Parkinson's Disease Dysarthria Research Articles

Hypokinetic Dysarthria in Parkinson's Disease: A Narrative Review.

Numerous disabling motor and non-motor symptoms occur during Parkinson's disease (PD), including speech disorders, often referred to as hypokinetic dysarthria. PD is the most common cause of this type of dysarthria. About 90% of PD patients experience hypokinetic dysarthria, which is exacerbated as the disease progresses and makes it very difficult for other people to understand the person with PD. This disorder is characterized by a monotonous speech pattern, reduced and monotonous loudness, decreased stress, a breathy or hoarse voice quality, an increase in speech rate, rapid repetition of phonemes, and impreciseness in consonant production. However, patients may also have sensory symptoms including inaccurate perceptions of their own loudness and decreased awareness of speech problems. Hypokinetic dysarthria in PD may not only result from dopamine degeneration in the nigrostriatal pathway but also from disturbances in the motor and somatosensory systems. All speech components, such as phonation, articulation, respiration, resonance, and prosody should be assessed carefully in PD patients with hypokinetic dysarthria. Taking medical history, an oral motor assessment, a perceptual evaluation of speech characteristics, intelligibility, efficiency, and participation in communication all need to be a part of the assessment. The tasks of maximum phonation time, diadochokinetic rate, reading sentences, words, and passages, describing pictures, and spontaneous speech are used to assess the features of speech components and intelligibility. The evaluation should include physiological, acoustic, or imaging modalities as well. Speech therapy is typically the main treatment of speech problems in PD. The management of PD-related hypokinetic dysarthria basically focuses on speaker-oriented and communication-oriented strategies. In addition to these strategies, Augmentative Alternative Communication (AAC) should be considered in patients with severe dysarthria. Loudness, intelligibility, and sound perception may all significantly improve with the Lee Silverman Voice Therapy LOUD (LSVT LOUD) program which is an evidence-based program. The beneficial effect of pharmacological and surgical treatment approaches has not been proven in improving speech. Deep brain stimulation may carry the risk of the deterioration of speech as the illness progresses.

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.

Prosodic Improvement in Persons with Parkinson Disease Receiving SPEAK OUT!® Voice Therapy

Background/Aims: Hypokinetic dysarthria in Parkinson disease (PD) hinders the ability to verbally communicate and interferes with activities of daily living. SPEAK OUT!® is a therapy program designed to improve functional communicative ability. In contrast to the Lee Silverman Voice Treatment program, SPEAK OUT!® promotes speaking with intent to effect loud speech. This study evaluated the efficacy of SPEAK OUT!® in persons with idiopathic PD in 3 domains: self-reported voice handicap, clinical ratings of dysarthria and prosody, and acoustic analysis of prosody. Participants and Methods: Pre-/post-therapy data included PD participants’ scores on the Voice Handicap Index (VHI) and the Voice-Related Quality of Life (V-RQOL) questionnaire, audio recordings, perceptual evaluation scores, and demographic data, such as age, sex, handedness, diagnosis, and onset of PD. Results: Participants achieved a statistically and clinically significant improvement in speech intensity, pitch range, normalized pairwise variability index for pitch, sustained vowel duration, reading intelligibility, and vocal quality after SPEAK OUT!® training, consistent with both of the self-report voice scores, i.e., the VHI and the V-RQOL, and with the perceptual speech evaluation scores. Longer PD duration was associated with lowered efficacy. Conclusions: SPEAK OUT!® is effective and should be administered as early as possible after disease onset.

Frenchay dysarthria assessment (FDA-2) in Parkinson's disease: cross-cultural adaptation and psychometric properties of the European Portuguese version.

Hypokinetic dysarthria is a common symptom in those with Parkinson's disease (PD); there is currently no standardized or validated tool for assessing speech in this population. To translate into European Portuguese (EP) the FDA-2 and perform a cultural adaptation followed by an evaluation of its psychometric properties in PD in a sample of people with PD in different stages of disease progression. Translation, back-translation, experts' analysis, pre-test and final version test were performed. The EP version of the FDA-2 was administered to 80 people with PD (PwP) with dysarthria, feasibility and acceptability, reliability (internal consistency and inter-rater reliability) and validity (face and convergent) were measured. Overall, the EP-FDA-2 proved to be similar to the original demonstrating the same conceptual meanings, semantics, idiomatic and score equivalences. It has good feasibility (missing data <5%), acceptability (ceiling and floor effects <15%), a high reliability of the total score (0.94), an excellent inter-rater agreement for the total score (0.96) and moderate to large construct validity for 81% of its items. It is well correlated with the gold standard for disease severity assessment in PD, the MDS-UPDRS. The EP-FDA-2 has shown the salient features of a valid tool that can be used by speech and language therapists in the assessment of dysarthria in PD in clinical practice as in the research field.

Deep brain stimulation exacerbates hypokinetic dysarthria in a rat model of Parkinson's disease.

Motor symptoms of Parkinson's disease (PD) follow the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Deep brain stimulation (DBS) treats some parkinsonian symptoms, such as tremor, rigidity, and bradykinesia, but may worsen certain medial motor symptoms, including hypokinetic dysarthria. The mechanisms by which DBS exacerbates dysarthria while improving other symptoms are unclear and difficult to study in human patients. This study proposes an animal model of DBS-exacerbated dysarthria. We use the unilateral, 6-hydroxydopamine (6-OHDA) rat model of PD to test the hypothesis that DBS exacerbates quantifiable aspects of vocalization. Mating calls were recorded from sexually experienced male rats under healthy and parkinsonian conditions and during DBS of the subthalamic nucleus. Relative to healthy rats, parkinsonian animals made fewer calls with shorter and less complex vocalizations. In the parkinsonian rats, putatively therapeutic DBS further reduced call frequency, duration, and complexity. The individual utterances of parkinsonian rats spanned a greater bandwidth than those of healthy rats, potentially reducing the effectiveness of the vocal signal. This utterance bandwidth was further increased by DBS. We propose that the parkinsonism-associated changes in call frequency, duration, complexity, and dynamic range combine to constitute a rat analog of parkinsonian dysarthria. Because DBS exacerbates the parkinsonism-associated changes in each of these metrics, the subthalamic stimulated 6-OHDA rat is a good model of DBS-induced hypokinetic dysarthria in PD. This model will help researchers examine how DBS alleviates many motor symptoms of PD while exacerbating parkinsonian speech deficits that can greatly diminish patient quality of life.

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

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). 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. 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. 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.

Acoustic and Perceptual Consequences of Clear and Loud Speech

Objective: Several issues concerning F2 slope in dysarthria were addressed by obtaining speech acoustic measures and judgments of intelligibility for sentences produced in Habitual, Clear and Loud conditions by speakers with Parkinson's disease (PD) and healthy controls. Patients and Methods: Acoustic measures of average and maximum F2 slope for diphthongs, duration and intensity were obtained. Listeners judged intelligibility using a visual analog scale. Differences in measures among groups and conditions as well as relationships among measures were examined. Results: Average and maximum F2 slope metrics were strongly correlated, but only average F2 slope consistently differed among groups and conditions, with shallower slopes for the PD group and steeper slopes for Clear speech versus Habitual and Loud. Clear and Loud speech were also characterized by lengthened durations, increased intensity and improved intelligibility versus Habitual. F2 slope and intensity were unrelated, and F2 slope was a significant predictor of intelligibility. Conclusion: Average diphthong F2 slope was more sensitive than maximum F2 slope to articulatory mechanism involvement in mild dysarthria in PD. F2 slope holds promise as an objective measure of treatment-related changes in the articulatory mechanism for therapeutic techniques that focus on articulation.

Acoustic evaluation of short-term effects of repetitive transcranial magnetic stimulation on motor aspects of speech in Parkinson’s disease

Hypokinetic dysarthria in Parkinson's disease (PD) can be characterized by monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice. Using acoustic analysis, we studied the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) applied over the primary orofacial sensorimotor area (SM1) and the left dorsolateral prefrontal cortex (DLPFC) on motor aspects of voiced speech in PD. Twelve non-depressed and non-demented men with PD (mean age 64.58 ± 8.04 years, mean PD duration 10.75 ± 7.48 years) and 21 healthy age-matched men (a control group, mean age 64 ± 8.55 years) participated in the speech study. The PD patients underwent two sessions of 10 Hz rTMS over the dominant hemisphere with 2,250 stimuli/day in a random order: (1) over the SM1; (2) over the left DLPFC in the "on" motor state. Speech examination comprised the perceptual rating of global speech performance and an acoustic analysis based upon a standardized speech task. The Mann-Whitney U test was used to compare acoustic speech variables between controls and PD patients. The Wilcoxon test was used to compare data prior to and after each stimulation in the PD group. rTMS applied over the left SM1 was associated with a significant increase in harmonic-to-noise ratio and net speech rate in the sentence tasks. With respect to the vowel task results, increased median values and range of Teager-Kaiser energy operator, increased vowel space area, and significant jitter decrease were observed after the left SM1 stimulation. rTMS over the left DLPFC did not induce any significant effects. The positive results of acoustic analysis were not reflected in a subjective rating of speech performance quality as assessed by a speech therapist. Our pilot results indicate that one session of rTMS applied over the SM1 may lead to measurable improvement in voice quality and intensity and an increase in speech rate and tongue movements. Nevertheless, these changes were not accompanied by changes in a perceptual evaluation of speech performance by a speech therapist. Future placebo-controlled studies in larger patient cohorts should verify if rTMS would be clinically useful for treating hypokinetic dysarthria in PD.

Subthalamic nucleus stimulation and dysarthria in Parkinson's disease: a PET study.

In Parkinson's disease, functional imaging studies during limb motor tasks reveal cerebral activation abnormalities that can be reversed by subthalamic nucleus (STN) stimulation. The effect of STN stimulation on parkinsonian dysarthria has not, however, been investigated using PET. The aim of the present study was to evaluate the effect of STN stimulation on regional cerebral blood flow (rCBF) during speech production and silent articulation in patients with Parkinson's disease. Ten Parkinson's disease patients surgically implanted bilaterally in the STN and with significant improvement of their dysarthria induced by STN stimulation were included. Ten healthy control subjects also participated in this study. Control subjects performed six sessions of [15O]H2O-PET scanning corresponding to three duplicated conditions externally cued by an auditory signal. The conditions were: (i) rest; (ii) production of a short, simple sentence; and (iii) silent articulation of the same sentence. Parkinson's disease patients carried out the six PET sessions twice, i.e., in the ON and OFF STN stimulation states. PET data analysis was performed using statistical parametric mapping (SPM99). In control subjects, speech production (SP) compared with rest was associated with increased rCBF bilaterally in the primary motor cortex (M1) corresponding to the orofacial somatotopy, the supplementary motor area (SMA), the associative auditory cortex and the cerebellar hemispheres. Silent articulation (SA) compared with rest induced a bilateral rCBF increase restricted to the orofacial M1 and cerebellar hemispheres. In Parkinson's disease patients in the OFF stimulation condition, during both SP and SA there was a lack of activation in the right orofacial M1 and in the cerebellum, abnormal increased rCBF in the right superior premotor cortex, and overactivation of the SMA. There was also an abnormal, increased rCBF in the dorsolateral prefrontal cortex (DLPFC) only during SP and increased rCBF in the left insula only during SA. In Parkinson's disease patients ON stimulation, for both SP and SA the activation pattern appeared similar to that in control subjects. In conclusion, our results suggest that parkinsonian dysarthria is associated with altered recruitment of the main motor cerebral regions (orofacial M1, cerebellum), and increased involvement of the premotor and prefrontal cortices (DLPFC, SMA, superior premotor cortex). These abnormal activations are different from those reported during hand motor tasks. They could be a compensatory mechanism, but might also arise directly as part of the pathophysiology of Parkinson's disease. STN stimulation tends to reverse these abnormal activations, which is consistent with the observed improvement of Parkinson's disease dysarthria.