This page intentionally left blank Neuropsychological Neurology The Neurocognitive Impairments of Neurological Disorders Neuropsychological Neurology The Neurocognitive Impairments of Neurological Disorders A. J. Larner Consultant Neurologist, Cognitive Function Clinic, Walton Centre for Neurology and Neurosurgery, Liverpool, UK CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521717922 © A. J. Larner 2008 This publication is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2008 ISBN-13 978-0-511-45520-9 eBook (EBL) ISBN-13 978-0-521-71792-2 paperback Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Every effort has been made in preparing this publication to provide accurate and up-to-date information which is in accord with accepted standards and practice at the time of publication. Although case histories are drawn from actual cases, every effort has been made to disguise the identities of the individuals involved. Nevertheless, the authors, editors and publishers can make no warranties that the information contained herein is totally free from error, not least because clinical standards are constantly changing through research and regulation. The authors, editors and publishers therefore disclaim all liability for direct or consequential damages resulting from the use of material contained in this publication. Readers are strongly advised to pay careful attention to information provided by the manufacturer of any drugs or equipment that they plan to use. To Jo – because no one has dedicated a book to you before Disorders of intellect ... happen much more often than superficial observers will easily believe. Samuel Johnson, The History of Rasselas, Prince of Abyssinia (1759) Contents Acknowledgements page ix Introduction 1 1 Cognitive function, neuropsychological evaluation, and syndromes of cognitive impairment 6 1.1 Attention 8 1.2 General intelligence, IQ 10 1.3 Memory 11 1.4 Language 15 1.5 Perception 16 1.6 Praxis 19 1.7 Executive function, ‘frontal function’ 20 1.8 ‘Bedside’ neuropsychological test instruments 22 1.9 Normal aging 32 1.10 Dementia, delirium, depression 33 1.11 Cortical versus subcortical dementias, thalamic dementia 35 1.12 Disconnection syndromes 37 2 Neurodegenerative disorders 39 2.1 Alzheimer’s disease (AD) 40 2.2 Frontotemporal lobar degenerations (FTLD) 49 2.3 Motor neurone disease (MND), amyotrophic lateral sclerosis (ALS) 63 2.4 Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB) 69 vii viii Contents 2.5 Prion diseases 82 6.3 Sarcoidosis 165 2.6 Mild cognitive impairment (MCI) 87 6.4 Systemic lupus erythematosus (SLE) 166 3 Cerebrovascular disease: vascular 6.5 Sjo¨gren’s syndrome 168 dementia and vascular cognitive 6.6 Behc¸et’s disease 169 impairment 90 6.7 Rheumatoid arthritis (RhA) 170 3.1 Cortical vascular dementia, 6.8 Scleroderma, systemic sclerosis 170 multi-infarct dementia (MID), 6.9 Relapsing polychondritis 171 post-stroke dementia 93 6.10 Cerebral vasculitides 171 3.2 Subcortical vascular dementia, 6.11 Sydenham’s chorea, paediatric Binswanger’s disease, lacunar autoimmune neuropsychiatric state, subcortical ischaemic disorders associated with vascular disease (SIVD) 95 streptococcal infections 3.3 Strategic infarct dementia, (PANDAS) 173 strategic strokes 97 6.12 Limbic encephalitis 174 3.4 Subarachnoid haemorrhage (SAH) 101 6.13 Hashimoto’s encephalopathy 3.5 Intracranial vascular (HE) 176 malformations 104 6.14 Erdheim–Chester disease 176 3.6 Vasculopathies 106 6.15 Bilateral vestibulopathy 177 3.7 Other cerebrovascular disorders 112 7 Structural brain lesions 178 4 The epilepsies 115 7.1 Brain tumours and their treatment 178 4.1 Epilepsy and cognitive impairment 115 7.2 Hydrocephalic dementias 182 4.2 Cognitive decline and epilepsy: 7.3 Other structural lesions 186 shared aetiology 116 4.3 Seizures causing acquired 8 Endocrine, metabolic, and toxin-related cognitive impairment 120 disorders 188 4.4 Antiepileptic drug therapy 8.1 Endocrine disorders 188 causing cognitive impairment 122 8.2 Metabolic disorders 193 4.5 Treatment of cognitive problems 8.3 Toxin-related disorders 200 in epilepsy 123 9 Infective disorders 204 5 Neurogenetic disorders 125 9.1 Encephalitides and 5.1 Hereditary dementias 126 meningoencephalitides 205 5.2 Hereditary ataxias 135 9.2 Meningitides 209 5.3 Hereditary spastic paraplegia 140 9.3 Human immunodeficiency virus 5.4 Hereditary movement disorders 141 (HIV) and related conditions 210 5.5 Hereditary metabolic disorders 146 9.4 Other disorders of infective 5.6 Hereditary neurocutaneous aetiology 211 syndromes (phakomatoses) 155 10 Neuromuscular disorders 215 6 Inflammatory, immune-mediated, and 10.1 Myotonic dystrophy systemic disorders 157 (Steinert disease) 215 6.1 Multiple sclerosis (MS) 157 10.2 Myasthenia gravis (MG) 216 6.2 Acute disseminated encephalomyelitis (ADEM) 165 Index 218 Acknowledgements First and foremost I thank my wife Philippa, and children Thomas and Elizabeth, for their forbear- ance and moral support (perhaps involuntary) in allowing me to write another book. I thank the many colleagues with whom I have worked and from whom I have learned much: Mark Doran, Eric Ghadiali, Daniel du Plessis, and Pavla Hancock in Liverpool; Alex Leff, Jonathan Schott, Nick Fox, Angus Kennedy, John Janssen, Lisa Cipolotti, Gail Robinson, Richard Wise, and Martin Rossor in London; and John Hodges in Cambridge. I thank also the colleagues and friends who have offered advice on particular topics in this book: Rustam Al-Shahi, Alasdair Coles, Kalvinder Gahir, Desmond Kidd, Michael and Sally Mansfield, and Sivakumar Sathasivam. All errors or misconceptions which remain are entirely my own work. I shall be pleased to hear from readers who detect errors or omissions. ix Introduction The aim of this book is to review what is known There is a perception in some quarters that about the neuropsychological or neurocognitive neuropsychology is something rather separate from impairments which occur in neurological dis- clinical neurology. The case may perhaps be per- orders, and in some general medical conditions suasively made for academic cognitive neuro- which may be seen by neurologists. Such neuro- psychology, which aims to infer mental structure psychological deficits are of course relatively well from neuropsychological test performance, often in defined in those disorders which present with, or single case studies of highly unusual but instructive whose clinical features are largely restricted to, patients (Shallice, 1988; Ellis & Young, 1996), and cognitive impairment, specifically the dementia even ‘clinical’ neuropsychology texts (e.g. McCarthy syndromes, of both neurodegenerative and vascu- & Warrington, 1990; Groth-Marnat, 2001; Halligan lar aetiology, and these account for a fair propor- et al., 2003; Devinsky & D’Esposito, 2004) may con- tion of this book. However, cognitive dysfunction tain more than a practising clinician would require, may also occur in other neurological disorders, an or possibly desire. Nonetheless, clinical neurologists observation which may have implications for both neglect cognitive function at their peril. It should not clinical diagnosis and case management. Few texts be forgotten that cognitive neuroscience has neuro- have, to my knowledge, specifically addressed this logical foundations (D’Esposito 2003; Panegyres, area (e.g. Grant & Adams, 1996; Green, 2000; Harrison 2004). & Owen, 2002), and some only in passing. To be It is well recognized that the standard neuro- sure, there are a number of excellent texts which logical examination is focused predominantly on tackle the classical neuropsychological syndromes functions mediated by the parietal and occipital such as amnesia, aphasia, alexia, agraphia, apraxia, lobes, with frontal and temporal lobe functions agnosia, and executive dysfunction (e.g. Baddeley being relatively untested. Since, in the context of the et al., 1995; Benson & Ardila, 1996; Kirshner, 2002; clinical history, neurological signs help to focus on Heilman & Valenstein, 2003). The case-study the likely locale of pathology (Larner, 2006), it would approach to the neuropsychological features of seem desirable to be able to tap the functions of neurological disorders (e.g. Kapur, 1996; Ogden, these areas of the brain as well. 2005) has even spilled over into populist texts, but A neuropsychological examination provides the though such in-depth case studies are informative, opportunity to do this; such assessment permits a they may not immediately correspond to the case more fine-grained analysis of cognitive function, a mix seen by clinical neurologists. Textbooks of refinement which may have localizing and diag- neurology may mention dementia as a feature of nostic value. Just as one would not contemplate certain neurological diseases, often in a rather omitting the visual field examination or the plantar diffuse