Enhancing Speech Rehabilitation in a Young Adult with Trisomy 21: Integrating Transcranial Direct Current Stimulation (tDCS) with Rapid Syllable Transition Training for Apraxia of Speech.

Apraxia of speech is a persistent speech motor disorder that affects speech intelligibility. Studies on speech motor disorders with transcranial Direct Current Stimulation (tDCS) have been mostly directed toward examining post-stroke aphasia. Only a few tDCS studies have focused on apraxia of speech or childhood apraxia of speech (CAS), and no study has investigated individuals with CAS and Trisomy 21 (T21, Down syndrome). This N-of-1 randomized trial examined the effects of tDCS combined with a motor learning task in developmental apraxia of speech co-existing with T21 (ReBEC RBR-5435x9). The accuracy of speech sound production of nonsense words (NSWs) during Rapid Syllable Transition Training (ReST) over 10 sessions of anodal tDCS (1.5 mA, 25 cm) over Broca's area with the cathode over the contralateral region was compared to 10 sessions of sham-tDCS and four control sessions in a 20-year-old male individual with T21 presenting moderate-severe childhood apraxia of speech (CAS). The accuracy for NSW production progressively improved (gain of 40%) under tDCS (sham-tDCS and control sessions showed < 20% gain). A decrease in speech severity from moderate-severe to mild-moderate indicated transfer effects in speech production. Speech accuracy under tDCS was correlated with Wernicke's area activation (P3 current source density), which in turn was correlated with the activation of the left supramarginal gyrus and the Sylvian parietal-temporal junction. Repetitive bihemispheric tDCS paired with ReST may have facilitated speech sound acquisition in a young adult with T21 and CAS, possibly through activating brain regions required for phonological working memory.

Development and Validation of a Probe Word List to Assess Speech Motor Skills in Children.

Purpose The aim of the study was to develop and validate a probe word list and scoring system to assess speech motor skills in preschool and school-age children with motor speech disorders. Method This article describes the development of a probe word list and scoring system using a modified word complexity measure and principles based on the hierarchical development of speech motor control known as the Motor Speech Hierarchy (MSH). The probe word list development accounted for factors related to word (i.e., motoric) complexity, linguistic variables, and content familiarity. The probe word list and scoring system was administered to 48 preschool and school-age children with moderate-to-severe speech motor delay at clinical centers in Ontario, Canada, and then evaluated for reliability and validity. Results One-way analyses of variance revealed that the motor complexity of the probe words increased significantly for each MSH stage, while no significant differences in the linguistic complexity were found for neighborhood density, mean biphone frequency, or log word frequency. The probe word list and scoring system yielded high reliability on measures of internal consistency and intrarater reliability. Interrater reliability indicated moderate agreement across the MSH stages, with the exception of MSH Stage V, which yielded substantial agreement. The probe word list and scoring system demonstrated high content, construct (unidimensionality, convergent validity, and discriminant validity), and criterion-related (concurrent and predictive) validity. Conclusions The probe word list and scoring system described in the current study provide a standardized method that speech-language pathologists can use in the assessment of speech motor control. It can support clinicians in identifying speech motor difficulties in preschool and school-age children, set appropriate goals, and potentially measure changes in these goals across time and/or after intervention.

Speech Sound Disorders in Children: An Articulatory Phonology Perspective.

Speech Sound Disorders (SSDs) is a generic term used to describe a range of difficulties producing speech sounds in children (McLeod and Baker, 2017). The foundations of clinical assessment, classification and intervention for children with SSD have been heavily influenced by psycholinguistic theory and procedures, which largely posit a firm boundary between phonological processes and phonetics/articulation (Shriberg, 2010). Thus, in many current SSD classification systems the complex relationships between the etiology (distal), processing deficits (proximal) and the behavioral levels (speech symptoms) is under-specified (Terband et al., 2019a). It is critical to understand the complex interactions between these levels as they have implications for differential diagnosis and treatment planning (Terband et al., 2019a). There have been some theoretical attempts made towards understanding these interactions (e.g., McAllister Byun and Tessier, 2016) and characterizing speech patterns in children either solely as the product of speech motor performance limitations or purely as a consequence of phonological/grammatical competence has been challenged (Inkelas and Rose, 2007; McAllister Byun, 2012). In the present paper, we intend to reconcile the phonetic-phonology dichotomy and discuss the interconnectedness between these levels and the nature of SSDs using an alternative perspective based on the notion of an articulatory "gesture" within the broader concepts of the Articulatory Phonology model (AP; Browman and Goldstein, 1992). The articulatory "gesture" serves as a unit of phonological contrast and characterization of the resulting articulatory movements (Browman and Goldstein, 1992; van Lieshout and Goldstein, 2008). We present evidence supporting the notion of articulatory gestures at the level of speech production and as reflected in control processes in the brain and discuss how an articulatory "gesture"-based approach can account for articulatory behaviors in typical and disordered speech production (van Lieshout, 2004; Pouplier and van Lieshout, 2016). Specifically, we discuss how the AP model can provide an explanatory framework for understanding SSDs in children. Although other theories may be able to provide alternate explanations for some of the issues we will discuss, the AP framework in our view generates a unique scope that covers linguistic (phonology) and motor processes in a unified manner.

Measuring and Training Speech-Language Pathologists' Orofacial Cueing: A Pilot Demonstration.

Tactile-kinesthetic-proprioceptive (TKP) input used to facilitate speech motor control is considered an active ingredient within speech motor interventions. Objective metrics identifying skill level differences across speech-language pathologists (S-LP) providing TKP cues are crucial for monitoring treatment delivery fidelity. The study examined three kinematic measures indicating accuracy and consistency of TKP inputs by 3 S-LPs with varying experience levels (S-LP 1: novice; S-LP 2 and S-LP 3: advanced). Confidence interval measures were used to compare the accuracy of jaw movement amplitudes of the vowel /a/ made by a model participant versus S-LPs giving the TKP input. Generalised Orthogonal Procrustes Analysis (GPA) and cyclic Spatial Temporal Index (cSTI) were used to determine movement consistency. Results revealed passive jaw excursions induced by S-LP 2 and 3 to be not statistically significant from the model participant's active jaw movements. cSTI values decreased with advanced level of experience (19.28, 12.14, and 9.33 for S-LP 1, S-LP 2, and S-LP 3, respectively). GPA analyses revealed a similar pattern for S-LPs with more experience demonstrating lower mean RMS values (0.22, 0.03, and 0.11 for S-LP 1, S-LP 2, and S-LP 3, respectively). Findings suggest kinematic measures adapted from the motor control literature can be applied to assess S-LP skill differences in providing TKP cues.

Parent-child interaction in motor speech therapy.

PURPOSE: This study measures the reliability and sensitivity of a modified Parent-Child Interaction Observation scale (PCIOs) used to monitor the quality of parent-child interaction. The scale is part of a home-training program employed with direct motor speech intervention for children with speech sound disorders. METHOD: Eighty-four preschool age children with speech sound disorders were provided either high- (2×/week/10 weeks) or low-intensity (1×/week/10 weeks) motor speech intervention. Clinicians completed the PCIOs at the beginning, middle, and end of treatment. Inter-rater reliability (Kappa scores) was determined by an independent speech-language pathologist who assessed videotaped sessions at the midpoint of the treatment block. Intervention sensitivity of the scale was evaluated using a Friedman test for each item and then followed up with Wilcoxon pairwise comparisons where appropriate. RESULTS: We obtained fair-to-good inter-rater reliability (Kappa = 0.33-0.64) for the PCIOs using only video-based scoring. Child-related items were more strongly influenced by differences in treatment intensity than parent-related items, where a greater number of sessions positively influenced parent learning of treatment skills and child behaviors. CONCLUSION: The adapted PCIOs is reliable and sensitive to monitor the quality of parent-child interactions in a 10-week block of motor speech intervention with adjunct home therapy. Implications for rehabilitation Parent-centered therapy is considered a cost effective method of speech and language service delivery. However, parent-centered models may be difficult to implement for treatments such as developmental motor speech interventions that require a high degree of skill and training. For children with speech sound disorders and motor speech difficulties, a translated and adapted version of the parent-child observation scale was found to be sufficiently reliable and sensitive to assess changes in the quality of the parent-child interactions during intervention. In developmental motor speech interventions, high-intensity treatment (2×/week/10 weeks) facilitates greater changes in the parent-child interactions than low intensity treatment (1×/week/10 weeks). On one hand, parents may need to attend more than five sessions with the clinician to learn how to observe and address their child's speech difficulties. On the other hand, children with speech sound disorders may need more than 10 sessions to adapt to structured play settings even when activities and therapy materials are age-appropriate.

Random Item Generation Is Affected by Age.

Purpose: Random item generation (RIG) involves central executive functioning. Measuring aspects of random sequences can therefore provide a simple method to complement other tools for cognitive assessment. We examine the extent to which RIG relates to specific measures of cognitive function, and whether those measures can be estimated using RIG only. Method: Twelve healthy older adults (age: M = 70.3 years, SD = 4.9; 8 women and 4 men) and 20 healthy young adults (age: M = 24 years, SD = 4.0; 12 women and 8 men) participated in this pilot study. Each completed a RIG task, along with the color Stroop test, the Repeatable Battery for the Assessment of Neuropsychological Status, and the Peabody Picture Vocabulary Test-Fourth Edition (Dunn & Dunn, 2007). Several statistical features extracted from RIG sequences, including recurrence quantification, were found to be related to the other measures through correlation, regression, and a neural-network model. Results: The authors found significant effects of age in RIG and demonstrate that nonlinear machine learning can use measures of RIG to accurately predict outcomes from other tools. Conclusions: These results suggest that RIG can be used as a relatively simple predictor for other tools and in particular seems promising as a potential screening tool for selective attention in healthy aging.

The assessment of fidelity in a motor speech-treatment approach.

OBJECTIVE: To demonstrate the application of the constructs of treatment fidelity for research and clinical practice for motor speech disorders, using the Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT) Fidelity Measure (PFM). Treatment fidelity refers to a set of procedures used to monitor and improve the validity and reliability of behavioral intervention. While the concept of treatment fidelity has been emphasized in medical and allied health sciences, documentation of procedures for the systematic evaluation of treatment fidelity in Speech-Language Pathology is sparse. METHODS: The development and iterative process to improve the PFM, is discussed. Further, the PFM is evaluated against recommended measurement strategies documented in the literature. This includes evaluating the appropriateness of goals and objectives; and the training of speech-language pathologists, using direct and indirect procedures. Three expert raters scored the PFM to examine inter-rater reliability. RESULTS: Three raters, blinded to each other's scores, completed fidelity ratings on three separate occasions. Inter-rater reliability, using Krippendorff's Alpha, was >80% for the PFM on the final scoring occasion. This indicates strong inter-rater reliability. CONCLUSION: The development of fidelity measures for the training of service providers and treatment delivery is important in specialized treatment approaches where certain 'active ingredients' (e.g. specific treatment targets and therapeutic techniques) must be present in order for treatment to be effective. The PFM reflects evidence-based practice by integrating treatment delivery and clinical skill as a single quantifiable metric. PFM enables researchers and clinicians to objectively measure treatment outcomes within the PROMPT approach.

Visual speech gestures modulate efferent auditory system.

Visual and auditory systems interact at both cortical and subcortical levels. Studies suggest a highly context-specific cross-modal modulation of the auditory system by the visual system. The present study builds on this work by sampling data from 17 young healthy adults to test whether visual speech stimuli evoke different responses in the auditory efferent system compared to visual non-speech stimuli. The descending cortical influences on medial olivocochlear (MOC) activity were indirectly assessed by examining the effects of contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) at 1, 2, 3 and 4 kHz under three conditions: (a) in the absence of any contralateral noise (Baseline), (b) contralateral noise + observing facial speech gestures related to productions of vowels /a/ and /u/ and (c) contralateral noise + observing facial non-speech gestures related to smiling and frowning. The results are based on 7 individuals whose data met strict recording criteria and indicated a significant difference in TEOAE suppression between observing speech gestures relative to the non-speech gestures, but only at the 1 kHz frequency. These results suggest that observing a speech gesture compared to a non-speech gesture may trigger a difference in MOC activity, possibly to enhance peripheral neural encoding. If such findings can be reproduced in future research, sensory perception models and theories positing the downstream convergence of unisensory streams of information in the cortex may need to be revised.

Peripheral auditory tuning for vowels.

In this study, 35 young, healthy adults were tested on whether speech-like stimuli evoke a unique response in the auditory efferent system. To this end, descending cortical influences on medial olivocochlear (MOC) activity were indirectly evaluated by studying the effects of contralateral suppression on distortion product otoacoustic emissions (DPOAEs) under four conditions: (a) in the absence of any contralateral noise (Baseline), (b) presence of contralateral broadband noise (Noise Baseline), (c) vowel discrimination-in-noise task (VDN) and (d) tone discrimination-in-noise (TDN) task. A statistically significant release from suppression was evident across all tested DPOAE frequencies (1, 1.5 and 2 kHz) only for the VDN task (p < 0.05), which yielded greater release from suppression than the TDN task. These findings indicate that during active listening in the presence of noise, the MOC activity may be differentially modulated depending on the type of stimulus (vowel vs. tone). Specifically, in the presence of background noise, vowels may show a greater release from suppression in the cochlea than frequency, intensity and duration matched tones.

Relationship between speech motor control and speech intelligibility in children with speech sound disorders.

UNLABELLED: The current study was undertaken to investigate the impact of speech motor issues on the speech intelligibility of children with moderate to severe speech sound disorders (SSD) within the context of the PROMPT intervention approach. The word-level Children's Speech Intelligibility Measure (CSIM), the sentence-level Beginner's Intelligibility Test (BIT) and tests of speech motor control and articulation proficiency were administered to 12 children (3:11 to 6:7 years) before and after PROMPT therapy. PROMPT treatment was provided for 45 min twice a week for 8 weeks. Twenty-four naïve adult listeners aged 22-46 years judged the intelligibility of the words and sentences. For CSIM, each time a recorded word was played to the listeners they were asked to look at a list of 12 words (multiple-choice format) and circle the word while for BIT sentences, the listeners were asked to write down everything they heard. Words correctly circled (CSIM) or transcribed (BIT) were averaged across three naïve judges to calculate percentage speech intelligibility. Speech intelligibility at both the word and sentence level was significantly correlated with speech motor control, but not articulatory proficiency. Further, the severity of speech motor planning and sequencing issues may potentially be a limiting factor in connected speech intelligibility and highlights the need to target these issues early and directly in treatment. LEARNING OUTCOMES: The reader will be able to: (1) outline the advantages and disadvantages of using word- and sentence-level speech intelligibility tests; (2) describe the impact of speech motor control and articulatory proficiency on speech intelligibility; and (3) describe how speech motor control and speech intelligibility data may provide critical information to aid treatment planning.

Speech motor skill and stuttering.

The authors review converging lines of evidence from behavioral, kinematic, and neuroimaging data that point to limitations in speech motor skills in people who stutter (PWS). From their review, they conclude that PWS differ from those who do not in terms of their ability to improve with practice and retain practiced changes in the long term, and that they are less efficient and less flexible in their adaptation to lower (motor) and higher (cognitive-linguistic) order requirements that impact on speech motor functions. These findings in general provide empirical support for the position that PWS may occupy the low end of the speech motor skill continuum as argued in the Speech Motor Skills approach (Van Lieshout, Hulstijn, & Peters, 2004).

Sensory feedback dependence hypothesis in persons who stutter.

The present study investigated the role of sensory feedback (auditory, proprioception, and tactile) at the intra- and inter-gestural levels of speech motor coordination in normal and fast speech rate conditions in two groups: (1) persons who stutter (PWS) and (2) those who do not (PNS). Feedback perturbations were carried out with the use of masking noise (auditory), tendon vibration (proprioception), and nonwords that differed in the amount of required tactile lip contact (/api/+tactile and /awi/-tactile). Comparisons were also made between jaw-free and jaw-immobilized (with a bite-block) task conditions. It was hypothesized that if PWS depend more strongly on sensory feedback control during speech production, they would show an increase in variability of movement coordination in the combined presence of fast speech rates and feedback perturbations, in particular, when jaw motions are blocked and adaptations in the other articulators are required to achieve the task goals. Significant feedback perturbation effects were found for both groups, but the only significant between-group effect was found at fast speech rates in the jaw-free condition, showing that control speakers were more perturbed at the intra-gestural level of coordination than PWS when simultaneous (auditory, proprioceptive, and tactile) perturbations were present. The findings do not provide support for either the feedback dependency or the sensory deficit hypotheses described in the literature to explain movement characteristics found in fluent speech production of PWS.

Bite-block perturbation in people who stutter: immediate compensatory and delayed adaptive processes.

UNLABELLED: This exploratory study investigated sensory-motor mechanisms in five people who stutter (PWS) and five people who do not (PNS). Lip kinematic and coordination data were recorded as they produced bi-syllabic nonwords at two rates (normal and fast) in three conditions (jaw-free, immediately after insertion of a bite-block, and after a 10-min accommodation period). At normal speech rates, effects of bite-blocks on lip kinematics were similar for both PWS and PNS speakers showing larger amplitudes, peak velocities, shorter durations and more stable movement cycle patterns. However, at fast speech rates upper lip responses of PWS exhibited larger amplitudes and peak velocities. At both speech rates, the presence of a bite-block changed movement coordination patterns only for PNS. However, at fast speech rates bite-blocks decreased variability of coordination patterns for both groups. No adaptive changes in movement stability were found for either group, but a practice-related increase in lower lip peak velocity was found at normal speech rates. These findings indicate that bite-block perturbation did not exacerbate any hypothesized limitation or difficulty in controlling individual articulatory movements or their coordination in PWS. The results also support the position that specific motor control strategies are used by PWS as compared to PNS to compensate for bite-block perturbations under increased speech rate demands. LEARNING OUTCOMES: The reader will be able to: (1) distinguish between compensatory and adaptive responses to bite-block perturbation; (2) explain the measurement of articulatory stability; (3) summarize the potential role of motor control strategies in people who stutter; and (4) discuss the assumptions of the motor skills approach to stuttering.

Investigating speech motor practice and learning in people who stutter.

UNLABELLED: In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.