Visualizing the Knowledge Domain of Motor Speech Disorders: A Scientific Review (2000-2019)

This review visualizes the knowledge domain of motor speech disorders (MSDs) in linguistics between 2000 and 2019 by means of scientometric methods. With topic searches, the study collected 869 bibliographic records and 20, 411 references from Web of Science Core Collection (WoSCC) of Thomson Reuter. The clustered and visualized document co-citation network of the MSDs knowledge domain in CiteSpace identifies 15 research foci in different periods, including apraxia of speech, acoustics, children, technology, aphemia, childhood apraxia of speech, primary progressive aphasia, speech motor delay, Parkinson’s disease, amyotrophic lateral sclerosis, rhythm, foreign accent syndrome, phonation, phonological awareness, dose and speech perception. Revolving around linguistics, these foci could be divided into studies on speech characteristics of MSDs in terms of phonology and phonetics, remedies for MSDs in terms of neurolinguistics and acoustic phonetics, dysarthria secondary to neurological diseases based on pathological linguistics, subtypes of apraxia of speech, methods of MSDs based on auditory phonetics and a newly recognized subtype of MSDs. Meanwhile, the emerging trends of MSDs in linguistics are detected by the analysis of reference citation bursts, suggesting growing research in remedies for MSDs with the focus on assessments and effectiveness of treatments, speech characteristics and indexes of dysarthria secondary to neurological diseases and assistance to diagnose apraxia of speech. To sum up, the review has indicated that the acoustic measures to assess MSDs and acoustic remedies for dysarthria may not only be the past foci but also be future trends.

(Dys)Prosody in Parkinson’s Disease: Effects of Medication and Disease Duration on Intonation and Prosodic Phrasing

The phonology of prosody has received little attention in studies of motor speech disorders. The present study investigates the phonology of intonation (nuclear contours) and speech chunking (prosodic phrasing) in Parkinson’s disease (PD) as a function of medication intake and duration of the disease. Following methods of the prosodic and intonational phonology frameworks, we examined the ability of 30 PD patients to use intonation categories and prosodic phrasing structures in ways similar to 20 healthy controls to convey similar meanings. Speech data from PD patients were collected before and after a dopaminomimetic drug intake and were phonologically analyzed in relation to nuclear contours and intonational phrasing. Besides medication, disease duration and the presence of motor fluctuations were also factors included in the analyses. Overall, PD patients showed a decreased ability to use nuclear contours and prosodic phrasing. Medication improved intonation regardless of disease duration but did not help with dysprosodic phrasing. In turn, disease duration and motor fluctuations affected phrasing patterns but had no impact on intonation. Our study demonstrated that the phonology of prosody is impaired in PD, and prosodic categories and structures may be differently affected, with implications for the understanding of PD neurophysiology and therapy.

Vagus Nerve Stimulation as a Potential Adjuvant to Rehabilitation for Post-stroke Motor Speech Disorders

Stroke often leaves lasting impairments affecting orofacial function. While speech therapy is able to enhance function after stroke, many patients see only modest improvements after treatment. This partial restoration of function after rehabilitation suggests that there is a need for further intervention. Rehabilitative strategies that augment the effects of traditional speech therapy hold promise to yield greater efficacy and reduce disability associated with motor speech disorders. Recent studies demonstrate that brief bursts of vagus nerve stimulation (VNS) can facilitate the benefits of rehabilitative interventions. VNS paired with upper limb rehabilitation enhances recovery of upper limb function in patients with chronic stroke. Animal studies reveal that these improvements are driven by VNS-dependent synaptic plasticity in motor networks. Moreover, preclinical evidence demonstrates that a similar strategy of pairing VNS can promote synaptic reorganization in orofacial networks. Building on these findings, we postulate that VNS-directed orofacial plasticity could target post-stroke motor speech disorders. Here, we outline the rationale for pairing VNS with traditional speech therapy to enhance recovery in the context of stroke of speech motor function. We also explore similar treatments that aim to enhance synaptic plasticity during speech therapy, and how VNS differs from these existing therapeutic strategies. Based on this evidence, we posit that VNS-paired speech therapy shows promise as a means of enhancing recovery after post-stroke motor speech disorders. Continued development is necessary to comprehensively establish and optimize this approach, which has the potential to increase quality of life for the many individuals suffering with these common impairments.

Motor Speech Disorders and Communication Limitations in Progressive Supranuclear Palsy

Purpose This study describes motor speech disorders and associated communication limitations in six variants of progressive supranuclear palsy (PSP). Method The presence, nature, and severity of dysarthria and apraxia of speech (AOS) were documented, along with scores on the Apraxia of Speech Rating Scale–Version 3 (ASRS-3) for 77 (40 male and 37 female) patients with PSP. Clinician-estimated and patient-estimated communication limitations were rated using the Motor Speech Disorders Severity Rating (MSDSR) Scale and the Communicative Effectiveness Survey (CES), respectively. Descriptive statistics were calculated for each of these dependent variables. One-tailed t tests were conducted to test mean differences in ASRS-3 and CES between participants with and without AOS and between participants with and without dysarthria. Spearman rank correlations were calculated between ASRS-3 scores and clinical judgments of AOS and dysarthria severity and between MSDSR and CES ratings. Results Nine participants (12%) had normal speech. Eighty-seven percent exhibited dysarthria; hypokinetic and mixed hypokinetic–spastic dysarthria were observed most frequently. AOS was observed in 19.5% of participants across all variants, but in only 10% exclusive of the PSP speech and language variant. Nearly half presented with AOS in which neither phonetic nor prosodic features clearly predominated. The mean ASRS-3 score for participants with AOS was significantly higher than for those without and correlated strongly with clinician judgment of AOS severity. Mean ASRS-3 was higher for participants with dysarthria than for those without but correlated weakly with dysarthria severity. Mean MSDSR and CES ratings were lower in participants with AOS compared to those without and moderately correlated with each other. Conclusions Motor speech disorders that negatively impact communicative effectiveness are common in PSP and occur in many variants. This is the first description of motor speech disorders across PSP variants, setting the stage for future research characterizing neuroanatomical correlates, progression of motor speech disorders, and benefits of targeted interventions. Supplemental Material https://doi.org/10.23641/asha.14111837

Atraso motor de fala não especificado: revisão integrativa

Objetivo: realizar uma revisão bibliográfica sobre o atraso motor de fala não especificado, como ele é avaliado e ainda como se diferencia de outras desordens motoras da fala. Estratégia de pesquisa: Trata-se de uma revisão integrativa da literatura. Realizou-se a busca nas bases SciELO, PubMed, Medine e Scopus no mês de novembro de 2019. Para as quatro bases foram utilizados os seguintes construtos e descritores: “motor speech disorders” OR “childhood apraxia of speech” OR “childhood apraxia of speech cas” OR “developmental dyspraxia” OR “speech sound disorder” AND “speech motor control”, além da utilização de dois filtros: sujeitos até 18 anos e humanos. Critérios de seleção: Artigos publicados em português, inglês ou espanhol foram incluídos, sendo ou não de periódicos de acesso livre. Foram excluídos artigos que não estavam relacionados ao atraso motor de fala não especificado e estudos de revisão de literatura. Resultados: Foram encontrados56 artigos nas bases de dados, sendo 33 da base Scopus, 19 da PubMed, 3 da SciElo e 1 da Medline. Após análise e seleção pelos critérios de inclusão, foram selecionados 14 estudos. Posteriormente a leitura integral dos artigos, 8 estudos foram excluídos, pois não respondiam as perguntas norteadoras da pesquisa, obtendo-se um n de 6 estudos. Conclusão: Muitas crianças com atraso significativo na fala são diagnosticadas erroneamente, sendo o DMS-NOS a desordem de maior prevalência na infância.

Rapid Syllable Transition Treatment—A Treatment for Childhood Apraxia of Speech and Other Pediatric Motor Speech Disorders

Purpose Childhood apraxia of speech (CAS) is a speech disorder that many generalist speech-language pathologists feel underqualified to treat. For children with CAS, this may result in ad hoc interventions resulting in slower progress. Research evidence for various CAS treatments is primarily limited to single-case experimental design studies; however, two treatments (Rapid Syllable Transition Treatment [ReST] and the Nuffield Dyspraxia Programme, Third Edition) have been compared in a single randomized controlled trial. Conclusion This tutorial describes one of those treatments: ReST which was designed to address the three consensus core features of CAS simultaneously: consistency and accuracy of sounds, sequencing, and prosody. The treatment uses nonwords to help children build and store accurate motor plans and programs using principles of motor learning. Treatment data are described, and commonly reported clinical issues are discussed. Recommendations for which children may be suitable for ReST and for evidence-based practice are described.