The Nature of Acquired Dysgraphia

300 Pages·2015·3.25 MB·English

The Nature of Acquired Dysgraphia:
Patterns of Impairment and Rehabilitation

Janna Geertruida (Trudy) Krajenbrink

A thesis submitted in fulfillment of the requirements for the degree of

Doctor of Philosophy

ARC Centre of Excellence in Cognition and its Disorders (CCD)
Department of Cognitive Science
Macquarie University, Sydney, Australia

April, 2015
Declaration

The work in this thesis is my own original work. It has not been submitted for a higher
degree in any other university or institution. All of the work reported in this thesis was
undertaken during the time I was enrolled as a PhD student at Macquarie University,
under the supervision of Prof Lyndsey Nickels and Dr Saskia Kohnen. Ethics approval for
the studies reported in this thesis was obtained from Macquarie University’s Human
Research Ethics Committee, Reference No. 5201200905.

Signed:

Trudy Krajenbrink
10 April 2015

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Table of Contents
Title Page i
Declaration ii
Table of Contents iii
Acknowledgements v
General Summary ix

GENERAL INTRODUCTION 1
STUDY ONE 17
Graphemic Output Buffer Impairment with Fragment Errors: a Case of
Rapid Decay of Activation from the Buffer
Abstract 18
Introduction 19
Case Report 27
Writing to Dictation: Comprehensive Analysis 42
Fragment errors 60
Discussion 76
Conclusion 83
References 84
Appendix A 89
Appendix B 90
Appendix C 91
Appendix D 92
Appendix E 93
STUDY TWO 95
Patterns of Sub-Lexical Impairment in Aphasia
Abstract 96
Introduction 97
Participants 104
Tests 107
Results 109
Overview of sub-lexical spelling performance: Controls and PWA 109
Detailed analysis of PGC spelling in people with aphasia 116
Effects of context on sub-lexical spelling 125
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Discussion 129
Conclusion 133
References 134
Appendix A 136
Appendix B 137
STUDY THREE 139
Generalisation after Treatment of Acquired Spelling Impairments: A
review
Abstract 140
Introduction 141
Generalisation Effects: a Review of Treatment Studies 152
Discussion 191
Future Directions 197
Conclusion 199
References 201
STUDY FOUR 211
The Effect of Orthographic Neighbourhood on Treatment of Acquired
Dysgraphia
Abstract 212
Introduction 213
Case Reports 222
Treatment Program 230
Results 237
Discussion 250
Conclusion 258
Acknowledgements 260
References 261
Appendix A 267
Appendix B 269
Appendix C 271
Appendix D 272
Appendix E 273
GENERAL DISCUSSION 275

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Acknowledgements
During the time of my PhD I could not have wished for better guidance. I would like to
express my deepest gratitude to Lyndsey Nickels, my primary supervisor, who
convinced me to come back to Macquarie to start a PhD, and to my second supervisor,
Saskia Kohnen. I have truly enjoyed learning from their wide range of expertise, and
have been inspired by their energy and enthusiasm for research. Thank you for being so
generous with your time and feedback, and for always reminding me to ask the right
questions.

Thank you to the directors from IDEALAB for their time and energy in setting up a
wonderful and valuable international collaboration: Prof Roelien Bastiaanse, Prof Ria de
Bleser, Prof David Howard, Prof Barbara Höhle, Prof Gabriele Miceli, and Prof Lyndsey
Nickels.

I would like to thank the participants in my research, in particular the people with
aphasia. I admire the enthusiasm and energy with which they performed many tasks,
that may have been challenging at times. In particular I would like to thank GEC and JOD
and their partners. I am thankful for their hard work during the many sessions, and I
have truly enjoyed the chats over tea and (many) biscuits. This research would not have
been possible without their ongoing enthusiasm and commitment.

The friendly and supportive environment at CCD (MACCS) have contributed to my
enthusiasm for research, and have made my time as a PhD student so wonderful. I would
like to thank Lesley, Katie, Teri, Marcus and Craig for helping out along the way.
Over the years colleagues became friends, and have made it such a nice place to work.
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In particular I would like to thank Anastasiya, Britta, Danielle, Huachen, Linda, Nathan,
Rochelle, Serje, Thushara, and Yvette.
Thank you also to my dear friends back home, showing that friendship can cover great
distances: Nienke, Laura, Martine, Vera, Rimke, Suzanne, Jeanine, Mariska and Rinie.

I have always felt greatly supported by my parents in my decision to start a PhD in
Australia for which I am grateful. Pap en mam – ik heb mij altijd zeer gesteund gevoeld in
mijn keuzes. Bedankt voor jullie brede interesse en het voortdurende vertrouwen in mijn
werk. Also many thanks to my brother Henk, and Anne, for their valuable support and
interest in my work. Finally, I am very grateful to Pete, for being so caring and
supportive, and for always making me laugh.

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This PhD has been carried out as part of the Erasmus Mundus joint
International Doctorate for Experimental
Approaches to Language and Brain
(IDEALAB)

Macquarie University (Australia)
University of Newcastle (UK)
University of Groningen (the Netherlands)
University of Potsdam (Germany)
University of Trento (Italy)

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General Summary
This thesis focuses on the processes involved in spelling, and in particular explores the
nature of impairment and rehabilitation of acquired dysgraphia, using a cognitive
neuropsychological approach. The first study investigates the spelling impairment of
GEC, a man with acquired dysgraphia. GEC showed characteristics of graphemic output
buffer impairment, together with lexical influences (e.g., frequency) on performance and
a large number of deletion errors of multiple letters (fragment errors). A detailed error
analysis provided evidence to support the hypothesis that fragment errors can be the
result of rapid decay of activation from the graphemic output buffer. The study also
concludes that lexical influences could be observed in graphemic output buffer
impairment due to cascading of activation.
The second study investigates the nature of acquired sub-lexical spelling
impairments. Data from spelling sounds in isolation and spelling non-words are
analysed to inform three issues: the relationship between performance on the two
spelling tasks, the effects of phoneme-grapheme consistency and frequency on spelling,
and the use of context when spelling a vowel in a non-word. Results indicated that
people with aphasia show comparable difficulty spelling single sounds and sounds in
initial position of the non-word. Furthermore, accuracy of individual PGCs was
influenced by frequency and consistency of the non-word. Finally, no evidence was
found for a loss context sensitive rules when spelling vowels.
The final two studies focus on rehabilitation of acquired dysgraphia. Study three
comprises a literature review on generalisation effects after treatment of acquired
dysgraphia. This study summarises 40 treatment studies, investigating the link between
type of impairment, method of treatment, and generalisation. Some treatment studies in
the literature have found an improvement in untreated items, however it is unclear
what predicts such generalisation of treatment effects.
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Study three highlights that a mechanism of interactive processing may play a role
in treatment and generalisation. The final study therefore investigates this mechanism
of interactivity within the spelling process in two treatment studies examining the role
of orthographic neighbourhood size on the effects of treatment and generalisation in
two individuals with acquired dysgraphia. Feedback between the orthographic lexicon
and the graphemic output buffer predicts a target word will activate orthographically
related words. However, while treatment improved spelling for treated items, there was
no generalisation and no evidence for effects of orthographic neighbourhood size on
treatment. It was hypothesised that severe impairment to the graphemic output buffer
reduced the feedback within the spelling system.
This thesis contributes to our understanding of the nature of spelling impairment
and rehabilitation. Furthermore, the thesis highlights the value of cognitive
neuropsychological methods in research of acquired dysgraphia.

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