The effectiveness of traditional methods and altered auditory feedback in improving speech rate and intelligibility in speakers with Parkinson's disease

Speech's syllabic rhythm and articulatory features produced under different auditory feedback conditions identify Parkinsonism

Diagnostic tests for Parkinsonism based on speech samples have shown promising results. Although abnormal auditory feedback integration during speech production and impaired rhythmic organization of speech are known in Parkinsonism, these aspects have not been incorporated into diagnostic tests. This study aimed to identify Parkinsonism using a novel speech behavioral test that involved rhythmically repeating syllables under different auditory feedback conditions. The study included 30 individuals with Parkinson's disease (PD) and 30 healthy subjects. Participants were asked to rhythmically repeat the PA-TA-KA syllable sequence, both whispering and speaking aloud under various listening conditions. The results showed that individuals with PD had difficulties in whispering and articulating under altered auditory feedback conditions, exhibited delayed speech onset, and demonstrated inconsistent rhythmic structure across trials compared to controls. These parameters were then fed into a supervised machine-learning algorithm to differentiate between the two groups. The algorithm achieved an accuracy of 85.4%, a sensitivity of 86.5%, and a specificity of 84.3%. This pilot study highlights the potential of the proposed behavioral paradigm as an objective and accessible (both in cost and time) test for identifying individuals with Parkinson's disease.

Machine Learning-Based Classification of Parkinson's Disease Patients Using Speech Biomarkers

BACKGROUND

Parkinson's disease (PD) is the most prevalent neurodegenerative movement disorder and a growing health concern in demographically aging societies. The prevalence of PD among individuals over the age of 60 and 80 years has been reported to range between 1% and 4%. A timely diagnosis of PD is desirable, even though it poses challenges to medical systems.

OBJECTIVE

This study aimed to classify PD and healthy controls based on the analysis of voice records at different frequencies using machine learning (ML) algorithms.

METHODS

The voices of 252 individuals aged 33 to 87 years were recorded. Based on the voice record data, ML algorithms can distinguish PD patients and healthy controls. One binary decision variable was associated with 756 instances and 754 attributes. Voice records data were analyzed through supervised ML algorithms and pipelines. A 10-fold cross-validation method was used to validate models.

RESULTS

In the classification of PD patients, ML models were performed with 84.21 accuracy, 93 precision, 89 Sensitivity, 89 F1-scores, and 87 AUC. The pipeline performance improved to accuracy: 85.09, precision: 92, Sensitivity:91, F1-score: 89, and AUC: 90. The Pipeline methods improved the performance of classifying PD from voice record.

CONCLUSIONS

Our study demonstrated that ML classifiers and pipelines can classify PD patients based on speech biomarkers. It was found that pipelines were more effective at selecting the most relevant features from high-dimensional data and at accurately classifying PD patients and healthy controls. This approach can therefore be used for early diagnosis of initial forms of PD.

Voice improvement following conventional speech therapy combined with singing intervention in people with Parkinson's disease: A three-arm randomised controlled trial

BACKGROUND

Although speech and voice disorders are common in Parkinson's disease (PD), there is insufficient evidence to support the effectiveness of behavioural speech therapies in these patients.

AIMS

This study aimed to examine the effects of a new tele-rehabilitation program, a combining of conventional speech therapy and singing intervention, on voice deficits in patients with PD.

METHODS & PROCEDURES

This study was a three-armed, assessor-masked, randomised controlled trial. Thirty-three people with PD were randomly assigned to the combination therapy, conventional speech therapy, or singing intervention group. This study followed the Consolidated Standards of Reporting Trials guidelines for non-pharmacological treatment. Each patient participated in 12 tele-rehabilitation sessions over 4 weeks. The combination therapy group received speech and singing interventions simultaneously (respiratory, speech, voice, and singing exercises). Voice intensity as a primary outcome and the voice handicap index (VHI), maximum frequency range, jitter and shimmer as secondary outcomes were evaluated 1 week before the first intervention session, 1 week after the last intervention session and 3 months after the last evaluation.

OUTCOMES & RESULTS

The results of repeated measures analysis of variance showed a significant main effect of time on all outcomes in all three groups after treatment (p < 0.001). There was a significant group effect for voice intensity (p < 0.001), VHI (p < 0.001), maximum frequency range (p = 0.014) and shimmer (p = 0.001). The combination therapy group demonstrated a significant outperformance in the VHI and shimmer than the speech therapy (p = 0.038) and singing intervention (p < 0.001) groups. The results of this study also indicated that combination therapy group compared to singing intervention group had a larger effect on voice intensity (p < 0.001), shimmer (p < 0.001) and maximum frequency range (p = 0.048).

CONCLUSIONS & IMPLICATION

The results demonstrated that combining speech therapy with a singing intervention delivered through tele-rehabilitation might be more effective in improving voice problems in patients with PD.

WHAT THIS PAPER ADDS

What is already known on the subject Parkinson's disease (PD) is a neurological disorder that frequently causes disturbances in speech and voice, which negatively affect patients' quality of life. Although speech difficulties occur in 90% of patients with PD, evidence-based treatment options for speech and language problems in these patients are limited. Therefore, further studies are required to develop and assess evidence-based treatment programs. What this study adds The findings of this study showed that a combination therapy program including conventional speech therapy approaches and individual singing intervention provided through tele-rehabilitation may have a greater effect on the improvement of voice problems in people with PD compared to speech therapy and singing intervention alone. What are the clinical implications of this work? Tele-rehabilitation combination therapy is an inexpensive and enjoyable behavioural treatment. The advantages of this method are that it is easy to access, appropriate for many stages of voice problems in PD, requires no prior singing training, encourages voice health and self-management and maximises treatment resources available to people with PD. We believe that the results of this study can provide a new clinical basis for treatment of voice disorders in people with PD.

Acoustic characteristics in relation to intelligibility reduction in noise for speakers with Parkinson's disease

Decreased speech intelligibility in noisy environments is frequently observed in speakers with Parkinson's disease (PD). This study investigated which acoustic characteristics across the speech subsystems contributed to poor intelligibility in noise for speakers with PD. Speech samples were obtained from 13 speakers with PD and five healthy controls reading 56 sentences. Intelligibility analysis was conducted in quiet and noisy listening conditions. Seventy-two young listeners transcribed the recorded sentences in quiet and another 72 listeners transcribed in noise. The acoustic characteristics of the speakers with PD who experienced large intelligibility reduction from quiet to noise were compared to those with smaller intelligibility reduction in noise and healthy controls. The acoustic measures in the study included second formant transitions, cepstral and spectral measures of voice (cepstral peak prominence and low/high spectral ratio), pitch variation, and articulation rate to represent speech components across speech subsystems of articulation, phonation, and prosody. The results show that speakers with PD who had larger intelligibility reduction in noise exhibited decreased second formant transition, limited cepstral and spectral variations, and faster articulation rate. These findings suggest that the adverse effect of noise on speech intelligibility in PD is related to speech changes in the articulatory and phonatory systems.

Quickcard-Based Approach to Guiding Specific Nonpharmacological Treatments in a German Parkinson's Network

Interdisciplinary care has been shown to be effective at optimizing the treatment of patients with Parkinson's disease. An optimized collaboration between the various healthcare providers involved in the treatment process facilitates successful care. One of the main shortcomings in the German healthcare system is the limited and unstandardized communication between practitioners. The Parkinson's network Münsterland+ (PNM+) is an interdisciplinary network of medical and non-medical experts involved in the treatment of Parkinson's patients: neurologists, physiotherapists, occupational therapists, speech therapists, psychologists, Parkinson's nurses, pharmacists, patients, and relatives. The PNM+ elaborates guideline-based therapy recommendations, provided as so-called "Quickcards". Thereby, the communication of the treating neurologist and therapists is based on a coordinated feedback system and suggestions to adequately select and, if necessary, adjust the therapy. In the German healthcare system, with its fragmented structures, the PNM+ and its activities have been shown to enhance integration of the healthcare providers and thereby optimize the care of Parkinson's disease patients. Future research should evaluate the effects and cost-effectiveness.

Bio-inspired dimensionality reduction for Parkinson's disease (PD) classification

Given the demand for developing the efficient Machine Learning (ML) classification models for healthcare data, and the potentiality of Bio-Inspired Optimization (BIO) algorithms to tackle the problem of high dimensional data, we investigate the range of ML classification models trained with the optimal subset of features of PD data set for efficient PD classification. We used two BIO algorithms, Genetic Algorithm (GA) and Binary Particle Swarm Optimization (BPSO), to determine the optimal subset of features of PD data set. The data set chosen for investigation comprises 756 observations (rows or records) taken over 755 attributes (columns or dimensions or features) from 252 PD patients. We employed MaxAbsolute feature scaling method to normalize the data and one hold cross-validation method to avoid biased results. Accordingly, the data is split in to training and testing set in the ratio of 70% and 30%. Subsequently, we employed GA and BPSO algorithms separately on 11 ML classifiers (Logistic Regression (LR), linear Support Vector Machine (lSVM), radial basis function Support Vector Machine (rSVM), Gaussian Naïve Bayes (GNB), Gaussian Process Classifier (GPC), k-Nearest Neighbor (kNN), Decision Tree (DT), Random Forest (RF), Multilayer Perceptron (MLP), Ada Boost (AB) and Quadratic Discriminant Analysis (QDA)), to determine the optimal subset of features (reduction of dimensionality) contributing to the highest classification accuracy. Among all the bio-inspired ML classifiers employed: GA-inspired MLP produced the maximum dimensionality reduction of 52.32% by selecting only 359 features and delivering 85.1% of the classification accuracy; GA-inspired AB delivered the maximum classification accuracy of 90.7% producing the dimensionality reduction of 41.43% by selecting only 441 features; And, BPSO-inspired GNB produced the maximum dimensionality reduction of 47.14% by selecting 396 features and delivering the classification accuracy of 79.3%; BPSOMLP delivered the maximum classification accuracy of 89% and produced 46.48% of the dimensionality reduction by selecting only 403 features.

Person-centered home-based rehabilitation for persons with Parkinson's disease: A scoping review

BACKGROUND

Due to vague, initial symptoms, persons with Parkinson's disease (PD) usually receive a definitive diagnosis after a prolonged period of time. At the time of diagnosis, they have already experienced limitations in activities of daily living and quality of life and are thus in need of immediate rehabilitation.

OBJECTIVE

To describe the existing knowledge on the rehabilitation of persons with PD suitable to a home environment and to describe the person-centeredness, interprofessionality and clinical effectiveness of existing rehabilitation activities.

SOURCES OF EVIDENCE

67 full-text papers from the EBSCO, CINAHL, Medline, Google and Google Scholar databases, published in English, Swedish or Finnish between January 2010 and October 2018, were charted (type of rehabilitation, sample, instrumentation, reported effects) and summarized.

RESULTS

Rehabilitation through physical activities still appears to be the most common form of rehabilitation, varying from walking to individually tailored exercise programs. The majority of physical rehabilitation activities were conducted outside the home even though they were suitable for a home setting. Physical activities not only improved several physical outcomes but also quality of life, well-being and activities of daily living functions, especially when digital devices were used. Cognitive and psychosocial rehabilitation were much less researched but seen to be an emerging area of research. The focus of rehabilitation seems to lie on persons with PD, not their near-ones. The majority of interventions were planned without discussing in advance with the persons with PD about their preferences, needs or values. Very few interventions were individually tailored or conducted in a home setting, and many studies included patient-recorded outcome measures, but only as secondary to clinical measures. Only a few studies focused on an interprofessional approach to PD rehabilitation, despite the approach being found effective in regard to quality of life for persons with PD.

CONCLUSIONS

There appears to be a focus on physical outcomes and symptom management in the rehabilitation of persons with PD, even though cognitive and psychosocial well-being are often explored as secondary outcomes. Very few rehabilitation interventions were planned with persons or conducted in a home setting, and no interventions were seen that included near-ones. The majority of interventions were planned without the involvement of persons with PD. Still, many of the studies included patient-recorded outcome measures. Digital devices that assist in physical rehabilitation and an interprofessional approach to rehabilitation yield positive clinical outcomes, which in turn promotes a person-centered and holistic approach to rehabilitation.

Treating Speech Movement Hypokinesia in Parkinson's Disease: Does Movement Size Matter?

Purpose

This study evaluates the effects of a novel speech therapy program that uses a verbal cue and gamified augmented visual feedback regarding tongue movements to address articulatory hypokinesia during speech in individuals with Parkinson's disease (PD).

Method

Five participants with PD participated in an ABA single-subject design study. The treatment aimed to increase tongue movement size using a combination of a verbal cue and augmented visual feedback and was conducted in 10 45-min sessions over 5 weeks. The presence of visual feedback was manipulated during treatment. Articulatory working space of the tongue was the primary outcome measure and was examined during treatment and in cued and uncued sentences pre- and posttreatment. Changes in speech intelligibility in response to a verbal cue pre- and posttreatment were also examined.

Results

During treatment, 4/5 participants showed a beneficial effect of visual feedback on tongue articulatory working space. At the end of the treatment, they used larger tongue movements when cued, relative to their pretreatment performance. None of the participants, however, generalized the effect to the uncued sentences. Speech intelligibility of cued sentences was judged as superior posttreatment only in a single participant.

Conclusions

This study demonstrated that using an augmented visual feedback approach is beneficial, beyond a verbal cue alone, in addressing articulatory hypokinesia in individuals with PD. An optimal degree of articulatory expansion might, however, be required to elicit a speech intelligibility benefit.

Rhythmic performance in hypokinetic dysarthria: Relationship between reading, spontaneous speech and diadochokinetic tasks

•We investigated speech rhythm in people with Parkinson’s Disease (PwPD) and controls. •Even mildly affected PwPD differed from controls in their rhythmic performance. •PwPD showed less difference between reading and spontaneous speech. •Spontaneous speech highlighted more differences between speakers than reading. •DDK performance did not relate to rhythmic behaviour in connected speech.

Predicting Intelligibility Gains in Individuals With Dysarthria From Baseline Speech Features

PURPOSE

Across the treatment literature, behavioral speech modifications have produced variable intelligibility changes in speakers with dysarthria. This study is the first of two articles exploring whether measurements of baseline speech features can predict speakers' responses to these modifications.

METHODS

Fifty speakers (7 older individuals and 43 speakers with dysarthria) read a standard passage in habitual, loud, and slow speaking modes. Eighteen listeners rated how easy the speech samples were to understand. Baseline acoustic measurements of articulation, prosody, and voice quality were collected with perceptual measures of severity.

RESULTS

Cues to speak louder and reduce rate did not confer intelligibility benefits to every speaker. The degree to which cues to speak louder improved intelligibility could be predicted by speakers' baseline articulation rates and overall dysarthria severity. Improvements in the slow condition could be predicted by speakers' baseline severity and temporal variability. Speakers with a breathier voice quality tended to perform better in the loud condition than in the slow condition.

CONCLUSIONS

Assessments of baseline speech features can be used to predict appropriate treatment strategies for speakers with dysarthria. Further development of these assessments could provide the basis for more individualized treatment programs.

Predicting Intelligibility Gains in Dysarthria Through Automated Speech Feature Analysis

PURPOSE

Behavioral speech modifications have variable effects on the intelligibility of speakers with dysarthria. In the companion article, a significant relationship was found between measures of speakers' baseline speech and their intelligibility gains following cues to speak louder and reduce rate (Fletcher, McAuliffe, Lansford, Sinex, & Liss, 2017). This study reexamines these features and assesses whether automated acoustic assessments can also be used to predict intelligibility gains.

METHOD

Fifty speakers (7 older individuals and 43 with dysarthria) read a passage in habitual, loud, and slow speaking modes. Automated measurements of long-term average spectra, envelope modulation spectra, and Mel-frequency cepstral coefficients were extracted from short segments of participants' baseline speech. Intelligibility gains were statistically modeled, and the predictive power of the baseline speech measures was assessed using cross-validation.

RESULTS

Statistical models could predict the intelligibility gains of speakers they had not been trained on. The automated acoustic features were better able to predict speakers' improvement in the loud condition than the manual measures reported in the companion article.

CONCLUSIONS

These acoustic analyses present a promising tool for rapidly assessing treatment options. Automated measures of baseline speech patterns may enable more selective inclusion criteria and stronger group outcomes within treatment studies.

The effect of intensive speech rate and intonation therapy on intelligibility in Parkinson's disease

PURPOSE

Most studies on treatment of prosody in individuals with dysarthria due to Parkinson's disease are based on intensive treatment of loudness. The present study investigates the effect of intensive treatment of speech rate and intonation on the intelligibility of individuals with dysarthria due to Parkinson's disease.

METHODS

A one group pretest-posttest design was used to compare intelligibility, speech rate, and intonation before and after treatment. Participants included eleven Dutch-speaking individuals with predominantly moderate dysarthria due to Parkinson's disease, who received five one-hour treatment sessions per week during three weeks. Treatment focused on lowering speech rate and magnifying the phrase final intonation contrast between statements and questions. Intelligibility was perceptually assessed using a standardized sentence intelligibility test. Speech rate was automatically assessed during the sentence intelligibility test as well as during a passage reading task and a storytelling task. Intonation was perceptually assessed using a sentence reading task and a sentence repetition task, and also acoustically analyzed in terms of maximum fundamental frequency.

RESULTS

After treatment, there was a significant improvement of sentence intelligibility (effect size .83), a significant increase of pause frequency during the passage reading task, a significant improvement of correct listener identification of statements and questions, and a significant increase of the maximum fundamental frequency in the final syllable of questions during both intonation tasks.

CONCLUSION

The findings suggest that participants were more intelligible and more able to manipulate pause frequency and statement-question intonation after treatment. However, the relationship between the change in intelligibility on the one hand and the changes in speech rate and intonation on the other hand is not yet fully understood. Results are nuanced in the light of the operated research design.

LEARNING OUTCOMES

The reader will be able to: (1) describe the effect of intensive speech rate and intonation treatment on intelligibility of speakers with dysarthria due to PD, (2) describe the effect of intensive speech rate treatment on rate manipulation by speakers with dysarthria due to PD, and (3) describe the effect of intensive intonation treatment on manipulation of the phrase final intonation contrast between statements and questions by speakers with dysarthria due to PD.

Listener Perception of Monopitch, Naturalness, and Intelligibility for Speakers With Parkinson's Disease

PURPOSE

Given the potential significance of speech naturalness to functional and social rehabilitation outcomes, the objective of this study was to examine the effect of listener perceptions of monopitch on speech naturalness and intelligibility in individuals with Parkinson's disease (PD).

METHOD

Two short utterances were extracted from monologue samples of 16 speakers with PD and 5 age-matched adults without PD. Sixteen listeners evaluated these stimuli for monopitch, speech naturalness and intelligibility using the visual sort and rate method.

RESULTS

Naïve listeners can reliably judge monopitch, speech naturalness, and intelligibility with minimal familiarization. While monopitch and speech intelligibility were only moderately correlated, monopitch and speech naturalness were highly correlated.

CONCLUSIONS

A great deal of attention is currently being paid to improvement of vocal loudness and thus speech intelligibility in PD. Our findings suggest that prosodic characteristics such as monopitch should be explored as adjuncts to this treatment of dysarthria in PD. Development of such prosodic treatments may enhance speech naturalness and thus improve quality of life.

Behavioral treatments for speech in Parkinson's disease: meta-analyses and review of the literature

SUMMARY 

Parkinson's disease (PD) results from neurodegenerative processes leading to alteration of motor functions. Most motor symptoms respond well to pharmacological and neurosurgical treatments, except some axial symptoms such as speech impairment, so-called dysarthria. However, speech therapy is rarely proposed to PD patients. This review aims at evaluating previous research on the effects of speech behavioral therapies in patients with PD. We also performed two meta-analyses focusing on speech loudness and voice pitch. We showed that intensive therapies in PD are the most effective for hypophonia and can lead to some improvement of voice pitch. Although speech therapy is effective in handling PD dysarthria, behavioral speech rehabilitation in PD still needs further validation.

Variations on a theme: Songbirds, variability, and sensorimotor error correction

Songbirds provide a powerful animal model for investigating how the brain uses sensory feedback to correct behavioral errors. Here, we review a recent study in which we used online manipulations of auditory feedback to quantify the relationship between sensory error size, motor variability, and vocal plasticity. We found that although inducing small auditory errors evoked relatively large compensatory changes in behavior, as error size increased the magnitude of error correction declined. Furthermore, when we induced large errors such that auditory signals no longer overlapped with the baseline distribution of feedback, the magnitude of error correction approached zero. This pattern suggests a simple and robust strategy for the brain to maintain the accuracy of learned behaviors by evaluating sensory signals relative to the previously experienced distribution of feedback. Drawing from recent studies of auditory neurophysiology and song discrimination, we then speculate as to the mechanistic underpinnings of the results obtained in our behavioral experiments. Finally, we review how our own and other studies exploit the strengths of the songbird system, both in the specific context of vocal systems and more generally as a model of the neural control of complex behavior.

Cognitive-perceptual examination of remediation approaches to hypokinetic dysarthria

PURPOSE

To determine how increased vocal loudness and reduced speech rate affect listeners' cognitive-perceptual processing of hypokinetic dysarthric speech associated with Parkinson's disease.

METHOD

Fifty-one healthy listener participants completed a speech perception experiment. Listeners repeated phrases produced by 5 individuals with dysarthria across habitual, loud, and slow speaking modes. Listeners were allocated to habitual ( n = 17), loud ( n = 17), or slow ( n = 17) experimental conditions. Transcripts derived from the phrase repetition task were coded for overall accuracy (i.e., intelligibility), and perceptual error analyses examined how these conditions affected listeners' phonemic mapping (i.e., syllable resemblance) and lexical segmentation (i.e., lexical boundary error analysis).

RESULTS

Both speech conditions provided obvious perceptual benefits to listeners. Overall, transcript accuracy was highest in the slow condition. In the loud condition, however, improvement was evidenced across the experiment. An error analysis suggested that listeners in the loud condition prioritized acoustic-phonetic cues in their attempts to resolve the degraded signal, whereas those in the slow condition appeared to preferentially weight lexical stress cues.

CONCLUSIONS

Increased loudness and reduced rate exhibited differential effects on listeners' perceptual processing of dysarthric speech. The current study highlights the insights that may be gained from a cognitive-perceptual approach.

Characterizing intonation deficit in motor speech disorders: an autosegmental-metrical analysis of spontaneous speech in hypokinetic dysarthria, ataxic dysarthria, and foreign accent syndrome

PURPOSE

The autosegmental-metrical (AM) framework represents an established methodology for intonational analysis in unimpaired speaker populations but has found little application in describing intonation in motor speech disorders (MSDs). This study compared the intonation patterns of unimpaired participants (CON) and those with Parkinson's disease (PD), ataxic dysarthria (AT), and foreign accent syndrome (FAS) to evaluate the approach's potential for distinguishing types of MSDs from each other and from unimpaired speech.

METHOD

Spontaneous speech from 8 PD, 8 AT, 4 FAS, and 10 CON speakers were analyzed in relation to inventory and prevalence of pitch patterns, accentuation, and phrasing. Acoustic-phonetic baseline measures (maximum-phonation-duration, speech rate, and F0-variability) were also performed.

RESULTS

The analyses yielded differences between MSD and CON groups and between the clinical groups in regard to prevalence, accentuation, and phrasing. AT and FAS speakers used more rising and high pitch accents than PD and CON speakers. The AT group used the highest number of pitch accents per phrase, and all 3 MSD groups produced significantly shorter phrases than the CON group.

CONCLUSIONS

The study succeeded in differentiating MSDs on the basis of intonational performances by using the AM approach, thus, demonstrating its potential for charting intonational profiles in clinical populations.

Comparison of speech and language therapy techniques for speech problems in Parkinson's disease

BACKGROUND

Patients with Parkinson's disease commonly suffer from speech and voice difficulties such as impaired articulation and reduced loudness. Speech and language therapy (SLT) aims to improve the intelligibility of speech with behavioural treatment techniques or instrumental aids.

OBJECTIVES

To compare the efficacy and effectiveness of novel SLT techniques versus a standard SLT approach to treat Parkinsonian speech problems.

SEARCH METHODS

We identified relevant, published prior to 11(th) April 2011, by electronic searches of numerous literature databases including CENTRAL, MEDLINE and CINAHL, as well as handsearching relevant conference abstracts and examining reference lists in identified studies and other reviews.

SELECTION CRITERIA

Only randomised controlled trials (RCT) of one type of speech and language therapy versus another were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and resolved differences by discussion.

MAIN RESULTS

Six trials involving 159 patients satisfied the inclusion criteria. Data could not be analysed from one trial due to changes in patient numbers and from a second because the data provided were not in a usable format. All trials reported intelligibility measures but a statistically significant result was only reported for the diagnostic rhyme test used in the study of Lee Silverman Voice Treatment -LOUD (LSVT-LOUD) versus a modified version of this therapy (LSVT-ARTIC). In this case a difference of 12.5 points (95% confidence interval (CI) -22.2 to -2.8; P = 0.01) between the mean changes in favour of the LSVT-LOUD group was reported for a speech sample overlaid with Babble noise; this difference was not reproduced for the two additional noise conditions under which the speech samples were assessed. LSVT-LOUD also outperformed LSVT-ARTIC and Respiration therapy (RT) in improving loudness, with a difference in reading a sample text of 5.0 dB (95%CI -8.3 to -1.7; P = 0.003) and 5.5 dB (95% CI 3.4 to 7.7; P < 0.00001) respectively, and a difference in monologue speech of 2.9 dB (95% CI 0.6 to 5.2; P = 0.01) versus RT.

AUTHORS' CONCLUSIONS

Considering the small patient numbers in these trials, there is insufficient evidence to support or refute the efficacy of any form of SLT over another to treat speech problems in patients with Parkinson's disease.

Speech, voice and language in Parkinson’s disease: changes and interventions

SUMMARY This article covers recent developments in the understanding of communication changes in idiopathic Parkinson’s disease and selected issues in intervention. By contrast to earlier narrow considerations of voice and speech, the effects on communication of cognitive–linguistic and prosody perception and production are also highlighted. Decline can occur from the earliest stages, even when listeners perceive no frank changes. Communication may be relatively trouble-free in one-to-one quiet clinical situations but declines in multi-talker, dual/competing task situations. Assessment should reflect this to gain more accurate insights into daily living performance. Currently, therapies focusing on attention-to-effort in voice production and on monitoring the sense of effort and loudness production appear to be most successful. Medical and surgical treatments have little effect on intelligibility and communication and may even exacerbate the situation.

A cognitive-perceptual approach to conceptualizing speech intelligibility deficits and remediation practice in hypokinetic dysarthria

Hypokinetic dysarthria is a common manifestation of Parkinson's disease, which negatively influences quality of life. Behavioral techniques that aim to improve speech intelligibility constitute the bulk of intervention strategies for this population, as the dysarthria does not often respond vigorously to medical interventions. Although several case and group studies generally support the efficacy of behavioral treatment, much work remains to establish a rigorous evidence base. This absence of definitive research leaves both the speech-language pathologist and referring physician with the task of determining the feasibility and nature of therapy for intelligibility remediation in PD. The purpose of this paper is to introduce a novel framework for medical practitioners in which to conceptualize and justify potential targets for speech remediation. The most commonly targeted deficits (e.g., speaking rate and vocal loudness) can be supported by this approach, as well as underutilized and novel treatment targets that aim at the listener's perceptual skills.

A comparison of speech and language therapy techniques for dysarthria in Parkinson's disease

BACKGROUND

Dysarthria is a common manifestation of Parkinson's disease that increases in frequency and intensity with the progress of the disease (Streifler 1984). Up to 20% of Parkinsonian patients are referred for speech and language therapy (S & LT), its aim being to improve the intelligibility of the patient's speech.

OBJECTIVES

To compare the efficacy and effectiveness of novel S & LT techniques versus standard S & LT to treat dysarthria in patients with Parkinson's disease. To compare the efficacy and effectiveness of one S & LT technique versus a second form of S & LT to treat Parkinsonian dysarthria.

SEARCH STRATEGY

Relevant trials were identified by electronic searches of MEDLINE, EMBASE, CINAHL, ISI-SCI, AMED, MANTIS, REHABDATA, REHADAT, GEROLIT, Pascal, LILACS, MedCarib, JICST-EPlus, AIM, IMEMR, SIGLE, ISI-ISTP, DISSABS, Conference Papers Index, Aslib Index to Theses, the Cochrane Controlled Trials Register, the CentreWatch Clinical Trials listing service, the metaRegister of Controlled Trials, ClinicalTrials.gov, CRISP, PEDro, NIDRR and NRR; and examination of the reference lists of identified studies and other reviews.

SELECTION CRITERIA

Only randomised controlled trials (RCT) were included.

DATA COLLECTION AND ANALYSIS

Data was abstracted independently by KD and RW and differences settled by discussion.

MAIN RESULTS

Only two trials were identified with only 71 patients. The method of randomisation was good in only one trial and the concealment of allocation was inadequate in both trials. These methodological problems could potentially lead to bias from a number of sources. The methods used in the two studies varied so much that meta-analysis of the results was not possible. Scott 83 compared prosodic exercises with visual cues with prosodic exercises alone (See Glossary: Table 01). The authors examined prosody and intelligibility as outcome measures immediately after therapy. Ramig 95 compared the Lee Silverman Voice Therapy (LSVT) which emphasises increased vocal effort, with respiratory therapy which aimed to increase respiratory muscle activity. Ramig 95 examined a wide range of vocal characteristics, activities of daily living affected by speech, depression and the carer's impressions of the patient's speech quality. Some of these outcomes were measured up to 24 months after the end of the therapy. However, in neither study were changes in outcomes due to 'Therapy A' compared with the changes due to 'Therapy B' statistically. Therefore no comment on the comparative efficacy of these types of speech and language therapy can be made.

REVIEWER'S CONCLUSIONS

Considering the methodological flaws in both of these studies, the small number of patients examined, and the possibility of publication bias, there is insufficient evidence to support or refute the efficacy of any given form of S & LT over another to treat dysarthria in Parkinson's disease. Given the lack of evidence from RCTs to support or refute the efficacy of S & LT in Parkinson's disease (see Cochrane review 'Speech and Language therapy for Dysarthria in Patients with Parkinson's Disease'), the consensus as to what is considered 'best-practice' S & LT must be proved first through a large well-designed placebo-controlled randomised trial before examining variations in S & LT methodology. The design of these trials should minimise bias and be reported fully using CONSORT guidelines (CONSORT 1996). Outcome measures with particular relevance to patients, their carers, physicians and speech and language therapists should be chosen and the patients followed for at least 6 months to determine the duration of any improvement.