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THE BERGER RHYTHM
96
THE BERGER RHYTHM
be possible to devise criteria which would leave unhampered any reputable practitioner of " " manipulative surgery while giving the public some guarantee against gross abuse ? We can think of none--certainly neither adherence to the osteopathic doctrine nor the assurance that the practitioner has passed through such a curriculum as that outlined on p. III would furnish satisfactory evidence of competence in the science and art of manipulative surgery. There are many branches of medicine in which the services of the skilful layman are valuable, and it would be wrong if any professional rule against " covering " were to prevent the full use of such services where a practitioner thought they might help his patient. But proposals whereby sick persons are encouraged to seek, in the first instance, the advice and treatment of the unqualified must be condemned, though protests from doctors will always be regarded askance. For to the public the reputation of the successful outlaw will always appeal, and medical criticism may be held as mere evidence of the trade-union spirit. If the public and Parliament-whether owing to their folly or our failureare tiring of common sense, and insist on fostering the conduct of medical work by men and women whose training is by modern standards incomplete, they are of course at perfect liberty so to do. But such a policy is as unsound in principle as we believe it would be damaging in practice.
THE BERGER RHYTHM SINCE 1924 Prof. BERGER of Jena has been making observations on certain changes in electrical potential in the human head, which he believed to come from the cerebral cortex ; their only constant feature is the occurrence of regular and comparatively large waves at the rate of about 10 per second. These variations have now been studied also by Prof. ADRIAN and Mr. MATTHEWS at Cambridge, and the reportof their work follows closely on their letter2 disclaiming credit for the original discovery. BERGER’S latest account3 of his conclusions appeared at the end of last year and a comparison of the two papers shows that ADRIAN and MATTHEWS have added not only confirmation but also precision to our knowledge. Using moistened electrodes placed on the surface of the scalp over the parted hair they obtained photographic records of potential variations from a Matthews’ oscillograph, and they are able to arrive at some very interesting conclusions. The Berger rhythm, they maintain, is due to the synchronous discharge of comparatively large numbers of neighbouring neurones in the occipital lobes of the brain, in a region concerned with pattern-vision This but probably not the area striata itself. and not is characteristic of the resting discharge of the functionally active condition of the neurones ; it is at its maximum when the eyes are closed, when the mind is at rest, and when external stimuli are reduced to a minimum. Of these conditions, closure of the eyes is by far the most important ; for in 1 Adrian, E. D., F.R.S., and Matthews, B. H. C. : Brain, 2 THE LANCET, 1934, ii., 1311. 1934, lvii., 355. 3 Berger, H. : Deut. med. Woch., Dec. 21st, 1934, p. 1947.
rhythm is abolished by the opening them, by mental effort, and by sensory excitation to which " affect " is attached, though it is unaltered by even the most intense muscular effort. Despite the established relation of the occipital lobes to vision, it is surprising that the mere acts of opening and closing the eyes, even in complete darkness, should have so great an effect. The explanation suggested by ADRIAN all normal
cases
the
act of
and MATTHEWS is that these two acts are automatically associated on the one hand with expectation and effort to see, and on the other hand with withdrawal of attention from vision. After the eyes have been opened in darkness several times in succession the effect of this action wears off and the rhythm persists unchanged by iti.e., the expectation to see has been abolished by repeated disappointment. It is found that a uniformly illuminated field, without central pattern (provided the subject makes no effort to discover irregularities or pattern) does not induce persistent abolition of the Berger rhythm, and simple variations in intensity of illumination have, strangely enough, no effect at all. It is the perception of pattern or the attempt to discover it that destroys the waves at once. This being so, it is not clear why the explanation that pattern-vision abolishes the rhythm, by turning the synchronous discharge of rest into the asynchronous discharge of activity, has been preferred by ADRIAN and MATTHEWS to the alternative explanation that pattern-vision automatically fixes attention and that this aloneapart from patterned retinal stimulation-abolishes the rhythm, as is done by mental concentration of any other kind. The amplitude of the waves can be varied slightly at will ; they can always be increased by closure of the eyes, and possibly also by intense muscular effort, and they can be diminished by non-visual activities and by sensory stimulation ; but their rate can be disturbed by one means only-by a flickering illumination of the visual field. This is all the more surprising because single, sharp alterations of illumination have comparatively little if any effect. Yet by flicker-stimulation the frequency of the flicker can be completely substituted for that of the spontaneous 10 per second rhythm, up to rates of 25 per second. That the processes underlying the spontaneous rhythm are not entirely interrupted, but are merely in abeyance during this substitution, is shown by two facts : there is a tendency to revert to the normal 10 per second rhythm when the flicker-rate is exactly twice this (i.e., 20 per second), and the effects of flicker are reinforced by these spontaneous processes when the flicker-rate and the spontaneous rhythm In this case the are equal (i.e., 10 per second). waves are not only of increased amplitude and regularity but also more resistant to interference by other factors. The most important of the differences apparent between the results of BERGER and those of ADRIAN and MATTHEWS is that the former finds that the waves are maximal in amplitude when the electrodes are furthest removed from one another, wherever either may be, whereas the latter find
TOXIC GOITRE AND ITS TREATMENT
maximal whenever one electrode is just the external occipital protuberance and the above other is more than 3 in. away-its position being otherwise immaterial. In conformity with these discrepant observations, BERGER believes that the source of the potential variations is distributed throughout the brain and is connected with those activities of which the brain partakes as a whole (in his term " psychological "), whereas ADRIAN and MATTHEWS hold that it is restricted to the occipital lobes. Both say that localised changes in activity or local impairment of the vitality of the brain will not produce any alteration in the rhythm that could be used clinically for topographical diagnosis. BERGER gives a short list of disturbances which he finds may impair the rhythm, but the collection-including, as it does, persistent fever, increase of intracranial pressure, and many forms of dementia-is so heterogeneous that it is hard to suggest any common factor. If ADRIAN and MATTHEWS are right in thinking that the appearance of this rhythm depends solely on the functional quiescence of the occipital lobes, then changes in activity or impairment of other parts of the brain cannot be expected to alter it except by abolishing it ; for synchronous activity of the neurones can occur only under such artificial conditions as
they
are
during flicker-stimulation, functionally inactive.
or
when
they
are
Within the last twenty years the electrical variations in almost every part of the body have been studied. In nearly all organs functional to correspond with electrical is found inactivity quiescence, while activity leads to changes in electrical potential. It is significant that, apart from the present work, the only organs whose behaviour offers a conspicuous exception to this rule are also parts of the visual apparatus. In the eye and in the optic ganglion of certain invertebrates (e.g., the water-beetle) the spontaneous rhythmic alterations in potential which appear when all light is withheld are abolished directly the eye is illuminated. The Berger rhythm from the occipital cortex is also an expression of functional inactivity, and not the least interesting thing about it is its disappearance when attention is concentrated upon purely intellectual exercises, such as a problem in mental arithmetic, and its return from time to time whenever attention wanders from this task. So much of recent analytical psychology gives the impression that the mind becomes a riot of morbid activity as soon as the censorship of conscious attention is withdrawn, that it is comforting to believe once more that though " sometimes I sits and thinks " there may also be occasions when " I just sits."
TOXIC GOITRE AND ITS TREATMENT DURING the last ten years opinion has been crystallising into an agreed view that operation is the right treatment for most cases of toxic goitre which do not readily respond to other measures.
cases
In
a
reviewmade in 1920 of all the surgical wards of Guy’s
in the medical and
1 Quart. Jour. Med., 1921,
xv., 55.
97
Hospital, Dr. MAURICE CAMPBELL concluded that the late results of surgical treatment were not greatly superior to those obtained by medical treatment ; in the surgical wards, however, there were a smaller number of fatal cases, even allowing for the operative mortality. Now with the more complete operation, with a greater knowledge of when the operation should be done, and with
complete cooperation between physician and surgeon, the surgical results are certainly better. The value of surgical intervention is fully confirmed by Prof. F. R. FRASER in summing up the results more
of treatment at the conclusion of three lectures delivered before the Derby Medical Society in May last, and printed in St. Bartholomew’s Hospital Reports for 1934. In the present state of our knowledge, he writes, thyroidectomy is the best method of saving life in toxic goitre ; but, he adds, the decision to employ this method and when to employ it depends upon the surgical skill and experience available. The non-surgical cases of the period 1926-30 at St. Bart.’s, even when they seemed to do fairly well at the time, showed when followed up an unexpectedly large number of deaths later. In the fourth lecture of the series Sir THOMAS DUNHILL makes it clear how intimate has been the cooperation between surgeon and physician at every stage. He deprecates the giving of large doses of iodine continuously to patients with toxic goitre; thus given, iodine may lose its power to improve and fail to help the surgeon when he most needs it. Even with iodine and practised operators he does not think all patients can be rendered safe for operation, but then he thinks the blame should rest on those who have deferred operation until the chances of anything approaching a complete recovery have slipped away. For clinical purposes FRASER classifies his cases into diffuse toxic goitre and nodular toxic goitre, covering respectively the groups generally known as primary and secondary toxic goitre, which have the convenience of a direct bearing on the natural history of the disease. In the former, which includes most of the cases known as Graves’s disease or exophthalmic goitre, the disease often starts suddenly and tends to be self-limited, though recovery may take two or three years apart from surgical treatment. In the latter, the onset may be very gradual but the disease generally progresses, slowly or quickly, and if it is at all severe is unlikely to be cured except by operation. Cardiac complications too are much more common. While psychological factors are more likely to be causative in the primary cases, the worries and anxieties seen in the secondary cases are for the most part the result of the disease. FRASER dwells on the need for knowing the life-history of patients with toxic goitre ; he has been able to follow some of them for as long as 15 years, noting their chronic course with acute relapses from time to time and moderate health in the intervals. Any simple goitre which has been present for so long is likely to become nodular, although little is known of the factors which may, in the event, make it toxic. Some patients with neurasthenia and some with localised infections may have a slight goitre,
THE BERGER RHYTHM
be possible to devise criteria which would leave unhampered any reputable practitioner of " " manipulative surgery while giving the public some guarantee against gross abuse ? We can think of none--certainly neither adherence to the osteopathic doctrine nor the assurance that the practitioner has passed through such a curriculum as that outlined on p. III would furnish satisfactory evidence of competence in the science and art of manipulative surgery. There are many branches of medicine in which the services of the skilful layman are valuable, and it would be wrong if any professional rule against " covering " were to prevent the full use of such services where a practitioner thought they might help his patient. But proposals whereby sick persons are encouraged to seek, in the first instance, the advice and treatment of the unqualified must be condemned, though protests from doctors will always be regarded askance. For to the public the reputation of the successful outlaw will always appeal, and medical criticism may be held as mere evidence of the trade-union spirit. If the public and Parliament-whether owing to their folly or our failureare tiring of common sense, and insist on fostering the conduct of medical work by men and women whose training is by modern standards incomplete, they are of course at perfect liberty so to do. But such a policy is as unsound in principle as we believe it would be damaging in practice.
THE BERGER RHYTHM SINCE 1924 Prof. BERGER of Jena has been making observations on certain changes in electrical potential in the human head, which he believed to come from the cerebral cortex ; their only constant feature is the occurrence of regular and comparatively large waves at the rate of about 10 per second. These variations have now been studied also by Prof. ADRIAN and Mr. MATTHEWS at Cambridge, and the reportof their work follows closely on their letter2 disclaiming credit for the original discovery. BERGER’S latest account3 of his conclusions appeared at the end of last year and a comparison of the two papers shows that ADRIAN and MATTHEWS have added not only confirmation but also precision to our knowledge. Using moistened electrodes placed on the surface of the scalp over the parted hair they obtained photographic records of potential variations from a Matthews’ oscillograph, and they are able to arrive at some very interesting conclusions. The Berger rhythm, they maintain, is due to the synchronous discharge of comparatively large numbers of neighbouring neurones in the occipital lobes of the brain, in a region concerned with pattern-vision This but probably not the area striata itself. and not is characteristic of the resting discharge of the functionally active condition of the neurones ; it is at its maximum when the eyes are closed, when the mind is at rest, and when external stimuli are reduced to a minimum. Of these conditions, closure of the eyes is by far the most important ; for in 1 Adrian, E. D., F.R.S., and Matthews, B. H. C. : Brain, 2 THE LANCET, 1934, ii., 1311. 1934, lvii., 355. 3 Berger, H. : Deut. med. Woch., Dec. 21st, 1934, p. 1947.
rhythm is abolished by the opening them, by mental effort, and by sensory excitation to which " affect " is attached, though it is unaltered by even the most intense muscular effort. Despite the established relation of the occipital lobes to vision, it is surprising that the mere acts of opening and closing the eyes, even in complete darkness, should have so great an effect. The explanation suggested by ADRIAN all normal
cases
the
act of
and MATTHEWS is that these two acts are automatically associated on the one hand with expectation and effort to see, and on the other hand with withdrawal of attention from vision. After the eyes have been opened in darkness several times in succession the effect of this action wears off and the rhythm persists unchanged by iti.e., the expectation to see has been abolished by repeated disappointment. It is found that a uniformly illuminated field, without central pattern (provided the subject makes no effort to discover irregularities or pattern) does not induce persistent abolition of the Berger rhythm, and simple variations in intensity of illumination have, strangely enough, no effect at all. It is the perception of pattern or the attempt to discover it that destroys the waves at once. This being so, it is not clear why the explanation that pattern-vision abolishes the rhythm, by turning the synchronous discharge of rest into the asynchronous discharge of activity, has been preferred by ADRIAN and MATTHEWS to the alternative explanation that pattern-vision automatically fixes attention and that this aloneapart from patterned retinal stimulation-abolishes the rhythm, as is done by mental concentration of any other kind. The amplitude of the waves can be varied slightly at will ; they can always be increased by closure of the eyes, and possibly also by intense muscular effort, and they can be diminished by non-visual activities and by sensory stimulation ; but their rate can be disturbed by one means only-by a flickering illumination of the visual field. This is all the more surprising because single, sharp alterations of illumination have comparatively little if any effect. Yet by flicker-stimulation the frequency of the flicker can be completely substituted for that of the spontaneous 10 per second rhythm, up to rates of 25 per second. That the processes underlying the spontaneous rhythm are not entirely interrupted, but are merely in abeyance during this substitution, is shown by two facts : there is a tendency to revert to the normal 10 per second rhythm when the flicker-rate is exactly twice this (i.e., 20 per second), and the effects of flicker are reinforced by these spontaneous processes when the flicker-rate and the spontaneous rhythm In this case the are equal (i.e., 10 per second). waves are not only of increased amplitude and regularity but also more resistant to interference by other factors. The most important of the differences apparent between the results of BERGER and those of ADRIAN and MATTHEWS is that the former finds that the waves are maximal in amplitude when the electrodes are furthest removed from one another, wherever either may be, whereas the latter find
TOXIC GOITRE AND ITS TREATMENT
maximal whenever one electrode is just the external occipital protuberance and the above other is more than 3 in. away-its position being otherwise immaterial. In conformity with these discrepant observations, BERGER believes that the source of the potential variations is distributed throughout the brain and is connected with those activities of which the brain partakes as a whole (in his term " psychological "), whereas ADRIAN and MATTHEWS hold that it is restricted to the occipital lobes. Both say that localised changes in activity or local impairment of the vitality of the brain will not produce any alteration in the rhythm that could be used clinically for topographical diagnosis. BERGER gives a short list of disturbances which he finds may impair the rhythm, but the collection-including, as it does, persistent fever, increase of intracranial pressure, and many forms of dementia-is so heterogeneous that it is hard to suggest any common factor. If ADRIAN and MATTHEWS are right in thinking that the appearance of this rhythm depends solely on the functional quiescence of the occipital lobes, then changes in activity or impairment of other parts of the brain cannot be expected to alter it except by abolishing it ; for synchronous activity of the neurones can occur only under such artificial conditions as
they
are
during flicker-stimulation, functionally inactive.
or
when
they
are
Within the last twenty years the electrical variations in almost every part of the body have been studied. In nearly all organs functional to correspond with electrical is found inactivity quiescence, while activity leads to changes in electrical potential. It is significant that, apart from the present work, the only organs whose behaviour offers a conspicuous exception to this rule are also parts of the visual apparatus. In the eye and in the optic ganglion of certain invertebrates (e.g., the water-beetle) the spontaneous rhythmic alterations in potential which appear when all light is withheld are abolished directly the eye is illuminated. The Berger rhythm from the occipital cortex is also an expression of functional inactivity, and not the least interesting thing about it is its disappearance when attention is concentrated upon purely intellectual exercises, such as a problem in mental arithmetic, and its return from time to time whenever attention wanders from this task. So much of recent analytical psychology gives the impression that the mind becomes a riot of morbid activity as soon as the censorship of conscious attention is withdrawn, that it is comforting to believe once more that though " sometimes I sits and thinks " there may also be occasions when " I just sits."
TOXIC GOITRE AND ITS TREATMENT DURING the last ten years opinion has been crystallising into an agreed view that operation is the right treatment for most cases of toxic goitre which do not readily respond to other measures.
cases
In
a
reviewmade in 1920 of all the surgical wards of Guy’s
in the medical and
1 Quart. Jour. Med., 1921,
xv., 55.
97
Hospital, Dr. MAURICE CAMPBELL concluded that the late results of surgical treatment were not greatly superior to those obtained by medical treatment ; in the surgical wards, however, there were a smaller number of fatal cases, even allowing for the operative mortality. Now with the more complete operation, with a greater knowledge of when the operation should be done, and with
complete cooperation between physician and surgeon, the surgical results are certainly better. The value of surgical intervention is fully confirmed by Prof. F. R. FRASER in summing up the results more
of treatment at the conclusion of three lectures delivered before the Derby Medical Society in May last, and printed in St. Bartholomew’s Hospital Reports for 1934. In the present state of our knowledge, he writes, thyroidectomy is the best method of saving life in toxic goitre ; but, he adds, the decision to employ this method and when to employ it depends upon the surgical skill and experience available. The non-surgical cases of the period 1926-30 at St. Bart.’s, even when they seemed to do fairly well at the time, showed when followed up an unexpectedly large number of deaths later. In the fourth lecture of the series Sir THOMAS DUNHILL makes it clear how intimate has been the cooperation between surgeon and physician at every stage. He deprecates the giving of large doses of iodine continuously to patients with toxic goitre; thus given, iodine may lose its power to improve and fail to help the surgeon when he most needs it. Even with iodine and practised operators he does not think all patients can be rendered safe for operation, but then he thinks the blame should rest on those who have deferred operation until the chances of anything approaching a complete recovery have slipped away. For clinical purposes FRASER classifies his cases into diffuse toxic goitre and nodular toxic goitre, covering respectively the groups generally known as primary and secondary toxic goitre, which have the convenience of a direct bearing on the natural history of the disease. In the former, which includes most of the cases known as Graves’s disease or exophthalmic goitre, the disease often starts suddenly and tends to be self-limited, though recovery may take two or three years apart from surgical treatment. In the latter, the onset may be very gradual but the disease generally progresses, slowly or quickly, and if it is at all severe is unlikely to be cured except by operation. Cardiac complications too are much more common. While psychological factors are more likely to be causative in the primary cases, the worries and anxieties seen in the secondary cases are for the most part the result of the disease. FRASER dwells on the need for knowing the life-history of patients with toxic goitre ; he has been able to follow some of them for as long as 15 years, noting their chronic course with acute relapses from time to time and moderate health in the intervals. Any simple goitre which has been present for so long is likely to become nodular, although little is known of the factors which may, in the event, make it toxic. Some patients with neurasthenia and some with localised infections may have a slight goitre,