantitative automated acoustic analysis of 10 speech dimensions was performed.

RESULTS

Automated speech analysis allowed us to differentiate between participants with HD and controls, with areas under the curve of 0.74 for pre-symptomatic, 0.92 for prodromal, and 0.97 for manifest stages. In addition to irregular alternating motion rates and prolonged pauses seen only in manifest HD, both prodromal and manifest HD displayed slowed articulation rate, slowed alternating motion rates, increased loudness variability, and unstable steady-state position of articulators. In participants with premanifest HD, speech alteration severity was associated with cognitive slowing (r = -0.52, p < 0.001) and the extent of bradykinesia (r = 0.43, p = 0.004). Speech alterations correlated with a measure of exposure to mutant gene products (CAG-age-product score; r = 0.60, p < 0.001).

CONCLUSION

Speech abnormalities in HD are associated with other motor and cognitive deficits and are measurable already in premanifest stages of HD. Therefore, automated speech analysis might represent a quantitative HD biomarker with potential for assessing disease progression.

Fundamental frequency related parameters in Brazilians with COVID-19

This study compares fundamental frequency (f_o) and fundamental frequency standard deviation (f_oSD) of COVID-19 patients with the same parameters in the speech of subjects without COVID-19, and verifies whether there is an effect of age and sex in the patient group. Both groups, subjects with and without COVID-19, are formed by Brazilian Portuguese speakers. Speech samples were obtained from 100 patients with mild to severe symptoms of COVID-19, and 100 healthy subjects. A single 31-syllable Portuguese sentence was used as the elicitation material for all subjects. The recordings were divided into four age groups. The acoustic measures were semi-automatically extracted and analyzed by a series of analyses of variance. Patients with COVID-19 present vocal differences in f_o-related parameters when compared to healthy subjects, that is, patient voices presented higher f_o and f_oSD with respect to control voices. In addition, for patient voices, there was an age and sex effect on f_o SD values. Vocal parameters of women and elderly subjects showed more marked differences in f_o-related parameters, indicating that patient voices are higher-pitched and have a higher variation of f_o SD. Consequently, f_o-related parameters may be tested as vocal biomarkers in the screening of respiratory insufficiency by voice analysis, in patients with severe symptoms of COVID-19.

Dysarthria in hereditary spastic paraplegia type 4

OBJECTIVE

To describe the speech pattern of patients with hereditary Spastic Paraplegia type 4 (SPG4) and correlated it with their clinical data.

METHODS

Cross-sectional study was carried out in two university hospitals in Brazil. Two groups participated in the study: the case group (n = 28) with a confirmed genetic diagnosis for SPG4 and a control group (n = 17) matched for sex and age. The speech assessment of both groups included: speech task recording, acoustic analysis, and auditory-perceptual analysis. In addition, disease severity was assessed with the Spastic Paraplegia Rating Scale (SPRS).

RESULTS

In the auditory-perceptual analysis, 53.5% (n = 15) of individuals with SPG4 were dysarthric, with mild to moderate changes in the subsystems of phonation and articulation. On acoustic analysis, SPG4 subjects' performances were worse in measurements related to breathing (maximum phonation time) and articulation (speech rate, articulation rate). The articulation variables (speech rate, articulation rate) are related to the age of onset of the first motor symptom.

CONCLUSION

Dysarthria in SPG4 is frequent and mild, and it did not evolve in conjunction with more advanced motor diseases. This data suggest that diagnosed patients should be screened and referred for speech therapy evaluation and those pathophysiological mechanisms of speech involvement may differ from the length-dependent degeneration of the corticospinal tract.

Speech and language characteristics differentiate Alzheimer's disease and dementia with Lewy bodies

Introduction

Early differential diagnosis of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) is important, but it remains challenging. Different profiles of speech and language impairments between AD and DLB have been suggested, but direct comparisons have not been investigated.

Methods

We collected speech responses from 121 older adults comprising AD, DLB, and cognitively normal (CN) groups and investigated their acoustic, prosodic, and linguistic features.

Results

The AD group showed larger differences from the CN group than the DLB group in linguistic features, while the DLB group showed larger differences in prosodic and acoustic features. Machine-learning classifiers using these speech features achieved 87.0% accuracy for AD versus CN, 93.2% for DLB versus CN, and 87.4% for AD versus DLB.

Discussion

Our findings indicate the discriminative differences in speech features in AD and DLB and the feasibility of using these features in combination as a screening tool for identifying/differentiating AD and DLB.

Predicting clinical scores in Huntington's disease: a lightweight speech test

OBJECTIVES

Using brief samples of speech recordings, we aimed at predicting, through machine learning, the clinical performance in Huntington's Disease (HD), an inherited Neurodegenerative disease (NDD).

METHODS

We collected and analyzed 126 samples of audio recordings of both forward and backward counting from 103 Huntington's disease gene carriers [87 manifest and 16 premanifest; mean age 50.6 (SD 11.2), range (27-88) years] from three multicenter prospective studies in France and Belgium (MIG-HD (ClinicalTrials.gov NCT00190450); BIO-HD (ClinicalTrials.gov NCT00190450) and Repair-HD (ClinicalTrials.gov NCT00190450). We pre-registered all of our methods before running any analyses, in order to avoid inflated results. We automatically extracted 60 speech features from blindly annotated samples. We used machine learning models to combine multiple speech features in order to make predictions at individual levels of the clinical markers. We trained machine learning models on 86% of the samples, the remaining 14% constituted the independent test set. We combined speech features with demographics variables (age, sex, CAG repeats, and burden score) to predict cognitive, motor, and functional scores of the Unified Huntington's disease rating scale. We provided correlation between speech variables and striatal volumes.

RESULTS

Speech features combined with demographics allowed the prediction of the individual cognitive, motor, and functional scores with a relative error from 12.7 to 20.0% which is better than predictions using demographics and genetic information. Both mean and standard deviation of pause durations during backward recitation and clinical scores correlated with striatal atrophy (Spearman 0.6 and 0.5-0.6, respectively).

INTERPRETATION

Brief and examiner-free speech recording and analysis may become in the future an efficient method for remote evaluation of the individual condition in HD and likely in other NDD.

Voice processing for COVID-19 scanning and prognostic indicator

COVID-19 pandemic has posed serious risk of contagion to humans. There is a need to find reliable non-contact tests like vocal correlates of COVID-19 infection. Thirty-six Asian ethnic volunteers 16 (8M & 8F) infected subjects and 20 (10M &10F) non-infected controls participated in this study by vocalizing vowels /a/, /e/, /i/, /o/, /u/. Voice correlates of 16 COVID-19 positive patients were compared during infection and after recovery with 20 non-infected controls. Compared to non-infected controls, significantly higher values of energy intensity for /o/ (p = 0.048); formant F1 for /o/ (p = 0.014); and formant F3 for /u/ (p = 0.032) were observed in male patients, while higher values of Jitter (local, abs) for /o/ (p = 0.021) and Jitter (ppq5) for /a/ (p = 0.014) were observed in female patients. However, formant F2 for /u/ (p = 0.018), mean pitch F0 for /e/, /i/ and /o/ (p = 0.033; 0.036; 0.047) decreased for female patients under infection. Compared to recovered conditions, HNR for /e/ (p = 0.014) was higher in male patients under infection, while Jitter (rap) for /a/ (p = 0.041); Jitter (ppq5) for /a/ (p = 0.032); Shimmer (local, dB) for /i/ (p = 0.024); Shimmer (apq5) for /u/ (p = 0.019); and formant F4 for vowel /o/ (p = 0.022) were higher in female patients under infection. However, HNR for /e/ (p = 0.041); and formant F1 for /o/ (p = 0.002) were lower in female patients compared to their recovered conditions. Obtained results support the hypothesis since changes in voice parameters were observed in the infected patients which can be correlated to a combination of acoustic measures like fundamental frequency, formant characteristics, HNR, and voice perturbations like jitter and shimmer for different vowels. Thus, voice analysis can be used for scanning and prognosis of COVID-19 infection. Based on the findings of this study, a mobile application can be developed to analyze human voice in real-time to detect COVID-19 symptoms for remedial measures and necessary action.

Understanding speech and swallowing difficulties in individuals with Huntington disease: Validation of the HDQLIFE Speech Difficulties and Swallowing Difficulties Item Banks

PURPOSE

As Huntington disease (HD) progresses, speech and swallowing difficulties become more profound. These difficulties have an adverse effect on health-related quality of life (HRQOL), thus psychometrically robust measures of speech and swallowing are needed to better understand the impact of these domains across the course of the disease. Therefore, the purpose of this study is to establish the clinical utility of two new patient-reported outcome measures (PROs), HDQLIFE Speech Difficulties and HDQLIFE Swallowing Difficulties.

METHODS

Thirty-one participants with premanifest or manifest HD, and 31 age- and sex-matched healthy control participants were recruited for this study. Participants completed several PROs [HDQLIFE Speech Difficulties, HDQLIFE Swallowing Difficulties, Communication Participation Item Bank (CPIB)], as well as several clinician-rated assessments of speech and functioning. A computational algorithm designed to detect features of spoken discourse was also examined. Analyses were focused on establishing the reliability and validity of these new measures.

RESULTS

Internal consistency was good for Swallowing (Cronbach's alpha = 0.89) and excellent for Speech and the CPIB (both Cronbach's alpha ≥ 0.94), and convergent/discriminant validity was supported. Known groups validity for the PROs was supported by significant group differences among control participants and persons with different stages of HD (all p < 0.0001). All PROs were able to distinguish those with and without clinician-rated dysarthria (likelihood ratios far exceeded the threshold for clinical decision making [all ≥ 3.28]).

CONCLUSIONS

Findings support the clinical utility of the HDQLIFE Speech and Swallowing PROs and the CPIB for use across the HD disease spectrum. These PROs also have the potential to be clinically useful in other populations.

Voice Quality Evaluation in Patients With COVID-19: An Acoustic Analysis

Objectives

With the COVID-19 outbreak around the globe and its potential effect on infected patients’ voice, this study set out to evaluate and compare the acoustic parameters of voice between healthy and infected people in an objective manner.

Methods

Voice samples of 64 COVID-19 patients and 70 healthy Persian speakers who produced a sustained vowel /a/ were evaluated. Between-group comparisons of the data were performed using the two-way ANOVA and Wilcoxon's rank-sum test.

Results

The results revealed significant differences in CPP, HNR, H1H2, F0SD, jitter, shimmer, and MPT values between COVID-19 patients and the healthy participants. There were also significant differences between the male and female participants in all the acoustic parameters, except jitter, shimmer and MPT. No interaction was observed between gender and health status in any of the acoustic parameters.

Conclusion

The statistical analysis of the data revealed significant differences between the experimental and control groups in this study. Changes in the acoustic parameters of voice are caused by the insufficient airflow, and increased aperiodicity, irregularity, signal perturbation and level of noise, which are the consequences of pulmonary and laryngological involvements in patients with COVID-19.

Vocalisation as a Viable Assessment for Phenotyping Minipigs Transgenic for the Huntington Gene?

BACKGROUND

Large animal models, such as the transgenic (tg) Huntington disease (HD) minipig, have been proposed to improve translational reliability and assessment of safety, efficacy and tolerability in preclinical studies. Minipigs are characterised by high genetic homology and comparable brain structures to humans. In addition, behavioural assessments successfully applied in humans could be explored in minipigs to establish similar endpoints in preclinical and clinical studies. Recently, analysis of voice and speech production was established to characterise HD patients.

OBJECTIVE

The aim of this study was to investigate whether vocalisation could also serve as a viable marker for phenotyping minipigs transgenic for Huntington's disease (tgHD) and whether tgHD minipigs reveal changes in this domain compared to wildtype (wt) minipigs.

METHODS

While conducting behavioural testing, incidence of vocalisation was assessed for a cohort of 14 tgHD and 18 wt minipigs. Statistical analyses were performed using Fisher's Exact Test for group comparisons and McNemar's Test for intra-visit differences between tgHD and wt minipigs.

RESULTS

Vocalisation can easily be documented during phenotyping assessments of minipigs. Differences in vocalisation incidences across behavioural conditions were detected between tgHD and wt minipigs. Influence of the genotype on vocalisation was detectable during a period of 1.5 years.

CONCLUSION

Vocalisation may be a viable marker for phenotyping minipigs transgenic for the Huntington gene. Documentation of vocalisation provides a non-invasive opportunity to capture potential disease signs and explore phenotypic development including the age of disease manifestation.

Speech-Language Pathology Evaluation and Management of Hyperkinetic Disorders Affecting Speech and Swallowing Function

Background

Hyperkinetic dysarthria is characterized by abnormal involuntary movements affecting respiratory, phonatory, and articulatory structures impacting speech and deglutition. Speech–language pathologists (SLPs) play an important role in the evaluation and management of dysarthria and dysphagia. This review describes the standard clinical evaluation and treatment approaches by SLPs for addressing impaired speech and deglutition in specific hyperkinetic dysarthria populations.

Methods

A literature review was conducted using the data sources of PubMed, Cochrane Library, and Google Scholar. Search terms included 1) hyperkinetic dysarthria, essential voice tremor, voice tremor, vocal tremor, spasmodic dysphonia, spastic dysphonia, oromandibular dystonia, Meige syndrome, orofacial, cervical dystonia, dystonia, dyskinesia, chorea, Huntington’s Disease, myoclonus; and evaluation/treatment terms: 2) Speech–Language Pathology, Speech Pathology, Evaluation, Assessment, Dysphagia, Swallowing, Treatment, Management, and diagnosis.

Results

The standard SLP clinical speech and swallowing evaluation of chorea/Huntington’s disease, myoclonus, focal and segmental dystonia, and essential vocal tremor typically includes 1) case history; 2) examination of the tone, symmetry, and sensorimotor function of the speech structures during non-speech, speech and swallowing relevant activities (i.e., cranial nerve assessment); 3) evaluation of speech characteristics; and 4) patient self-report of the impact of their disorder on activities of daily living. SLP management of individuals with hyperkinetic dysarthria includes behavioral and compensatory strategies for addressing compromised speech and intelligibility. Swallowing disorders are managed based on individual symptoms and the underlying pathophysiology determined during evaluation.

Discussion

SLPs play an important role in contributing to the differential diagnosis and management of impaired speech and deglutition associated with hyperkinetic disorders.

Hypernasality associated with basal ganglia dysfunction: evidence from Parkinson's disease and Huntington's disease

Background

Although increased nasality can originate from basal ganglia dysfunction, data regarding hypernasality in Parkinson’s disease (PD) and Huntington’s disease (HD) are very sparse. The aim of the current study was to analyze acoustic and perceptual correlates of velopharyngeal seal closure in 37 PD and 37 HD participants in comparison to 37 healthy control speakers.

Methods

Acoustical analysis was based on sustained phonation of the vowel /i/ and perceptual analysis was based on monologue. Perceptual analysis was performed by 10 raters using The Great Ormond Street Speech Assessment ’98. Acoustic parameters related to changes in a 1/3-octave band centered on 1 kHz were proposed to reflect nasality level and behavior through utterance.

Results

Perceptual analysis showed the occurrence of mild to moderate hypernasality in 65% of PD, 89% of HD and 22% of control speakers. Based on acoustic analyses, 27% of PD, 54% of HD and 19% of control speakers showed an increased occurrence of hypernasality. In addition, 78% of HD patients demonstrated a high occurrence of intermittent hypernasality. Further results indicated relationships between the acoustic parameter representing fluctuation of nasality and perceptual assessment (r = 0.51, p < 0.001) as well as the Unified Huntington Disease Rating Scale chorea composite subscore (r = 0.42, p = 0.01).

Conclusions

In conclusion the acoustic assessment showed that abnormal nasality was not a common feature of PD, whereas patients with HD manifested intermittent hypernasality associated with chorea.

Automatic Evaluation of Speech Rhythm Instability and Acceleration in Dysarthrias Associated with Basal Ganglia Dysfunction

Speech rhythm abnormalities are commonly present in patients with different neurodegenerative disorders. These alterations are hypothesized to be a consequence of disruption to the basal ganglia circuitry involving dysfunction of motor planning, programing, and execution, which can be detected by a syllable repetition paradigm. Therefore, the aim of the present study was to design a robust signal processing technique that allows the automatic detection of spectrally distinctive nuclei of syllable vocalizations and to determine speech features that represent rhythm instability (RI) and rhythm acceleration (RA). A further aim was to elucidate specific patterns of dysrhythmia across various neurodegenerative disorders that share disruption of basal ganglia function. Speech samples based on repetition of the syllable /pa/ at a self-determined steady pace were acquired from 109 subjects, including 22 with Parkinson's disease (PD), 11 progressive supranuclear palsy (PSP), 9 multiple system atrophy (MSA), 24 ephedrone-induced parkinsonism (EP), 20 Huntington's disease (HD), and 23 healthy controls. Subsequently, an algorithm for the automatic detection of syllables as well as features representing RI and RA were designed. The proposed detection algorithm was able to correctly identify syllables and remove erroneous detections due to excessive inspiration and non-speech sounds with a very high accuracy of 99.6%. Instability of vocal pace performance was observed in PSP, MSA, EP, and HD groups. Significantly increased pace acceleration was observed only in the PD group. Although not significant, a tendency for pace acceleration was observed also in the PSP and MSA groups. Our findings underline the crucial role of the basal ganglia in the execution and maintenance of automatic speech motor sequences. We envisage the current approach to become the first step toward the development of acoustic technologies allowing automated assessment of rhythm in dysarthrias.

Phonatory dysfunction as a preclinical symptom of Huntington disease

Purpose

Although dysphonia has been shown to be a common sign of Huntington disease (HD), the extent of phonatory dysfunction in gene positive premanifest HD individuals remains unknown. The aim of the current study was to explore the possible occurrence of phonatory abnormalities in prodromal HD.

Method

Sustained vowel phonations were acquired from 28 premanifest HD individuals and 28 healthy controls of comparable age. Data were analysed acoustically for measures of several phonatory dimensions including airflow insufficiency, aperiodicity, irregular vibration of vocal folds, signal perturbations, increased noise, vocal tremor and articulation deficiency. A predictive model was built to find the best combination of acoustic features and estimate sensitivity/specificity for differentiation between premanifest HD subjects and controls. The extent of voice deficits according to a specific phonatory dimension was determined using statistical decision making theory. The results were correlated to global motor function, cognitive score, disease burden score and estimated years to disease onset.

Results

Measures of aperiodicity and increased noise were able to significantly differentiate between premanifest HD individuals and controls (p<0.01). The combination of these aspects of dysphonia led to a sensitivity of 91.5% and specificity of 79.2% to correctly distinguish speakers with premanifest HD from healthy individuals. Some form of disrupted phonatory function was revealed in 68% of our premanifest HD subjects, where 18% had one affected phonatory dimension and 50% showed impairment of two or more dimensions. A relationship between pitch control and cognitive score was also observed (r = −0.50, p = 0.007).

Conclusions

Phonatory abnormalities are detectable even the in premotor stages of HD. Speech investigation may have the potential to provide functional biomarkers of HD and could be included in future clinical trials and therapeutic interventions.

Characteristics and occurrence of speech impairment in Huntington's disease: possible influence of antipsychotic medication

Although motor speech impairment is a common manifestation of Huntington's disease (HD), its description remains limited. The aim of the current study was therefore to estimate the occurrence and characteristics of speech disorder in HD and to explore the influence of antipsychotic medication on speech performance. Speech samples, including reading passage and monologue, were acquired from 40 individuals diagnosed with HD and 40 age- and sex-matched healthy controls. Objective acoustic analyses were used to evaluate key aspects of speech including vowel articulation, intensity, pitch and timing. A predictive model was constructed to detect the occurrence and most prominent patterns of speech dysfunction in HD. We revealed that 93% of HD patients manifest some degree of speech impairment. Decreased number of pauses, slower articulation rate, imprecise vowel articulation and excess intensity variations were found to be the most salient patterns of speech dysfunction in HD. We further demonstrated that antipsychotic medication may induce excessive loudness and pitch variations perceptually resembling excess patterns of word stress, and may also accentuate general problems with speech timing. Additionally, antipsychotics induced a slight improvement of vowel articulation. Specific speech alterations observed in HD patients indicate that speech production may reflect the pathophysiology of the disease as well as treatment effects, and may therefore be considered a valuable marker of functional disability in HD.

A distinct variant of mixed dysarthria reflects parkinsonism and dystonia due to ephedrone abuse

A distinctive alteration of speech has been reported in patients suffering from ephedrone-induced parkinsonism. However, an objective assessment of dysarthria has not been performed in ephedrone users. We studied 28 young Caucasian men from Georgia with a previous history of ephedrone abuse and compared them to 25 age-matched healthy controls. Speech examination, brain MRI, and NNIPPS-Parkinson plus scale were performed in all patients. The accurate differential diagnosis of dysarthria subtypes was based on the quantitative acoustic analyses of 15 speech dimensions. We revealed a distinct variant of mixed dysarthria with a combination of hyperkinetic and hypokinetic components representing the altered motor programming of dystonia and bradykinesia in ephedrone-induced parkinsonism. According to acoustic analyses, all patients presented at least one affected speech dimension, whereas dysarthria was moderate in 43% and severe in 36% of patients. Further findings indicated relationships between motor subscores of dystonia and bradykinesia and speech components of loudness (r = -0.54, p < 0.01), articulation (r = 0.40, p < 0.05), and timing (r = -0.53, p < 0.01). In ephedrone-induced parkinsonism a prominent mixed hyperkinetic-hypokinetic dysarthria occurs that appears related to marked dystonia and bradykinesia and probably reflects manganese induced toxic and neurodegenerative damage to the globus pallidus internus and substantia nigra.