Thesis (B.Sc)--University of Hong Kong, 2001. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences). The University of Hong Kong, May 4, 2001." Also available in print.

Thesis (B.Sc)--University of Hong Kong, 2001. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, 4 May 2001." Also available in print.

Thesis (B.Sc)--University of Hong Kong, 1992. / A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), University of Hong Kong, April 30, 1992. Also available in print.

Thesis (B.Sc)--University of Hong Kong, 1992. / A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), University of Hong Kong, April 30, 1992. Also available in print.

Thesis (Ph.D.)--Brown University, 2005. / Vita. Thesis advisor: Julie Sedivy. Includes bibliographical references (leaves 167-178). Also available online.

Thesis (M.S.) -- Boston University. / BACKGROUND: The continual increase in the number of bi/multilingual aphasic patients has given rise to the question of efficacy of treatment across languages. One question at the forefront of current research is the extent to which language control interacts with cross-language facilitation treatment in these patients. Theories of bilingual language processing suggest that there exists bidirectional and asymmetrical relationships between the two lexicons (e.g., Revised Hierarchical Model, Kroll et al., 2010). Such a model allows for the prediction of cross-language generalization resulting in improved facilitation of translations and semantically related translations, a finding observed in treatment studies of rehabilitation of bilingual aphasia (Edmonds & Kiran, 2006; Kiran & Roberts, 2010). Recent studies examining the nature of bilingual language processing and lexical access, however, have hypothesized that cognitive-linguistic control plays a central role in selecting language representations. The neurocognitive model of language control, proposed by Green and Abutalebi (2007), states that the interplay between cortical (e.g., pre-frontal cortex, anterior cingulate cortex) and sub cortical regions (e.g., basal ganglia) sustains the intensive cognitive demand of managing two languages. This neural circuit regulates such tasks as appropriate language selection and language switching that allows for inhibition of potential cross-linguistic competitors during language production (Luk et al., 2011). Recent studies of bilingual aphasia have begun to provide evidence for impaired language/cognitive control and interference (e.g., Goral et al; 2006; Green et al., 2010). AIMS: In order to better understand the potential for cross-linguistic generalization and interference in multilingual aphasic patients, this current case study follows a trilingual woman with aphasia through two periods of rehabilitation. Several research questions are posed: (1) Does training in the weaker language (French) result in generalization to semantically related items in the target language as well as trained and untrained items in the stronger language (English); (2) Does a second period of treatment in the stronger language (English) reveal differences in treatment gains and/or in crosslinguistic generalization patterns; and (3) What is the effect of cognitive control on cross-linguistic generalization during rehabilitation of lexical access? METHODS AND PROCEDURES: The participant was a 59-year-old trilingual woman (Amharic, L1-English, L2-French, L3) who presented with a fluent aphasia secondary to left frontal tumor resection in 2008. Post-surgery CT and MRI revealed a left frontal infarct over the pre-central gyrus with extension into the basal ganglia. A detailed language use questionnaire was used to obtain information regarding the patient’s language use for each of the three languages. A single subject case study design was implemented following procedures previously developed in Edmonds & Kiran (2006) and Kiran & Roberts (2009). Following an assessment of the patient’s current language and cognitive abilities, the patient completed a 10-week treatment period in French, followed by a 10- week treatment period in English. RESULTS: Results demonstrated overall improvement on trained items in the target language across treatment periods in both languages. Within-language generalization to semantically related items and cross-linguistic generalization to translations of trained and semantically related items were not observed. In addition, error patterns revealed a considerable increase of interference of the treatment language into the non-treatment language on trained items relative to the respective treatment phase. Although the patient did show learning of new items (as evidenced by an increase in conceptual scores), as treatment progressed in one language, the patient’s ability to inhibit this language during non-treatment language probes decreased substantially. In addition, a non-linguistic flanker task targeting interference suppression demonstrated impaired non-linguistic cognitive control. Evidence from this case study suggests that facilitation may sometimes be overridden by language interference and provides support for the model of neurocognitive language control.

Aphasia can severely impact an individual’s ability to communicate. However, existing research on interventions is limited. The current study compared different stimulus fading procedures with an older adult diagnosed with aphasia. A multielement within a multiple baseline design across behaviors was used to measure the efficacy of each approach. Results showed that the time delay procedure was more efficient at fading prompts when teaching intraverbals.

People with aphasia (PWA) frequently present with nonlinguistic deficits, in addition to their compromised language abilities, which may contribute to their problems with reading comprehension. Treatment of attention, working memory and executive control may elicit reading comprehension improvements in PWA, particularly those with mild reading problems. This study evaluated the efficacy of Attention Process Training-3 (APT-3), an intervention combining direct attention training and metacognitive facilitation, for improving reading comprehension in individuals with mild aphasia and concomitant reading comprehension difficulties. A multiple-baseline design across six participants was used to evaluate treatment effects. The primary outcome measure was a maze reading task. Pre- and post-treatment evaluation included cognitive and reading measures. Semi-structured interviews were conducted to evaluate participant-perceived changes in cognition and reading. Visual inspection of graphed maze reading performance data indicated a basic effect between APT-3 and improved maze reading for three of the six participants. Quantitative analyses, using Tau-U, corroborated findings identified through visual analysis. The results suggest that the use of APT-3 has the potential to improve reading in PWA but that it may be more efficacious under certain conditions. Treatment and participant variables, including intensity of treatment and metacognitive strategy usage, are discussed as potential influences on participants' responsiveness to APT-3.

The role of white matter pathways in language networks has received much attention inrecent years. This is largely due to advances in diffusion imaging techniques, which haveenabled exploration of white matter properties in vivo. The emergent model from suchwork proposes that language processing is underpinned by a dorsal and a ventral pathwayconnecting anterior and posterior regions involved in language. This thesis aimed toexplore whether consideration of white matter measures could aid understanding ofperformance profiles in chronic stroke aphasia. To this end, a group of participants withchronic stroke aphasia were recruited and their performance on a large battery oflanguage assessments was related to their neuroimaging data. The neuroimaging datacomprised high resolution T1-weighted structural scans, fractional anisotropy (FA) maps,and data generated using a tractography-based technique called Anatomical ConnectivityMapping (ACM) which provides an index of long-range connectivity that has not yetbeen applied to chronic stroke aphasia.Chapter 3 established, in a small series of case examples, that connectivityinformation from ACM can help explain variations in performance in chronic strokeaphasia. Chapter 4 extended this work to a larger group of participants. Differencesbetween aphasic participants and controls, and between groups with different aphasicsubtypes and controls, were calculated and compared across imaging methods. ACMoffered insights into connectivity differences that were complementary to informationfrom T1-weighted and FA data. In addition to revealing areas where connectivity wasreduced relative to controls, ACM revealed an increase in connectivity in the righthemisphere dorsal route homologue of aphasic participants.Chapter 5 aimed to improve our ability to capture aphasic performance and torelate it to neuroimaging data. Principal components analysis (PCA) was used to derivefactors underlying performance on the language battery. Phonological, semantic, andcognitive factors emerged from the PCA and participants’ factor scores were used ascontinuous regressors in a voxel-level analysis of their T1-weighted images. Regions thatemerged as significantly related to language abilities aligned with those found usingother methodologies. Chapter 6 brought together work from the previous chapters byrelating PCA-derived factor scores to FA maps and ACM, in order to assess therelationship between behavioural performance and the status of key white matterpathways. In line with recent characterisations of the dual route system, phonologicalperformance related to dorsal route measures and semantic performance related to ventralroute measures. Better cognitive performance was found to relate to increasedconnectivity relative to controls in the right frontal lobe. Overall these results suggest thatconsideration of white matter abnormalities, both reductions and increases, can helpexplain patterns of performance in chronic stroke aphasia and that ACM can be a usefulsource of such information given its sensitivity to connectivity remote from the lesion.These findings both provide hypotheses for future research and could be used to informtherapeutic interventions.

The purpose of this study was to investigate the effects of semantic associational strength (SAS) upon adult aphasics' auditory comprehension abilities. Twenty-eight adult aphasics (25 males and 3 females) and 12 normal control subjects were presented three experimental tasks, each containing 45 items. Experimental task 1 contained single word picture sets of high SAS, moderate SAS, and low SAS words. Experimental task 2 contained two word picture sets of high, moderate, and low SAS words, and experimental task 3 contained three word picture sets of high, moderate, and low SAS words. Subjects heard one, two, and three word verbal sequences for experimental tasks 1, 2, and 3, respectively, and pointed to the appropriate picture sequence. Level of SAS was determined on the basis of the two most frequently occurring word associations of 50 normal individuals to 195 words selected from the most frequently occurring 3,000 English words. The findings in this study revealed that aphasics had substantially more difficulty auditorily selecting picture sequences of high SAS words than sequences of moderate and low SAS words, and more difficulty auditorily selecting picture sequences of moderate SAS words than sequences of low SAS words. Results further indicated that, irrespective of degree of SAS between words, aphasics' retentional ability was adversely influenced by an increase in verbal sequence length. The presence of a significant interaction between the SAS and length factors negated the support for an interaction hypothesis that degree of SAS would differentially affect aphasics' comprehension as message length increased. Aphasics' performance on the experimental task was highly related to their overall communicative ability as assessed by the Porch Index of Communicative Ability.