BOOK REVIEWS 679

aphasia-paraphasia and jargon-are the topic of Chapter 19 written by Ryalls, Valdois and Lecours. Although reading and writing disorders are often associated with aphasia sometimes they can be the only symptom of a brain dysfunction. They are treated by Friedman (Acquired alexia, Chapter 20) and Bub and Chertkow (Agraphia, Chapter 21). The various forms of calculation breakdown are discussed in the last chapter, where the neuropsychology of the disorder is related to the major methodological and theoretical advances in the field of the models of normal number processing, (Grafman, Chapter 22). This part of the book is very comprehensive and the different aspects of language dysfunction are thoroughly discussed.

In this book the traditional and indispensable clinical approach to neuropsychology is coupled with the theoretical issues arising from the cognitive models of human brain functioning. It provides an important reference point to clinicians, researchers and students.

ANNA BEKTI

Subcortical Dementia. Edited by J. L. CUMMINGS. Oxford University Press, New York, 1990, 267 pp

THE CONCEPT of subcortical dementia is a relattvely recent one, since it was codified for contemporary analysis and dispute by Albert and coworkers in 1974. Since then the concept of subcortical dementia has become very popular and very controversial. This book tries to put together in a single source all the relevant information dealing with (and supporting) this controversial concept.

The term “subcortical dementia” refers to a pattern of neuropsychological impairment characterized by slowing of motor and cognitive functions, defective recall with better-preserved recognition, disorders of emotions and affects with apathy and depression and impairment of control and executive functions involving concept formation and the ability to shift mental sets. This pattern of neuropsychological impairment usually contrasts with a preservation of those instrumental cortical functions (namely language, praxis and perceptual recognition) which are typically impaired in focal cortical lesions or in cortical (Alzheimer’s type) dementia.

Features of subcortical dementia have been consistently described in v,arious extrapyramidal diseases (such as Huntington’s disease, Parkinson’s disease and Progressive supranuclear palsy) in vascular syndromes preferentially affecting the basal ganglia, thalamus and adjacent white matter, in metabolic disorders (such as Wilson’s disease and hypoparathyroidism) and in demyelinating diseases, such as the multiple sclerosis and the AIDS dementia complex. The results of all these investigations are clearly summarized in this book, which also provides a good survey of the neuroanatomical and of the neurochemical mechanisms which could subserve the subcortical dementia syndrome. We refer here in particular to the description of parallel neural circuits linking together definite parts of the frontal lobes, of the basal ganglia. of the thalamus and again of the frontal lobes and mediating distinct motor, cognitive and affective-emotional functions.

In spite of the controversies and objections addressed to the term “subcortical dementia”, I therefore agree with Cummings (who has carefully edited this book) in maintaining that this terminological shortcoming refers to an important area of clinical phenomena. which result from very different etiologies, but are unified by a number of basic pathophysiological mechanisms. A detailed analysis of these phenomena could therefore help to better understand these mechanisms.

Among the several important contributions to this book I have particularly appreciated the most general and the most basic ones, such as the Introduction by Cummings (who surveys the main theoretical and conceptual issues regarding subcortical dementia), the basicchapters by Domesick and Moore (who survey. respectively, the circuitry of the striatum and the chemical neuroanatomy of the non-thalamic subcortical&cortical projection\) and the concluding chapter by Cummings and Benson (who reconsider the subcortical mechanisms of human thought from the viewpoint of the contribution that they can give to general models of human mind).

In conclusion, this is an interesting book, which could be useful not only to pratictioners engaged in the evaluation and care of intellectually impaired patients. but also to neurologists, psychiatrists and neuropsychologists as well as to any other person interested to better understand the brain behaviour relationships.

G~IIIO GAINOTTI

Transient Global Amnesia and Related Disorders. By H. J. MAKKOWITSCH. Hogrefe and Huber, 1990

HANS MARKOWITKH has done an excellent job by bringing together a number of authorities on transient amnesic states. This has provided a valuable collection for anyone directly involved in research on this topic. As a reference source, especially to the non-English literature, it is unsurpassed. Unfortunately, the clinical chapters are the weakest. There is the feel ofa conference proceedings which lacks overall editorial direction. Having read this book, general readers will 1 feel be left with uncertainty as to what exactly constitutes transient global amnesia (TGA). The chapters dealing with the aetiology are contradictory. Caplan’s critical review of the diagnostic criteria for TGA is outstanding. He argues cogently why it is necessary to establish clear diagnostic guidelines and the need to exclude aberrant cases from the core syndrome. His overall conclusion, that there is no general evidence to support the

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widely-held belief that TGA has a cerebrovascular basis, fits with more recent epidemiological research, In the following chapters, other authors go over much of the same ground but draw different conclusions about the aetiology. Anyone unaware of the nuances of the subject would emerge bewildered and confused after reading these varying accounts.

One of the best aspects of the book are the chapters dealing with clinical topics related to TGA. Of these, the chapters by Trillet and co-workers are particularly valuable because they bring together data on the effects of benzodiazepines and other drugs on memory, cerebral blood flow, pharmacological challenge and atypical amnesic syndromes, all of which are not easy to find in any collected fashion elsewhere. The inclusion of a section of medico- legal aspects is also extremely useful. Kapur’s section on transient epileptic amnesia represents a significant contribution to the nosology of seizure disorders.

Moving on to the neuropsychological sections, their relatively small contribution to the overall book size sadly reflects the neglect of this area. Mazzucchi and Parma’s review of the psychological test data during TGA and on follow-up is scholarly, comprehensive and very readable. They conclude that there is now overwhelming evidence that anterograde memory for both verbal and non-verbal memory is profoundly impaired during TGA. As in patients with permanent amnesic syndromes, immediate (short-term) memory is preserved. Retrograde memory has been less thoroughly investigated but appears to be variably affected. They highlight the fact that non-declarative and semantic memory have not been systematically studied during TGA. They also review the question of residual memory impairment following attacks,

My principle criticism of the neuropsychological coverage is the failure to take a wider perspective. In particular, there is no attempt to consider the deficit in TGA in the context of continuing theoretical debates in amnesia research. TGA offers an almost unique opportunity to examine subjects whilst densely amnesic and again when recovered. Several key issues, such as the dissociability of anterograde and retrograde memory processes and the true status of the temporal retrograde memory gradient in amnesia, could be addressed by the study of patients in TGA. Also, there has been little attempt to link the clinical neurology and neuropsychological sections. The issue of what the neuropsychological deficits tell us about the pathogenesis and aetiology of TGA is barely touched upon.

The degree of referencing of the text is a bonus for the dedicated reader, but makes following the text extremely difficult. In some sections there are more references than intervening text.

In conclusion, this book serves as an excellent reference source for the specialist. The neuropsychological coverage is rather disappointing in its length and scope. For its price, I would recommend it to all behavioural neurologists. Neuropsychologists should persuade their local library to purchase a copy.

JOHN HOUGES