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Lessons from Hemispherectomy
514 It is doubtful whether the new distribution of central responsibilities is going to help to solve these problems. According to the Government, the purpose of the order is to provide a better distribution of Ministerial and Governmental functions between certain departments of State." Reduced to essentials, we assume this to mean a more expeditious despatch of business, fewer civil servants, and fewer coordinating, interdepartmental, and inter-authority committees. Vague talk about overworked Ministers, and departments burdened with too many functions, is largely irrelevant compared to the day-to-day realities of administration-particularly as we still have the same load of responsibilities carried by two Ministers and two departments. The two main dangers implicit in the new arrangement are, we judge, the danger of less efficiency in administration rather than more, and the danger, which MoRANT pointed out many years ago, of a special ad-hoc department for health work laying too much stress on treatment and too little on
departments.
B
"
preventive
medicine.
Lessons from
Hemispherectomy
THE exact clinical observations of HUGHLINGS JACKSON1 on hemiplegia and " convulsions beginning unilaterally," and his inspired analysis of these conditions, together with FERRIER’S2 pioneer experimental work, formed the foundations for our present knowledge of localisation of function in the cerebral cortex. But, as WALSHE3 has persistently argued, the clinical findings are not compatible with the view that movements are represented in fixed points of the motor cortex; and this argument is supported by the experiments of LIDDELL and PHILLIPS,4 discussed on p.’ 455 last week, in which different responses were obtained when the motor cortex was excited by different stimuli. If specific functions are not exclusively represented in sharply defined areas of the cortex, we must look on the textbook maps of the motor cortex and speech areas as general guides, no longer inferring from the labels that each small group of cortical cells has one function and one function only under all circumstances. A new approach to the problems of cerebrallocalisation is -by studying the effects of hemispherectomy the surgical removal of one cerebral hemisphere. This operation, first performed some years ago by DANDY in the U.S.A., is now being done in this country in cases of infantile hemiplegia as a means of stopping epileptic attacks and improving the patient’s mental state. KRY-wATjw5 has recently reported 12 cases in which he removed the whole cerebral cortex on one side, except the part medial to the tail of the caudate nucleus, together with the putamen and globus pallidus. All the hemispheres removed were grossly abnormal pathologically, with dilatation of the lateral ventricle and a porencephalic cyst, general sclerosis, or microgyrial formations. The operation never caused more than a transient increase in the existing hemiparesis, and after a few weeks some of the patients actually had more power in the paralysed side than -
1. Jackson, Hughlings, Selected Writings. London, 1931. 2. Ferrier, D. TheFunctions of the Brain. London, 1876. 3. Walshe, F. M. R. Critical Studies in Neurology. Edinburgh 1948. On the Contribution of Clinical Study to the Physiology of the Cerebral Motor Cortex. Edinburgh, 1949. 4. Liddell, E. J. T., Phillips, C. J. Brain, 1950, 73, 125. 5. Krynauw, R. A. J. Neurol. Neurosurg. Psychiat. 1950, 13, 243.
before the operation. There was at first a profound loss of all cortical sensory modalities, but improvement soon followed, and after some months the sensory changes no longer caused any subjective disability : none of the patients developed a thalamic syndrome." KRYNAUW found, by using the routine sensory tests,. that quantitative and qualitative appreciation of pain and tactile sensation returned to normal, as compared with the opposite side. Some impairment of position sense, particularly in the fingers, a raised threshold for two-point discrimination, and a homonymous hemianopia persisted. None of the patients showed defects of the body-image or of spatial orientation of the type sometimes seen with acquired parietal lesions. Why does the removal of a cerebral hemisphere leave such slight disturbances ? On page 481 Dr. GOODDY and Mr. McKISSOCK put forward some suggestions. If we understand their argument, they think that the baby at birth has no absolute localisation of function in its cerebral cortex ; the brain " stands ready for training." If one hemisphere is damaged, whether by developmental abnormality, birth trauma, or some disease process occurring shortly after birth, other parts of the brain to some extent take over the functions which in normal people are performed by the parts which cannot develop-" functional sites must have been reallocated." The possibilities are that the functions of the damaged hemisphere have been taken over (1) by lower centres on the same side, (2) by cortical or subcortical centres on the opposite side, or (3) by a combination of these. It is not yet clear which of these is the main mechanism, but the uncrossed tracts in the central nervous system, such as the direct pyramidal tract, may play an important part in these patients. In the adult " nervous system, where physiological centres and pathways have been laid down, the possibility of in cortical function to compensate for cerebral damage largely depends on the patient’s age and the rate of progress of the pathological lesion. In selected cases of infantile hemiplegia hemispherectomy seems to relieve epilepsy and improve the patient’s mental condition. This is the justification for performing so severe an operation. Adding to our knowledge of brain function is a by-product of -the operation, but a valuable one, and for that reason every hemispherectomy should be preceded and followed by careful clinical and electro-encephalographic studies. "
"
readjustment
Mechanism of Venous Thrombosis the last few years the changes that take place
IN when blood clots outside blood-vessels have been studied in great detail. Much less attention has been given to the clinically more important problem of how clotting takes place inside blood-vessels, and what limits or favours the spread of these clots. MACFARLANE1 declared rightly that many more patients die of thrombosis and its effects than of inefficient blood-coagulation; thrombosis, he said, is brought about by a combination of tissue damage and circulatory stasis that may displace the clottinganticlotting equilibrium in favour of coagulation." We need especially to know more about the factors causing intravascular thrombi to grow in size ; and "
1.
Macfarlane, R. G.
J. clin. Path.
1948, 1,
137.
departments.
B
"
preventive
medicine.
Lessons from
Hemispherectomy
THE exact clinical observations of HUGHLINGS JACKSON1 on hemiplegia and " convulsions beginning unilaterally," and his inspired analysis of these conditions, together with FERRIER’S2 pioneer experimental work, formed the foundations for our present knowledge of localisation of function in the cerebral cortex. But, as WALSHE3 has persistently argued, the clinical findings are not compatible with the view that movements are represented in fixed points of the motor cortex; and this argument is supported by the experiments of LIDDELL and PHILLIPS,4 discussed on p.’ 455 last week, in which different responses were obtained when the motor cortex was excited by different stimuli. If specific functions are not exclusively represented in sharply defined areas of the cortex, we must look on the textbook maps of the motor cortex and speech areas as general guides, no longer inferring from the labels that each small group of cortical cells has one function and one function only under all circumstances. A new approach to the problems of cerebrallocalisation is -by studying the effects of hemispherectomy the surgical removal of one cerebral hemisphere. This operation, first performed some years ago by DANDY in the U.S.A., is now being done in this country in cases of infantile hemiplegia as a means of stopping epileptic attacks and improving the patient’s mental state. KRY-wATjw5 has recently reported 12 cases in which he removed the whole cerebral cortex on one side, except the part medial to the tail of the caudate nucleus, together with the putamen and globus pallidus. All the hemispheres removed were grossly abnormal pathologically, with dilatation of the lateral ventricle and a porencephalic cyst, general sclerosis, or microgyrial formations. The operation never caused more than a transient increase in the existing hemiparesis, and after a few weeks some of the patients actually had more power in the paralysed side than -
1. Jackson, Hughlings, Selected Writings. London, 1931. 2. Ferrier, D. TheFunctions of the Brain. London, 1876. 3. Walshe, F. M. R. Critical Studies in Neurology. Edinburgh 1948. On the Contribution of Clinical Study to the Physiology of the Cerebral Motor Cortex. Edinburgh, 1949. 4. Liddell, E. J. T., Phillips, C. J. Brain, 1950, 73, 125. 5. Krynauw, R. A. J. Neurol. Neurosurg. Psychiat. 1950, 13, 243.
before the operation. There was at first a profound loss of all cortical sensory modalities, but improvement soon followed, and after some months the sensory changes no longer caused any subjective disability : none of the patients developed a thalamic syndrome." KRYNAUW found, by using the routine sensory tests,. that quantitative and qualitative appreciation of pain and tactile sensation returned to normal, as compared with the opposite side. Some impairment of position sense, particularly in the fingers, a raised threshold for two-point discrimination, and a homonymous hemianopia persisted. None of the patients showed defects of the body-image or of spatial orientation of the type sometimes seen with acquired parietal lesions. Why does the removal of a cerebral hemisphere leave such slight disturbances ? On page 481 Dr. GOODDY and Mr. McKISSOCK put forward some suggestions. If we understand their argument, they think that the baby at birth has no absolute localisation of function in its cerebral cortex ; the brain " stands ready for training." If one hemisphere is damaged, whether by developmental abnormality, birth trauma, or some disease process occurring shortly after birth, other parts of the brain to some extent take over the functions which in normal people are performed by the parts which cannot develop-" functional sites must have been reallocated." The possibilities are that the functions of the damaged hemisphere have been taken over (1) by lower centres on the same side, (2) by cortical or subcortical centres on the opposite side, or (3) by a combination of these. It is not yet clear which of these is the main mechanism, but the uncrossed tracts in the central nervous system, such as the direct pyramidal tract, may play an important part in these patients. In the adult " nervous system, where physiological centres and pathways have been laid down, the possibility of in cortical function to compensate for cerebral damage largely depends on the patient’s age and the rate of progress of the pathological lesion. In selected cases of infantile hemiplegia hemispherectomy seems to relieve epilepsy and improve the patient’s mental condition. This is the justification for performing so severe an operation. Adding to our knowledge of brain function is a by-product of -the operation, but a valuable one, and for that reason every hemispherectomy should be preceded and followed by careful clinical and electro-encephalographic studies. "
"
readjustment
Mechanism of Venous Thrombosis the last few years the changes that take place
IN when blood clots outside blood-vessels have been studied in great detail. Much less attention has been given to the clinically more important problem of how clotting takes place inside blood-vessels, and what limits or favours the spread of these clots. MACFARLANE1 declared rightly that many more patients die of thrombosis and its effects than of inefficient blood-coagulation; thrombosis, he said, is brought about by a combination of tissue damage and circulatory stasis that may displace the clottinganticlotting equilibrium in favour of coagulation." We need especially to know more about the factors causing intravascular thrombi to grow in size ; and "
1.
Macfarlane, R. G.
J. clin. Path.
1948, 1,
137.