Light and biological rhythms in man Edited by L. Wetterberg. 448 pp. Pergamon Press, 1993

Preparing a book on the topic "Dementia and normal aging" is always a risk and a challenge, for two reasons. First, at least some of the theories and experimental data selected for presentation may become obsolete already during the preparation of the book. Second, an enormous amount of information must be squeezed into relatively few pages, possibly neglecting several relevant articles and even excluding the work of brilliant scientists from the reference list. The Editors of this multi-authored book seem to have coped successfully with these difficulties by focusing on a specific problem, i.e. the relationship between normal aging and dementia, seen as a continuum by some authors and a dichotomy by others. Indeed most of the book is devoted to an analysis of this relationship and an evaluation-perhaps even a validation--of the hypothesis that dementia may be on a continuum with age-dependent changes. The first parts of the book offers useful historical surveys of the problem including old references, generally ignored in previous recent publications on the subject. Other chapters deal with present diagnostic and clinical problems and with brain imaging in demented patients. Yet others give a comprehensive and clear overview of the neuropathologic, neurochemical and genetic literature on dementia. The final part of the book deals with practical health-care and social policy issues. The main question as to whether changes seen in dementm relate to changes found m normal aging, and to what extent there is a continuum from normal aging to severe dementia through intermediate stages, ~s addressed in depth with clear and detailed contributions from a wide range of disciplines. In my opinion the only weak point of the book appears to be the lack of a chapter on electrophysiology and the neglect of the results of many extensive investigations on normal aging and dementia using EEG and evoked-potentials. Event-related responses are useful mdexes of information processing by the brain. Electrophysiological signs of normal aging can be minimal or absent, and a minority of demented patients may present a normal E EG. This could be an argument in favour of the continuum hypothesis. Moreover, the P300 response has been used by several authors for discriminating truedementia from pseudodementia. In the book, the EEG is discussed only in relation to sleep disturbances IP 282), and evoked potentials are only mentioned in passing (p. 356). The statement on p. 375 that the right hemisphere ages more rapidly than the left, based on performance on visuospatlal tasks, is contradicted by EEG studies. There are a few Inconsistencies in the use of Latin terms (e.g. locus caeruleus on pp. 49 and 51 becomes locus coeruleus on p. 65) and surely the correct Italian expression for "hurriedly baptized" is not "fretta battezzate" (p. 34), a mutilated sentence which should read "'troppo m fretta battezzate". However these minor imperfections do not detract from the generally good quality of the text. In summary, because of its many excellent chapters, updated references and cogent discussions the book should constitute a very informative and instructive reading for neurologists, psychiatrists, gerontologists and psychologists. It can also be of interest to geneticists and sociologists, and be recommended as a comprehensive reference on aging and dementia to nurses, medical students and general practitioners SALVATORE GIAQUINTO