Anita van der Merwe

A speech motor learning approach to treating apraxia of speech : rationale and effects of intervention with an adult with acquired apraxia of speech

Background: In this paper the rationale for a treatment of apraxia of speech, the speech motor learning (SML) approach, is described and the effects of its application explored. The SML approach endeavours to address the underlying inability to plan and program the production of different speech motor targets (SMTs) in changing phonetic contexts and in utterances exceeding a single word/nonword in length. Aims: The aims of the study were to determine (1) if treatment effects generalised to untreated nonwords and untreated real words with trained vowels and consonants, (2) if a learning effect was maintained, (3) if the treatment task hierarchy of the SML approach could be confirmed, and (4) if the number of speech errors judged perceptually declined across the treatment period on treated and untreated stages. Methods & Procedures: A multiple baseline single-participant design across behaviours and contexts was used to assess the effects of treatment with a speaker with chronic pure AOS. The first six stages of an eleven-stage treatment hierarchy were consecutively treated. The last five remained untreated. Outcomes & Results: During treatment, production of untrained nonwords and words containing trained and untrained SMTs improved. For three treated stages the improvement was greater during the treatment phase than during baseline, for words, nonwords, or both. Stage 4 vowels only improved once treatment commenced. Untreated consonant clusters of Stage 10 improved negligibly. Improvement was maintained 2 years post-treatment. The number of speech errors decreased across the treatment period. Conclusions: Preliminary evidence is provided supporting a general improvement in speech motor planning and programming ability for this participant. The relative value of components of the SML approach needs to be verified in future.Background: In this paper the rationale for a treatment of apraxia of speech, the speech motor learning (SML) approach, is described and the effects of its application explored. The SML approach endeavours to address the underlying inability to plan and program the production of different speech motor targets (SMTs) in changing phonetic contexts and in utterances exceeding a single word/nonword in length. Aims: The aims of the study were to determine (1) if treatment effects generalised to untreated nonwords and untreated real words with trained vowels and consonants, (2) if a learning effect was maintained, (3) if the treatment task hierarchy of the SML approach could be confirmed, and (4) if the number of speech errors judged perceptually declined across the treatment period on treated and untreated stages. Methods & Procedures: A multiple baseline single-participant design across behaviours and contexts was used to assess the effects of treatment with a speaker with chronic pure AOS. The first six stag...

Self‐correction in apraxia of speech: The effect of treatment

Background: Overt attempts at self‐correction of speech errors reflect conscious monitoring of speech output. The ability to monitor speech reveals something about the dynamics of motor control. Speakers with apraxia of speech (AOS) attempt to self‐correct speech, but systematic analyses of self‐correction in AOS have rarely been done. Aims: The aims of the study were to determine the effect of treatment on the number of overt attempted self‐corrections during the course of treatment, on the number of overt attempted self‐corrections as a percentage of the total number of incorrect productions, and on successful self‐corrections as a percentage of the total number of self‐corrections. Methods & Procedures: One speaker with AOS was treated for a period of 18 months. Self‐corrections were noted during three repetitions of 110 words and 110 nonwords. Three pre‐treatment baseline probes and four subsequent probes, spanning the treatment period, were performed. Outcomes & Results: The number of attempted self‐corrections decreased and the percentage of successful self‐corrections increased during treatment. However, attempted self‐corrections as a percentage of the total number of incorrect productions remained fairly stable during treatment. Conclusions: The results indicate that success of overt self‐corrections improved during treatment. However, the almost unchanged number of self‐corrections as a percentage of the total number of incorrect productions suggests that the process of internal predictive control remained dysfunctional. The inadvertent occurrence of speech errors points towards a loss or dysfunction of volitional control of speech production. Mental practice as a complementary treatment technique may need to be considered. A continuum of volitional control of speech is presented to explain AOS.Background: Overt attempts at self‐correction of speech errors reflect conscious monitoring of speech output. The ability to monitor speech reveals something about the dynamics of motor control. Speakers with apraxia of speech (AOS) attempt to self‐correct speech, but systematic analyses of self‐correction in AOS have rarely been done. Aims: The aims of the study were to determine the effect of treatment on the number of overt attempted self‐corrections during the course of treatment, on the number of overt attempted self‐corrections as a percentage of the total number of incorrect productions, and on successful self‐corrections as a percentage of the total number of self‐corrections. Methods & Procedures: One speaker with AOS was treated for a period of 18 months. Self‐corrections were noted during three repetitions of 110 words and 110 nonwords. Three pre‐treatment baseline probes and four subsequent probes, spanning the treatment period, were performed. Outcomes & Results: The number of attempted self‐...

Development of speech sounds and syllable structure of words in Zulu-speaking children

This study investigated development of speech sounds and syllable structure of words in 18 Zulu-speaking children between the ages of 3.0 and 6.2. A 100-word spontaneous conversational sample was elicited from each subject. All samples were transcribed phonetically by a stringent transcription procedure. The UNIBET was used to code the transcription into computer recognisable-symbols. The Phonetic Calculator Program (PCP) analysed the samples in terms of speech sound inventory, syllable structure of words and the frequency of occurrence of speech sounds and syllable structures. The data were processed to allow for the comparison of the findings at three age levels, namely 3.0–4.0 (Group 1), 4.1–5.1 (Group 2) and 5.2–6.2 (Group 3). There was developmental progression, but much speech and syllable structure development seems to occur before the age of 3.0. However, the speech sound inventory and syllable structure inventory were incomplete by the age of 6.2. The nasals, plosives, approximants and fricatives were found to develop earlier than the affricates, clicks and prenasalised consonant sounds. The shorter syllable strings were found to develop earlier than the longer syllable strings. The phonetically more complex sounds and syllable structures were produced more frequently by the older subjects, demonstrating developmental progression. The findings have important clinical implications for the speech-language therapist.

Idiosyncratic sound systems of the South African Bantu languages: Research and clinical implications for speech-language pathologists and audiologists

The objective of this article is to create awareness amongst speech-language pathologists and audiologists in South Africa regarding the difference between the sound systems of Germanic languages and the sound systems of South African Bantu languages. A brief overview of the sound systems of two Bantu languages, namely isiZulu and Setswana, is provided. These two languages are representative of the Nguni language group and the Sotho group respectively.Consideration is given to the notion of language-specific symptoms of speech, language and hearing disorders in addition to universal symptoms. The possible impact of speech production, language and hearing disorders on the ability to produce and perceive speech in these languages, and the challenges that this holds for research and clinical practice, are pointed out.The objective of this article is to create awareness amongst speech-language pathologists and audiologists in South Africa regarding the difference between the sound systems of Germanic languages and the sound systems of South African Bantu languages. A brief overview of the sound systems of two Bantu languages, namely isiZulu and Setswana, is provided. These two languages are representative of the Nguni language group and the Sotho group respectively.Consideration is given to the notion of language-specific symptoms of speech, language and hearing disorders in addition to universal symptoms. The possible impact of speech production, language and hearing disorders on the ability to produce and perceive speech in these languages, and the challenges that this holds for research and clinical practice, are pointed out.

Vocal effectiveness of speech-language pathology students: Before and after voice use during service delivery

Background As a professional voice user, it is imperative that a speech-language pathologists (SLP) vocal effectiveness remain consistent throughout the day. Many factors may contribute to reduced vocal effectiveness, including prolonged voice use, vocally abusive behaviours, poor vocal hygiene and environmental factors. Objectives To determine the effect of service delivery on the perceptual and acoustic features of voice. Method A quasi-experimental., pre-test–post-test research design was used. Participants included third- and final-year speech-language pathology students at the University of Pretoria (South Africa). Voice parameters were evaluated in a pre-test measurement, after which the participants provided two consecutive hours of therapy. A post-test measurement was then completed. Data analysis consisted of an instrumental analysis in which the multidimensional voice programme (MDVP) and the voice range profile (VRP) were used to measure vocal parameters and then calculate the dysphonia severity index (DSI). The GRBASI scale was used to conduct a perceptual analysis of voice quality. Data were processed using descriptive statistics to determine change in each measured parameter after service delivery. Results A change of clinical significance was observed in the acoustic and perceptual parameters of voice. Conclusion Guidelines for SLPs in order to maintain optimal vocal effectiveness were suggested.

Temporal parameters of speech production in bilingual speakers with apraxic or phonemic paraphasic errors

Background: The four‐level framework of speech production (Van der Merwe, 1997) suggests that language of production of a bilingual speaker can be viewed as a contextual factor increasing the complexity of speech production. A comparison of first‐ versus second‐language speech production in individuals with apraxia of speech or phonemic paraphasic speech errors may clarify the difference in the underlying disorders in these two populations. Aims: This study examined the effect of first‐ versus second‐language (L1 versus L2) speech production on specific temporal parameters of speech in bilingual normal speakers and bilingual speakers with either apraxic or phonemic paraphasic speech errors. The purpose was to determine if second‐language speech production will differentiate between normal speakers and speakers with speech‐level neurogenic disorders and between speakers with phonological planning or speech motor planning and programming disorders. Methods and Procedures: Three persons with apraxia of speech (AOS), three with phonemic paraphasias (PP), and five normal‐speaking participants were included in the study. Participants were required to read phonemically similar L1 and L2 CVC words in a two‐word carrier phrase, five times each, at a normal and fast speaking rate. Acoustic analysis of on‐target productions included vowel duration, utterance duration, utterance onset duration, and voice onset time. Data processing involved a descriptive approach using a measure of central tendency—the mean. Intra‐participant comparisons were made across contexts (L1, L2, fast speaking rate, and normal speaking rate). Outcomes and Results: Five participants with AOS and PP seemed to be influenced by speaking in L2 to a greater extent than the normal speakers and one participant with PP, in that they more frequently experienced difficulty with durational adjustments (decreasing duration in the fast speaking rate) in L2 than in L1. Furthermore, the participants with AOS or PP also exhibited a greater extent of durational adjustment in L1 than in L2. Conclusions: The results of this study suggest that L2 speech production is more challenging than speech production in L1 for participants with either AOS or PP. The current study could not differentiate between all speakers with a disorder in phonological planning and speakers with a motor planning and programming disorder. Individual patterns appear to exist in speakers with PP. Increased processing demands seem to impact on the phonological planning and the speech motor planning and programming levels of speech production.

What can speech production errors tell us about cross-linguistic processing in bilingual aphasia? Evidence from four English/Afrikaans bilingual individuals with aphasia

Introduction The aim of this study is contribute to clinical practice of bilinguals around the globe, as well as to add to our understanding of bilingual aphasia processing, by analysing confrontation naming data from four Afrikaans/English bilingual individuals with acquired aphasia due to a left hemisphere stroke. Methods This is a case series analysis of four Afrikaans/English bilingual aphasic individuals following a left cerebrovascular accident. Error analysis of confrontation naming data in both languages was performed. Research questions were directed toward the between language differences in lexical retrieval abilities, types of errors produced and degree of cognate overlap. Results Three of the four participants showed significantly higher naming accuracy in first acquired language (L1) relative to the second acquired language (L2) and the largest proportion of error type for those three participants in both L1 and L2 was omission. One of the four participants (linguistically balanced) showed no between language accuracy difference. Regarding cognate overlap, there was a trend for higher accuracy for higher cognate words (compared to low). Discussion This study showed that naming performance in these four individuals was reflective of their relative language proficiency and use patterns prior to their stroke. These findings are consistent with the hierarchical model, in normal bilingual speakers and with persons with bilingual aphasia.

Development of a Setswana tonal minimal pair word list as research tool

This study reports on the development of a Setswana tonal minimal pair word list, which could be implemented as research tool in the field of Bantu language linguistics and in speech pathology in South Africa. The development of the list was conducted in four phases. These are described as four separate studies. All involved Setswana L1 participants living in the urban areas of Gauteng. In Study 1, a 45-pair preliminary list was compiled from dictionaries. During Study 2, eleven L1 speakers’ familiarity with each word was determined. Based on these results the list was narrowed down to 20 pairs. Study 3 entailed the validation of pictorial stimuli, which illustrate the target words. Ten different participants took part. Four pairs were not consistently familiar and were removed, resulting in the experimental list of 16 pairs. This list was validated in Study 4 and involved nine typical L1 speakers and five listeners. Word-specific analyses revealed that some words had a negative impact on the results. Six pairs were removed. A final list of 10 pairs rendered results more aligned to the expectation of typical speakers and listeners. Validation should continue to determine applicability in populations from exclusively rural or urban areas.

The effect of methylphenidate-OROS® on the narrative ability of children with attention-deficit hyperactivity disorder

Background and objective Children with attention-deficit hyperactivity disorder (ADHD) experience difficulty with expressive language, including form (e.g. grammatical construction) and content (e.g. coherence). The current study aimed to investigate the effect of methylphenidate-Osmotic Release Oral System® (MPH-OROS®) on the narrative ability of children with ADHD and language impairment, through the analysis of microstructure and macrostructure narrative elements. Method In a single group off–on medication test design, narratives were obtained from 12 children with ADHD, aged 7–13 years, using wordless picture books. For microstructure, number of words, type–token ratio and mean length of utterance were derived from narrative samples using Systematic Analysis of Language Transcripts conventions. For macrostructure, the narratives were coded according to the Narrative Scoring Scheme, which includes seven narrative characteristics, as well as a composite score reflecting the child’s overall narrative ability. Results The administration of MPH-OROS® resulted in a significant difference in certain aspects of language macrostructure: cohesion and overall narrative ability. Little effect was noted in microstructure elements. Conclusion We observed a positive effect of stimulant medication on the macrostructure, but not on the microstructure, of narrative production. Although stimulant medication improves attention and concentration, it does not improve all aspects of language abilities in children with ADHD. Language difficulties associated with ADHD related to language content and use may be more responsive to stimulant medication than language form, which is likely to be affected by cascading effects of inattention, hyperactivity and impulsivity beginning very early in life and to progress over a more protracted period. Therefore, a combination of treatments is advocated to ensure that children with ADHD are successful in reaching their full potential.

Model-Driven Treatment of Childhood Apraxia of Speech: Positive Effects of the Speech Motor Learning Approach

Purpose The aim of the study was to propose the speech motor learning approach (Van der Merwe, 2011) as a treatment for childhood apraxia of speech and to determine if it will effect positive change in the ability of a 33-month-old child to produce untreated nonwords and words containing treated age-appropriate consonants (Set 1 sounds), untreated age-appropriate consonants (Set 2), and untreated age-inappropriate consonants (Set 3) and also to determine the nature and number of segmental speech errors before and after treatment. Method An A-B design with multiple target measures and follow-up was implemented to assess the effects of treatment of Set 1. Effect sizes for whole-word accuracy were determined, and two criterion lines were generated following the conservative dual criterion method. Speech errors were judged perceptually. Results Conservative dual criterion analyses indicated no reliable treatment effect due to rising baseline scores. Effect sizes showed significant improvement in whole-word accuracy of untreated nonwords and real words containing age-appropriate treated sounds and real words containing age-appropriate untreated sounds. The number of errors for all three sound sets declined. Sound distortion was the most frequent error type. Conclusions Preliminary evidence suggests potentially positive treatment effects. However, rising baseline scores limit causal inference. Replication with more children of different ages is necessary. Supplemental Materials https://doi.org/10.23641/asha.5596708.