A Multivariate Analytic Approach to the Differential Diagnosis of Apraxia of Speech

A targeted review of prosodic production in agrammatic aphasia

It is unclear whether individuals with agrammatic aphasia have particularly disrupted prosody, or in fact have relatively preserved prosody they can use in a compensatory way. A targeted literature review was undertaken to examine the evidence regarding the capacity of speakers with agrammatic aphasia to produce prosody. The aim was to answer the question, how much prosody can a speaker "do" with limited syntax? The literature was systematically searched for articles examining the production of grammatical prosody in people with agrammatism, and yielded 16 studies that were ultimately included in this review. Participant inclusion criteria, spoken language tasks, and analysis procedures vary widely across studies. The evidence indicates that timing aspects of prosody are disrupted in people with agrammatic aphasia, while the use of pitch and amplitude cues is more likely to be preserved in this population. Some, but not all, of these timing differences may be attributable to motor speech programming deficits (AOS) rather than aphasia, as these conditions frequently co-occur. Many of the included studies do not address AOS and its possible role in any observed effects. Finally, the available evidence indicates that even speakers with severe aphasia show a degree of preserved prosody in functional communication.

Stability Over Time of Word Syllable Duration for Speakers With Acquired Apraxia of Speech

PURPOSE

Neurogenic speech and language disorders-such as acquired apraxia of speech (AOS) and aphasia with phonemic paraphasia (APP)-are often misdiagnosed due to similarities in clinical presentation. Word syllable duration (WSD)-a measure of average syllable length in multisyllabic words-serves as a proxy for speech rate, which is an important and arguably more objective clinical characteristic of AOS and APP. This study reports stability of WSD over time for speakers with AOS (and aphasia).

METHOD

Twenty-nine participants with AOS and aphasia (11 women and 18 men, Mage = 53.5 years, SD = 13.3) repeated 30 multisyllabic words (of three-, four-, and five-syllable lengths) on three occasions across 4 weeks. WSDs were calculated for each word and then averaged across each list (i.e., word length), as well as across combined lists (i.e., all 30 words) to yield four WSDs for each participant at each time point. Stability over time was calculated using Friedman's test for the group and using Spearman's rho for the individual level. Effects of time and word length were examined using robust mixed-effects linear regression.

RESULTS

Friedman's tests and correlations indicated no significant difference in WSDs across sampling occasions for each word length separately or combined. WSD correlated positively with AOS severity and negatively with intelligibility but was not correlated with aphasia severity. Regression analyses confirmed WSD to be stable over time, while WSD calculated from only five tokens (i.e., WSD-5) was less stable over time.

CONCLUSIONS

Results indicate that WSD can be a stable measure over time, at the individual and group level, providing support for its use in diagnosis and/or as an outcome measure, both clinically and for research. In general, WSD outperformed WSD-5, suggesting that it may be better to calculate WSD from more than five tokens. Stability of WSD in other populations and suitability for differential diagnosis need to be determined. Currently, differentiating disorders by speaking rate, alone, is not recommended.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25438735.

Word Repetition Paired With Startling Stimuli Decreases Aphasia and Apraxia Severity in Severe-to-Moderate Stroke: A Stratified, Single-Blind, Randomized, Phase 1 Clinical Trial

PURPOSE

This prospective, single-blinded, parallel, stratified, randomized clinical trial via telehealth aimed to investigate the impact of Startle Adjuvant Rehabilitation Therapy (START) on aphasia, apraxia of speech (AOS), and quality of life in individuals with chronic stroke. The study hypothesized that START would have a greater effect on AOS-related measures and more severe individuals.

METHOD

Forty-two participants with poststroke aphasia, AOS, or both were randomly assigned to the START or control group. Both groups received 77-dB GET READY and GO cues during a word repetition task for three 1-hr sessions on consecutive days. The START group additionally received 105-dB white noise GO cues during one third of trials. The Western Aphasia Battery-Revised, Apraxia Battery for Adults, Stroke Impact Scale, and Communication Outcomes After Stroke scale were administered at Day 1, Day 5, and 1-month follow-up.

RESULTS

START improved performance on some subtests of the Western Aphasia Battery (Comprehension, Repetition, Reading) and measures of AOS (Diadochokinetic Rate, Increasing Word Length) in individuals with moderate/severe aphasia, whereas moderate/severe controls saw no changes. Individuals with mild aphasia receiving START had improved Reading, whereas mild controls saw improved Comprehension. The START group had increased mood and perceived communication recovery by Day 5, whereas controls saw no changes in quality of life.

CONCLUSIONS

This study is the first to evaluate the impact of training with startling acoustic stimuli on clinical measures of aphasia and AOS. Our findings suggest START can enhance both nontrained speech production and receptive speech tasks in moderate/severe aphasia, possibly by reducing poststroke cortical inhibition. Our findings should be considered carefully, as our limitations include small effect sizes, within-group variability, and low completion rates for quality-of-life assessments and follow-up visits. Future studies should explore a mechanism of action, conduct larger and longer Phase 2 clinical trials, and evaluate long-term retention.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24093519.

An online survey of clinical practice and confidence in diagnosing acquired apraxia of speech in Cantonese speakers

PURPOSE

The assessment and diagnosis of apraxia of speech (AOS) have been well studied in the English context, yet there is limited understanding of the clinical practice in speakers of other languages, like Cantonese. This study aimed to obtain information about the clinical practice of assessment methods and diagnostic criteria used, and confidence in diagnosing, AOS in Cantonese speakers.

METHOD

An online survey constructed with Google Forms was completed by 27 speech-language pathologists (SLPs) in Hong Kong. The questionnaire comprised 12 questions covering (a) demographic information, (b) experience working with speakers with AOS, (c) confidence in making AOS diagnosis in Cantonese speakers, (d) assessment tasks or methods used for assessing AOS in Cantonese speakers, (e) clinical features used for diagnostic purposes, and (f) assessment tasks used to determine the presence of clinical features for diagnostic purposes.

RESULT

All respondents (100%) made AOS diagnoses based on the observed clinical features, while no respondents made diagnoses using only standardised tests or quantitative measures. Six clinical features were commonly used by most of the respondents: articulatory groping (100%), inconsistent articulatory errors (100%), length effects (85.2%), difficulty initiating speech (81.5%), automaticity effects (81.5%), and sound distortions (77.8%). More than half of the respondents collected connected speech samples (64%), and conducted diadochokinesis (64%) and repetition tasks (64%). The average confidence level of the respondents for making AOS diagnoses was fair (3.63/5).

CONCLUSION

The SLPs in Hong Kong make AOS diagnoses based on the observed clinical features that have been reported in the English literature. Although some of the clinical features have been updated as non-discriminatory for AOS, they are still being used for AOS diagnosis in Cantonese speakers. Tendencies were observed with respect to the assessment tasks selected. The fair diagnostic confidence level suggests a need for future investigations of AOS in Cantonese speakers and the development of assessment tools.

Assessment protocol for acquired apraxia of speech

PURPOSE

To develop an assessment protocol for speech motor planning with phonologically balanced stimuli for Brazilian Portuguese, including all necessary variables for this diagnosis.

METHODS

Three stages were carried out: In the first, word lists were built with the main criterion being syllabic and accentual patterns. From the survey conducted in Stage 1, the words that composed the first version of the protocol lists in Stage 2 were selected, and grouped into two fundamental tasks for diagnosing acquired apraxia of speech (AOS): repetition and Reading Aloud (RA). In Stage 3, the occurrence of words was investigated using the Brazilian Corpus (PUC-SP) - Linguateca database, and a statistical analysis was performed to verify if the repetition and RA lists were balanced in terms of the occurrences. Thus, the lists were distributed in quartiles and submitted to both descriptive and bivariate analyses. A significance level of 5% (p<0.05) was adopted.

RESULTS

After completion of all stages, the words that composed the lists of the repetition and RA tasks were obtained. Finally, other tasks considered essential for the assessment of AOS, such as diadochokinetic rates and the board for spontaneous oral emission, were then added to the protocol.

CONCLUSION

The developed protocol contains the tasks considered standard for the assessment of AOS according to the international literature, which makes this instrument important for diagnosing this disorder in speakers of Brazilian Portuguese.

Three-Dimensional Speech Profiles in Stroke Aphasia and Apraxia of Speech

PURPOSE

Behaviorally, acquired apraxia of speech (AOS) is a multidimensional syndrome that the experienced clinician recognizes based on impaired articulation and abnormal temporal prosody. We conducted this study to determine the extent to which three core features of AOS-when defined quantitatively-distinguish categorically among aphasia with no or minimal speech sound involvement, aphasia with AOS, and aphasia with phonemic paraphasia (APP).

METHOD

The study involved retrospective analysis of 195 participants with stroke-induced aphasia. We used three quantitative measures (phonemic error frequency, distortion error frequency, and word syllable duration [WSD]) to divide the sample into four participant groups according to the most likely speech diagnosis: aphasia with minimal speech sound errors, AOS, APP, and a borderline group with mixed profiles. We then conducted nonparametric comparisons across groups for which the measures were not defined and visualized all three measures in a three-dimensional graph.

RESULTS

The measures distributed as multidimensional spectra rather than discrete diagnostic entities, and there was considerable behavioral overlap among participant groups. Thirty percent of participants presented with aphasia with minimal sound production difficulties, and they were statistically indistinguishable from the APP group on distortion frequency and WSD. Distortion frequency and WSD were in a borderline region between AOS and APP for 29% of participants. Compared to all other groups, participants with AOS produced significantly more errors that affected listeners' phonemic perception.

CONCLUSIONS

The results suggest that the current AOS-APP dichotomy has limited validity. We conclude that a continuous multidimensional view of speech variation would be a constructive perspective from which to understand how the left cerebral hemisphere produces speech and that quantitative and normed speech measures should be used to inform differential diagnosis in clinical settings.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21807609.

Translation into Brazilian Portuguese and transcultural adaptation of the Apraxia of Speech Rating Scale 3.5

PURPOSE

To present the translation into Brazilian Portuguese and cross-cultural adaptation of the Apraxia of Speech Rating Scale (ASRS) version 3.5.

METHODS

Validation study restricted to translation and cross-cultural adaptation. The following steps were carried out: translation and synthesis of translations; verification of applicability of the scale synthesis by judges recruited for this purpose; analysis of the relevance and feasibility of the scale calculated by the Content Validity Index (CVI), individual (CVI-I) and total (CVI-T). Eighteen speech therapists were selected. Their answers were used for the analysis of agreement (intraclass correlation coefficients - ICC) and for the calculation of the Content Validity Index (CVI). Finally, the synthesis of the translation was matched in terms of semantic, idiomatic, experiential, conceptual, syntactic, grammatical, and operational equivalence.

RESULTS

The ICC ranged between 0.83 and 0.94. Six items obtained values higher than 0.9. The other items presented values between 0.8 and 0.9. The CVI-I and CVI-T had excellent values (CVI ≥ 0.78) for relevance and feasibility.

CONCLUSION

The Brazilian version of the ASRS 3.5 presents semantic, idiomatic, experiential, conceptual, and syntactic/grammatical equivalence to the original document. Thus, it is ready for the next validation steps.

The Apraxia of Speech Rating Scale: Reliability, Validity, and Utility

PURPOSE

The purpose of this study was to examine the interrater reliability and validity of the Apraxia of Speech Rating Scale (ASRS-3.5) as an index of the presence and severity of apraxia of speech (AOS) and the prominence of several of its important features.

METHOD

Interrater reliability was assessed for 27 participants. Validity was examined in a cohort of 308 participants (120 with and 188 without progressive AOS) through item analysis; item-Total score correlations; correlations among ASRS Total score and component subscores and independent clinical ratings of AOS, dysarthria and aphasia severity, intelligibility, and articulatory errors, as well as years postonset and age; and regression models assessing item and Total score prediction of AOS presence.

RESULTS

Interrater reliability was good or excellent for most items and excellent for the Total score. Item and Total score analyses revealed good separation of participants with versus without AOS. Inter-item and item-Total score correlations were generally moderately high as were correlations between the ASRS Total score and independent ratings of AOS severity, intelligibility, and articulatory errors. The Total score was not meaningfully correlated with ratings of aphasia and dysarthria severity, years postonset, or age. Total scores below 7 and above 10 revealed excellent diagnostic sensitivity and specificity for AOS. The presence of eight or more abnormal features was also highly predictive of AOS presence.

CONCLUSIONS

The ASRS-3.5 is a reliable and valid scale for identifying the presence and severity of AOS and its predominant features. It has excellent sensitivity to AOS presence and excellent specificity relative to aphasia and dysarthria in patients with neurodegenerative disease.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21817584.

Speech biomarkers of risk factors for vascular dementia in people with mild cognitive impairment

Introduction

In this study we intend to use speech analysis to analyze the cognitive impairments caused by pathologies of vascular origin such as diabetes, hypertension, hypercholesterolemia and heart disease, predictors of the development of vascular dementia.

Methods

In this study, 40 participants with mild cognitive impairment were asked to read while being recorded and they were inquired about their history of the aforementioned conditions. Their speech was then analyzed.

Results

We found that some speech parameters of frequencies and syllabic rhythm vary due to these pathologies. In addition, we conducted a discriminant analysis in which we found that diabetes and hypertension can be predicted with an accuracy over 95% with few speech parameters, and hypercholesterolemia and heart disease with an accuracy over 80%.

Discussion

The predictor parameters found are heterogeneous, including voice quality, amplitude, frequency, and rhythm parameters. This result may lead to investigate why such important qualitative changes occur in the voice of older adults with these pathologies. Rather than trying to find a diagnostic procedure already existing in classical medicine, we expect this finding to contribute to explore the causes and concomitant pathologies of these diseases. We discuss the implications of behavioral traits, such as speech, as digital biomarkers.

The efficacy of acoustic-based articulatory phenotyping for characterizing and classifying four divergent neurodegenerative diseases using sequential motion rates

Despite the impacts of neurodegeneration on speech function, little is known about how to comprehensively characterize the resulting speech abnormalities using a set of objective measures. Quantitative phenotyping of speech motor impairments may have important implications for identifying clinical syndromes and their underlying etiologies, monitoring disease progression over time, and improving treatment efficacy. The goal of this research was to investigate the validity and classification accuracy of comprehensive acoustic-based articulatory phenotypes in speakers with distinct neurodegenerative diseases. Articulatory phenotypes were characterized based on acoustic features that were selected to represent five components of motor performance: Coordination, Consistency, Speed, Precision, and Rate. The phenotypes were first used to characterize the articulatory abnormalities across four progressive neurologic diseases known to have divergent speech motor deficits: amyotrophic lateral sclerosis (ALS), progressive ataxia (PA), Parkinson's disease (PD), and the nonfluent variant of primary progressive aphasia and progressive apraxia of speech (nfPPA + PAOS). We then examined the efficacy of articulatory phenotyping for disease classification. Acoustic analyses were conducted on audio recordings of 217 participants (i.e., 46 ALS, 52 PA, 60 PD, 20 nfPPA + PAOS, and 39 controls) during a sequential speech task. Results revealed evidence of distinct articulatory phenotypes for the four clinical groups and that the phenotypes demonstrated strong classification accuracy for all groups except ALS. Our results highlight the phenotypic variability present across neurodegenerative diseases, which, in turn, may inform (1) the differential diagnosis of neurological diseases and (2) the development of sensitive outcome measures for monitoring disease progression or assessing treatment efficacy.

Acoustic and Kinematic Assessment of Motor Speech Impairment in Patients With Suspected Four-Repeat Tauopathies

PURPOSE

The aim of this study was to use acoustic and kinematic speech measures to characterize type of motor speech impairment-apraxia of speech (AOS) versus dysarthria-in individuals with four-repeat tauopathy (4RT)-associated syndromes, including nonfluent variant primary progressive aphasia (nfvPPA), primary progressive AOS (PPAOS), corticobasal syndrome (CBS), and progressive supranuclear palsy syndrome (PSPs).

METHOD

Twenty patient participants were recruited and stratified into two groups: (a) a motor-speech-impaired group of individuals with nfvPPA, PPAOS, CBS, or PSPs and suspected 4RT pathology ("MSI+") and (b) a non-motor-speech-impaired group of individuals with logopenic variant primary progressive aphasia ("MSI-"). Ten healthy, age-matched controls also participated in the study. Participants completed a battery of speech tasks, and 15 acoustic and kinematic speech measures were derived. Quantitative speech measures were grouped into feature categories ("AOS features," "dysarthria features," "shared features"). In addition to quantitative speech measures, two certified speech-language pathologists made independent, blinded auditory-perceptual ratings of motor speech impairment. A principal component analysis (PCA) was conducted to investigate the relative contributions of quantitative features.

RESULTS

Quantitative speech measures were generally concordant with independent clinician ratings of motor speech impairment severity. Hypothesis-driven groupings of quantitative measures differentiated predominantly apraxic from predominantly dysarthric presentations within the MSI+ group. PCA results provided additional evidence for differential profiles of motor speech impairment in the MSI+ group; heterogeneity across individuals is explained in large part by varying levels of overall severity-captured by the shared feature variable group-and degree of apraxia severity, as measured by the AOS feature variable group.

CONCLUSIONS

Quantitative features reveal heterogeneity of MSI in the 4RT group in terms of both overall severity and subtype of MSI. Results suggest the potential for acoustic and kinematic speech assessment methods to inform characterization of motor speech impairment in 4RT-associated syndromes.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21401778.

Correlates of vowel clarity in the spectrotemporal modulation domain: Application to speech impairment evaluation

This article reports on vowel clarity metrics based on spectrotemporal modulations of speech signals. Motivated by previous findings on the relevance of modulation-based metrics for speech intelligibility assessment and pathology classification, the current study used factor analysis to identify regions within a bi-dimensional modulation space, the magnitude power spectrum, as in Elliott and Theunissen [(2009). PLoS Comput. Biol. 5(3), e1000302] by relating them to a set of conventional acoustic metrics of vowel space area and vowel distinctiveness. Two indices based on the energy ratio between high and low modulation rates across temporal and spectral dimensions of the modulation space emerged from the analyses. These indices served as input for measurements of central tendency and classification analyses that aimed to identify vowel-related speech impairments in French native speakers with head and neck cancer (HNC) and Parkinson dysarthria (PD). Following the analysis, vowel-related speech impairment was identified in HNC speakers, but not in PD. These results were consistent with findings based on subjective evaluations of speech intelligibility. The findings reported are consistent with previous studies indicating that impaired speech is associated with attenuation in energy in higher spectrotemporal modulation bands.

Identifying segmental and prosodic errors associated with the increasing word length effect in acquired apraxia of speech

Purpose: Individuals with stroke-related apraxia of speech (AOS) plus aphasia tend to produce more speech errors with increasing word length. The Words of Increasing Length task (WIL) uses a 3-point scale to score word accuracy but penalises for error types that can arise either from language or motor impairment, reducing the test's sensitivity and specificity. The purpose here was to identify error types explaining variance in the WIL score, and those associated with AOS and word length.Method: Speech errors were perceptually identified on the WIL task for 51 Australian English-speaking adults with stroke-related aphasia, 25 with concomitant AOS. Multiple regression and linear mixed effects modelling were applied.Result: Variance in WIL scores was best explained with four error types: consonant additions, incorrect number of syllables, false starts and consonant substitutions/distortions. False starts were significantly associated with AOS diagnosis. Incorrect number of syllables, consonant omissions, false starts, and lexical stress errors increased in frequency for longer words and, while the interaction with diagnosis did not reach significance, the effect appeared driven by the AOS group.Conclusion: Findings provide further support for using polysyllabic word production to assess apraxic speech. The WIL task has limitations that may bias patients' performance and clinicians' perceptual evaluation. Data provide valuable information for designing a more sensitive diagnostic protocol for AOS.

Impact of Startling Acoustic Stimuli on Word Repetition in Individuals With Aphasia and Apraxia of Speech Following Stroke

PURPOSE

The StartReact effect, whereby movements are elicited by loud, startling acoustic stimuli (SAS), allows the evaluation of movements when initiated through involuntary circuitry, before auditory feedback. When StartReact is applied during poststroke upper extremity movements, individuals exhibit increased muscle recruitment, reaction times, and reaching distances. StartReact releases unimpaired speech with similar increases in muscle recruitment and reaction time. However, as poststroke communication disorders have divergent neural circuitry from upper extremity tasks, it is unclear if StartReact will enhance speech poststroke. Our objective is to determine if (a) StartReact is present in individuals with poststroke aphasia and apraxia and (b) SAS exposure enhances speech intelligibility.

METHOD

We remotely delivered startling, 105-dB white noise bursts (SAS) and quiet, non-SAS cues to 15 individuals with poststroke aphasia and apraxia during repetition of six words. We evaluated average word intensity, pitch, pitch trajectories, vowel formants F1 and F2 (first and second formants), phonemic error rate, and percent incidence of each SAS versus non-SAS-elicited phoneme produced under each cue type.

RESULTS

For SAS trials compared to non-SAS, speech intensity increased (∆ + 0.6 dB), speech pitch increased (∆ + 22.7 Hz), and formants (F1 and F2) changed, resulting in a smaller vowel space after SAS. SAS affected pitch trajectories for some, but not all, words. Non-SAS trials had more stops (∆ + 4.7 utterances) while SAS trials had more sustained phonemes (fricatives, glides, affricates, liquids; ∆ + 5.4 utterances). SAS trials had fewer distortion errors but no change in substitution errors or overall error rate compared to non-SAS trials.

CONCLUSIONS

We show that stroke-impaired speech is susceptible to StartReact, evidenced by decreased intelligibility due to altered formants, pitch trajectories, and articulation, including increased incidence of sounds that could not be produced without SAS. Future studies should examine the impact of SAS on voluntary speech intelligibility and clinical measures of aphasia and apraxia.

Types of motor speech impairments associated with neurologic diseases

Speech disturbances are common consequences of acquired brain injury or neurodegenerative impairment. Although sudden difficulties with speech may signal acute pathologic conditions such as cerebrovascular accidents, determining the etiology of insidious disruptions in communication can be less straightforward. The identification of motor speech impairment, independent of difficulties with language, can be useful for diagnosis since there are subtle, albeit distinct, patterns of speech production impairments associated with different neurologic conditions. Furthermore, the identification of impairments specific to speech production can help elucidate the suspected pathologic mechanisms or even the neuroanatomic structures compromised. During a routine clinical evaluation, early warning signs of motor speech impairment may go undetected if a clinician is unaccustomed to examining motor speech or is unaware of its manifestations. Accordingly, this chapter provides clinicians with a concise yet thorough guide for the practical assessment and differential diagnosis of motor speech disorders (MSDs)-apraxia of speech and dysarthrias. This chapter is divided into neurologic conditions associated with disorders of speech planning/programming, execution, and articulatory control. The underlying mechanisms associated with these impairments are presented both from a clinical perspective as well as through a scientific discussion of recent research in the field on MSDs.

Behavioral interventions for poststroke aphasia

There is a long history of behavioral interventions for poststroke aphasia with hundreds of studies supporting the benefits of aphasia treatment. However, interventions for aphasia are complex with many interacting components, and no one treatment is appropriate for all persons with aphasia. We present a novel, simple framework for classifying aphasia interventions. The framework is incorporated within the overarching International Classification of Functioning, Disability, and Health (ICF) model and is consistent with the commonly-held definition that aphasia is a multimodality disorder that impairs, in varying degrees, the understanding and expression of both oral and written language modalities. Furthermore, within the language impairment level, it distinguishes between the linguistic areas of phonology, semantics, and syntax that may be impaired individually or in combination. We define the terminology of the proposed framework and then categorize some common examples of behavioral interventions for post-stroke aphasia. We describe some of these interventions in greater detail to illustrate the extensive toolbox of evidence-based treatments for aphasia. We address some key issues that clinicians, usually speech-language pathologists, consider when selecting interventions for their specific patients with aphasia, including dose. Finally, we address various models of service delivery for persons with aphasia such as Intensive Comprehensive Aphasia Programs (ICAPs) and Aphasia Centers.

Brain changes underlying progression of speech motor programming impairment

Aquired apraxia of speech is a disorder that impairs speech production, despite intact peripheral neuromotor function. Its pathomechanism remains to be established. Neurodegenerative lesion models provide an unequalled opportunity to explore the neural correlates of apraxia of speech, which is present in a subset of patients diagnosed with non-semantic variants of primary progressive aphasia. The normalized pairwise variability index, an acoustic measure of speech motor programming, has shown high sensitivity and specificity for apraxia of speech in cross-sectional studies. Here, we aimed to examine the strength of the pairwise variability index and overall word duration (i.e. articulation rate) as markers of progressive motor programming deficits in primary progressive aphasia with apraxia of speech. Seventy-nine individuals diagnosed with primary progressive aphasia (39 with non-fluent variant and 40 with logopenic variant) and 40 matched healthy controls participated. Patients were followed-up annually (range 1-6 years, median number of visits = 2). All participants completed a speech assessment task and a high-resolution MRI. Our analyses investigated trajectories of speech production (e.g. pairwise variablity index and word duration) and associations with cortical atrophy in the patients. At first presentation, word duration differentiated the nonfluent and logopenic cases statistically, but the range of scores overlapped substantially across groups. Longitudinally, we observed progressive deterioration in pairwise variability index and word duration specific to the non-fluent group only. The pairwise variability index showed particularly strong associations with progressive atrophy in speech motor programming brain regions. Of novelty, our results uncovered a key role of the right frontal gyrus in underpinning speech motor programming changes in non-fluent cases, highlighting the importance of right-brain regions in responding to progressive neurological changes in the speech motor network. Taken together, our findings validate the use of a new metric, the pairwise variability index, as a robust marker of apraxia of speech in contrast to more generic measures of speaking rate. Sensitive/specific neuroimaging biomarkers of the emergence and progression of speech impairments will be useful to inform theories of the pathomechanisms underpinning impaired speech motor control. Our findings justify developing more sensitive measures of rhythmic temporal control of speech that may enable confident detection of emerging speech disturbances and more sensitive tracking of intervention-related changes for pharmacological, neuromodulatory and behavioural interventions. A more reliable detection of speech disturbances has relevance for patient care, with predominance of progressive apraxia of speech a high-risk factor for later diagnosis of progressive supranuclear palsy or corticobasal degeneration.

Effects of Verb Network Strengthening Treatment on Sound-Level and Speech Production Errors in Individuals With Aphasia and Acquired Apraxia of Speech

Purpose This retrospective pilot study investigated whether sound-level and speech production errors decreased in confrontation naming following Verb Network Strengthening Treatment (VNeST) for four participants with acquired apraxia of speech (A-AOS) and aphasia for whom lexical retrieval was previously reported. Specifically, we investigated a potential increase in correct number of syllables per word and posttreatment changes across three domains of speech: segmental production, fluency, and prosody. It was hypothesized that treatment shown to increase lexical retrieval in persons with aphasia and A-AOS could potentially facilitate a reduction in sound-level and speech production errors consistent with dual diagnoses of A-AOS and aphasia. Method Naming responses from four participants with aphasia and A-AOS who previously participated in VNeST studies were investigated for correct number of syllables per word and measures of segmental speech, fluency, and prosody. Results Significant gains in at least one measure of speech production were reported for three of the participants. One participant demonstrated decreased segmental speech errors, two showed significant reduction on syllable segmentation, and two demonstrated a significant reduction on false starts and pauses. Significant gains in production of correct number of syllables were limited to one participant, and one participant did not demonstrate increased accuracy on any measure of speech production. Conclusions While speech production errors consistent with motor speech impairment cannot always be definitively distinguished from the confound of aphasia, two participants produced significantly decreased segmentation of syllables, a characteristic unique to A-AOS. The sound-level and speech production changes recorded may be attributed to a combination of interacting motor and language processes and resource allocation. In addition, specific components of VNeST may have contributed to speech production changes. Future work will focus on a prospective study of effects of language therapy (e.g., VNeST) on measures of speech production with investigation beyond the single-word level.

Outcomes of semantic feature analysis treatment for aphasia with and without apraxia of speech

BACKGROUND

To date, studies have not explored whether a dual diagnosis of aphasia plus apraxia of speech (AOS) versus aphasia alone (APH) affects the response to language-based naming treatments.

AIMS

To compare the effects of semantic feature analysis (SFA) treatment for individuals with APH versus aphasia plus AOS, and to test if the presence of AOS impacted the effects of treatment.

METHODS AND PROCEDURES

A non-randomized experimental group study was conducted to explore the treatment, generalization and maintenance effects between the AOS and APH groups. Participants included nine individuals with aphasia and 11 with concomitant aphasia and AOS. Dependent measures included lexical accuracy, number of sound-level distortions, and lexical stress and syllable segmentation errors.

OUTCOMES AND RESULTS

Both groups showed significantly improved naming accuracy of trained items for up to 2 months post-treatment. Improvement on naming accuracy of untrained items post-treatment, both semantically related and unrelated to trained items, was lower in magnitude. That this may have been due to effects of repeated probing (which included target repetition) or regression to the mean cannot be excluded. There was a tendency for the AOS group to respond slightly better to treatment than the APH group overall, which was not correlated with aphasia severity. Also, measures of phonetic accuracy and fluency improved for both groups, with no main effect of group. Treatment effects did not generalize to formal measures of (untrained) picture naming or expression of correct information units in discourse in a story retelling task.

CONCLUSIONS AND IMPLICATIONS

Findings indicate that individuals with aphasia plus AOS can gain equivalent benefits in word retrieval and production from the language-based SFA treatment as individuals with aphasia alone. This may be, in part, due to the tendency for SFA to incorporate principles of practice that are known to support motor learning in AOS, such as high intensity, random stimulus presentation and variable practice. Findings provide further support for high-intensity practice and use of self-generated features to facilitate maintenance of effects. What this paper adds What is already known on the subject SFA treatment is the most common intervention for word-finding difficulties for individuals with aphasia. AOS is a common concomitant disorder to aphasia. However, it is not clear whether the effects of language-based SFA treatment are mitigated by the presence of AOS, which tends to respond well to treatments focused on articulatory-kinematic aspects of speech movement. What this paper adds to the existing knowledge This study compares the effects of SFA in a group of individuals with aphasia alone and a group with similar severity of aphasia but with concomitant AOS, ranging from mild to moderate-severe. Overall, AOS did not have a negative effect on response to the treatment. What are the potential or actual clinical implications of this work? Individuals with aphasia plus AOS can be expected to benefit to a similar degree from SFA as people with aphasia alone. It is likely that the use of practice principles of high intensity, random stimulus presentation and varied practice are important components of the protocol.

Speech Metrics and Samples That Differentiate Between Nonfluent/Agrammatic and Logopenic Variants of Primary Progressive Aphasia

Purpose Of the three currently recognized variants of primary progressive aphasia, behavioral differentiation between the nonfluent/agrammatic (nfvPPA) and logopenic (lvPPA) variants is particularly difficult. The challenge includes uncertainty regarding diagnosis of apraxia of speech, which is subsumed within criteria for variant classification. The purpose of this study was to determine the extent to which a variety of speech articulation and prosody metrics for apraxia of speech differentiate between nfvPPA and lvPPA across diverse speech samples. Method The study involved 25 participants with progressive aphasia (10 with nfvPPA, 10 with lvPPA, and five with the semantic variant). Speech samples included a word repetition task, a picture description task, and a story narrative task. We completed acoustic analyses of temporal prosody and quantitative perceptual analyses based on narrow phonetic transcription and then evaluated the degree of differentiation between nfvPPA and lvPPA participants (with the semantic variant serving as a reference point for minimal speech production impairment). Results Most, but not all, articulatory and prosodic metrics differentiated statistically between the nfvPPA and lvPPA groups. Measures of distortion frequency, syllable duration, syllable scanning, and-to a limited extent-syllable stress and phonemic accuracy showed greater impairment in the nfvPPA group. Contrary to expectations, classification was most accurate in connected speech samples. A customized connected speech metric-the narrative syllable duration-yielded excellent to perfect classification accuracy. Discussion Measures of average syllable duration in multisyllabic utterances are useful diagnostic tools for differentiating between nfvPPA and lvPPA, particularly when based on connected speech samples. As such, they are suitable candidates for automatization, large-scale study, and application to clinical practice. The observation that both speech rate and distortion frequency differentiated more effectively in connected speech than on a motor speech examination suggests that it will be important to evaluate interactions between speech and discourse production in future research.

Intra- and Interjudge Reliability of the Apraxia of Speech Rating Scale in Early Stroke Patients

PURPOSE

There is a recognized need for a reliable assessment instrument for apraxia of speech (AOS) diagnosis for post stroke patients. In 2014, Strand and colleagues reported high to excellent intra- and interjudge reliability of the Apraxia of Speech Rating Scale (ASRS) in neurodegenerative speech and language disorders. Excellent interjudge reliability of the ASRS total score has also recently been reported in another study of individuals with chronic AOS after stroke, where the ratings were carried out by two experienced researchers not involved in the development of the instrument. However, it is still not fully determined whether the ASRS is a reliable instrument in assessment of patients in an early phase after stroke, where severe AOS is not uncommon. It is also not determined whether ASRS ratings can be performed reliably by practicing speech-language pathologists (SLPs) without long common experience and joint training. This study therefore addresses these questions.

METHOD

The ASRS was administered to thirty-six individuals in the first six months after stroke. The assessment procedures were video recorded. Ten of the recordings were selected for the reliability study, representative of patients typically seen at the actual inpatient ward with varying degrees of AOS severity. Five SLPs from different hospital departments participated as raters. The raters viewed each video and independently rated the presence and severity of AOS using the ASRS. To study intrajudge reliability, a rescoring was performed after a minimum of three weeks. Reliability was calculated using the intraclass correlation coefficient (ICC).

RESULTS

Intrajudge agreement for the ASRS total score varied from moderate to excellent (mean ICC = 0.69, 95 % CI [0.60, 0.77]) with most of the mean item level agreements within the categories 'moderate' or 'good. Interjudge reliability was poor for the ASRS total score (ICC = 0.42, 95 % CI [0.35, 0.50]). The item level results varied between moderate and poor, with lack of agreement on several items.

CONCLUSIONS

For clinicians without expert knowledge of AOS and limited training using the ASRS, intra- and interjudge reliability of the ASRS is not satisfactory. Also, since some items in the protocol require a certain level of speech production to target the diagnostic marker, findings indicate that the ASRS in its present design has limitations in assessment of severe AOS. As suggested by Strand and colleagues, video examples that illustrate the ASRS characteristics could be one helpful alternative to support clinician training. A minor revision of response definitions of the scale may improve the applicability of the ASRS in severe AOS.

Differential Diagnosis of Apraxia of Speech in Children and Adults: A Scoping Review

Purpose Despite having distinct etiologies, acquired apraxia of speech (AOS) and childhood apraxia of speech (CAS) share the same central diagnostic challenge (i.e., isolating markers specific to an impairment in speech motor planning/programming). The purpose of this review was to evaluate and compare the state of the evidence on approaches to differential diagnosis for AOS and CAS and to identify gaps in each literature that could provide directions for future research aimed to improve clinical diagnosis of these disorders. Method We conducted a scoping review of literature published between 1997 and 2019, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines. For both AOS and CAS, literature was charted and summarized around four main methodological approaches to diagnosis: speech symptoms, quantitative speech measures, impaired linguistic-motor processes, and neuroimaging. Results Results showed that similar methodological approaches have been used to study differential diagnosis of apraxia of speech in adults and children; however, the specific measures that have received the most research attention differ between AOS and CAS. Several promising candidate markers for AOS and CAS have been identified; however, few studies report metrics that can be used to assess their diagnostic accuracy. Conclusions Over the past two decades, there has been a proliferation of research identifying potential diagnostic markers of AOS and CAS. In order to improve clinical diagnosis of AOS and CAS, there is a need for studies testing the diagnostic accuracy of multiple candidate markers, better control over language impairment comorbidity, more inclusion of speech-disordered control groups, and an increased focus on translational work moving toward clinical implementation of promising measures.

A domain-general perspective on the role of the basal ganglia in language and music: Benefits of music therapy for the treatment of aphasia

In addition to cortical lesions, mounting evidence on the links between language and the subcortical regions suggests that subcortical lesions may also lead to the emergence of aphasic symptoms. In this paper, by emphasizing the domain-general function of the basal ganglia in both language and music, we highlight that rhythm processing, the function of temporal prediction, motor programming and execution, is an important shared mechanism underlying the treatment of non-fluent aphasia with music therapy. In support of this, we conduct a literature review on the music therapy treating aphasia. The results show that rhythm processing plays a key role in Melodic Intonation Therapy in the rehabilitation of non-fluent aphasia patients with lesions on the basal ganglia. This paper strengthens the correlation between the basal ganglia lesions and language deficits, and provides support to the direction of taking advantage of rhythm as an important point in music therapy in clinical studies.

Clinical Assessment of Characteristics of Apraxia of Speech in Primary Progressive Aphasia

Purpose We sought to examine interrater reliability in clinical assessment of apraxia of speech (AOS) in individuals with primary progressive aphasia and to identify speech characteristics predictive of AOS diagnosis. Method Fifty-two individuals with primary progressive aphasia were recorded performing a variety of speech tasks. These recordings were viewed by 2 experienced speech-language pathologists, who independently rated them on the presence and severity of AOS as well as 14 associated speech characteristics. We calculated interrater reliability (percent agreement and Cohen's kappa) for these ratings. For each rater, we used stepwise regression to identify speech characteristics significantly predictive of AOS diagnosis. We used the overlap between raters to create a more parsimonious model, which we evaluated with multiple linear regression. Results Results yielded high agreement on the presence (90%) and severity of AOS (weighted Cohen's κ = .834) but lower agreement for specific speech characteristics (weighted Cohen's κ ranging from .036 to .582). Stepwise regression identified 2 speech characteristics predictive of AOS diagnosis for both raters (articulatory groping and increased errors with increased length/complexity). These alone accounted for ≥ 50% of the variance of AOS severity in the constrained model. Conclusions Our study adds to a growing body of research that highlights the difficulty in objective clinical characterization of AOS and perceptual characterization of speech features. It further supports the need for consensus diagnostic criteria with standardized testing tools and for the identification and validation of objective markers of AOS. Additionally, these findings underscore the need for a training protocol if diagnostic tools are to be effective when shared beyond the research teams that develop and test them and disseminated to practicing speech-language pathologists, in order to ensure consistent application.

Use of diverse diagnostic criteria for acquired apraxia of speech: a scoping review

BACKGROUND

There is a growing body of evidence that speech and language therapy (SLT) intervention is effective in improving communication ability for individuals with non-progressive acquired apraxia of speech (AOS). However, there is no universally agreed diagnostic standard for AOS, and diverging opinions on its diagnostic features. This has led to claims that diverse diagnostic criteria may be used to select participants for AOS research studies. These claims raise concerns for evidence-based practice in AOS but have yet to be systematically investigated.

AIMS

To determine the presence, nature and extent of diversity in the diagnostic criteria for non-progressive AOS used in both published studies and clinical practice internationally.

METHODS & PROCEDURES

The study used a scoping review methodology that followed the 2005 framework of Arksey and O'Malley and included a consultation exercise in the form of an online survey of international SLTs. The scoping review included 157 studies involving participants with acquired AOS, published between 1997 and 2017. There were 264 respondents to the online survey of SLTs, with a completion rate of 72%. Respondents came from 15 countries and had varying levels of clinical experience.

MAIN CONTRIBUTION

This study found that no common set of diagnostic criteria for AOS was used universally across research and practice. Although the diagnostic criteria used to select participants with AOS were reported explicitly in most studies, they varied from study to study. Some studies used directly conflicting criteria. Use of specific diagnostic criteria in studies was influenced by year of publication but not by location. There was a trend towards increasing consistency in diagnostic criteria in recent years. Compared with the research, the survey revealed relatively greater consistency among SLTs on the speech features considered indicative of AOS, although the SLTs who responded to the survey showed variation in how diagnostic criteria were combined into sets. Use of specific diagnostic criteria was not associated with SLTs' location or experience. There were differences between the diagnostic criteria for AOS used most commonly in research studies and those selected most commonly by SLTs in the survey. These findings have implications for the generalizability of AOS research to clinical practice, as well as implications for effective research synthesis.

CONCLUSIONS & IMPLICATIONS

The claim that research and practice in the field of AOS is characterized by the use of diverse diagnostic criteria is supported by this scoping review. The findings support the need to develop a universal consensus standard for AOS diagnosis to ensure consistency across research and clinical practice.

Interrater Reliability and Concurrent Validity for the Apraxia of Speech Rating Scale 3.0: Application With Persons With Acquired Apraxia of Speech and Aphasia

Purpose This investigation was designed to provide interrater reliability data for the Apraxia of Speech Rating Scale 3.0 (ASRS 3.0; Strand, Duffy, Clark, & Josephs, 2014 ). Importantly, ratings were completed by investigators who were not involved with the ASRS development. Another aim was to evaluate the relationship of the ASRS 3.0 total score to word intelligibility. Method Two investigators independently completed ASRS 3.0 ratings for 28 participants with chronic apraxia of speech and aphasia. Intelligibility scores were obtained for all participants. Results Consistency of ratings for each feature and total score of the ASRS 3.0 was measured using intraclass correlation coefficients. Twelve of 13 intraclass correlation coefficients for feature ratings reached significance; clinical meaningfulness ranged from poor to excellent. Interrater reliability for the total scores was excellent. Similarly, absolute difference of ratings was minimal for the total scores, but varied across the 13 feature ratings. Correlations between the intelligibility scores and ASRS 3.0 total score were moderate to strong. Conclusion The total ASRS 3.0 score may be viewed as a reliable indicator of prevalence of apraxia of speech features. Although there was good to acceptable correspondence in ratings of the majority of the individual features, additional operationalization of rating procedures may be needed to improve interrater reliability for a few features.

Phonological and phonetic impairment in aphasic speech: an acoustic study of the voice onset time of six French-speaking aphasic patients

The aim of the present study is to contribute to the description of the speech production deficits in French-speaking aphasic patients, so as to shed light on their potential phonetic and/or phonological disorders. Acoustic studies of aphasics' speech productions remain relatively infrequent, especially in French, and when entering into the specifics, often lead to inconsistent results. We conducted a multiple-case study on six aphasic patients, four with non-fluent aphasia and two with fluent aphasia. They were administered a variety of language and neuropsychological tasks, then they participated in a customized non-word repetition task. Acoustic analyses of their speech productions were performed, focussing on VOT as the main acoustic correlate of the voicing contrast for oral stops. Other atypicalities in their productions were also classified. Results showed variable and mainly "mixed" phonetic-phonological impairment profiles that differed from the traditional hypotheses made in the literature about the speech deficits to be expected as a function of type of aphasia. Our results support the use of acoustic analyses in order to complete language examination in aphasic patients but also suggest that the frontier between phonological and phonetic impairment is not clear-cut. These outcomes are better accounted for by theories and models postulating close relationships between the phonological and phonetic levels of processing.

Contemporary Approaches to the Management of Post-stroke Apraxia of Speech

Apraxia of speech (AOS) is a motor speech disorder that disrupts the planning and programming of speech motor movements. In the acute stage of stroke recovery, AOS following unilateral (typically) left hemisphere stroke can occur alongside dysarthria, an impairment in speech execution and control, and/or aphasia, a higher-level impairment in language function. At this time, perceptual evaluation (the systematic, although subjective, description of speech and voice characteristics) is perhaps the only "gold standard" for differential diagnosis when it comes to motor speech disorders. This poses a challenge for speech-language pathologists charged with the evaluation of poststroke communication abilities, as distinguishing production impairments associated with AOS from those that can occur in aphasia and/or dysarthria can be difficult, especially when more than one deficit is present. Given the need for more objective, reliable methods to identify and diagnose AOS, several studies have turned to acoustic evaluation and neuroimaging to supplement clinical assessment. This article focuses on these recent advances. Studies investigating acoustic evaluation of AOS will be reviewed, as well as those that have considered the extent that neuroimaging can guide clinical decision making. Developments in the treatment of AOS will also be discussed. Although more research is needed regarding the use of these methods in everyday clinical practice, the studies reviewed here show promise as emerging tools for the management of AOS.

Vowel Formant Dispersion Reflects Severity of Apraxia of Speech

BACKGROUND

Apraxia of Speech (AOS) has been associated with deviations in consonantal voice-onset-time (VOT), but studies of vowel acoustics have yielded conflicting results. However, a speech motor planning disorder that is not bound by phonological categories is expected to affect vowel as well as consonant articulations.

AIMS

We measured consonant VOTs and vowel formants produced by a large sample of stroke survivors, and assessed to what extent these variables and their dispersion are predictive of AOS presence and severity, based on a scale that uses clinical observations to rate gradient presence of AOS, aphasia, and dysarthria.

METHODS & PROCEDURES

Picture-description samples were collected from 53 stroke survivors, including unimpaired speakers (12) and speakers with primarily aphasia (19), aphasia with AOS (12), primarily AOS (2), aphasia with dysarthria (2), and aphasia with AOS and dysarthria (6). The first three formants were extracted from vowel tokens bearing main stress in open-class words, as well as VOTs for voiced and voiceless stops. Vowel space was estimated as reflected in the formant centralization ratio. Stepwise Linear Discriminant Analyses were used to predict group membership, and ordinal regression to predict AOS severity, based on the absolute values of these variables, as well as the standard deviations of formants and VOTs within speakers.

OUTCOMES AND RESULTS

Presence and severity of AOS were most consistently predicted by the dispersion of F1, F2, and voiced-stop VOT. These phonetic-acoustic measures do not correlate with aphasia severity.

CONCLUSIONS

These results confirm that the AOS affects articulation across-the-board and does not selectively spare vowel production.