Treatment of sound errors in aphasia and apraxia of speech: Effects of phonological complexity

Letter Migrations between Words in Reading Aloud Can Result Either from an Impairment in Orthographic Input or in Phonological Output

Letter migrations between words in reading aloud (e.g., reading “cane love” as “lane love” or “lane cove”) are known to result from a deficit in the visual-orthographic analysis and characterize attentional dyslexia. In spontaneous speech, individuals with impairment in the phonological output buffer may show migrations of phonemes between words. The purpose of this study was to examine whether migrations between words in reading aloud can also result from a deficit in the phonological output buffer, to explore the characteristics of migrations resulting from orthographic input and from phonological output deficits, and to examine methods to distinguish these two sources. Using tasks of reading aloud of lists of 92–182 word pairs, we identified 18 adults and adolescents with developmental dyslexia who made between-word letter migrations in reading aloud, significantly more than age-matched controls (372 adults, 26 7th-graders and 44 4th–5th-graders). To distinguish between the orthographic input and phonological output sources for these migrations, we administered a test assessing orthographic input without spoken output (written semantic decision on 140 migratable word pairs) and a repetition test of 36 auditorily presented migratable word pairs, assessing spoken output without orthographic input (as well as nonword repetition and 3 span tests). These tests indicated that the migrations in reading aloud of 10 of the participants with dyslexia resulted from an orthographic input deficit—they made migrations not only in reading aloud but also in written word pair comprehension, but not in word pair repetition. For the other 8 participants, the migrations resulted from a phonological output deficit: they made migrations in reading aloud and in word pair repetition, but not in comprehension, and had limited spans and made errors in nonword repetition. We identified several differences between the two types of between-word errors: first, the individuals with attentional dyslexia made omissions of a letter that appeared in the same position in the two words, but the phonological output buffer group did not make such omissions. Second, the groups differed in the origin of migration: orthographic input migrations involve letters that are orthographically adjacent, whereas phonological output migrations involve phonologically adjacent phonemes: phonemes that have just been spoken or that are prepared together in the phonological buffer for production. Migrations from the line below and from 2 lines above the target occurred only in the orthographic input group. This study thus indicates that between-word migrations in reading aloud can result not only from attentional dyslexia, but also from a phonological output buffer deficit, and offers ways to distinguish between the two.

A Pilot Single-Case Experimental Design Study of Rapid Syllable Transition Treatment for Italian Children With Childhood Apraxia of Speech

Background The Rapid Syllable Transition (ReST) treatment is an effective intervention designed to address the planning and programming disorder found in childhood apraxia of speech. To date, no study has considered its use with children who speak languages other than English. Aim This pilot study aimed to examine the use of ReST treatment with Italian children. We hypothesized that the ReST approach would improve the overall accuracy of the targeted behaviors of lexical stress, smoothness, and phonemic accuracy, whereas phonemic and phonetic accuracy of untreated items would remain stable. Method Two monolingual Italian-speaking children with childhood apraxia of speech received therapy in 12 one-hour sessions, 2-3 times per week, using a single-case experimental design. The treatment procedures used in English were replicated in Italian with one change: In English, two stress patterns are treated. Italian commonly uses three stress patterns; therefore, the stimuli were modified accordingly. Accuracy of articulation, lexical stress, and smoothness were assessed at pretreatment and 1 day, 1 week, and 4 months posttreatment in treated and untreated pseudowords and in real words and sentences. Results Both children improved on treated pseudowords and real words with moderate effect sizes, but only one child generalized to untreated pseudowords. Maintenance of treatment results was observed in both participants. Articulation of control phonemes did not change. Conclusions ReST treatment in Italian is feasible, and a treatment effect was found, showing that its use may be valid in languages other than English. Further research is required. Supplemental Material https://doi.org/10.23641/asha.14348060.

Does Voicing Affect Patterns of Transfer in Nonnative Cluster Learning?

Purpose Previous studies have demonstrated that speakers can learn novel speech sequences, although the content and specificity of the learned speech motor representations remain incompletely understood. We investigated these representations by examining transfer of learning in the context of nonnative consonant clusters. Specifically, we investigated whether American English speakers who learn to produce either voiced or voiceless stop-stop clusters (e.g., /gd/ or /kt/) exhibit transfer to the other voicing pattern. Method Each participant (n = 34) was trained on disyllabic nonwords beginning with either voiced (/gd/, /db/, /gb/) or voiceless (/kt/, /kp/, /tp/) onset consonant clusters (e.g., /gdimu/, /ktaksnæm/) in a practice-based speech motor learning paradigm. All participants were tested on both voiced and voiceless clusters at baseline (prior to practice) and in two retention sessions (20 min and 2 days after practice). We compared changes in cluster accuracy and burst-to-burst duration between baseline and each retention session to evaluate learning (performance on the trained clusters) and transfer (performance on the untrained clusters). Results Participants in both training conditions improved with respect to cluster accuracy and burst-to-burst duration for the clusters they practiced on. A bidirectional transfer pattern was found, such that participants also improved the cluster accuracy and burst-to-burst duration for the clusters with the other untrained voicing pattern. Post hoc analyses also revealed that improvement in the production of untrained stop-fricative clusters that originally were added as filler items. Conclusion Our findings suggest the learned speech motor representations may encode the information about the coordination of oral articulators for stop-stop clusters independently from information about the coordination of oral and laryngeal articulators.

A Phonomotor Approach to Apraxia of Speech Treatment

Purpose This study continued Phase I investigation of a modified Phonomotor Treatment (PMT) Program on motor planning in two individuals with apraxia of speech (AOS) and aphasia and, with support from prior work, refined Phase I methodology for treatment intensity and duration, a measure of communicative participation, and the use of effect size benchmarks specific to AOS. Method A single-case experimental design with multiple baselines across behaviors and participants was used to examine acquisition, generalization, and maintenance of treatment effects 8-10 weeks posttreatment. Treatment was distributed 3 days a week, and duration of treatment was specific to each participant (criterion based). Experimental stimuli consisted of target sounds or clusters embedded nonwords and real words, specific to each participants' deficit. Results Findings show improved repetition accuracy for targets in trained nonwords, generalization to targets in untrained nonwords and real words, and maintenance of treatment effects at 10 weeks posttreatment for one participant and more variable outcomes for the other participant. Conclusions Results indicate that a modified version of PMT can promote generalization and maintenance of treatment gains for trained speech targets via a multimodal approach emphasizing repeated exposure and practice. While these results are promising, the frequent co-occurrence of AOS and aphasia warrants a treatment that addresses both motor planning and linguistic deficits. Thus, the application of traditional PMT with participant-specific modifications for AOS embedded into the treatment program may be a more effective approach. Future work will continue to examine and maximize improvements in motor planning, while also treating anomia in aphasia.

Acquired Apraxia of Speech: Comparison of Electropalatography Treatment and Sound Production Treatment

Purpose This investigation compared 2 treatment approaches for acquired apraxia of speech. The effects of a treatment that uses an articulatory-kinematic approach in conjunction with visual biofeedback (VBFB) via electropalatography (EPG) were compared to Sound Production Treatment (SPT), an established behavioral treatment that is also an articulatory-kinematic approach. Method A multiple baseline design across behaviors and participants was used with 2 participants with chronic apraxia of speech and aphasia. Accuracy of target speech sounds in treated and untreated words or phrases in probe sessions served as the dependent variable. The effects of 2 treatments based on an articulatory-kinematic approach were compared: (a) VBFB via EPG and (b) SPT. The order of treatments was counterbalanced across participants. Results Positive changes in articulatory accuracy were observed for SPT and VBFB treatment via EPG. Generalization to untreated stimulus items composed of treated speech sounds was also positive for both treatments. However, participants achieved greater articulatory accuracy with SPT during treatment and better long-term maintenance. Discussion Both treatment approaches resulted in improved speech production accuracy, but gains were greater for SPT. However, further research with additional participants is needed due to the small sample size included in this investigation.

Role of Massed Versus Distributed Practice in Learning Novel Foreign Language Utterances

The current study compared the role of massed versus distributed practice in learning novel foreign language utterances. Fifty healthy native English-speaking participants were randomly assigned to either massed or distributed practice groups. All participants practiced eight novel French utterances 25 times each for a total of 200 times, with the spacing of practice sessions differing between the two groups. Both the groups completed an immediate retention as well as a delayed retention test. Participants' learning was evaluated based on phonetic accuracy and naturalness of the French utterances. The findings revealed that participants involved in distributed practice demonstrated better learning over participants involved in massed practice. Future research should aim to extrapolate these findings in treating speech disorders.

Perceptual Characteristics of Consonant Production in Apraxia of Speech and Aphasia

Purpose This retrospective analysis examined group differences in error rate across 4 contextual variables (clusters vs. singletons, syllable position, number of syllables, and articulatory phonetic features) in adults with apraxia of speech (AOS) and adults with aphasia only. Group differences in the distribution of error type across contextual variables were also examined. Method Ten individuals with acquired AOS and aphasia and 11 individuals with aphasia participated in this study. In the context of a 2-group experimental design, the influence of 4 contextual variables on error rate and error type distribution was examined via repetition of 29 multisyllabic words. Error rates were analyzed using Bayesian methods, whereas distribution of error type was examined via descriptive statistics. Results There were 4 findings of robust differences between the 2 groups. These differences were found for syllable position, number of syllables, manner of articulation, and voicing. Group differences were less robust for clusters versus singletons and place of articulation. Results of error type distribution show a high proportion of distortion and substitution errors in speakers with AOS and a high proportion of substitution and omission errors in speakers with aphasia. Conclusion Findings add to the continued effort to improve the understanding and assessment of AOS and aphasia. Several contextual variables more consistently influenced breakdown in participants with AOS compared to participants with aphasia and should be considered during the diagnostic process. Supplemental Material https://doi.org/10.23641/asha.9701690.

Non-word writing does not require the phonological output buffer: Neuropsychological evidence for a direct phonological-orthographic route

What is the route that is used for writing non-words to dictation? Does it have to pass through phonological output? Two possibilities are found in the literature. In one, writing non-words requires access from the phonological input buffer to the phonological output buffer and from there, via phoneme-to-grapheme conversion, to the orthographic output buffer. The second approach maintains that writing non-words can proceed directly from the phonological input buffer to the orthographic output buffer. In this study, we discriminate between these two options using a cognitive neuropsychological approach. Specifically, we present a multiple case study of 24 individuals with a developmental impairment to the phonological output buffer, who nevertheless show unimpaired non-word writing. These data lead to the conclusion that the phonological output buffer is not necessary when writing non-words and that writing non-words to dictation can proceed directly from the phonological input buffer to the orthographic output buffer. We suggest that the cognitive assumption that non-word writing proceeds through the phonological output buffer may have resulted from graphic conventions and the depiction of the lexical processing model: in the common depiction of the model drawing a line through the phonological output buffer is visually simpler than a direct line (which would require lines to cross or long bypass lines).

Orthographic Visualisation Induced Brain Activations in a Chronic Poststroke Global Aphasia with Dissociation between Oral and Written Expression

We propose a method of orthographic visualisation strategy in a poststroke severe aphasia person with dissociation between oral and written expression. fMRI results suggest that such strategy may induce the engagement of alternative nonlanguage networks and visual representations may help improving oral output. This choice of rehabilitation method can be based on the remaining capacities and, therefore, on written language. Most notably, no study so far addressed how orthographic visualisation strategy during speech rehabilitation might influence clinical outcomes in nonfluent aphasia and apraxia patients.

Speech and nonspeech: What are we talking about?

Understanding of the behavioural, cognitive and neural underpinnings of speech production is of interest theoretically, and is important for understanding disorders of speech production and how to assess and treat such disorders in the clinic. This paper addresses two claims about the neuromotor control of speech production: (1) speech is subserved by a distinct, specialised motor control system and (2) speech is holistic and cannot be decomposed into smaller primitives. Both claims have gained traction in recent literature, and are central to a task-dependent model of speech motor control. The purpose of this paper is to stimulate thinking about speech production, its disorders and the clinical implications of these claims. The paper poses several conceptual and empirical challenges for these claims - including the critical importance of defining speech. The emerging conclusion is that a task-dependent model is called into question as its two central claims are founded on ill-defined and inconsistently applied concepts. The paper concludes with discussion of methodological and clinical implications, including the potential utility of diadochokinetic (DDK) tasks in assessment of motor speech disorders and the contraindication of nonspeech oral motor exercises to improve speech function.

Articulatory Control in Childhood Apraxia of Speech in a Novel Word-Learning Task

PURPOSE

Articulatory control and speech production accuracy were examined in children with childhood apraxia of speech (CAS) and typically developing (TD) controls within a novel word-learning task to better understand the influence of planning and programming deficits in the production of unfamiliar words.

METHOD

Participants included 16 children between the ages of 5 and 6 years (8 CAS, 8 TD). Short- and long-term changes in lip and jaw movement, consonant and vowel accuracy, and token-to-token consistency were measured for 2 novel words that differed in articulatory complexity.

RESULTS

Children with CAS displayed short- and long-term changes in consonant accuracy and consistency. Lip and jaw movements did not change over time. Jaw movement duration was longer in children with CAS than in TD controls. Movement stability differed between low- and high-complexity words in both groups.

CONCLUSIONS

Children with CAS displayed a learning effect for consonant accuracy and consistency. Lack of change in movement stability may indicate that children with CAS require additional practice to demonstrate changes in speech motor control, even within production of novel word targets with greater consonant and vowel accuracy and consistency. The longer movement duration observed in children with CAS is believed to give children additional time to plan and program movements within a novel skill.

A Randomized Controlled Trial for Children With Childhood Apraxia of Speech Comparing Rapid Syllable Transition Treatment and the Nuffield Dyspraxia Programme-Third Edition

PURPOSE

This randomized controlled trial compared the experimental Rapid Syllable Transition (ReST) treatment to the Nuffield Dyspraxia Programme-Third Edition (NDP3; Williams & Stephens, 2004), used widely in clinical practice in Australia and the United Kingdom. Both programs aim to improve speech motor planning/programming for children with apraxia of speech (CAS), but they differ in types of stimuli used, level of stimulus complexity at initiation of treatment, and the principles of motor learning that they apply.

METHOD

Treatment was delivered to 26 children with mild to severe CAS aged 4-12 years through trained and supervised speech-language pathology students in 1-hr sessions, 4 days a week for 3 weeks at a university clinic. Articulation and prosodic accuracy were assessed at pretreatment, 1 week, 1 month, and 4 months posttreatment using blinded independent assessors to compare treatment, maintenance, and generalization effects.

RESULTS

The ReST and NDP3 treatments demonstrated large treatment effects. ReST maintained treatment gains from 1-week to 4-months posttreatment more effectively than the NDP3. Significant generalization to untreated stimuli was observed for both ReST and NDP3.

CONCLUSIONS

ReST and NDP3 have strong evidence of treatment and generalization gains in children with CAS when delivered intensively. Overall, ReST has greater external evidence from multiple sources but both treatments have support for clinical use.

Treatment for Acquired Apraxia of Speech: A Systematic Review of Intervention Research Between 2004 and 2012

OBJECTIVES

The aim was for the appointed committee of the Academy of Neurological Communication Disorders and Sciences to conduct a systematic review of published intervention studies of acquired apraxia of speech (AOS), updating the previous committee's review article from 2006.

METHOD

A systematic search of 11 databases identified 215 articles, with 26 meeting inclusion criteria of (a) stating intention to measure effects of treatment on AOS and (b) data representing treatment effects for at least 1 individual stated to have AOS.

RESULTS

All studies involved within-participant experimental designs, with sample sizes of 1 to 44 (median = 1). Confidence in diagnosis was rated high to reasonable in 18 of 26 studies. Most studies (24/26) reported on articulatory-kinematic approaches; 2 applied rhythm/rate control methods. Six studies had sufficient experimental control for Class III rating according to the Clinical Practice Guidelines Process Manual (American Academy of Neurology, 2011), with 15 others satisfying all criteria for Class III except use of independent or objective outcome measurement.

CONCLUSIONS

The most important global clinical conclusion from this review is that the weight of evidence supports a strong effect for both articulatory-kinematic and rate/rhythm approaches to AOS treatment. The quantity of work, experimental rigor, and reporting of diagnostic criteria continue to improve and strengthen confidence in the corpus of research.

Acquired Apraxia of Speech: Features, Accounts, and Treatment

The features of apraxia of speech (AOS) are presented with regard to both traditional and contemporary descriptions of the disorder. Models of speech processing, including the neurological bases for apraxia of speech, are discussed. Recent findings concerning subcortical contributions to apraxia of speech and the role of the insula are presented. The key features to differentially diagnose AOS from related speech syndromes are identified. Treatment implications derived from motor accounts of AOS are presented along with a summary of current approaches designed to treat the various subcomponents of the disorder. Finally, guidelines are provided for treating the AOS patient with coexisting aphasia.

Training Pseudoword Reading in Acquired Dyslexia: A Phonological Complexity Approach

BACKGROUND

Individuals with acquired phonological dyslexia experience difficulty associating written letters with corresponding sounds, especially in pseudowords. Previous studies have shown that reading can be improved in these individuals by training letter-sound correspondence, practicing phonological skills, or using combined approaches. However, generalization to untrained items is typically limited.

AIMS

We investigated whether principles of phonological complexity can be applied to training letter-sound correspondence reading in acquired phonological dyslexia to improve generalization to untrained words. Based on previous work in other linguistic domains, we hypothesized that training phonologically "more complex" material (i.e., consonant clusters with small sonority differences) would result in generalization to phonologically "less complex" material (i.e., consonant clusters with larger sonority differences), but this generalization pattern would not be demonstrated when training the "less complex" material.

METHODS & PROCEDURES

We used a single-participant, multiple baseline design across participants and behaviors to examine phonological complexity as a training variable in five individuals. Based on participants' error data from a previous experiment, a "more complex" onset and a "less complex" onset were selected for training for each participant. Training order assignment was pseudo-randomized and counterbalanced across participants. Three participants were trained in the "more complex" condition and two in the "less complex" condition while tracking oral reading accuracy of both onsets.

OUTCOMES & RESULTS

As predicted, participants trained in the "more complex" condition demonstrated improved pseudoword reading of the trained cluster and generalization to pseudowords with the untrained, "simple" onset, but not vice versa.

CONCLUSIONS

These findings suggest phonological complexity can be used to improve generalization to untrained phonologically related words in acquired phonological dyslexia. These findings also provide preliminary support for using phonological complexity theory as a tool for designing more effective and efficient reading treatments for acquired dyslexia.

Sound production treatment: effects of blocked and random practice

PURPOSE

This investigation was designed to further the development of a treatment for acquired apraxia of speech (AOS), Sound Production Treatment (SPT), by examining the effects of blocked and random practice.

METHOD

A multiple-baseline design across participants and behaviors was used with 6 speakers with chronic AOS and aphasia. Accuracy of production of target sounds in treated and untreated words produced in probe sessions served as the primary dependent variable. Stimulus generalization was also measured to phrase production and sentence completion. Participants received SPT applied with blocked presentation of treatment words (SPT-blocked) and SPT applied with random presentation of treatment words (SPT-random).

RESULTS

Increases in accuracy of articulation of target sounds in treated words were observed for all participants for both conditions of treatment. SPT-random appeared to be associated with better maintenance for 2 participants. Generalization to untreated words was positive for all participants for SPT-random and SPT-blocked. Stimulus generalization effects varied across participants and measurement conditions; patterns of generalization did not appear to be associated with treatment condition.

CONCLUSIONS

There may be an advantage for SPT-random for some speakers with AOS. Findings from the nonspeech motor learning literature may not translate directly to the treatment of AOS.

Motor-based intervention protocols in treatment of childhood apraxia of speech (CAS)

This paper reviews current trends in treatment for childhood apraxia of speech (CAS), with a particular emphasis on motor-based intervention protocols. The paper first briefly discusses how CAS fits into the typology of speech sound disorders, followed by a discussion of the potential relevance of principles derived from the motor learning literature for CAS treatment. Next, different motor-based treatment protocols are reviewed, along with their evidence base. The paper concludes with a summary and discussion of future research needs.

Orthographically sensitive treatment for dysprosody in children with childhood apraxia of speech using ReST intervention

OBJECTIVE

Impaired prosody is a core diagnostic feature of Childhood Apraxia of Speech (CAS) but there is limited evidence of effective prosodic intervention. This study reports the efficacy of the ReST intervention used in conjunction with bisyllabic pseudo word stimuli containing orthographic cues that are strongly associated with either strong-weak or weak-strong patterns of lexical stress.

METHODS

Using a single case AB design with one follow-up and replication, four children with CAS received treatment of four one-hour sessions per week for three weeks. Sessions contained 100 randomized trials of pseudo word treatment stimuli. Baseline measures were taken of treated and untreated behaviors; retention was measured at one day and four weeks post-treatment.

RESULTS

Children's production of lexical stress improved from pre to post-treatment. Treatment effects and maintenance varied among participants.

CONCLUSIONS

This study provides support for the treatment of prosodic deficits in CAS.

Treating apraxia of speech with an implicit protocol that activates speech motor areas via inner speech

BACKGROUND

Treatments of apraxia of speech (AOS) have traditionally relied on overt practice. One alternative to this method is implicit phoneme manipulation which was derived from early models on inner speech. Implicit phoneme manipulation requires the participant to covertly move and combine phonemes to form a new word. This process engages a system of self-monitoring which is referred to as fully conscious inner speech.

AIMS

The present study aims to advance the understanding and validity of a new treatment for AOS, implicit phoneme manipulation. Tasks were designed to answer the following questions. 1. Would the practice of implicit phoneme manipulation improve the overt production of complex consonant blends in words? 2. Would this improvement generalize to untrained complex and simpler consonant blends in words? 3. Would these treatment tasks activate regions known to support motor planning and programming as verified by fMRI?

METHOD & PROCEDURES

The participant was asked to covertly manipulate phonemes to create a new word and to associate this newly formed word to a target picture among 4 phonologically-related choices. To avoid overt practice, probes were collected only after each block of training was completed. Probe sessions assessed the effects of implicit practice on the overt production of simple and complex consonant blends in words. An imaging protocol compared semantic baseline tasks to treatment tasks to verify that implicit phoneme manipulation activated brain regions of interest.

OUTCOMES & RESULTS

Behavioral: Response to implicit training of complex consonant blends resulted in improvements which were maintained 6 weeks after treatment. Further, this treatment generalized to simpler consonant blends in words. Imaging: Functional imaging during implicit phoneme manipulation showed significant activation in brain regions responsible for phonological processing when compared to the baseline semantic task.

CONCLUSIONS

Implicit phoneme manipulation offers an alternative to traditional methods that require overt production for treatment of AOS. Additionally, this implicit treatment method was shown to activate neural areas known to be involved in phonological processing, motor planning and programming.

Training verb argument structure production in agrammatic aphasia: behavioral and neural recovery patterns

INTRODUCTION

Neuroimaging and lesion studies indicate a left hemisphere network for verb and verb argument structure processing, involving both frontal and temporoparietal brain regions. Although their verb comprehension is generally unimpaired, it is well known that individuals with agrammatic aphasia often present with verb production deficits, characterized by an argument structure complexity hierarchy, indicating faulty access to argument structure representations for production and integration into syntactic contexts. Recovery of verb processing in agrammatism, however, has received little attention and no studies have examined the neural mechanisms associated with improved verb and argument structure processing. In the present study we trained agrammatic individuals on verbs with complex argument structure in sentence contexts and examined generalization to verbs with less complex argument structure. The neural substrates of improved verb production were examined using functional magnetic resonance imaging (fMRI).

METHODS

Eight individuals with chronic agrammatic aphasia participated in the study (four experimental and four control participants). Production of three-argument verbs in active sentences was trained using a sentence generation task emphasizing the verb's argument structure and the thematic roles of sentential noun phrases. Before and after training, production of trained and untrained verbs was tested in naming and sentence production and fMRI scans were obtained, using an action naming task.

RESULTS

Significant pre- to post-training improvement in trained and untrained (one- and two-argument) verbs was found for treated, but not control, participants, with between-group differences found for verb naming, production of verbs in sentences, and production of argument structure. fMRI activation derived from post-treatment compared to pre-treatment scans revealed upregulation in cortical regions implicated for verb and argument structure processing in healthy controls.

CONCLUSIONS

Training verb deficits emphasizing argument structure and thematic role mapping is effective for improving verb and sentence production and results in recruitment of neural networks engaged for verb and argument structure processing in healthy individuals.

A motor learning perspective for optimizing intervention intensity

Baker (2012) has addressed the critical issue of optimizing intervention intensity in the field of speech-language pathology. While this provides a useful framework from which to examine treatment intensities across a variety of approaches, it does little to inform how certain factors (e.g., feedback frequency, practice schedules) might be manipulated to optimize learning in ways that are effective and efficient. Evidence from the speech and non-speech motor learning literature suggests that the optimal intensities for utilizing practice and feedback are dependent on interactive factors such as task variability, target complexity, and therapeutic goals. In light of the complex interactions of treatment factors, it is proposed that the principles of motor learning be used as a guide to develop precise, interactive models that describe the optimal treatment conditions for specific approaches to intervention in speech-language pathology.

Acquired apraxia of speech: the effects of repeated practice and rate/rhythm control treatments on sound production accuracy

PURPOSE

This investigation was designed to elucidate the effects of repeated practice treatment on sound production accuracy in individuals with apraxia of speech (AOS) and aphasia. A secondary purpose was to determine if the addition of rate/rhythm control to treatment provided further benefits beyond those achieved with repeated practice.

METHOD

A single-subject design was employed with 10 speakers with chronic AOS and aphasia. Articulation accuracy served as the dependent measure. Participants received repeated practice treatment until a plateau in performance was observed or high levels of accuracy were achieved. If performance criterion was not reached, rate/rhythm control was added to the treatment to determine if additional gains would be made.

RESULTS

For 8 of the participants, improvements were evident for all applications of repeated practice treatment, and positive response generalization was observed in most cases. When rate/rhythm control treatment was applied, modest additional gains were apparent for the majority of the applications. The 2 participants who did not benefit from repeated practice treatment also did not show improvements with rate/rhythm control treatment.

CONCLUSIONS

Repeated practice treatment resulted in improved articulation for the majority of participants. The amount of improvement varied within and across participants. Rate/rhythm control appeared to have limited additional benefits for some participants.

Syllable- and Rhythm-Based Approaches in the Treatment of Apraxia of Speech

This paper presents new treatment approaches for patients with apraxia of speech (AOS), which are based on current theoretical work relating to the pathomechanism of AOS. Particularly, we focus on the question of which speech units and structural properties are involved in the error mechanism of speakers with apraxia. Based on a psycholinguistic model of spoken language production (Levelt, Roelofs, & Meyer, 1999), we review data from single-word production experiments and from analyses of spontaneous speech demonstrating an impact on (a) the degree of “over-learnedness” of syllables (syllable frequency), (b) the internal structure of syllables (syllable complexity), and (c) supra-syllabic, metrical aspects of utterances (word stress) on error production in AOS.

In the second section, we present two experimental learning studies and a treatment study that take these results into consideration. The first learning experiment suggests that syllables are more natural units than segments in the treatment of patients with severe AOS. Based on the results of the second learning study, we recommend a treatment approach which uses formally related training syllables in the reacquisition of complex target syllables. Finally, results of a treatment study using a metrical pacing technique led to the assumption that fluency and segmental accuracy could be enhanced by external rhythmic cues.

A treatment for dysprosody in childhood apraxia of speech

PURPOSE

Dysprosody is considered a core feature of childhood apraxia of speech (CAS), especially impaired production of lexical stress. Few studies have tested the effects of intervention for dysprosody. This Phase II study with 3 children investigated the efficacy of a treatment targeting improved control of relative syllable durations in 3-syllable nonwords representing strong-weak (SW) and weak-strong (WS) stress patterns (e.g., BAtigu or baTIgu). Treatment sessions were structured along the principles of motor learning (PML) approach.

METHOD

Three children, age 7 to 10 years, with mild to moderate CAS and normal language development participated in an intensive 3-week treatment. Within-participant designs with multiple baselines across participants and behaviors were used to examine acquisition, generalization, and maintenance of skill.

RESULTS

All children improved in their ability to control relative duration of syllables in SW and WS nonwords. Improvement was also noted in control of loudness and pitch contrasts. Treatment effects generalized to untreated nonword stimuli, but minimal change was seen in production of real words.

CONCLUSION

Findings support the efficacy of this approach for improving production of lexical stress contrasts. Structuring the intervention according to the PML approach likely stimulated strong maintenance and generalization effects.

Effects of directional exercise on lingual strength

PURPOSE

To examine the application of known muscle training principles to tongue strengthening exercises and to answer the following research questions: (a) Did lingual strength increase following 9 weeks of training? (b) Did training conducted using an exercise moving the tongue in one direction result in strength changes for tongue movements in other directions? (c) Were differential training effects observed for participants completing exercises sequentially (in isolation) versus concurrently (several exercises in combination)? (d) Were strength gains maintained after exercise was discontinued? Methods Participants were 39 healthy adults assigned to sequential or concurrent lingual strength training. Lingual exercise (elevation, protrusion, and/or lateralization) was conducted for 9 weeks, with lingual strength and cheek strength (control variable) assessed weekly.

RESULTS

All lingual strength measures increased with training, but cheek strength remained unchanged. Training effects were not related to training condition (sequential vs. concurrent), nor were specificity effects observed for direction of exercise. Significant decreases in lingual strength were noted 2-4 weeks after exercise was discontinued.

CONCLUSIONS

The findings replicate those of earlier studies demonstrating that lingual strength may be increased with a variety of exercise protocols and confirm that detraining effects may be observed when training is discontinued. The findings further suggest that the lingual musculature may demonstrate less dramatic training specificity than what has been reported for skeletal muscles.

Effects of feedback frequency and timing on acquisition, retention, and transfer of speech skills in acquired apraxia of speech

PURPOSE

Two studies examined speech skill learning in persons with apraxia of speech (AOS). Motor-learning research shows that delaying or reducing the frequency of feedback promotes retention and transfer of skills. By contrast, immediate or frequent feedback promotes temporary performance enhancement but interferes with retention and transfer. These principles were tested in the context of a common treatment for AOS.

METHOD

Two studies (N = 4, N = 2) employed single-subject treatment designs to examine acquisition and retention of speech skills in adults with AOS under different feedback conditions.

RESULTS

Reduced-frequency or delayed feedback enhanced learning in 3 participants with AOS. Feedback manipulation was not an influential variable in 3 other cases in which stimulus-complexity effects may have masked treatment effects.

CONCLUSIONS

These findings demonstrate that individuals with AOS can benefit from structured intervention. They provide qualified support for reduction and delay of feedback, although interaction with other factors such as stimulus complexity or task difficulty needs further exploration. This study adds to the growing body of literature investigating the use of principles of motor learning in treating AOS and provides impetus for consideration of pre-treatment variables that affect outcome in treatment studies.

Principles of motor learning in treatment of motor speech disorders

PURPOSE

There has been renewed interest on the part of speech-language pathologists to understand how the motor system learns and determine whether principles of motor learning, derived from studies of nonspeech motor skills, apply to treatment of motor speech disorders. The purpose of this tutorial is to introduce principles that enhance motor learning for nonspeech motor skills and to examine the extent to which these principles apply in treatment of motor speech disorders.

METHOD

This tutorial critically reviews various principles in the context of nonspeech motor learning by reviewing selected literature from the major journals in motor learning. The potential application of these principles to speech motor learning is then discussed by reviewing relevant literature on treatment of speech disorders. Specific attention is paid to how these principles may be incorporated into treatment for motor speech disorders.

CONCLUSIONS

Evidence from nonspeech motor learning suggests that various principles may interact with each other and differentially affect diverse aspects of movements. Whereas few studies have directly examined these principles in speech motor (re)learning, available evidence suggests that these principles hold promise for treatment of motor speech disorders. Further research is necessary to determine which principles apply to speech motor (re)learning in impaired populations.

Complexity in language learning and treatment

PURPOSE

To introduce a Clinical Forum focused on the Complexity Account of Treatment Efficacy (C. K. Thompson, L. P. Shapiro, S. Kiran, & J. Sobecks, 2003), a counterintuitive but effective approach for treating language disorders. This approach espouses training complex structures to promote generalized improvement of simpler, linguistically related structures. Three articles are included, addressing complexity in treatment of phonology, lexical-semantics, and syntax.

METHOD

Complexity hierarchies based on models of normal language representation and processing are discussed in each language domain. In addition, each article presents single-subject controlled experimental studies examining the complexity effect. By counterbalancing treatment of complex and simple structures across participants, acquisition and generalization patterns are examined as they emerge.

RESULTS

In all language domains, cascading generalization occurs from more to less complex structures; however, the opposite pattern is rarely seen. The results are robust, with replication within and across participants.

CONCLUSIONS

The construct of complexity appears to be a general principle that is relevant to treating a range of language disorders in both children and adults. While challenging the long-standing clinical notion that treatment should begin with simple structures, mounting evidence points toward the facilitative effects of using more complex structures as a starting point for treatment.

Single subject controlled experiments in aphasia: the science and the state of the science

This paper discusses the use of single subject controlled experimental designs for investigating the effects of treatment for aphasia. A brief historical perspective is presented, followed by discussions of the advantages and disadvantages of single subject and group approaches, the basic requirements of single subject experimental research, and crucial considerations in design selection. In the final sections, results of reviews of published single subject controlled experiments are discussed, with emphasis on internal validity issues, the number of participants enrolled in published studies, operational specification of the dependent and independent variables, and reliability of measurement.

LEARNING OUTCOMES

As a result of reading this paper, the participant will: (1) understand the mechanisms required for demonstration of internal and external validity using single subject controlled experimental designs, (2) become familiar with the basic requirements of single subject controlled experimental research, (3) understand the types of single subject controlled experimental designs that are the most appropriate for studying the effects of treatment for aphasia, and (4) become familiar with trends in the published aphasia treatment literature in which single subject controlled experimental designs have been used.

Phonological change and the representation of consonant clusters in Spanish: a case study

This single-subject case study evaluates effects of treatment of a complex onset on the sound system of a monolingual Spanish-speaking child (female, aged 3;9) with phonological delay. Pre-treatment, the child excluded all consonant+liquid clusters, as well as tap /[symbol: see text]/ and trill /r/. Immediately following training on /f[symbol: see text]-/ in non-words, the child generalized across consonant+liquid clusters and the tap singleton. These improvements continued to 2 months post-treatment follow-up, with the ultimate addition of the trill at that point in time. Consonant+glide sequences, whose structural status as complex onsets is debated in the Spanish phonology literature, patterned differently from consonant+liquid sequences. Specific findings are viewed in light of linguistic markedness, syllable structure, sonority sequencing, and the representation of consonant clusters.

Treating agrammatic aphasia within a linguistic framework: Treatment of Underlying Forms

BACKGROUND: Formal linguistic properties of sentences-both lexical, i.e., argument structure, and syntactic, i.e., movement-as well as what is known about normal and disordered sentence processing and production, were considered in the development of Treatment of Underlying Forms (TUF), a linguistic approach to treatment of sentence deficits in patients with agrammatic aphasia. TUF is focused on complex, non-canonical sentence structures and operates on the premise that training underlying, abstract, properties of language will allow for effective generalisation to untrained structures that share similar linguistic properties, particularly those of lesser complexity. AIMS: In this paper we summarise a series of studies focused on examining the effects of TUF. METHODS #ENTITYSTARTX00026;PROCEDURES: In each study, sentences selected for treatment and for generalisation analysis were controlled for their lexical and syntactic properties, with some structures related and others unrelated along theoretical lines. We use single-subject experimental designs-i.e., multiple baseline designs across participants and behaviours-to chart improvement in comprehension and production of both trained and untrained structures. One structure was trained at a time, while untrained sentences were tested for generalisation. Participants included individuals with mild to moderately severe agrammatic, Broca's aphasia with characteristic deficits patterns. OUTCOMES #ENTITYSTARTX00026; RESULTS: Results of this work have shown that treatment improves the sentence types entered into treatment, that generalisation occurs to sentences which are linguistically related to those trained, and that treatment results in changes in spontaneous discourse in most patients. Further, we have found that generalisation is enhanced when the direction of treatment is from more to less complex structures, a finding that led to the Complexity Account of Treatment Efficacy (CATE, Thompson, Shapiro, Kiran, & Sobecks, 2003). Finally, results of recent work showing that treatment appears to affect processing of trained sentences in real time and that treatment gains can be mapped onto the brain using functional magnetic resonance imaging (fMRI) are discussed. CONCLUSIONS: These findings indicate that TUF is effective for treating sentence comprehension and production in patients who present with language deficit patterns like those seen in our patients. Patients receiving this treatment show strong generalisation effects to untrained language material. Given the current healthcare climate, which limits the amount of treatment that aphasic patients receive following stroke, it is important that clinicians deliver treatment that results in optimal generalisation in the least amount of time possible.

The role of syntactic complexity in treatment of sentence deficits in agrammatic aphasia: the complexity account of treatment efficacy (CATE)

This experiment examined the hypothesis that training production of syntactically complex sentences results in generalization to less complex sentences that have processes in common with treated structures. Using a single subject experimental design, 4 individuals with agrammatic aphasia were trained to comprehend and produce filler-gap sentences with wh-movement, including, from least to most complex, object-extracted who-questions, object clefts, and sentences with object-relative clausal embedding. Two participants received treatment first on the least complex structure (who-questions), and 2 received treatment first on the most complex form (object-relative constructions), while untrained sentences and narrative language samples were tested for generalization. When generalization did not occur across structures, each was successively entered into treatment. Results showed no generalization across sentence types when who-questions were trained; however, as predicted, object-relative training resulted in robust generalization to both object clefts and who-questions. These findings support those derived from previous work, indicating not only that generalization occurs across structures that are linguistically related, but also that generalization is enhanced when the direction of treatment is from more complex to less complex constructions. This latter finding supports the authors' newly coined "complexity account of treatment efficacy" (CATE).