The research for this dissertation focused on how children with Specific Language Impairment (SLI) use language in their interactions with peers. The study had three broad objectives: (1) to ascertain patterns of language use by the children with SLI in different contexts, (2) to evaluate the relationship of those patterns to difficulties in peer interaction reported in the literature, and (3) to explore the ramifications of groups composed uniquely of children with SLI for peer talk and peer interaction. / The participants were several children (mean age 4 years, 10 months) enrolled in a preschool language program designed specifically for children with SLI. These children were observed in a number of contexts over a period of several weeks. / The children with SLI were first observed in dyadic play with different conversational partners. Initiating and responding, communicative acts, and communication breakdowns were examined. Dyads composed of two children with SLI were more successful in some aspects of conversation, while mixed dyads, composed of one child with SLI and one with TLD, were more successful in others. The conversational behaviours of the children with SLI were, however, generally quite similar to their peers with TLD. / The same children with SLI were observed during recess and during free play in their classroom. There were no significant differences in interactional patterns across the two group play contexts. In both contexts, the children with SLI spent significantly more time in interactive activity than in solitary activity, and most of that interaction was verbal. They tended, even during recess when other interlocutors were available, to talk and interact among themselves, and there was evidence of stable friendships within the SLI group. / Snack, circle time, and pretend play sequences were also observed. A schema for the analysis of children's discourse was piloted. The analysis showed that the children with SLI used language for a variety of instrumental and interactional purposes, and did so in ways that were consistent with those reported in the literature for children with TLD. / The combined results indicated pragmatic strengths and successful peer interaction in this group of children with SLI. These results can be explained by characteristics of the children and of the program in which they were enrolled.

This thesis investigated the speech-gesture relationship of chronic adult stutterers in comparison to fluent controls based on previous work by McNeill (1979, 1986). Significant differences were found in the speech and gesture characteristics of the narratives of stutterers as compared to fluent controls on a cartoon retelling task. Stutterers produced fewer cartoon details in their speech and fewer meanings per gesture. As well, stutterers were unable to begin a representational gesture at the same moment as a stuttered disfluency resulting in the freezing of gestures or maintaining the hand at rest. A second experiment showed that stutterers were able to maintain and initiate non-communicative hand movements at the same moment as stuttering. Gesture did not replace speech during moments of stuttering even though manual movement during stuttering was possible. The results demonstrate the strength of the speech-gesture relationship and show that stuttering affects both modalities of expression.

The objective of this study was to investigate predictors of language growth within the context of parent-child interaction among preschoolers with autism spectrum disorders (ASDs) and typically developing (TYP) toddlers. Children with ASDs are known to have delays in play and language development. Previous research has demonstrated concurrent and predictive associations between play skills and language ability in children with ASDs and in TYP children. Parent verbal responsiveness, or the extent to which parents' verbalizations are contingent on their children's focus of attention, has also been linked to language development in young children. The present study used a longitudinal correlational design with 30 participants, 15 ASD and 15 TYP. Child play skills and parent verbal responsiveness were analysed. The groups did not differ on play abilities or on the extent to which parents' verbalizations were responsive to their children's attention. Symbolic play was associated with language ability at study outset in both groups, but play ability and parent responsiveness were not associated with language gain over the 1-year study. Methodological factors are discussed in the interpretation of these findings. / L'objectif de cette étude était d'analyser des variables impliquées lors du développement du langage dans un contexte d'interaction parent-enfant chez des enfants atteints du trouble du spectre de l'autisme (TSA) et avec un développement typique (DT). Des retards dans le développement du langage et du jeu sont répandus chez des enfants ayant des TSA. Des études antérieures ont démontré que les capacités de jeu peuvent prédire les habilités du langage chez les enfants ayant des TSA ou avec DT. La sensibilité verbale des parents, ou la tendance du parent de parler d'un objet sur lequel l'enfant concentre déjà son attention, est aussi associée au développement du langage chez des jeunes enfants. La présente étude a utilisé une méthodologie longitudinale et corrélationnelle chez 30 participants, dont 15 avec TSA et 15 avec DT. Les variables étudiées lors de cette étude étaient les suivantes : les capacités de jeu de l'enfant et la sensibilité verbale du parent. Aucune différence n'a été observée entre les deux groupes, que ce soit au niveau des capacités de jeu des enfants ou au niveau de la sensibilité verbale des parents. Le jeu symbolique a été associé au niveau du langage des enfants des deux groupes au début de l'étude. Cependant, ni les capacités de jeu ni la sensibilité verbale des parents n'ont été associées au développement du langage lors de l'année de l'étude. La méthodologie est abordée dans l'interprétation des résultats.

The present study was conducted to examine semantic and phonologically mediated priming in normal and brain-damaged populations. Non-fluent and fluent aphasic patients and age-matched control subjects performed an auditory lexical decision task in three separate experimental subtests: semantic priming (e.g., manner-way), minimally-distinct mediated priming (e.g., nanner-way), and maximally-distinct mediated priming (e.g., zanner-way). Consistent with expectations, the findings revealed semantic priming effects in all groups. Interestingly, contrary to predictions based on previous studies, both non-fluent and fluent aphasic patient groups demonstrated mediated priming in both the minimally-distinct and the maximally-distinct subtests that was comparable to mediated priming effects shown by the normal control subjects. The results are discussed in light of current hypotheses concerning the nature of lexical access impairments in brain-damaged individuals. In addition, implications for models of normal word recognition are considered.

The production of contrastive stress was studied in normal-hearing and severely and profoundly hearing-impaired children. A picture description task was used to elicit utterances. Contrastive stress was assigned by changing one element in the second and third pictures in sets of three pictures. Stress production was assessed perceptually and acoustically. The normal-hearing and the severely hearing-impaired children were judged to have consistently stressed the element that was changed in the pictures. Some of the profoundly hearing-impaired subjects were judged to have stressed the changed element more often than chance but some did not perform above chance. Acoustic measurements indicated that only the normal-hearing speakers significantly varied both duration and fundamental frequency when stressing words while some of the hearing-impaired children varied only duration. These findings were interpreted as indicating that profoundly hearing-impaired speakers had difficulty producing recognizable contrastive stress and showed deviations in the duration and fundamental frequency of their utterances.

The influence of bolus volume and viscosity on the distribution of anterior lingual force during the oral stage of swallowing was investigated using a new force transducer technology. The maximum force amplitudes from five normal adults were measured at anterior, right and left lateral tongue margins during ten volitional swallows of 5-, 10-, and 20-ml volumes of water, applesauce, and pudding. Results indicated significant increases in peak force amplitude as viscosity increased. Volume did not significantly influence maximum lingual force amplitudes. Individual subjects demonstrated consistent patterns of asymmetrical force distribution across the lingual margins tested. The results suggest bolus-specific properties influence the mechanics of oral stage lingual functioning. This finding has important clinical implications in the assessment and treatment of dysphagic individuals. Applications of the force transducer array in future research are addressed.

Two experiments were designed as a preliminary exploration of how stress is used by language-impaired children in the comprehension of spoken language. Response time was measured as subjects decided whether a probe word given immediately after a sentence had been present in the sentence. The results of the first experiment indicated that the probe latency technique was sensitive to the effects of word category (content versus function words) and word position on the response times of children with normal language in the kindergarten, first, third, and sixth grades. In the second experiment, the probe latency task was used to study the effects of stress in relation to word category, word position and sentence meaningfulness in a group of language-impaired children to whom control groups were matched for language ability and chronological age. The response times of the age-matched group were not affected by stress, word category or word position variations. The language-impaired and language matched groups responded to variations in stress and word category, and to sentence meaningfulness in similar ways. Response times to function words were increased significantly by the addition of stress. It was concluded that the absence of sensitivity to stress appears not to be a major causative factor of language impairment.

Remediation of phonological awareness (PA) deficits in preschool age children is essential to the prevention of delayed acquisition of reading abilities. The purpose of this research was to develop and assess the efficacy of a program to teach PA to preschool-aged children with delayed PA. Ten preschoolers with articulation disorders participated in 8 training sessions focusing on phonological awareness (PA) and phonemic perception. These children made significant improvements in their PA abilities such that their post-treatment PA test performance was not significantly poorer than that of normally developing children, but was significantly better than that of children with an articulation disorder who did not receive the PA training program. The clinical and theoretical implications of the results are discussed. Future research directions are proposed to confirm these results using an experimental design and to isolate the impact of phonemic perception on PA.

<p> The sequelae of brain injury often result in the need for life-long rehabilitation. Yet, patients in the United States often have limited opportunity to participate in a professional rehabilitation environment following their initial injury. This research investigates whether provision of a health literacy presentation on neuroplasticity and translational rehabilitation principles can contribute to increased internal Locus of Control (LoC) in rehabilitation participants. The researcher provided a 15 minute presentation to participants in two community brain injury groups. Results indicate an increase in the understanding of neuroplastic principles in two of three probes and in internal LoC in four of six probes. Clinical implications are discussed.</p>

Advances in Parkinson's disease research are uncovering a complex pathology that extends well beyond basal ganglia and dopamine-related structures, one that impacts sensory processing and sensorimotor integration as much as it does motor planning and execution, with implications for the functional consequences of the disorder. The current research project is motivated by evidence that perceptual, alongside classical motor deficits, may be ascribed to the clinical presentation of the hypokinetic dysarthria of Parkinson's disease. Three studies were conducted to assess the roles of auditory, somatosensory and sensorimotor integration processes involved in speakers' perception of the volume of their own speech. The combination of loudness magnitude estimation and masking of sensory feedback in the first two studies reveals differences in psychophysical loudness functions that suggest that speech loudness perception deficits in Parkinson's disease are the result of problems with the organization and integration of multi-sensory feedback due to inadequate motor planning. A third, electroencephalographic study supports this conclusion with evidence of atypical cortical event-related potentials among parkinsonian participants, indicating defective preparatory and corrective neural processes otherwise undetectable in the psychophysical experiments. Based on the findings from this series of experiments, the self-perception of speech intensity is attributed to motorically specified parameters of vocal effort. The interpretation of associated sensory feedback is determined by those parameters. The perceptual deficit associated with hypokinetic dysarthria is thus proposed to result directly from deficits in generating speech movements, with concomitant effects on the subsequent identification, organization and interpretation of reafferent information. / Les progrès de la recherche sur la maladie de Parkinson dévoilent une pathologie complexe qui s'étend bien au-delà des ganglions de la base et autres structures dopaminergiques, impacte les processus sensoriels et l'intégration sensorimotrice autant que la planification et l'exécution motrice, avec des implications pour les conséquences fonctionnelles de la maladie. Le projet de recherche actuel est motivé par l'observation que certains troubles perceptuels, parallèles aux troubles moteurs classiques, font partie de la présentation clinique de la dysarthrie hypokinétique de la maladie de Parkinson. Trois études ont été entreprises afin d'évaluer les rôles des processus auditifs, somatosensoriels, et d'intégration sensorimotrice impliqués dans l'auto-perception du volume de la voix. Les analyses d'estimation d'ampleur vocalique et de masquage de la rétroaction sensorielle des deux premières études révèlent des différences dans les fonctions psychophysiques du volume. Les résultats suggèrent que les déficits de la perception parkinsonienne sont une conséquence des problèmes d'organisation et d'intégration de la rétroaction multisensorielle reliée au mouvement. La troisième étude, électro-encéphalographique, renforce cette hypothèse en démontrant la présence de potentiels évoqués corticaux atypiques parmi les participants parkinsoniens qui sont associés à des déficiences dans les processus préparatoires et correctifs par ailleurs indétectables avec les expériences psychophysiques. D'après les résultats de cette série d'expériences, l'auto-perception du volume de la voix est attribuée à des paramètres d'effort vocal spécifiés au niveau moteur. L'interprétation de toute rétroaction sensorielle associée se détermine selon ces paramètres. Le déficit perceptuel lié à la dysarthrie hypokinétique peut ainsi être interprété comme l'effet direct de déficiences dans la génération des mouvements de la parole, agissant par la suite sur l'identification, l'organisation et l'interprétation subséquente des informations ré-afférentes.