Date of Award

2016

Degree Type

Thesis

Degree Name

Doctor of Philosophy

School

School of Medical and Health Sciences

First Advisor

Dr Natalie Ciccone

Second Advisor

Dr Sonya Girdler

Third Advisor

Dr Jenny Downs

Fourth Advisor

Dr Helen Leonard

Abstract

Background Rett syndrome is a neurodevelopmental disorder primarily caused by mutations in the X-linked methyl-Cp2G-binding protein 2 (MECP2) gene. The disorder affects approximately 1 in 9000 females and is usually associated with language, physical and intellectual impairments, each of which contributes to difficulties with communication. In Rett syndrome, eye gaze is considered a common form of communication and conventional methods, such as talking and gestures, less common. Females appear to use these forms of communication to serve a number of functions including choice making, requesting, social convention, bringing attention to themselves, and to reject, comment and answer. However, the literature is limited due to poorly described case inclusion criteria, the inclusion of cases without a diagnosis of Rett syndrome and small sample sizes. Furthermore, there is a paucity of research on the numerous barriers and facilitators to successful communication. Therefore the aim of this research was to describe the performance of communication tasks in girls and women with Rett syndrome and to investigate factors that are positively and negatively associated with performance.

Methods Qualitative and quantitative methods were used to understand the communication performance of girls and women with Rett syndrome and the impairments of body function and structure, activity limitations and contextual factors that influence these. The International Classification of Functioning Disability and Health - Child and Youth Version (ICF-CY) and The Communication Matrix were used as the theoretical framework throughout the research. This thesis includes four studies of which the first employed interviews with caregivers, the second and third used caregiver questionnaire data and the final utilised video data of girls and women engaged in a communicative interaction. Data were used to describe the use of specific communication modalities such as eye gaze, gestures and speech, and communicative functions including the ability to make requests and choices. Relationships between the performance of these communication tasks and factors including MECP2 mutation type, age and level of motor abilities were investigated.

Results During interviews all parents reported their daughters were able to express discomfort and pleasure, and make requests and choices using a variety of modalities including body movements and eye gaze. They also reported level of functional abilities and environmental factors influenced communication performance. Questionnaire data on speech-language abilities showed 89% (685/766) acquired speech-language abilities in the form of babble or words at some point in time. Of those who acquired babble or words, 85% (581/685) experienced a regression in these abilities. Those with a p.Arg133Cys mutation were the most likely to use one or more words, prior to (RRR=3.45; 95% CI 1.15-10.41) and after (RRR=5.99; 95% CI 2.00-17.92) speech-language regression. Australian questionnaire data (n=151) found women aged 19 years or older had the lowest scores for eye gaze. Females with better gross motor abilities had higher scores for the use of eye gaze and gestures. The use of eye gaze did not vary across mutation groups, but those with a C-terminal deletion had the highest scores for use of gestures. The video study found 82.8% (53/64) of the sample made a choice, most using eye gaze. Of those who made a choice, 50% did so within 8 seconds.

Conclusions In using qualitative and quantitative methods, and the ICF-CY and The Communication Matrix as the theoretical framework, this thesis was able to provide new insight into the way in which females with Rett syndrome communicate while considering the influence of impairments of body function and structure, activity limitations and contextual factors. We found that females with Rett syndrome share communicative strengths including the use of eye gaze and the ability to make choices. Multidisciplinary assessment of communication abilities, considering the range of factors identified to impact communication, and using multiple sources of information, will likely result in a more accurate assessment of the communication abilities of girls and women with Rett syndrome. Interventions should target communicative strengths, such as the use of eye gaze, and factors shown to impact communication, including the skills of communication partners. Reporting and accounting for genetic information in future research would help improve our understanding of the relationship between MECP2 and communication abilities, which may in turn improve our knowledge of the role MECP2 plays in neurodevelopment.

Available for download on Saturday, December 01, 2018

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