Speech disorders of Parkinsonism: a review

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.

Parkinson's disease speech production network as determined by graph-theoretical network analysis

Parkinson's disease (PD) can affect speech as well as emotion processing. We employ whole-brain graph-theoretical network analysis to determine how the speech-processing network (SPN) changes in PD, and assess its susceptibility to emotional distraction. Functional magnetic resonance images of 14 patients (aged 59.6 ± 10.1 years, 5 female) and 23 healthy controls (aged 64.1 ± 6.5 years, 12 female) were obtained during a picture-naming task. Pictures were supraliminally primed by face pictures showing either a neutral or an emotional expression. PD network metrics were significantly decreased (mean nodal degree, p < 0.0001; mean nodal strength, p < 0.0001; global network efficiency, p < 0.002; mean clustering coefficient, p < 0.0001), indicating an impairment of network integration and segregation. There was an absence of connector hubs in PD. Controls exhibited key network hubs located in the associative cortices, of which most were insusceptible to emotional distraction. The PD SPN had more key network hubs, which were more disorganized and shifted into auditory, sensory, and motor cortices after emotional distraction. The whole-brain SPN in PD undergoes changes that result in (a) decreased network integration and segregation, (b) a modularization of information flow within the network, and (c) the inclusion of primary and secondary cortical areas after emotional distraction.

Speech rate and fluency in young-onset Parkinson's disease: A longitudinal case study from early to post brain surgery stage

The aim of this study is to analyse the speech rate, pausing and fluency of a patient with young-onset Parkinson's Disease in different stages of the disease. Speech samples of the patient were recorded in the early stages of the disease until after the brain surgery. The recordings were compared to the speech of healthy control speakers. Speech rate, articulation rate, pausing and the frequency of disfluencies were analysed. Results show that all parameters are influenced by the severity of the disease, but articulation rate is the most affected.

Investigating the Impact of Voice Impairment on Quality of Life in Stroke Patients: The Voice Handicap Index (VHI) Questionnaire Study

The Voice Handicap Index (VHI) is a patient-centered evaluation tool specifically designed for assessing voice-related quality of life. Although the VHI has been extensively used in patients with voice disorders, its applicability in stroke patients has not been fully established. This prospective cross-sectional study aimed to investigate the feasibility of using the VHI questionnaire in identifying stroke patients with voice problems. The study included a cohort of acute to subacute first-ever stroke patients (n = 48), with or without voice problems, as well as other non-stroke patients (n = 31) who agreed to complete the VHI questionnaire. Stroke patients with self-reported voice problems demonstrated significantly higher VHI scores and poorer life quality scores compared to the control groups. These patients also had lower Mini-Mental State Examination (MMSE), Modified Barthel Index (MBI), and Euro-QoL-5D-5L (EQ-5D-5L) scores. Spearman correlation analysis revealed an inverse association between VHI scores and EQ-5D-5L (rho = -0.77, p < 0.001), Korean Mann Assessment of Swallowing Ability (rho = -0.51, p < 0.001), and other functional parameters, including the National Institutes of Health Stroke Scale, MMSE, and MBI scores. Multiple regression analysis indicated that the VHI score was the biggest contributing factor to EQ scores. This is the first study to demonstrate that stroke patients with voice problems may experience reduced quality of life, even after controlling for other confounding factors such as dysphagia or neurological deficits. Future studies are needed whether addressing these issues by implementing the VHI may facilitate the improvement of patients' quality of life.

What Can Altered Auditory Feedback Paradigms Tell Us About Vocal Motor Control in Individuals With Voice Disorders?

Purpose

The goal of this review article is to provide a summary of the progression of altered auditory feedback (AAF) as a method to understand the pathophysiology of voice disorders. This review article focuses on populations with voice disorders that have thus far been studied using AAF, including individuals with Parkinson's disease, cerebellar degeneration, hyperfunctional voice disorders, vocal fold paralysis, and laryngeal dystonia. Studies using AAF have found that individuals with Parkinson's disease, cerebellar degeneration, and laryngeal dystonia have hyperactive auditory feedback responses due to differing underlying causes. In persons with PD, the hyperactivity may be a compensatory mechanism for atypically weak feedforward motor control. In individuals with cerebellar degeneration and laryngeal dystonia, the reasons for hyperactivity remain unknown. Individuals with hyperfunctional voice disorders may have auditory-motor integration deficits, suggesting atypical updating of feedforward motor control.

Conclusions

These findings have the potential to provide critical insights to clinicians in selecting the most effective therapy techniques for individuals with voice disorders. Future collaboration between clinicians and researchers with the shared objective of improving AAF as an ecologically feasible and valid tool for clinical assessment may provide more personalized therapy targets for individuals with voice disorders.

Management of Parkinson's Disease Dysarthria: Can Artificial Intelligence Provide the Solution?

Speech disorder is a significant problem for people affected with Parkinson's disease (PD) leading to a substantial disability to communicate with others. PD affects the voice, including changes in pitch, intensity, articulation, and syllable rate.We aimed to study the current status of artificial intelligence (AI) using machine learning algorithms (MLAs) in the assessment of speech abnormalities in PD along with the generation of intelligible synthetic speech for voice rehabilitation. We searched the literature for studies focusing on speech/voice disorder in PD and rehabilitation techniques till June 18, 2022. We searched PubMed and Engineering Village (Compendex and Inspec combined) databases. After careful screening of the title and evaluation of abstracts, we used select articles describing the use of AI or its various forms in the management of speech abnormalities in PD to synthesize this review. MLAs classify PD and non-PD patients with an accuracy of more than 90% using only voice features. Non-acoustic sensors can rehabilitate PD patient by converting dysarthric speech to highly intelligible speech using MLAs. MLAs can automatically assess several speech features and quantify the progression of speech abnormalities in PD. PD speech rehabilitation using MLAs may prove superior to other available therapies.

Characteristics of Speech and Voice as Predictors of the Quality of Communication in Adults with Hypokinetic Dysarthria

Hypokinetic dysarthria is characterized by a speech that gradually becomes monotonous, poorly modulated, quiet and ultimately unintelligible. The goal of this research is to determine the acoustic characteristics of voice and speech in adults with hypokinetic dysarthria and the impact of the altered voice on the quality of communication. The sample consisted of 30 elderly respondents of both genders with Parkinson’s disease and hypokinetic dysarthria. In order to conduct a spectral analysis, the voice of patients was recorded while they were reading phonetically balanced text. The respondents conducted a self-assessment of the degree of their own handicap caused by voice disorder and impact of the voice handicap by completing the Voice Handicap Index (VHI). Statistically significant differences were determined in the position of some formants in respondents compared to the values of formants in typical speakers for the following vowels: F1 of the vowel /I/ and F2 of the vowels /E/, /I/, /O/ and /U/. By examining the relation between the score achieved on the VHI instrument and the value of formants, the only statistically significant correlation was achieved between the formant F1 of the vowel /A/ and functional and emotional subscale. By regression analysis used to determine the predictor of the quality of communication, it was confirmed that F1 of the vowel /A/ has a statistically significant contribution to the explanation of the score achieved on functional and emotional subscale, by explaining 15% of the functional subscale (Beta=-0,393 (11,30 – 47,37)) and 10% of the emotional subscale (Beta=-0,363 (-0,052 – 0,000)).

Contribution of the Cerebellum and the Basal Ganglia to Language Production: Speech, Word Fluency, and Sentence Construction-Evidence from Pathology

Evidence reported in recent decades increasingly confirms that both the cerebellum and the basal ganglia, which are primarily involved in movement control, also have a significant role in a vast range of cognitive and affective functions. Evidence from pathology indicates that the disorders of some aspects of language production which follow damage of the cerebellum or respectively basal ganglia, i.e., disorders of speech, word fluency, and sentence construction, have identifiable neuropsychological profiles and that most manifestations can be specifically attributed to the dysfunctions of mechanisms supported by one or the other of these structures. The cerebellum and the basal ganglia are reciprocally interconnected. Thus, it is plausible that some disorders observed when damage involves one of these structures could be remote effects of abnormal activity in the other. However, in a purely clinical-neuropsychological perspective, primary and remote effects in the network are difficult to disentangle. Functional neuroimaging and non-invasive brain stimulation techniques likely represent the indispensable support for achieving this goal.

Detection of Articulatory Deficits in Parkinson's Disease: Can Systematic Manipulations of Phonetic Complexity Help?

Purpose This study sought to determine the feasibility of using phonetic complexity manipulations as a way to systematically assess articulatory deficits in talkers with progressive dysarthria due to Parkinson's disease (PD). Method Articulatory kinematics were recorded using three-dimensional electromagnetic articulography from 15 talkers with PD (58-84 years old) and 15 healthy controls (55-80 years old) while they produced target words embedded in a carrier phrase. Majority of the talkers with PD exhibited a relatively mild dysarthria. For stimuli selection, phonetic complexity was calculated for a variety of words using the framework proposed by Kent (1992), and six words representative of low, medium, and high phonetic complexity were selected as targets. Jaw, posterior tongue, and anterior tongue kinematic measures that were used to test for phonetic complexity effects included movement speed, cumulative path distance, movement range, movement duration, and spatiotemporal variability. Results Significantly smaller movements and slower movement speeds were evident in talkers with PD, predominantly for words with high phonetic complexity. The effect sizes of between-groups differences were larger for several jaw kinematic measures than those of the tongue. Discussion and Conclusion Findings suggest that systematic manipulations of phonetic complexity can support the detection of articulatory deficits in talkers with PD. Phonetic complexity should therefore be leveraged for the assessment of articulatory performance in talkers with progressive dysarthria. Future work will be directed toward linking speech kinematic and auditory-perceptual measures to determine the clinical significance of the current findings.

Voice changes in Parkinson's disease: What are they telling us?

Emerging evidence suggests voice dysfunction is the earliest sign of motor impairment in Parkinson's disease (PD). The complexity and fine motor control involved in vocalization may result in dysfunction here before the limbs. The voice in PD demonstrates characteristic changes on perceptual and acoustic analyses. The physiological and anatomical correlates of these have been investigated through laryngoscopy, stroboscopy, photoglottography, laryngeal electromyography, computed-tomography, pulmonary function testing and aerodynamic assessments. These have revealed numerous abnormalities including incomplete glottic closure and vocal fold hypoadduction/bowing to account for these voice changes. Many of these phenomena are likely related to rigidity or bradykinesia of the laryngeal muscles. The early onset of voice changes is resonant with the pathophysiological insights offered by Braak's hypothesis and murine models of the disease. These physiological abnormalities and pathological models largely stand to support dopaminergic and non-dopaminergic mechanisms being implicated in the pathogenesis of voice dysfunction. This review focuses on characterizing the voice changes in PD. These stand as a promising area of enquiry to further our understanding of the pathophysiology of the disease and offer potential to be utilized as an early diagnostic biomarker or marker of disease progression.

The Effect of Telerehabilitation on Missed Appointment Rates

The purpose of this study was to examine the effect of telerehabilitation on missed appointment rates in a rehabilitation clinic. Clients fail to attend scheduled appointments for a variety of reasons. Unmet appointments represent a loss of financial support as well as diminished efficiency and capacity to provide services. Speech therapy utilizing multiple appointments is most difficult to maintain during a treatment regimen. This may cause individuals to miss appointments and therefore not achieve desired results. For this study, researchers utilized an intense speech therapy technique, the Lee Silverman Voice Treatment (LSVT®) to measure compliance with scheduled appointments. Participants were randomized to either in-person treatment or telerehabilitation treatment at a site distant from the speech-language pathologist. Participants in the telerehabilitation (TR) condition completed significantly more appointments than participants in the in-person (IP) condition. When comparing results of treatment for each condition, there were no significant differences in outcome whether treated in the IP or TR condition of the study for monologue and picture description tasks, which are closely associated with conversational speech. There was a difference in the reading task with participants demonstrating significantly better post treatment results in the IP condition. The reason for this disparity is unclear and warrants further study.

Verbal monitoring in Parkinson's disease: A comparison between internal and external monitoring

Patients with Parkinson's disease (PD) display a variety of impairments in motor and non-motor language processes; speech is decreased on motor aspects such as amplitude, prosody and speed and on linguistic aspects including grammar and fluency. Here we investigated whether verbal monitoring is impaired and what the relative contributions of the internal and external monitoring route are on verbal monitoring in patients with PD relative to controls. Furthermore, the data were used to investigate whether internal monitoring performance could be predicted by internal speech perception tasks, as perception based monitoring theories assume. Performance of 18 patients with Parkinson's disease was measured on two cognitive performance tasks and a battery of 11 linguistic tasks, including tasks that measured performance on internal and external monitoring. Results were compared with those of 16 age-matched healthy controls. PD patients and controls generally performed similarly on the linguistic and monitoring measures. However, we observed qualitative differences in the effects of noise masking on monitoring and disfluencies and in the extent to which the linguistic tasks predicted monitoring behavior. We suggest that the patients differ from healthy subjects in their recruitment of monitoring channels.

Automatic detection of Parkinson's disease in running speech spoken in three different languages

The aim of this study is the analysis of continuous speech signals of people with Parkinson's disease (PD) considering recordings in different languages (Spanish, German, and Czech). A method for the characterization of the speech signals, based on the automatic segmentation of utterances into voiced and unvoiced frames, is addressed here. The energy content of the unvoiced sounds is modeled using 12 Mel-frequency cepstral coefficients and 25 bands scaled according to the Bark scale. Four speech tasks comprising isolated words, rapid repetition of the syllables /pa/-/ta/-/ka/, sentences, and read texts are evaluated. The method proves to be more accurate than classical approaches in the automatic classification of speech of people with PD and healthy controls. The accuracies range from 85% to 99% depending on the language and the speech task. Cross-language experiments are also performed confirming the robustness and generalization capability of the method, with accuracies ranging from 60% to 99%. This work comprises a step forward for the development of computer aided tools for the automatic assessment of dysarthric speech signals in multiple languages.

A data mining methodology for predicting early stage Parkinson's disease using non-invasive, high-dimensional gait sensor data

Parkinson's disease (PD) is the second most common neurological disorder after Alzheimer's disease. Key clinical features of PD are motor-related and are typically assessed by healthcare providers based on qualitative visual inspection of a patient's movement/gait/posture. More advanced diagnostic techniques such as computed tomography scans that measure brain function, can be cost prohibitive and may expose patients to radiation and other harmful effects. To mitigate these challenges, and open a pathway to remote patient-physician assessment, the authors of this work propose a data mining driven methodology that uses low cost, non-invasive sensors to model and predict the presence (or lack therefore) of PD movement abnormalities and model clinical subtypes. The study presented here evaluates the discriminative ability of non-invasive hardware and data mining algorithms to classify PD cases and controls. A 10-fold cross validation approach is used to compare several data mining algorithms in order to determine that which provides the most consistent results when varying the subject gait data. Next, the predictive accuracy of the data mining model is quantified by testing it against unseen data captured from a test pool of subjects. The proposed methodology demonstrates the feasibility of using non-invasive, low cost, hardware and data mining models to monitor the progression of gait features outside of the traditional healthcare facility, which may ultimately lead to earlier diagnosis of emerging neurological diseases.

A pervasive assessment of motor function: a lightweight grip strength tracking system

With the growing cost associated with the diagnosis and treatment of chronic neuro-degenerative diseases, the design and development of portable monitoring systems becomes essential. Such portable systems will allow for early diagnosis of motor function ability and provide new insight into the physical characteristics of ailment condition. This paper introduces a highly mobile and inexpensive monitoring system to quantify upper-limb performance for patients with movement disorders. With respect to the data analysis, we first present an approach to quantify general motor performance using the introduced sensing hardware. Next, we propose an ailment-based analysis which employs a significant-feature identification algorithm to perform cross-patient data analysis and classification. The efficacy of the proposed framework is demonstrated using real data collected through a clinical trial. The results show that the system can be utilized as a preliminary diagnostic tool to inspect the level of hand-movement performance. The ailment-based analysis performs an intergroup comparison of physiological signals for cerebral vascular accident (CVA) patients, chronic inflammatory demyelinating polyneuropathy (CIDP) patients, and healthy individuals. The system can classify each patient group with an accuracy of up to 95.00% and 91.42% for CVA and CIDP, respectively.

Do basal Ganglia amplify willed action by stochastic resonance? A model

Basal ganglia are usually attributed a role in facilitating willed action, which is found to be impaired in Parkinson's disease, a pathology of basal ganglia. We hypothesize that basal ganglia possess the machinery to amplify will signals, presumably weak, by stochastic resonance. Recently we proposed a computational model of Parkinsonian reaching, in which the contributions from basal ganglia aid the motor cortex in learning to reach. The model was cast in reinforcement learning framework. We now show that the above basal ganglia computational model has all the ingredients of stochastic resonance process. In the proposed computational model, we consider the problem of moving an arm from a rest position to a target position: the two positions correspond to two extrema of the value function. A single kick (a half-wave of sinusoid, of sufficiently low amplitude) given to the system in resting position, succeeds in taking the system to the target position, with high probability, only at a critical noise level. But for suboptimal noise levels, the model arm's movements resemble Parkinsonian movement symptoms like akinetic rigidity (low noise) and dyskinesias (high noise).

A model of the neural substrates for exploratory dynamics in basal ganglia

We present a model of basal ganglia (BG) that departs from the classical Go/NoGo picture of the function of its key pathways-the Direct and Indirect Pathways (DP and IP). Between the Go and NoGo regimes, we posit a third Explore regime, which denotes random exploration of action alternatives. Striatal dopamine (DA) is assumed to switch between DP and IP activation. The IP is modeled as a loop of the subthalamic nucleus (STN) and the Globus Pallidus externa (GPe). Simulations reveal that while the model displays Go and NoGo regimes for extreme values of DA, at intermediate values of DA, it exhibits exploratory behavior, which originates from the chaotic activity of the STN-GPe loop. We describe a series of BG models based on Go/Explore/NoGo approach, to explain the role of BG in three cases: (1) a simple action selection task, (2) reaching, and (3) willed action.

Effect of deep brain stimulation on speech performance in Parkinson's disease

Deep brain stimulation (DBS) has been reported to be successful in relieving the core motor symptoms of Parkinson's disease (PD) and motor fluctuations in the more advanced stages of the disease. However, data on the effects of DBS on speech performance are inconsistent. While there are some series of patients documenting that speech function was relatively unaffected by DBS of the nucleus subthalamicus (STN), other investigators reported on improvements of distinct parameters of oral control and voice. Though, these ameliorations of single speech modalities were not always accompanied by an improvement of overall speech intelligibility. On the other hand, there are also indications for an induction of dysarthria as an adverse effect of STN-DBS occurring at least in some patients with PD. Since a deterioration of speech function has more often been observed under high stimulation amplitudes, this phenomenon has been ascribed to a spread of current-to-adjacent pathways which might also be the reason for the sporadic observation of an onset of dysarthria under DBS of other basal ganglia targets (e.g., globus pallidus internus/GPi or thalamus/Vim). The aim of this paper is to review and evaluate reports in the literature on the effects of DBS on speech function in PD.

Functional neuroanatomy of vocalization in patients with Parkinson's disease

In Parkinson's disease (PD) both speech production and self-monitoring of voiced speech are altered.

METHODS

In our previous study we used functional magnetic resonance imaging (fMRI) to examine which brain areas are involved in overt reading in nine female PD patients (mean age 66.0 ± 11.6 years) compared with eight age-matched healthy female controls (mean age 62.2 years ± 12.3). Here we performed the post-hoc seed-based functional connectivity analysis of our data to assess the functional connectivity between the periaqueductal gray matter (PAG; i.e. the core subcortical structure involved in human vocalization) and other brain regions in the same groups of PD patients and controls.

RESULTS

In PD patients as compared with controls we observed increased connectivity between PAG and basal ganglia, posterior superior temporal gyrus, supramarginal and fusiform gyri and inferior parietal lobule on the right side. In the PD group, the connectivity strength in the right putamen and the right sypramarginal gyrus was correlated with variability of pitch while the connectivity strength in the right posterior superior temporal gyrus and in the right inferior parietal lobule was correlated with speech loudness.

CONCLUSION

We observed functional reorganization in PD patients as compared with controls in both the motor basal ganglia-thalamo-cortical circuitry and cortical areas known to be engaged in-auditory and somatosensory feedback control of voiced speech. These changes were hemisphere-specific and might either reflect effects of dopaminergic treatment or at least partially successful compensatory mechanisms involved in early-stage PD.

Effects of subthalamic stimulation on speech of consecutive patients with Parkinson disease

OBJECTIVE

Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for advanced Parkinson disease (PD). Following STN-DBS, speech intelligibility can deteriorate, limiting its beneficial effect. Here we prospectively examined the short- and long-term speech response to STN-DBS in a consecutive series of patients to identify clinical and surgical factors associated with speech change.

METHODS

Thirty-two consecutive patients were assessed before surgery, then 1 month, 6 months, and 1 year after STN-DBS in 4 conditions on- and off-medication with on- and off-stimulation using established and validated speech and movement scales. Fifteen of these patients were followed up for 3 years. A control group of 12 patients with PD were followed up for 1 year.

RESULTS

Within the surgical group, speech intelligibility significantly deteriorated by an average of 14.2%±20.15% off-medication and 16.9%±21.8% on-medication 1 year after STN-DBS. The medical group deteriorated by 3.6%±5.5% and 4.5%±8.8%, respectively. Seven patients showed speech amelioration after surgery. Loudness increased significantly in all tasks with stimulation. A less severe preoperative on-medication motor score was associated with a more favorable speech response to STN-DBS after 1 year. Medially located electrodes on the left STN were associated with a significantly higher risk of speech deterioration than electrodes within the nucleus. There was a strong relationship between high voltage in the left electrode and poor speech outcome at 1 year.

CONCLUSION

The effect of STN-DBS on speech is variable and multifactorial, with most patients exhibiting decline of speech intelligibility. Both medical and surgical issues contribute to deterioration of speech in STN-DBS patients.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that STN-DBS for PD results in deterioration in speech intelligibility in all combinations of medication and stimulation states at 1 month, 6 months, and 1 year compared to baseline and to control subjects treated with best medical therapy.

Sequential changes in motor speech across a levodopa cycle in advanced Parkinson's disease

Previous research has indicated that in Parkinson's disease (PD) some motor speech characteristics are changed by levodopa administration, while others are not. In advanced PD, the time course of these changes and the correlations with motor performance have not been sufficiently investigated. The purpose was to investigate the sequential changes of respiratory, articulatory, and phonatory speech characteristics across a levodopa drug cycle, using spirometry, acoustic, and motor speech analysis. Seven patients with advanced PD were included. All patients were evaluated sequentually at 15 minute intervals before and following levodopa intake. Data were analysed using repeated measures ANOVA and non-parametric analysis. Significant changes were found in motor function, vital capacity, and standard deviation of the diadochokinetic period. A trend was present for shimmer and frequency of the first formant. Significant inter-individual differences in the sequential changes were demonstrated for nearly all evaluated parameters. The conclusion is that, in advanced PD, the evaluation of speech characteristics at one moment after levodopa administration is not representative of an entire drug cycle and that an individualized evaluation of an entire drug cycle is warranted before initiation of a speech-language pathology program.

Listener impressions of speakers with Parkinson's disease

Parkinson's disease (PD) has several negative effects on speech production and communication. However, few studies have looked at how speech patterns in PD contribute to linguistic and social impressions formed about PD patients from the perspective of listeners. In this study, discourse recordings elicited from nondemented PD speakers (n = 18) and healthy controls (n = 17) were presented to 30 listeners unaware of the speakers' disease status. In separate conditions, listeners rated the discourse samples based on their impressions of the speaker or of the linguistic content. Acoustic measures of the speech samples were analyzed for comparison with listeners' perceptual ratings. Results showed that although listeners rated the content of Parkinsonian discourse as linguistically appropriate (e.g., coherent, well-organized, easy to follow), the PD speakers were perceived as significantly less interested, less involved, less happy, and less friendly than healthy speakers. Negative social impressions demonstrated a relationship to changes in vocal intensity (loudness) and temporal characteristics (dysfluencies) of Parkinsonian speech. Our findings emphasize important psychosocial ramifications of PD that are likely to limit opportunities for communication and social interaction for those affected, because of the negative impressions drawn by listeners based on their speaking voice.

Functional abnormalities in the primary orofacial sensorimotor cortex during speech in Parkinson's disease

Parkinson's disease (PD) affects speech, including respiration, phonation, and articulation. We measured the blood oxygen level-dependent (BOLD) response to overt sentence reading in: (1) 9 treated female patients with mild to moderate PD (age; mean 66.0 +/- 11.6 years, mean levodopa equivalent 583.3 +/- 397.9 mg) and (2) 8 age-matched healthy female controls (age; mean 62.2 years +/- 12.3). Speech was recorded in the scanner to assess which brain regions underlie variations in the initiation and paralinguistic aspects (e.g., pitch, loudness, and rate) of speech production in the two groups. There were no differences in paralinguistic aspects of speech except for speech loudness; it was lower in PD patients compared with that in controls, when age was used as a covariate. In both groups, we observed increases in the BOLD response (reading-baseline) in brain regions involved in speech production and perception. In PD patients, as compared with controls, we found significantly higher BOLD signal in the right primary orofacial sensorimotor cortex and more robust correlations between the measured speech parameters and the BOLD response to reading, particularly, in the left primary orofacial sensorimotor cortex. These results might reflect compensatory mechanisms and/or treatment effects that take place in mild to moderately ill PD patients with quality of speech yet comparable with that of age-matched controls.

Perception of emotional speech in Parkinson's Disease

Nonmotor symptoms in Parkinson's disease (PD) involving cognition and emotionality have progressively received attention. The objective of the present study was to investigate recognition of emotional prosody in patients with PD (n = 14) in comparison to healthy control subjects (HC, n = 14). Event-related brain potentials (ERP) were recorded in a modified oddball paradigm under passive listening and active target detection instructions. Results showed a poorer performance of PD patients in classifying emotional prosody. ERP generated by emotional deviants (happy/sad) during passive listening revealed diminished amplitudes of the mismatch-related negativity for sad deviants, indicating an impairment of early preattentive processing of emotional prosody in PD.

The effects of levodopa on word intelligibility in Parkinson's disease

Dysarthria is a common manifestation in patients with idiopathic Parkinson's disease. This study investigated the effects of levodopa on intelligibility in patients with Parkinson's disease. Ten participants were tested during on- and off-states using the Yorkston and Beukelman intelligibility test (1980). Intelligibility as scored by a panel of speech therapists was significantly improved in the on-condition. No correlation was found, however, between intelligibility and overall severity of the disease or severity of the motor problems. EDUCATIONAL OUTCOMES: As a result of this activity the participant will be able to discuss the effects of levodopa on intelligibility in patients with Parkinson's disease.

Task-Based Profile of Vocal Intensity Decline in Parkinson’s Disease

This study examines intensity decay in the phonation of persons with Parkinson's disease (PD). The decline in vocal intensity (determined by linear regression of the intensity envelope) was compared across the following tasks: vowel prolongation, syllable repetition (diadochokinesis, DDK), isolated sentences and conversation. In contrast to previous studies, PD speakers demonstrated no significant differences in intensity decline from healthy speakers in vowel prolongation. The vocal intensity of speakers with PD declined more rapidly than that of controls in DDK tasks. While intensity slopes in conversation were more variable in both groups, some participants with PD exhibited abrupt changes in intensity. Results indicate that the DDK is particularly useful for describing intensity decay associated with PD. However, considering the inconsistent group differences across tasks, and the discrepant findings from previous studies, intensity decay is not a robust symptom of PD.

Changes induced by levodopa and subthalamic nucleus stimulation on parkinsonian speech

Levodopa (L-dopa) and subthalamic nucleus (STN) stimulation treatments have been associated with both improvement and exacerbation of dysarthria in Parkinson's disease (PD). We report four cases illustrating variant responses of dysarthria to dopaminergic and STN stimulation therapies. Patients' motor disability and dysarthria were perceptually rated by the Unified Parkinson's Disease Rating Scale (UPDRS) in four conditions according to medication and STN stimulation. Dedicated software packages allowed acquisition and analysis of acoustic recordings. Case 1, who had a severe off period aphonia, experienced improvement of speech induced by both levodopa and STN stimulation. In Case 2, both treatments worsened speech due to the appearance of dyskinesias. Case 3 had a dysarthria exacerbation induced by STN stimulation with parameters above optimal levels, interpreted as current diffusion from the STN to corticobulbar fibers. In Case 4, dysarthria exacerbation occurred with stimulation at an electrode contact located caudally to the target, also arguing for current diffusion as a potential mechanism of speech worsening. The presented cases demonstrated variant effects in relation to L-dopa and STN stimulation on speech. It seems that motor speech subcomponents can be improved like other limb motor aspect, but that complex coordination of all speech anatomical substrates is not responsive to STN stimulation. These hypotheses may be helpful for better understanding and management of STN stimulation effects on motor speech and skeleton-motor subsystems.

Effects of different electrical parameter settings on the intelligibility of speech in patients with Parkinson's disease treated with subthalamic deep brain stimulation

We evaluated the effects of different electrical parameter settings on the intelligibility of speech in patients with Parkinson's disease (PD) bilaterally treated with deep brain stimulation (DBS) in the subthalamic nucleus (STN). Ten patients treated with DBS for 15 +/- 5 months (mean, SD) with significant (P < 0.01) symptom reduction (Unified Parkinson's Disease Rating Scale III) were included. In the medication off condition, video laryngostroboscopy was performed and then, in random order, 11 DBS parameter settings were tested. Amplitude was increased and decreased by 25%, frequency was varied in the range 70 to 185 pps, and each of the contacts was tested separately as a cathode. The patients read a standard running text and five nonsense sentences per setting. A listener panel transcribed the nonsense sentences as perceived and valued the quality of speech on a visual analogue scale. With the patients' normally used settings, there was no significant (P = 0.058) group difference between DBS OFF and ON, but in four patients the intelligibility deteriorated with DBS ON. The higher frequencies or increased amplitude caused significant (P < 0.02) impairments of intelligibility, whereas changing the polarity between the separate contacts did not. The settings of amplitude and frequency have a major influence on the intelligibility of speech, emphasizing the importance of meticulous parameter adjustments when programming DBS to minimize side effects related to speech.

Treatments for dysarthria in Parkinson's disease

Dysarthria in Parkinson's disease can be characterised by monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice. Use of levodopa to replenish dopamine concentrations in the striatum seems to improve articulation, voice quality, and pitch variation, although some studies show no change in phonatory parameters. Traditional speech therapy can lead to improvement of dysarthria, and intensive programmes have had substantial beneficial effects on vocal loudness. Unilateral surgical lesions of subcortical structures are variably effective for the alleviation of dysarthria, whereas bilateral procedures typically lead to worsening of speech production. Among deep-brain stimulation procedures, only stimulation of the subthalamic nucleus improves some motor components of speech although intelligibility seems to decrease after surgery. Due to the variable treatment effects on parkinsonian speech, management of dysarthria is still challenging for the clinician and should be discussed with the patient.

[Treatment of vocal symptoms in Parkinson's disease: the Lee Silverman method]

Mild changes in voice quality and articulation of speech may be seen in early phases of Parkinson's disease (PD). Voice and speech disturbances in PD constitute a hypocinetic dysarthria or dysarthrophonia and are characterized by monotony and reduced intensity of voice, imprecise articulation and disturbances of rhythm. Favorable results with an intensive method (Lee Silverman Voice Treatment) for the treatment of voice disturbances in PD were recently reported. The main goal of the method is to augment vocal intensity through the increment of phonatory effort. The purpose of the present study was to characterize vocal abnormalities (hoarseness, breathiness, articulatory pattern and inteligibility) in a group of patients with PD and to evaluate the therapeutic efficacy of the Lee Silverman method. Acoustic as well as perceptive-auditory analysis showed statistically significant differences between pre and post treatment groups. Although the articulatory pattern has not considerably changed, the benefits obtained with the improvement in vocal quality positively influenced overall quality of oral communication.

Phonatory characteristics of parkinsonian speech before and after morning medication: the ON and OFF states

After prolonged treatment with L-dopa, patients with Parkinson's disease (PD) experience fluctuations in motor performance. Changes in voice production have been documented perceptually during periods of fluctuation, but few quantitative changes have been found. The purpose of this study is to examine the acoustic-phonatory characteristics of PD speech before and after taking medication, to determine if fluctuations affected phonation. Nine PD patients participated in this study. Multiple analyses were performed, and revealed that fundamental frequency (Fo) variability in vowels and mean Fo were higher, while intensity range was lower in PD patients compared to controls. When the PD subjects were examined after versus before medication, group differences were small, but phonatory improvements were seen in individual subjects. Discussion focuses on physiological changes and variability in PD, and implications of response fluctuations to speech production.

LEARNING OUTCOMES

As a result of this activity, the participant will be able to (1) acquire knowledge and understanding of PD and the voice characteristics commonly associated with PD and (2) understand the effects of L-dopa-related fluctuations on voice production in PD.

Speech motor stability in IPD: effects of rate and loudness manipulations

Increasing phonatory effort, an integral component of the Lee Silverman Voice Treatment, LSVT, has been identified as an effective management strategy for adults with hypokinetic dysarthria associated with Parkinsonism. The present study compares the effects of increased loudness on lower lip movements to those of changes in speaking rate, another approach to the treatment of hypokinetic dysarthria. Movements of the lower lip/jaw during speech were recorded from 8 adults with IPD, 8 healthy aged adults, and 8 young adults. The spatiotemporal index (STI), a measure of spatial and temporal variability, revealed that for all speaker groups slow rate was associated with the most variability. Compared to the other conditions, STI values from the loud condition were closest to those from habitual speech. Also, the normalized movement pattern for the loud condition resembled that of habitual speech. It is hypothesized that speaking loudly is associated with a spatial and temporal organization that closely resembles that used in habitual speech, which may contribute to the success of the LSVT.

Palilalia and repetitive speech: two case studies

Palilalia, a disorder of speech characterized by compulsive repetitions of utterances has been found in various neurological and psychiatric disorders. It has commonly been interpreted as a defect of motor speech. This article describes palilalia and other variants of verbal repetitive behavior, such as monosyllabic iterations and conduite d'approche. The clinical features of palilalia, its prevalence in different language tasks, and the individual patterns of verbal repetitive behavior are illustrated in two patients with a long-standing cerebrovascular disease. An attempt is made to locate the origin of different forms of verbal repetitions in a standard model of speech production (Butterworth, 1980a; Garrett, 1980; Levelt, 1989) by analysis of their morphology and correlation with impairments of lexical or phonological processes. From these observations it is suggested that palilalia results from control malfunctions at the level of the Articulator, whereas other variants of pathological verbal iterations result from an impairment of the Formulator or from malfunctions of both the Articulator and the Formulator.

Speech dysfluency exacerbated by levodopa in Parkinson's disease

The role of dopamine in the modulation of speech fluency is complex. In this report we describe two patients with Parkinson's disease whose speech dysfluency was exacerbated by the administration of levodopa. In doing so, we extend the observation that dopaminergic mechanisms may be involved in the regulation of speech fluency. It is important for clinicians to recognize that, in some instances, dopaminergic replacement therapy may exacerbate an underlying dysfluency syndrome in PD.

Impaired perception of vocal emotions in Parkinson's disease: influence of speech time processing and executive functioning

Little is known about the underlying dimensions of impaired recognition of emotional prosody that is frequently observed in patients with Parkinson's disease (PD). Because patients with PD also suffer from working memory deficits and impaired time perception, the present study examined the contribution of (a) working memory (frontal executive functioning) and (b) processing of the acoustic parameter speech rate to the perception of emotional prosody in PD. Two acoustic parameters known to be important for emotional classifications (speech duration and pitch variability) were systematically varied in prosodic utterances. Twenty patients with PD and 16 healthy controls (matched for age, sex, and IQ) participated in the study. The findings imply that (1) working memory dysfunctions and perception of emotional prosody are not independent in PD, (2) PD and healthy control subjects perceived vocal emotions categorically along two acoustic manipulation continua, and (3) patients with PD show impairments in processing of speech rate information.

Re-emergence of childhood stuttering in Parkinson's disease: a hypothesis

OBJECTIVE

To characterize speech patterns in patients with Parkinson's disease (PD) who have a history of childhood stuttering.

BACKGROUND

Childhood stuttering usually resolves, but it re-emerges in some patients after stroke or other brain disorders. This phenomenon of recurrent stuttering has not been characterized in childhood stutterers who later develop PD.

METHODS/PATIENTS

Twelve patients with a history of childhood stuttering that remitted and subsequently recurred were included in the study. A structured interview was administered to seven patients, and six were able to answer questions about childhood stuttering. The Johnson Severity Scale (JSS) (range 0-7) and a Situation Avoidance Scale (SAS) were used to rate stuttering severity (range 0-15) and avoidance (range 0-15).

RESULTS

The mean age at onset of childhood stuttering was 6.2 years (range 5-10); the mean latency from the onset of childhood stuttering to adult stuttering was 46.1 years; and the stuttering recurred on average 5.9 years (range 0-21) after the onset of PD. The stuttering characteristics in childhood and adulthood included repetitions of sounds and syllables at the beginnings of words, blocks and interjections, physical tension, and a worsening of symptoms with stress. The patients rated themselves as having mild-to-moderate childhood stuttering by the JSS (mean 3.0, range 2-4) and mild-to-moderate stuttering and avoidance by the SAS (mean stuttering score 5.3, range 3-7; mean avoidance score 4.2, range 3-6). There was no apparent association between the severity of childhood stuttering and the severity of PD, but those patients who had higher Unified Parkinson's Disease Rating Scale scores tended to have more and worse symptoms of stuttering.

CONCLUSION

Our patients provide evidence for the hypothesis that childhood stuttering may re-emerge in adulthood with the onset of PD.

Repetitive speech phenomena in Parkinson's disease

OBJECTIVES

Repetitive speech phenomena are morphologically heterogeneous iterations of speech which have been described in several neurological disorders such as vascular dementia, progressive supranuclear palsy, Wilson's disease, and Parkinson's disease, and which are presently only poorly understood. The present, prospective study investigated repetitive speech phenomena in Parkinson's disease to describe their morphology, assess their prevalence, and to establish their relation with neuropsychological and clinical background data.

METHODS

Twenty four patients with advanced Parkinson's disease and 29 subjects with mid-stage, stable idiopathic disease were screened for appearance, forms, and frequency of repetitive speech phenomena, and underwent a neuropsychological screening procedure comprising tests of general mental functioning, divergent thinking and memory. Patients with advanced Parkinson's disease had a significantly higher disease impairment, longer disease duration, and an unstable motor response to levodopa with frequent on-off fluctuations. Both groups were well matched as to their demographical, clinical, and cognitive background. Perceptual speech evaluation was used to count and differentiate forms of repetitive speech phenomena in different speech tasks. To compare the effect of the motor state, the appearance of repetitive speech phenomena was also assessed in a subgroup of patients with advanced Parkinson's disease during the on versus the off state.

RESULTS

Speech repetitions emerged mainly in two variants, one hyperfluent, formally resembling palilalia, and one dysfluent, stuttering-like. Both forms were present in each patient producing repetitive speech phenomena. The repetitive speech phenomena appeared in 15 patients (28.3 %), 13 of whom belonged to the advanced disease group, indicating a significant preponderance of repetitive speech phenomena in patients with a long term, fluctuating disease course. Repetitive speech phenomena appeared with almost equal frequency during the on and the off state of patients with advanced Parkinson's disease. Their distribution among different variants of speech was disproportional, with effort demanding speech tasks producing a significantly higher number of repetitive speech phenomena over semiautomatic forms of speech.

CONCLUSIONS

In idiopathic Parkinson's disease repetitive speech phenomena seem to emerge predominantly in a subgroup of patients with advanced disease impairment; manifest dementia is not a necessary prerequisite. They seem to represent a deficit of motor speech control; however, linguistic factors may also contribute to their generation. It is suggested that repetitions of speech in Parkinson's disease represent a distinctive speech disorder, which is caused by changes related to the progression of Parkinson's disease.

Effects of speech therapy and pharmacologic and surgical treatments on voice and speech in Parkinson's disease: a review of the literature

The purpose of this review was to examine the different treatment approaches for persons with Parkinson's Disease (PD) and to examine the effects of these treatments on speech. Treatment methods reviewed include speech therapy, pharmacological, and surgical. Research from the 1950s through the 1970s had not demonstrated significant improvements following speech therapy. Recent research has shown that speech therapy (when persons with PD are optimally medicated) has proven to be the most efficacious therapeutic method for improving voice and speech function. Pharmacological methods of treatment in isolation do not appear to significantly improve voice and speech function in PD across research studies. Surgical treatment methods including pallidotomy and deep brain stimulation may be significant treatment options which improve voice and speech function in some persons with PD. Possible explanations for the differential responses to treatment are discussed. Future studies should investigate the effects of combined treatment approaches. Perhaps the combination of pharmacological, surgical and speech treatment will prove superior to treatments combining pharmacological and surgical or pharmacological and speech therapy in improving the communication abilities of persons with PD.

Aerodynamic measurements of patients with Parkinson's disease

Patients with Parkinson's disease commonly complain of voice dysfunction. Most of these complaints can be attributed to the known muscular control disorders that occur with Parkinson's disease. However, the manifestations of Parkinson's disease muscular dysfunction on parameters of phonation such as airflow, laryngeal resistance, and subglottal pressure necessary to sustain phonation have not been reported. The purpose of this study was to examine the aerodynamic characteristics of flow, laryngeal resistance, and phonation pressure threshold in a heterogeneous population of patients with Parkinson's disease who had varying voice complaints and to compare the data to similar studies for human subjects who have no voice complaints. The studies used a noninvasive method of detecting flow and acoustic signal from the lips, oral cavity and nose during phonation and used an external flow interruption technique to estimate subglottal pressure and phonation threshold pressure. About one third of the patients could not produce phonation at regular and loud intensities that were comfortable for normal subjects. The mean subglottal pressure (SGP) of patients with Parkinson disease who could produce 3 levels of intensity comparable to normal subjects was significantly higher than the mean SGPs for normal subjects for the same intensities of vocal production. The mean flow rates measured from patients with Parkinson's disease at the same 3 intensities of phonation was not significantly greater than in normal subjects. This indicated that the mean laryngeal resistance calculated for patients with Parkinson's disease was notably and significantly greater than mean laryngeal resistance calculated for normal subjects at the same intensity levels. The mean vocal efficiency (VE) for normal subjects was not significantly different than the mean VE for patients with Parkinson's disease, because greater pressure was used to generate similar flow and acoustic energy. These findings correlate with the perception of patients with Parkinson's disease that they are working harder to produce phonation. The observation of notably greater laryngeal resistance and phonation threshold pressure in patients with Parkinson's disease suggests that further studies of the glottic aperture in patients with Parkinson' disease may be useful for understanding how this common motor disorder disturbs phonation.