Purpose: The purpose of this study was to determine whether individuals with right hemisphere damage (RHD) process impliciture sentences differently from matched controls. The research questions were: (a) Are participants with RHD less accurate than healthy controls in impliciture sentence processing? (b) Does the introduction of story context affect impliciture processing in participants with RHD? (c) Do participants with RHD demonstrate response time profiles that differ from controls?Method: Seven participants with RHD and 16 matched controls participated in two experiments. In Experiment 1, participants listened to 144 impliciture sentences, and verbally responded with the interpretation they thought best fit what the sentence meant. In Experiment 2, participants listened to 100 stories and verbally responded with their interpretation of what the final impliciture sentence meant. There were two story types for each sentence: one that facilitated the normally preferred interpretation, and one that negated that interpretation.Results: For Experiment 1, three participants were less accurate in impliciture comprehension when compared to controls. The results were significant for lexical, possessive, quantitative, and temporal implicitures. For Experiment 2, three participants demonstrated increased accuracy with context. The results were significant for hyperbole, possessive, quantitative, and temporal implicitures. However, item analysis showed that each participant with RHD had difficulty negating the preferred interpretation of the impliciture. For the response time analysis, the control group was significantly slower in the negating compared to the facilitating context condition (F<N>profile). In contrast, participants with RHD did not demonstrate a difference (F=N profile).Conclusions: These findings suggest that reduced accuracy in impliciture processing occurs in some individuals with RHD, although additional research is needed to determine what characteristics are related to poor impliciture comprehension. Participants also were unable to use story contexts as effectively as the control group, showing difficulty negating the normally-preferred interpretation. Because response time profiles differed between participants with RHD and the control group, it is likely that the integrity of the right hemisphere is required for normal processing of impliciture and use of contextual cues. The results suggest a number of additional avenues of research in both the normally aging and RHD populations.

This research was guided by a theoretical framework positing that children with typical language apply general cognitive resources, such as attention, to facilitate language acquisition, and limitations in these processes may contribute to poor language skills. From this perspective, studying the attentional functioning of children who exhibit difficulty with language would have value for both informing this theory and understanding the nature of the disorder. However, research on the attention of children with specific language impairment (SLI) is limited, as only a few subdomains have been addressed to date. In addition, although school-age children with SLI have been studied, the assessment of attentional functioning in preschool children with this disorder has been minimal. This is likely the result the limitations inherent to the methods used for evaluating attentional skills at younger ages. The purpose of this research was to extend a method previously used successfully with preschool children to study selected aspects of attentional control including susceptibility to distraction, inhibitory control, and updating skills. The research questions were: (a) Do children with SLI exhibit increased susceptibility to distraction relative to their typically-developing peers, and if so, does it vary according to the type of distracter (visual, nonverbal-auditory, linguistic) presented? (b) Do children with SLI exhibit poor inhibitory control relative to their typically-developing peers? (c) Do children with SLI and their typically-developing peers display evidence of updating? Thirty-one preschool children with SLI and 31 controls participated in two computer tasks designed to assess these mechanisms of attentional control. The susceptibility to distraction task involved resisting distracters presented in different stimulus modalities (visual and auditory-linguistic/nonlinguistic). Inhibition and updating skills were assessed using a stop signal paradigm. In comparison to typically-developing children, the children with SLI exhibited increased susceptibility to distraction and poor inhibitory control. Unlike the controls, they exhibited no evidence of updating. The results of this investigation will contribute to a long-term goal of addressing how attention may affect language acquisition in children with SLI. In addition, the successful methodology employed in this study may offer an improved procedure for diagnosing attentional difficulties at an early age, regardless of language status.

A common recommendation for communication partners of people with hearing loss is to speak clearly, but how effective is this simple instruction? Does everyone produce clear speech using the same strategies? Is clear speech produced when given minimal instruction the same as that produced when competing background noise is present? The present study examined the acoustic characteristics of passage level speech produced in four different conditions. Twelve talkers (8 female, 4 male) with a mean age of 21 years were audio recorded reading three paragraph length passages. In the first condition talkers read each passage conversationally as though speaking to a friend. In the three experimental conditions, talkers were instructed to speak as clearly as they could, speak as clearly as they could in the presence of multitalker babble, and speak as clearly as they could in the presence of speech-shaped noise. The babble and noise were presented over headphones at a level of 75 dB SPL. Acoustic measures examined changes in rate, frequency, and intensity across condition. Results of this study help clarify what changes talkers make in response to instructions to speak clearly compared to conditions with competing background noise.

Thesis (M Speech Path)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: This study investigated the effect of two shared-reading intervention programmes on the narratives of 87 Afrikaans-speaking Grade R learners from low income families. Intervention Programme I involved an interactive style where participants were encouraged to engage spontaneously in conversations about the characters’ intentions and goals, to make inferences and to ask questions. Intervention Programme II focused on observable entities and the content of the storybooks. Participants’ narratives were compared before and after intervention in terms of productivity, content and structure. Results indicated that (i) both methods of shared-reading improved the participants’ narratives in terms of productivity, number of different words, and the efficiency of references; (ii) only Intervention Programme I improved the participants’ narratives in terms of the percentage meta-verbs, number of key elements and Goal-Attempt-Outcome sequences included. Clinical implications and recommendations for future research are discussed. / AFRIKAANSE OPSOMMING: Hierdie studie het die effek van twee gedeelde-leesintervensieprogramme op die narratiewe van 87 Afrikaanssprekende Graad R-leerders vanuit lae-inkomstegesinne ondersoek. Intervensieprogram I het ‘n interaktiewe styl behels, waartydens deelnemers aangemoedig is om spontaan aan gesprekke deel te neem oor die karakters se motiverings en doelwitte, afleidings oor die stories te maak en vrae te vra. Intervensieprogram II het op die waarneembare feite en inhoud van die storieboeke gefokus. Deelnemers se narratiewe is voor en na afloop van die intervensie ten opsigte van produktiwiteit, inhoud en struktuur vergelyk. Resultate het aangedui dat (i) beide metodes van gedeelde-lees die deelnemers se narratiewe ten opsigte van produktiwiteit, totale aantal verskillende woorde, en doeltreffendheid van verwysings verbeter het; (ii) slegs Intervensieprogram I daarin geslaag het om deelnemers se insluiting van die persentasie meta-werkwoorde, aantal sleutelelemente en Doel-Poging-Uitkomsreekse in hul narratiewe te verbeter. Kliniese implikasies en aanbevelings vir toekomstige navorsing word bespreek.

Thesis (M Speech Path)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: This study investigated: (1) the effect of two visual modalities (wordless picture book and animated video) on the narratives of typically developing 9 year old children, and (2) the effect of dynamic assessment on the quality of narratives in both visual modalities. Twenty nine typically developing children between the ages of 8 years 5 months, and 9 years 4 months were selected from a higher socio-economic population. Participants were exposed to a wordless picture book and an animated video. Participants’ narrative performance was measured in terms of micro- and macro-structure variables in each visual modality, and before and after dynamic assessment in each visual modality. Micro-structure variables included productivity (total number of words, total number of T-units), syntactic complexity (mean length of T-unit) and lexical diversity measures (total number of different words). Macrostructure variables included goal-attempt-outcome (GAO) sequences, and inclusion of GAO elements (goal, attempt or outcome). Results indicated that: (i) both visual modalities elicited narratives of similar quality in terms of micro- and macro-structure variables, and (ii) participants’ narratives improved after dynamic assessment. / AFRIKAANSE OPSOMMING: Hierdie studie het (1) die effek van twee visuele modaleite (‘n woordlose prentboek en animasie video) op die narratiewe van tipiese ontwikkelende 9 jarige kinders bestudeer, asook (2) die effek van dinamiese assessering op die kwaliteit van narratiewe in beide visuele modaliteite. Nege-en-twintig tipiese ontwikkelende kinders tussen die ouderdom van 8 jaar 5 maande, en 9 jaar 4 maande is vanuit ‘n hoër sosio-ekonomiese populasie geselekteer. Deelnemers is blootgestel aan ‘n woordlose prentboek en ‘n animasie video. Deelnemers se narratiefvaardighede ten opsigte van mikro- and makro-struktuur veranderlikes in elke visuele modaliteit, asook voor en na dinamiese assessering in elke visuele modaliteit is gemeet. Mikro-struktuur veranderlikes het gefokus op produktiwiteit (totale aantal woorde, totale aantal Teenhede), sintaktiese kompleksiteit (gemiddelde lengte van T-eenheid) and leksikale diversiteit (totale aantal verskillende woorde). Makro-struktuur veranderlikes het gefokus op doelwit-poging-uitkoms (DPU) strukture, en die insluiting van DPU elemente (doelwit, poging of uitkoms). Die resultate het aangedui dat: (i) beide visuele modaliteite narratiewe van soortgelyke kwaliteit in terme van mikro- en makro-sruktuur veranderlikes ontlok het, en (ii) dat deelnemers se narratiewe verbeter het na dinamiese assessering.

Thesis (MPhill)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Compulsory Community Service for the speech-language and hearing therapy profession was implemented in 2003. This is the first study to assess the perceptions, attitudes and experiences of speech-language and hearing professionals of Stellenbosch University doing Compulsory Community Service. Information on the experiences of Compulsory Community Service professionals inform on the responsibilities of the university where undergraduate studies are completed, the Department of Health (the employer) and professionals doing Community Service. A mixed method study design, using a scale questionnaire, supplemented by open-ended questions was completed by all but one of the group doing Compulsory Community Service in 2009. Results suggested that speechlanguage and hearing therapists perceived themselves to have the required knowledge, but not necessarily adequate skills to perform Compulsory Community Service. Suggestions to include additional curriculum content were made. All professionals agreed that a positive contribution was made during Compulsory Community Service, but concerns about the shortage of speech-language and hearing therapy services, absence of mentors and supervision, inadequate budgets, amenities and resources were identified. Readjustment must involve adaptation from all stakeholders to ensure that Compulsory Community Service honours its original objectives.

Studies of speech perception indicate that it is more difficult for people with and without hearing loss to detect speech in noise. Functional communication in noise, however, has been less often studied; there is currently no well-designed measure of communication effectiveness. The Diapix Task (Baker & Hazan, 2011) has potential; it elicits dialogue by having two people converse to find differences between two pictures. The purpose of the present study was to develop a reliable measure of communication effectiveness and use this measure to determine how noise influences communication. Experiment 1 investigated use of the Diapix Task as a measure of communication effectiveness in noise. Seven young adults with normal hearing, paired with an assistant, completed the Task with three different picture pairs in a sound field of cafeteria noise. Communication effectiveness was measured by counting communication breakdowns. Results indicated that the Task did elicit breakdowns and, out of nine picture pairs, one elicited a different amount of breakdowns than the others; this pair was excluded. Experiment 2 used the Diapix Task to measure communication effectiveness in quiet and different types of noise. Relation between self-reported use of communication strategies and communication effectiveness was also explored. Fourteen young adults with normal hearing completed the Diapix Task with an assistant in three conditions: quiet, cafeteria noise, and competing dialogue. Results indicated that significantly more breakdowns occurred in noise than quiet, but that there was no significant difference between types of noise. Additionally, self-reported use of communication strategies did not correlate with communication effectiveness. Results support use of the Diapix Task as a functional measure of communication effectiveness in young adults with normal hearing; future research should investigate use of the Diapix Task to measure communication effectiveness in clinical populations.

The brain's neural responses to words of different frequencies provide information on lexical organization and the cognitive processes involved in word identification and retrieval of meaning. Monolingual research has shown that exposure to high frequency words yields less cognitive difficulty than low frequency words as demonstrated by smaller N400 waves within even-related potential (ERP) methodology. The purpose of the present study was to compare frequency effects in adult native (L1) and non-native (L2) speakers of English during a sentence reading task embedded with high and low frequency word-pairs. Both L1 and L2 groups produced N400 waves of larger amplitudes for high frequency words compared to low frequency words that peaked around the 400 ms time mark. Group comparison found no significant difference in N400 wave amplitude and peak latency between both groups. The results are discussed with respect to theories of L2 word learning and lexical organization.

One of the fundamental challenges for communication by speech is the variability in speech production/acoustics. Talkers vary in the size and shape of their vocal tract, in dialect, and in speaking mannerisms. These differences all impact the acoustic output. Despite this lack of invariance in the acoustic signal, listeners can correctly perceive the speech of many different talkers. This ability to adapt one's perception to the particular acoustic structure of a talker has been investigated for over fifty years. The prevailing explanation for this phenomenon is that listeners construct talker-specific representations that can serve as referents for subsequent speech sounds. Specifically, it is thought that listeners may either be creating mappings between acoustics and phonemes or extracting the vocal tract anatomy and shape for each individual talker. This research focuses on an alternative explanation. A separate line of work has demonstrated that much of the variance between talkers' productions can be captured in their neutral vocal tract shape (that is, the average shape of their vocal tract across multiple vowel productions). The current model tested is that listeners compute an average spectrum (long term average spectrum - LTAS) of a talker's speech and use it as a referent. If this LTAS resembles the acoustic output of the neutral vocal tract shape - the neutral vowel - then it could accommodate some of the talker based variability. The LTAS model results in four main hypotheses: 1) during carrier phrases, listeners compute an LTAS for the talker; 2) this LTAS resembles the spectrum of the neutral vowel; 3) listeners represent subsequent targets relative to this LTAS referent; 4) such a representation reduces talker-specific acoustic variability. The goal of this project was to further develop and test the predictions arising from these hypotheses. Results suggest that the LTAS model needs to be further investigated, as the simple model proposed does not explain the effects found across all studies.

Dosage has been identified as important element of intervention that has the potential to affect intervention efficacy. The purpose of this study was to examine the role of dose schedule for treatment of grammatical morphology deficits in children with Specific Language Impairment (SLI). Sixteen 4-5 year old children with SLI participated in a 6-week intervention program during which children received equivalent daily Enhanced Conversational Recast treatment targeting grammatical morpheme errors. Half of the children received treatment in one 30-minute session (massed condition). The other half received treatment in three 10-minutes sessions (spaced condition) over a 3-hour period. Progress was assessed three times weekly by probing a child’s use of his/her treatment morpheme and untreated morpheme (a maturational control) in untreated contexts. Pre-to-post treatment morpheme usage differed significantly for children regardless of dosage condition, demonstrating overall treatment efficacy. There were no differences in treatment effects for the massed and spaced conditions. In addition, nonverbal IQ and receptive vocabulary test scores correlated with treatment effect sizes. The study adds to evidence that Enhanced Conversational Recast can produce positive results, in a relatively short period of time, for children with specific language impairment. Moreover, it appears that clinicians may have some flexibility in terms of the dose schedule they employ to deliver this treatment in an evidence-based manner.