Phonological Disruption in Progressive Aphasia and Alzheimer's Disease

272 Pages·2003·0.97 MB·English

Phonological Disruption in
Progressive Aphasia and
Alzheimer's Disease
Karen Philippa Croot
Corpus Christi College
Dissertation submitted for the degree of Doctor of Philosophy
University of Cambridge
May 1997
Declaration
This dissertation is result of my own work and includes nothing which is
the outcome of work done in collaboration. No part of it has been submitted for
any other degree or qualification.
Chapter 3 is based on the paper by Croot, K., Patterson, K. & Hodges, J. R. (in
press). Single word production in non-fluent progressive aphasia. Brain and
Language.
Chapter 4 is based on a manuscript submitted for publication by Croot, K.,
Patterson, K. and Hodges, J. R. Familial progressive aphasia: Insights into the
nature and deterioration of single word processing.
The results from M.T., V.B. and K.M. in the naming, repetition and picture-
name judgement experiments described in Chapter 6 are reported in Croot, K.,
Patterson, K. & Hodges, J. R. (1996) Phonological disruption in atypical Dementia
of the Alzheimer's Type. Brain and Cognition, 32, 186-190.
Acknowledgements
I would like to acknowledge the contribution of my supervisors, Karalyn
Patterson and John R. Hodges, to the development of this thesis: in planning the
experimental work, clarifying theoretical ideas, and providing detailed feedback
on my writing. Thank you: I could not have hoped for better supervision.
I would also like to express my deep appreciation for the involvement of all
the people with progressive aphasia or DAT who have taken part in this research
over the past three and a half years: A.S., F.M., L.M., P.G., D.B., R.S., V.B., N.K., P.B.,
J.G., J.M., K.M., M.T., S.W., R.G., R.B., C.B., G.D., C.M., Y.B., R.Sp., and H.K., and my
appreciation too for the support and assistance of their spouses and families.
This research was supported financially by a three year Cambridge
Commonwealth Trust Scholarship, a three month maintenance award from Corpus
Christi College, a three month award from the Lundgren Fund managed by the
Board of Graduate Studies, Cambridge University, and by generous supplements
from my parents, Maureen and Raymond Croot.
I thank the scientific and support staff at the Medical Research Council
Applied Psychology Unit for their commitment to training research students. In
particular, thanks to Andrew W. Young for suggesting the idea for Chapter 3:
Experiment 2, and to Ian Nimmo-Smith and Peter Watson for statistical advice I
would also like to thank Kim Graham, Paul Atkins and Elisabeth Hill for staunch
moral support and frequent practical assistance, and Sophie Scott and Sarah Ward
for useful discussion and practical help.
Further thanks are due to Naida Graham, Lindsay Stuart-Green, and Elaine
Giles for my training in neuropsychological testing, and, together with Sarah
Ross and Cheryl James, for carrying out most of the standardised general
neuropsychological testing which is reported in this thesis. Kristin Breen also
carried out some of the neuropsychological testing reported for R.B and C.B.
Thanks also to Karalyn Patterson, Kim Graham and Richard Perry for the use of
unpublished test materials, and to Catherine and David Rush for the gift of their
car.
Finally, thanks to my parents, family, and friends, in Australia, England,
and elsewhere, for their love and encouragement all the way. It was worth it!
Now to him who is able to do immeasurably more than all we ask or imagine,
according to his power that is at work within us, to him be glory in the church and in
Christ Jesus throughout all generations! Amen. Ephesians 3: 20-21.
Abstract
This thesis presents a cognitive neuropsychological investigation of
phonological disruption in a series of patients with neurodegenerative disease.
The first aim was to give a principled account of the patients' phonological
impairments with reference to models of speech production derived from the
study of normal populations and patients with non-progressive aetiology. The
second aim was to consider how data from the studies reported here may constrain
theories of normal phonological processing. There are three experimental
chapters in the thesis.
The first experimental chapter describes an investigation of the spoken
single word production of two patients with non-fluent progressive aphasia, P.G.
and L.M. Speech production was facilitated by phonological information available
from task stimuli and by a correspondence between input and output modality.
Access to phonology in reading was positively related to the degree of correlation
between orthographic and phonological forms. These results are consistent with
an account of pathologically weakened connections between nodes in an
interactive spreading activation model of speech production of the type described
by Dell (1986).
A longitudinal investigation of the language deficits of R.B. and C.B., two
brothers with primary progressive aphasia, is presented in the second
experimental chapter. Six experiments assessed word production and another
investigated receptive word processing. R.B. was less successful in naming than
C.B., and made more errors to semantically related distractors in the input task,
whereas C.B. was more impaired than R.B. in repetition tasks and in detecting
phonological distractors at input. Like the patients reported in the previous
chapter, both R.B. and C.B. had characteristics of weakened connections in the
Dell network, however, R.B. showed additional semantic-level deficits, and, over
time, C.B. developed pathologically rapid decay of activation within the network.
The final experimental chapter presents data from a group of patients with
either probable or autopsy-confirmed Alzheimer's Disease who, atypically,
showed striking phonological disruption. This disruption was evident in
spontaneous speech and single word production and reception, demonstrating
that phonological processing is not always preserved in DAT. It is concluded that
these DAT patients have impaired activation of phonological representations
from semantic specifications, as well as specific phonological processing deficits.
Table of Contents
Chapter 1
Review of Phonological Processing in Normal and Aphasic Speech Production
1
A Brief Note on Some Terminology 1
MODELS OF NORMAL SPEECH PRODUCTION 3
Data from Normal Speech Errors 3
Levelt's Model of Speech Production 5
Dell's Interactive Activation Model of Production 9
Discrete Stages or Interactive Activation? 11
PHONOLOGICAL DISRUPTION IN APHASIC SYNDROMES 12
The Historical Development of Aphasic Syndrome Classifications 13
Syndrome-Based Investigations of Phonological Breakdown 17
The Neuroanatomy of Phonological Processing in Aphasic Syndromes 21
COGNITIVE NEUROPSYCHOLOGICAL STUDIES OF PHONOLOGICAL
DISRUPTION IN SPEECH PRODUCTION 24
Descriptive Accounts 25
Accounts Using Dell's Interactive Activation Model 27
INVESTIGATING PHONOLOGICAL DISRUPTION IN NEURODEGENERATIVE
DISEASE 28
Chapter 2
Review of Non-fluent Progressive Aphasia 30
PROGRESSIVE APHASIC SYNDROMES 30
Historical Overview 30
Subtypes of Primary Progressive Aphasia 31
Nosological Issues in the Study of Fluent and Non-fluent Progressive
Aphasia 34
NON-FLUENT PROGRESSIVE APHASIA 37
Summary of Reported Cases 37
Age, Sex and Neuropathological Data 40
Associated Deficits 43
Profile on Neuropsychological Testing 45
Experimental Investigations of Non-fluent Progressive Aphasia 46
MIXED PROGRESSIVE APHASIA 47
CONCLUDING REMARKS 49
Chapter 3
Single Word Production in Non-fluent Progressive Aphasia 50
CASE DESCRIPTIONS 51
EXPERIMENT 1: SINGLE WORD PRODUCTION IN NAMING, REPETITION AND
READING 57
Method 58
Materials 58
Procedure 59
Scoring 59
Results 60
Production of Correct Responses 62
Production of Phonologically Related Responses 64
Increased Error Rate in Long Words: A Linear Function of
Opportunity? 68
Formal Paraphasias: Lexically Mediated? 70
The Severity of the Disruption to Phonological Production 72
Is the Disruption Phonological or Articulatory? 76
Discussion 78
EXPERIMENT 2: SINGLE WORD PRODUCTION IN WRITTEN VERSUS SPOKEN
MODALITIES 80
Materials, Procedure and Scoring 81
Results 82
Discussion 85
EXPERIMENT 3: READING ALOUD WORDS VARYING IN THE
PREDICTABILITY OF CORRESPONDENCE BETWEEN ORTHOGRAPHY
AND PHONOLOGY 87
Materials, Procedure and Scoring 88
Results 91
Discussion 93
GENERAL DISCUSSION 95
Chapter 4
Familial Progressive Aphasia: Insights into the Nature and Deterioration of
Single Word Processing 102
CASE DESCRIPTIONS 103
INVESTIGATION OF SINGLE WORD PRODUCTION 109
EXPERIMENT 1: NAMING, REPETITION AND READING 109
Materials and Procedure 110
Results 111
Production of Correct Responses 114
Production of Phonologically Related Responses 115
Rate of Word versus Nonword Errors 116
Discussion 117
EXPERIMENT 2: NAMING ITEMS WITH PHONOLOGICALLY SIMPLE NAMES 118
Materials and Procedure 119
Results 119
Discussion 121
EXPERIMENT 3: NAMING WITH PROGRESSIVE PHONEMIC CUEING 121
Materials and Procedure 122
Results 122
Discussion 124
EXPERIMENT 4: IMMEDIATE WORD REPETITION 125
Materials and Procedure 126
Results 126
Discussion 128
EXPERIMENT 5: DELAYED WORD REPETITION 129
Method and Hypotheses 129
Results and Discussion 130
EXPERIMENT 6: IMMEDIATE REPETITION OF TWO-WORD STRINGS 131
Method 132
Results 133
Discussion 135
DISCUSSION OF WORD PRODUCTION 136
INVESTIGATION OF RECEPTIVE WORD PROCESSING 138
EXPERIMENT 7: PICTURE-NAME JUDGEMENT 138
Procedure 138
Materials 140
Results 142
DISCUSSION OF RECEPTIVE WORD PROCESSING 144
GENERAL DISCUSSION 145
Chapter 5
Review of Phonological Processing Abilities in Dementia of the Alzheimer
Type 149
THE SOURCE OF THE "DOGMA": EVIDENCE SUGGESTING THAT PHONOLOGY
IS UNIMPAIRED IN DAT 151
Connected Speech 151
Naming 152
Articulation 152
Receptive Word Processing 153
Reviews 153
CHALLENGING THE "DOGMA": HINTS THAT PHONOLOGICAL PROCESSING
MAY BREAK DOWN IN DAT 154
Early Reports 154
Connected Speech 155
Word and Sentence Production Tasks 156
PHONOLOGICAL DISRUPTION IN HISTOLOGICALLY-CONFIRMED
ALZHEIMER'S DISEASE 158
Familial Alzheimer's Disease 158
Sporadic Alzheimer's Disease 158
Distribution of Pathology 160
SUMMARY 161
Chapter 6
An Investigation of Phonological Disruption in Atypical Dementia of the
Alzheimer Type
163
Two Accounts of Phonological Errors in DAT 163
Word-finding Deficits in DAT 166
The Present Study 166
CASE DESCRIPTIONS 167
ANALYSIS OF SPONTANEOUS SPEECH 175
Method 176
Samples of Conversational Speech 176
Error Categories 178
Results 180
Discussion 182
ANALYSIS OF SERIES SPEECH 183
Method and Results 184
Discussion 187
SINGLE WORD PRODUCTION 188
Method 189
Naming, Repetition and Reading: 9 Patients 189
Picture Naming: DAT Patients Compared with Elderly Controls 190
Results 192
Picture Naming: DAT Patients Compared with Elderly Controls 192
Naming, Repetition and Reading: 9 Patients 193
Longitudinal Testing on Naming, Repetition and Reading:
5 Patients 197
Naming and Reading Data from Previous Testing: 4 Patients 200
Discussion 204
RECEPTIVE WORD PROCESSING 206
Method 207
Results 208
Discussion 210
GENERAL DISCUSSION 211
Chapter 7
Conclusions and Implications for Future Research 215
ACCOUNTS OF PHONOLOGICAL DISRUPTION IN NEURODEGENERATIVE
DISEASE 216
Non-fluent Progressive Aphasia 216
Other Primary Progressive Aphasic Syndromes 217
Dementia of the Alzheimer Type 218
THEORIES OF NORMAL PHONOLOGICAL PROCESSING 220
Dell's Interactive Activation Model of Production 220
Generalisability of the Model 220
Some Limitations of the Model 220
Global versus Local Processing Deficits 221
Advantages of Processing Accounts 222
Applications of the Continuity Assumption 222
Models of Phonological and Articulatory Processing 223
Neuroanatomical Localisation of Phonological Processing 225
CONCLUDING REMARKS
References
226
Appendices 250
Appendix I 250
Appendix II 258
Appendix III 259
Appendix IV 260
Chapter 1
Review of Phonological Processing in
Normal and Aphasic Speech Production
This thesis presents a cognitive neuropsychological investigation of
phonological disruption in a series of patients with neurodegenerative disease.
The first aim of the thesis is to give a principled account of the patients'
phonological impairments with reference to models of normal speech production,
while the second, and complementary, aim is to consider how data from the studies
reported here may constrain theories of normal phonological processing. As a
background to the experimental work in the thesis, this first chapter reviews a
number of influential models of normal speech production, focusing on the
phonological and articulatory processes these models describe. The chapter also
reviews some of the models of speech production which have been developed to
account for the phonological and articulatory disruption occurring in aphasic
syndromes. Finally, the chapter discusses the rationale for studying phonological
breakdown in patients with progressive disease.
A Brief Note on Some Terminology
It is important to clarify the use of the term phonological in this thesis, as
it has both general and specialised usage (Oxford English Dictionary). In its more
general sense, the term refers to the sound properties of a language, with little
theoretical specificity about the nature of those sounds, except that they are a
distinct level of organisation compared with, for example, the syntactic or
semantic levels of language. In the clinical literature, the term is usually used in
this general sense, for example, to describe patients with "phonological
breakdown" or the quality of their speech, which contains "phonological errors".
The term phonological may also refer to systematically occurring
properties of language sounds which are used within a language to encode
linguistically contrastive information (Clark & Yallop, 1990) . For example, in the
minimal pair [kQt] — [kQd], the difference between the length of the vowel and
the voicing of the final consonant in the two members of the pair flags a
systematic difference in meaning in English. The differing sounds could thus be
described as functioning in a phonologically contrastive manner in that
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