EEG handbook

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Electroencephalography and Clinical Neurophysiotogy Elsevier Publishing Company, A m s t e r d a m - Printed in The Netherlands

BOOK

REVIEWS

Edited by H . PETSCrm and JOHN R. HUGHES

EEG handbook. - - R. Hess. 1966, 148 p.).

(Sandoz Ltd., Hanover, N.J.,

This reviewer first had the pleasure of seeing this book in 1964 in its German edition. Despite the difficulty encountered with translation of the German text, the predominantly atlas character of the work nevertheless permitted a good understanding of the more than 100 figures illustrating a considerable range of EEG phenomena. The present very readable English translation lets one appreciate the eminently sensible approach to clinical EEG as outlined briefly in the preliminary sections and the value of the effort as a teaching collection. The original title of EEGFibel, in the sense of a primer, more accurately indicates the introductory character than does the word "handbook". The book is, in fact, an excellent choice for the serious beginner and a useful supplement to, for example, Clinical Electroencephalography by Kiloh and Osselton. The more extended discussion and range of material in the latter is complementary to the superior illustrations in the former. There is now a sufficient number of books on EEG to make such a comparison pertinent--and this applies equally to the courtesy prefatory remarks so commonly contributed by colleagues in related disciplines. Even more than the cautious optimism of Adrian in 1950 (Hill and Parr: Electroencephalography), and recently Roth (Kiloh and Osselton), do the words of the neurosurgeon Krayenbiihl deserve attention regarding "... the surprising difficulty experienced in conveying the (EEG) results to the physician for whom it is intended: all too often a diagnosis which is essentially correct fails to reach him in a form hecan understand." The problem is twofold. Although we can attempt to reduce the semantic confusion and ambiguity of our EEG reports we cannot reduce the referring physician's need for a better understanding of the elementary aspects of EEG. This book offers a ready means of gaining a considerable degree of such understanding. Because it is less didactic and more fundamental than the recent teaching effort of Laidlaw and Stanton (The EEG in clinical practice) and because the illustrations require more attention, it is at once more difficult and more rewarding to read. The brief section on Technical Background is really a non-technieal explanation of gain and filter controls. More informative is the illustration of sine-wave damping, although the 2-cycle signal fails to point up the value of a 1 sec time constant over one of 0.3 sec. The two pages devoted to "How to record an EEG" include, for the American reader, a refreshingly unemotional account of referential recording and the fictitious

indifferent electrode. The principles of bipolar recording and polarity identification are given with such a clear illustration of phase reversal that we now use it as a basic teaching lantern slide. Terminology is presented in the only sensible way, viz., with the definition supplemented by a clear illustration. These in turn are cross-referenced to more elaborate figures in the book, where they are dealt with in a clinical setting. It is instructive to find the normal adult waking record illustrated with something other than the "ideal" normal EEG. Six additional 12-channel samples show a considerable range of other normal records, an important concept for the non-specialist. These are followed by another seven examples of the EEG from age 1 month to 10 years. Normal sleep stages are similarly well illustrated. Although a different distribution and description of K complexes might be preferred, one welcomes the emphasis on oscitant theta activity in the child and vertex (normal) "spikes" in the adolescent. This section concludes with a brief discussion of activation by photic stimulation and hyperventilation, with generous slowing in the latter quite properly stated to be a normal physiologic effect. Most of the book is devoted to clinical EEG problems. Each includes a brief history, a statement of clinical and other findings, EEG features and a diagnostic or follow-up note. The EEG samples constitute the most valuable feature of the book, ranging from 8 to 16 channels, generally 12. With a photographic reduction of approximately 50%, the format of the book allows 17 sec of record per page, and a double page may include over 36 sec of record without the use of fold-outs. A full petit mal seizure discharge (Fig. 23) may thus be included to show the inevitable variability in such a pattern. The light paper binding makes for flexibility, with a fragility index no higher than that of expensive EEG volumes with hard covers; it is distributed gratis as a Sandoz Monograph. Because good EEG samples are the essence of a teaching text, further comment on these is warranted. The reader should not be put off by the rather poor contrast between black tracing and gray background; excellent detail (unsmoothed by retracing) is apparent on close observation. Although not stated, one suspects the equipment is Schwarzer, which would account for the absence of pen arc distortion. A further and most commendable feature of the illustrations is the invariable inclusion of not only the usual time and voltage calibrations but also of Ligh and low frequency filter settings. Remarkably, these latter parameters are rarely narrower than TC 0.3 and F 70. The slight discrepancy between ruled chart and seconds marker coordinates is similar to'that often seen in

Electroenceph. clin. Neurophysiol., 1968, 25:304-305

BOOK REVIEWS American instruments. Recording montages are clearly yet unobtrusively noted, derived (except for infants) from a system of 24 scalp electrodes shown diagrammatically but not otherwise specified as to location. This results in 3 A-P chains of 5 electrodes in each hemisphere and 3 transverse chains of 6 electrodes. Neither midline (Z) nor ear lobe leads are used; referential recording is to nose, chin or common average reference. "The electrodes are not so easy to attach as it may seem...". One third of the book is devoted to seizures, not only generalized and focal but also the "vast borderland of epilepsy" with or without EEG changes. Careful examination of the figures is instructive. The electrographic findings are given fair but not undue weight in the diagnostic evaluation. Presumably, not all would agree that the case illustrated on p. 62 is best described as one of "focal petit mal status". This reviewer's reservations about the value of the collective reference electrode technique are reinforced by the fact that even a sophisticated electroencephalographer has misinterpreted polarity on the preceding page. The best way to appreciate the section on suspected brain tumor is to assume the function of the electroencephalographer and evaluate independently each of the 23 patients presented. This can be done by first reviewing the history and findings, and then accepting the challenge posed by the very clear and apposite tracing. The reader's own interpretation can then be compared to the admirably succinct description in the text and the more general (and often enlightening) commentary on the probable significance of the EEG features for that patient. The follow-up data attest to the high quality of EEG work in the Kantonsspital of Zurich and reinforce the importance of good EEG technique and attention to even subtle alterations of normal "Grundaktivit/R". The brief treatment of head injuries is useful more by admonition than by demonstration of findings, although subdural hematoma is handled well here and in other parts of the book. Similarly, there are various examples of the usually non-diagnostic (non-specific) EEG changes in other disease states involving some alteration of CNS function. The author feels that EEG is not indispensable for the psychiatric hospital. It may have more value in outpatient practice, as illustrated by his case of a hysterical girl. The concluding section on artefacts, even with 18 figures, cannot be exhaustive but the explanations are of real value. How many readers, by ignoring the text, can identify the three genuine abnormalities? Any book must be judged in the light of its stated objective, in this instance to furnish the non-neurologically specialized physician with a handy reference against which he can evaluate the findings of the EEG laboratory. In Switzerland it is assumed that neurologists and psychiatrists have a working knowledge of EEG beyond what is presented in this book. In the United States, however, many an EEG report is signed by a record reader whose knowledge of EEG is considerably short of what is encompassed in this Fibel. By the range of material, the probable vs. the possible diagnostic alternatives, the attention to artefact, the well-illustrated grapho-elements and above all, the terse

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commentary on what is important in the tracing, this book achieves its high objective. CHARLES E. HENRY

The Cleveland Clinic Foundation, Cleveland, Ohio 44106 (U.S.A.) Electroenceph. clin. Neurophysiol., 1968, 25:304-305

The biology of dreaming. - - E. Hartmann. Springfield, IlL, 1967, 206 p., $9.75).

(C. C. Thomas,

The chance discovery, by Aserinsky and Kleitman in 1953, of a physiologically distinctive phase of sleep associated with dreaming has cleared a broad field of research which H a r t m a n n has now surveyed and parcelled with some of the spirit of a land speculator. His book covers the territory that has been mapped out in the past 15 years and constitutes a well-organized guide to the literature of the period; 568 of the 656 references date from 1954 or later. The clarity of the writing and the simplicity of the formulations render what is essentially an annotated bibliography a highly readable text. This result has been accomplished through an initial division of the phenomenology of sleep into two allegedly distinct states which are given new symbolic titles that tend to emphasize differences and obscure similarities, to reify rather than describe, and to establish proprietary claims rather than stimulate analytical investigation. Actually the central thesis that dreaming sleep is a third state of existence is original with Snyder. Hartmann warns the reader that he takes this position for heuristic purposes but he gives little attention to the price of this approach. Sleep is still so unitary a behavioral state as to demand at least an effort at unified description and theoretical analysis. And to ignore history is to risk repeating its mistakes: it seems to me that a new era of discovery is now over in sleep research and that the same theoretical and methodological problems that beset the investigation of the mechanism and function of sleep before 1953 are once again coming into focus. Only the complexity of the subject has increased. Further subdivision of the new "state" is efficiently if unsystematically achieved, as a summary of the chapter subjects indicates: phylogeny and ontogeny; peripheral and central physiology; deprivation effects; chemistry; biorhythmic aspects; psychiatric, medical, and psychosomatic implication; psychophysiological correlation; other related states; and functional questions. The scope of the work is this broad and, in 151 pages of text, admittedly superficial. Treatment of these subjects is extremely variable in breadth and depth. The clinical chapters, which together occupy almost half of the book (73 pages), are more complete and original than those dealing with animal research. Here the author is on sufficiently familiar ground to make informative and critical comments on methodology and interpretation of results, especially with respect to long-term descriptive and pharmacological studies as well as to review the literature. The center of the book consists of the chapters on

Electroenceph. clin. NeurophysioL, 1968, 25:305--306