Involuntary Movements Following Stereotactic Reference to Hemi-Chorea

J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

J. Neurol. Neurosurg. Psychiat., 1965, 28, 291

Involuntary movements following stereotactic operations for Parkinsonism with special reference to hemi-chorea (ballismus)

BRODIE HUGHES From the Department ofNeurosurgery, University of Birmingham

When one examines stained sections of the thalamic side by side and the physical destruction of both area of the brain and sees the mass of fibres and cells could well have no apparent clinical effect at all. in this area interconnecting almost every structure in Involuntary movements are most often the result the vicinity and receiving and sending millions of of infections, of degenerations of unknown cause, fibres to remote parts of the brain and spinal cord or of developmental anomalies. It is easy to conceive one marvels at the temerity of the early stereotactic that such processes may affect only facilitatory or surgeons who dared to place electrodes in this area inhibitory fibres, but not both, and that the gross guest. Protected by copyright. and make massive destructive lesions. One might physical lesions made by the surgeon destroy both imagine that such lesions would have a profound and cancel out the imbalance. Tremor and rigidity, effect on gait and motor control, on sensation and ballismus and athetosis, are very rarely caused by even mental function but, in practice, the clinical discrete physical lesions such as tumour growth, effects of such massive lesions are hardly detectable. though occasional cases are reported and this Whether this reflects the high degree of adaptability suggestion may well account for the fact that the in the brain or the relative unimportance of this area surgeon destroying large areas of the globus pallidus, is difficult to determine. The main difficulty en- lateral thalamus, and adjacent structures relatively countered by the surgeon probing this area is to seldom induces involuntary movements or makes produce any effect at all. All varieties of test pro- them worse. cedures are used to determine the efficacy of lesions Such complications do, however, occur, in a small -stimulation, micro-electrode recording, 'trial proportion of cases, about 2-5% overall, and the lesions' with heat or cold-andyet, in some instances, situation of such lesions, together with the pre- no clinical effect can be produced. existing state of the nervous system, seemed a worth- Most of such lesions are made for the treatment while study and forms the basis of this paper. of involuntary movements, particularly the tremor and rigidity of Parkinsonism. The results in general INCIDENCE OF INVOLUNTARY MOVEMENTS FOLLOWING are excellent, yet these abnormal movements are OPERATION presumed to be the result of cell and fibre destruction http://jnnp.bmj.com/ and it is a matter for great surprise that such lesions Personal contact with many neurosurgeons carrying do not in themselves invoke involuntary movements. out stereotactic operations has shown that all are That we find such concepts difficult to understand familiar with this complication. Perusal of the series may well reflect wrong thinking on our part con- of cases reported in the literature does not show, cerning the organization ofthe nervous system. When however, that this is a universal experience. In many we see a discrete tract of fibres, or a collection of cells series this complication is not mentioned specifically of similar size and connexions, we tend to think that though on the other hand no mention is made that they must serve some single function. We may accept such movements had never occurred following on September 24, 2021 by the idea that this function differs from time to time operation. In some cases in my own experience the and may well depend on the state of other parts of the movements have been very slight and short-lived nervous system at that time. Our minds, however, and possibly only personal observation of every are not sufficiently alive to the possibility that such a post-operative patient every day until the time of discrete system may well be serving several functions, discharge from hospital has brought them to light. often directly opposed to each other. Fibres which For example, Taarnh0j, Arnois, and Donahue facilitate or inhibit certain function may well run (1960) in 118 patients and Gillingham, Watson, 291 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from 292 Brodie Hughes 292BrdeHgs Donaldson, and Naughton (1960) in 60 patients do Brown (1962) the best attempt to define such move- not mention this as a complication though in a ments in physiological terms and his definition of later paper (Gillingham, Kalyanaraman, and athetosis and dystonia are supreme examples of Donaldson, 1964) they report one case in 344 acute observation combined with clear thinking and patients with a unilateral operation and three cases lucid description. Athetosis he considers to result in 83 bilateral operations. Spiegel and Wycis (1958) from the release of two conflicting postures, a in 50 cases of Parkinsonism do not record an example 'fluctuation in posture superimposed on a persistent but mention later in their paper that in cases of attitude'. The swing is usually from hyperextension choreoathetosis the movements may be made worse of fingers and wrist and pronation of the forearm by operation. The largest series of cases are those to full flexion of the fingers and wrist and supina- recorded by Cooper and he states (1961) that in his tion of the forearm. Athetosis refers to the swings of first 1,000 cases this complication occurred in 36 movement and not to the posture, for which he uses patients. The movements were all transitory and the term dystonia. lasted from one day to five months. Only one Chorea is more difficult of definition and the one example occurred in 500 operations on the globus may merge into the other. In chorea there is a con- pallidus, the others were related to thalamic lesions. tinual flow of movement without the irregular Of considerable interest are two recent series of alternation of posture that characterizes athetosis. operations in which a lesion has been deliberately There is no underlying posture. Denny-Brown states, made in the subthalamic area. A series of 58 patients however, that 'in a more coarse form the movements reported by Andy, Jurko, and Sias (1963) resulted become identical with those of athetosis' and later in ballismus in five. In three it stopped in a week that 'the movements as such, in terms of parts in- and in the other two in two months. Their lesions volved and variability in amplitude, are the same. were presumed to involve the field H of Forel, the The more rapid performance of choreic movementsguest. Protected by copyright. zona incerta, and the pre-rubral field medial to the is but a relative criterion'. subthalamic nucleus. All lesions causing ballismus were lateral to 10-5 mm. from the midline but many TREMOR AT REST This is the typical tremor of similarly placed lesions did not result in ballismus. Parkinsonism and needs no further definition. In no Spiegel, Wycis, Szekely, Adams, Flanagan, and case was this type of tremor initiated in patients in Baird (1963) report 25 cases in which similar lesions whom it had been absent before operation. This were made but none developed ballismus. appears to be a universal, though surprising, ex- Gros, Serrats, Adib-Yazdi, and Parker (1963) perience. It will also be recalled that it has proved report 185 cases with transient athetosis in 11 and very difficult to produce such tremor in animal persistent ballismus in one. Dierssen, Bergmann, experiments, even in the monkey. In some reported Gioino, and Cooper (1961) reported one case from cases tremor appears to have been aggravated after Cooper's series in which a post-mortem study had surgery, usually in the post-encephalitic cases. No been made. such aggravation was experienced in this series. In my own series involuntary movements have appeared in 10 cases in a series of 200. In all but one INTENTION TREMOR In this series 24 % of patients they have been mild and transitory. The overall had intention tremor before operation; in some it incidence amongst reported cases with thalamic or was severe and disabling. In most it was abolished

subthalamic lesions would appear to be a little over by thalamic lesions but in two, not included in the http://jnnp.bmj.com/ 2%. incidence figures, it was thought to be slightly worse after operation. This type of tremor is easy to de- TYPES OF INVOLUNTARY MOVEMENTS FOLLOWING monstrate and only too apparent to the patient but STEREOTACTIC SURGERY most difficult to quantitate. In both cases the worsen- ing was transitory and they will not be considered The nomenclature of involuntary movements is still further here. in a very unsatisfactory state and one can never be

quite certain just what an author means by terms ATHETOSIS This occurred in two cases. In each it on September 24, 2021 by such as ballismus, chorea, athetosis, etc. Careful affected the forearm, wrist, and fingers, and con- study of the individual patient, usually with the aid of sisted of a writhing movement with flexion and ex- slow-motion film, enables one to give a clear de- tension of the fingers and wrist, and pronation- scription of his movements but it is seldom possible supination of the forearm. They exemplified well to give them an exact definition in more general terms the alternation ofposture so well described by Denny- and, hence, the use of multiple terms such as choreo- Brown (1962). The movements were always the athetosis has become common. We owe to Denny- same, occurred in spasms, and were often absent J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

Involuntary movements following stereotactic operations for Parkinsonism 293 when the patients were at rest or their attention was violent because they involve the distal joints, are not occupied elsewhere. They lasted less than 48 hours continuous or involve only one limb, is simply and follow-up over several years has not shown any semantic pedantry. Many cases have been described recurrence. in which the initial movements were mild and affected only one limb or part of a limb and yet CHOREA (BALLISMUS) Terminology in this type of developed subsequently into the characteristic movement is difficult and many authors have con- picture of hemiballismus (Martin, 1927; Kelman, cerned themselves with the distinction between 1945; Russell Meyers, Sweeney, and Schwidde, chorea and ballismus: some consider them identical. 1949; Bedwell, 1960). There can be little doubt that In most cases the movements are persistent, com- the term hemiballismus has been used to denote a pletely irregular and faster than those of athetosis. special disease entity in which the mode of onset, One factor which may be agreed upon is a continual course, and pathology are as important as the type flow of movement. In some cases, mentioned of movement. The position was admirably summed below, the movements were at first quite slight and up by Martin and Alcock in 1934 who wrote: 'There intermittent. In one case they affected the distal may be some advantage in employing the special joints and were, at first, so mild that they were term hemiballismus for such an unusual and re- mistaken for simple fidgeting. They gradually markable symptom, but if it is employed it should, spread up the arm, however, and by the time the in our opinion, be used to denote a special intensity shoulder was affected were wild flinging movements of chorea and not a special form of it.' Lea-Plaza with rotation at the shoulder which would be recog- and Uiberall (1945) considered that there was a case nized immediately as ballismus. for considering ballismus as a special clinical

They appear at first sight to be quite irregular and syndrome rather than a special form of movement. guest. Protected by copyright. to have none of that regular alternation of posture Russell Meyers et al. (1949) put forward somewhat which characterizes athetosis. And yet if one watches more concrete evidence for considering that hemi- such patients over a period of time, in life or on film, ballismus was distinct from athetosis and chorea. it becomes apparent that many grotesque postures They were reporting cases in which ballismus had are adopted and these recur again and again, though been alleviated or cured by subpial resection of in quite random fashion. fibres in the pre-motor cortex. These operations had In some the movements affected the distal joints, been largely successful. They stated that similar were quite irregular, exhibited a continual flow of operations undertaken in cases of chorea and movement, and could easily be classed as chorea. athetosis had not been successful. It is not clear, In others, the movements were affecting the proxi- of course, just what they meant by these terms and it mal joints, were therefore of wide amplitude and is interesting to note that H. A. Riley in the dis- exhibited rotation at the shoulder, and therefore cussion on their paper said that he did not think could be classified as ballismus. In others, the initial that their cases were ballismus at all. The movements chorea became converted in the course of time to affected the face, which was not the case in ballismus, typical ballismic movements and it is this fact that and he would consider that they were largely choreic suggests the close relationship between the two. with a minor athetoid element! To what confusion Denny-Brown (1962) would distinguish ballismus can terminology lead one. absolutely from chorea on the grounds that the My conclusions would be that minor degrees of essential feature of the former is the rotary character athetosis do constitute a clinical entity, as defined http://jnnp.bmj.com/ of the movements, especially external rotation at by Denny-Brown. Where there is a 'continued flow the shoulder, and affection of proximal joints. He of movement' and regular alternations of posture admits, however, that they may 'in time develop a are not apparent then the term chorea should be flowing quality which could be termed choreic, but used. Athetosis may develop into chorea when the its characteristics are still those of mid-brain dis- movements become continual and many different order'. I find this distinction difficult to accept and postures are alternated in a random manner. record below one case at least in which chorea The severity and amplitude is largely related to appeared to develop into ballismus. the joints involved and the wide flinging movements on September 24, 2021 by The arguments have been clouded in some degree of ballismus may be related simply to this fact. From by a consideration of hemiballismus occurring personal observation I would state that the flowing spontaneously from vascular disease of the sub- movements of chorea may develop a rotary move- thalamic nucleus or elsewhere. The movements are ment at the proximal joints and hence become by violent, affect the proximal joints, are continuous and definition, ballismus. It is also an impression that irregular and affect one side of the body. To deny the sudden flinging movements, so characteristic of the term to similar movements which are less ballismus, may be myoclonic jerks superimposed J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

294 Brodie Hughes on chorea but this would necessitate more exact from the depth of the subarachnoid space, intracranial investigation to prove. tension, and lateral ventricular size. In this series five patients developed chorea im- The method of operation was the same in every case operation and in a further two cases though the exact site and size of the lesions varied a little mediately after from case to case as will be seen below. The Hughes it developed at a considerable time interval after stereotactic instrument was used throughout (Hughes, operation. 1961a). The lateral and third ventricles Were outlined with air and Myodil, and certain landmarks were identified MYOCLONUS Two patients suffered from typical and measured, allowance being made for x-ray distortion flexion jerks of myoclonus. In one these were mild and magnification. The reference points used were: the and affected the arm only, in the other they were anterior and posterior commissures and the minimal prolonged and affected both arms. Both recovered distance between them, the thalamic height, i.e., the distance between the intercommissural line and the completely. Denny-Brown (1962) has described highest point of the floor of the lateral ventricle, and the these as occurring spontaneously in several forms of width of the body of the lateral ventricle. A series of extrapyramidal disorder and has studied their outline diagrams of the various thalamic nuclei were physiological nature. prepared from standard atlases and a series of 30 brains sectioned after hardening. The nuclear outlines were con- RHYTHMIC BLINKING Two patients suffered from structed from percentage measurements of the distances rhythmic lid closure. In one there was an initial phase given above and the outline chosen for the series of of complete lid closure for several weeks, but even measurements which approximated most closely to those of the patient (Hughes, 1961a). during this time rhythmic closure movements were The primary location of the intracerebral electrode occurring all the time. Later the lids were opened was then selected from the nuclear outline, usually in the but forced blinking continued for some time after. centre of the nucleus. Two separate lesions were made inguest. Protected by copyright. In the other patient there was rhythmic blinking at each case, in the ventro-oralis anterior and ventro-oralis about two per second for a period of a week or so. posterior (Hassler, 1959). In half the cases the first lesion These movements correspond to the segmental was made in the anterior nucleus and in the other half dystonia of Denny-Brown and are evidently closely in the posterior nucleus. related to the oculogyric crises seen in the post- After insertion of the electrode two sets of observations encephalitic Parkinson patient. The essential differ- were made. First, records of electrical activity were taken be that these were move- from bipolar and unipolar electrodes, together with a ence, however, appeared to standard placement of scalp E.E.G. electrodes. In some ments and not postures. The regular alternation cases, micro-electrode recording was made during the seen may bear the same relationship to dystonia as insertion of the electrode. Secondly, the effect of stimula- athetosis. tion was tested using a square wave pulse, at three values, 8, 20, and 40 c/s., and pulse width 1 msec. Only effects MATERIALS AND METHODS produced by stimulation at a D.C. level of less than 5 volts were considered to be the result of local stimulation. These complications occurred in a series of 200 opera- In some cases the effect of a lesion was further tested by tions for Parkinsonism. All cases were classified under local cooling to +50C. with a cooling probe (Clarke, this heading and the majority were in middle-aged people 1963). From these various results a decision was then without apparent known aetiology. In 9% the aetiology made as to making the lesion. If, for instance, stimulation was thought to be some form ofencephalitis. In such cases had indicated close proximity to the internal capsule then electrode would be moved 2-3 mm. if either the condition had followed an illness identifiable the medially, http://jnnp.bmj.com/ as encephalitis lethargica, or there were other features proximity to sensory input nuclei it would be moved indicative of this aetiology, the chief amongst these anteriorly, and so forth. Lesions were made with an R.F. being the presence of oculogyric crises or tics, disturb- lesion generator, electrode size 5 mm. x 12 mm., and ances of ocular movement or pupillary reaction, or an the estimated size of lesions was 6 x 3 mm. onset in childhood or very early adult life. After each lesion an estimate was made of its effect on Pre-operative assessment was carried out in hospital tone, tremor, and power, and further scalp and depth after drugs had been withdrawn. This included a numeri- E.E.G. records were taken. The electrode might then be cal assessment of the patient's abilities modified from the moved or the lesion extended following these tests. For scheme of Schwab and England (1958), a numerical instance, if rigidity had been abolished in the arm but not on September 24, 2021 by assessment of the degree of tremor and rigidity in each in the leg the electrode would be moved a little laterally limb, trunk, head and neck, a numerical assessment of and inferiorly. The second lesion was then made on the akinesis, speech disturbance, mental change, and neuro- same principles. The appearance of theta and delta activity logical findings. A careful psychiatric assessment was in the E.E.G. was considered an absolute contra- carried out by Dr. Warburton and will be the subject of a indication to further lesions. further report. Routine scalp E.E.G. records were made It will be seen, therefore, that the site and extent of pre-operatively and post-operatively and the degree of lesions varied slightly from patient to patient, in terms of cerebral atrophy was assessed at the time of operation brain coordinates. It was felt, however, that adjusting the J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

Involuntary movements following stereotactic operations for Parkinsonism 295 electrode on this basis probably achieved a closer happenings are commoner with thalamic lesions anatomical or physiological uniformity of lesions than than those in the pallidum. It is commonly accepted reliance on brain coordinates alone. The theoretical that lesions of the red nucleus are associated with arguments concerning the location of these lesions is intention tremor and it may be that in these two cases dealt with more fully below. Post-operative assessments were made and E.E.G. post-lesion oedema had affected this nucleus tem- traces repeated before the patient left hospital, usually porarily. Against this hypothesis is the fact that after seven to 10 days. Follow-up assessments and E.E.G. lesions in the ventrolateral thalamus are highly records were made at three months and thereafter at efficacious in controlling intention tremor and in yearly intervals. 18 cases so treated this type of tremor was not aggravated in a single case. CLINICAL MATERLAL ATHETOSIS This was thought to have occurred in TREMOR AT REST It appears to be a universal two cases. This qualification is made because the finding that the tremor at rest of Parkinsonism is type of movement, although specified at the time as never aggravated by lesions in the thalamus, athetosis, was exactly similar to movements in globus pallidus, internal capsule and structures in- another patient which became more severe and cluded in this area. If degenerative disease in this clearly ballismic. area is the cause of tremor at rest this is a surprising finding but one which must be confirmed by ex- No. 29 M.G., female, aged 49. A four-year history of perience of thousands of cases throughout the world. tremor of right arm and leg. This was a wide amplitude Three theoretical explanations themselves. 'flapping' tremor. Rigidity was moderate and akinesis suggest slight. Total abilities rated at 74%. Post-operatively First, that such lesions inevitably destroy fibre there was slight weakness of the arm and leg completely guest. Protected by copyright. systems that inhibit tremor as well as those that recovered in 24 hours. Athetosis was noted 12 hours initiate it. It may well be that inhibitory/excitatory after operation, was confined to the wrist and fingers, systems consist of fibre tracts lying side by side and and completely disappeared in 48 hours. Follow-up at only intrinsic degenerative processes are capable of one and a half years showed no athetosis and an excellent destroying the one without the other. Secondly, that overall result with total ability rated at 90 %. more than one lesion is required to produce this type of tremor and the second is remote from the sites No. 36 Female, aged 39. A ten-year history of slurring usually damaged by surgery. Such an of speech and seven-year history of tremor. Tremor was explanation moderate and affected right limbs more than left. Rigidity seems unlikely, for in this group of patients tremor is was moderate, speech badly affected, and general akinesis already present and a second lesion, if such be needed, severe. Ability rated at 84 %. Left-sided operation resulted is presumably, already present. Thirdly, that lesions in abolition of tremor and rigidity and some improvement producing tremor are in some quite different area in speech. Athetosis was noted six hours after operation, of the brain. This may be a possible explanation, was similar to the previous case, and involved the fingers for most pathologists who have studied Parkinson and wrist and forearm. It was usually absent, came on patients claim that the initial lesions, and the most when her attention was directed to the limb and she advanced, are in the substantia nigra. Against such almost seemed to be able to bring it on at will. This had an explanation is the claim by Meyers, Fry, Fry, wholly disappeared within two weeks. Follow-up at Eggleton, and Schultz (1960) that nigral lesions are three years showed continued absence of tremor and

rigidity on the right side and no trace of athetosis. Her http://jnnp.bmj.com/ very effective in controlling tremor. abilities had been in the 95% range but at the time of That there may be some synergy between the two examination had fallen to 87% due to increasing tremor sides of the brain in the control of such motor and rigidity on the left side. functions seems amply confirmed by the common experience that whilst tremor is usually well-con- In the first case check of lesion sites showed that trolled on the contralateral side after such lesions, these were rather more posterior than usual and in that on the ipsilateral side sometimes gets worse both cases the lesions had extended a little way or appears if previously absent. below the anterior-posterior commissure line. It will be noted that both patients were rather younger on September 24, 2021 by INTENTION TREMOR Intention tremor is often present than the average age of Parkinson patients. in Parkinson patients (vide supra) and in a few cases this may be aggravated following stereotactic lesions. CHOREA (BALLISMUs) The majority of patients in Two such instances occurred in this series but both this series suffered from a post-operative involuntary were quite transitory, lasting no more than a few movement which conformed to chorea or in its days. Though my personal experience of lesions in extreme forms ballismus. There were four in the globus pallidus is small it would seem that such number. J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

296 Brodie Hughes No. 136 A.R., male, aged 45. A 24-year history of and short-lived, in only one did they persist in severe tremor on the left side. There was no history of ence- form over a period of several years. The site of phalitis or stigmata to suggest this. There was severe lesions appeared to be similar to the majority of tremor and rigidity on the left, slight on the right. lesions made for Parkinsonism and in no case was Moderate akinesis and slight speech defect. Right-sided the lesion estimated to have involved the sub- operation resulted in an excellent result and follow-up at in to have extended below one year showed improvement in ability from 63 to 86 %. thalamic nucleus or, fact, Mild ballismic movements were noted eight hours after the AC-PC line. operation and persisted occasionally for 10 days. These affected the left hand and forearm. There was no re- MYOCLONUS In two instances the abnormal move- currence after 10 days. ments following operation consisted of sudden jerks, usually flexion movements at elbow, shoulder, No. 39 T.K., aged 39, male. Twenty-year history of or hip. These were single movements occurring at tremor and stiffness of the right limbs with oculogyric irregular intervals. Usually absent at rest they were crises. Classified as post-encephalitic. There was severe tremor and rigidity of the right limbs, slight rigidity of the frequently initiated by drawing the patient's atten- left. Mild akinesis and no speech defect. Ability was rated tion to them. at 74%. Left-sided operation was carried out and after the first lesion in ventro-oralis anterior short bursts of No. 206 V.M., female, aged 44. Onset of rigidity high-voltage slow activity were seen in the monitoring and weakness after parturition at age of 41. Extreme E.E.G. The significance of this was not realized and a rigidity and akinesis was present. Left-sided operation second lesion was made in the posterior nucleus. About with excellent results on tremor and rigidity. Twenty- 30 minutes after the first lesion it was noticed that ballis- four hours after operation sudden jerks of the right arm mic movements in the arm had appeared and followed appeared, being flexion at the elbow. These were closely each burst ofslow activity in the E.E.G. These movements related to attention. They disappeared in 15 days and noguest. Protected by copyright. became worse for 48 hours and affected the arm severely return was noted in follow-up a year later. The general and the leg slightly less. During the next two weeks they effect of operation on rigidity was excellent. lessened to a mild degree but have persisted for a period of four years. No. 233 S.C., male, aged 57. Onset of severe tremor six years ago aged 51. Extreme degree of tremor involving No. 120 W.E., male, aged 61. A history ofencephalitis whole body. Right-sided operation including, in this at the age of 24 followed by slowly progressive weakness, instance, a lesion in the medial globus pallidus. Excellent tremor, and stiffness of the left limbs. There was severe control for tremor lasting a month only; operation tremor on the left and slight rigidity, no abnormal signs repeated four months later with again an excellent result. on the right, mild akinesis and no speech or mental He was so pleased with this that he persuaded me to do disturbance. His ability was rated at 58%. Right-sided the other (left) side at the same admission. This was operation was followed in 12 hours by the appearance of carried out two weeks later. Two types of involuntary fairly severe ballismic movements in the arm and to a movements developed within 24 hours of this second lesser degree in the leg. These got worse for three days side. The first type was a myoclonic movement consisting and then improved, ceasing at two weeks. Follow-up ofsuddenjerks offlexion ofelbow, adduction at shoulder, at five months showed an excellent overall result with flexion at hip, or rotation of the head. These started ability improved to 93 %, no tremor or rigidity, and no in the left arm and hand and rapidly spread to involve recurrence of ballismic movements. the whole of the left side of the body and then the arm on the opposite side. These gradually subsided and ceased No. 21 E.F., female, aged 45. A five-year history of at 15 days, there being no return at follow-up three years tremor and stiffness of the left arm, cramps in the legs, later. There were good clinical results in so far as tremor http://jnnp.bmj.com/ and slowing of speech. Right thalamotomy was carried was concerned. The second type consisted of screwing out with no complications and an excellent result. Good up of the eyelids with tight lid closure. In fact, he did not results were maintained but owing to steady deterioration open the eyes for a week but even when tightly closed on the right side a left thalamotomy was carried out two slow rhythmic movements of lid closure could be seen. years later. For 48 hours after operation there were These persisted for a further three weeks. The movement rapid 'sweeping movements of the right arm, mainly involved both eyes symmetrically, were irregular and adduction movement at the shoulder. These ceased after occurred in short bursts lasting 15 to 20 seconds at a rate 48 hours and there has been no recurrence at nine months. of less than one per second. The rate and symmetry remained the same throughout but as time went on the on September 24, 2021 by This group, although very small, seems to have bursts became shorter and with longer intervals between. certain characteristic features. The average age was low, 45 years, and the age of onset of disease much OTHERS The only other type of involuntary move- lower, being 25 years. Three were almost certainly ment following operation is that already described post-encephalitic cases and the average length of above, rhythmic blinking. Seen in severe form in history was long, 21-5 years, with a slow evolution S.C. described above it also occurred in lesser degree of symptoms. In three the movements were mild in one other patient. J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

Involuntary movements following stereotactic operations for Parkinsonism 297

No. 104 A.W., male, aged 53. After presumed ence- slight ballismic movements were noticed in the right hand phalitis in 1922 he presented with a 23-year history of and they have slowly increased since then. rigidity, immobility, and speech defect starting at the age of 33. There was no history of oculogyric crises or other No. 89 F.G., male, aged 57. An eight-year history of tics. Operation on the left side was carried out in 1961 increasing weakness and stiffness of the limbs, akinesis, with good effect. The second side, right, was undertaken and severe speech loss. Left thalamotomy was carried two and a half years later. This again produced excellent out and tremor was abolished and rigidity greatly im- effects on rigidity and the slight tremor that had been proved on the right side. Two and a half years later slight present. Twelve hours after operation it was noticed that ballismic movements appeared in the right hand and he continually blinked the eyes and this, as in the other wrist. These were mild and might have been mistaken for case, occurred in short bursts lasting 15 to 20 seconds at a fidgeting. Over a period of six months they have got rate of less than one per second. He was unable to control slightly worse. this and it was closely related to attention being directed to this symptom. It gradually declined and stopped two Two of these patients were post-encephalitic and weeks after operation without recurrence at follow-up the third had a longer history than usual in the three months later. group with very slow progression. It might be considered that these events were part of the natural DELAYED ONSET OF INVOLUNTARY MOVEMENTS So far evolution of the disease and unconnected with the I was not unduly concerned at this incidence of in- operation. The fact that in each case it occurred on voluntary movement, it seemed to be a universal the operated side is difficult, however, to overcome. experience and the incidence in our series was no That such an event does occur from the disease greater than in most and less than some. All but one alone is shown by one case in the series. had cleared completely in a few days to two weeks guest. Protected by copyright. without recurrence at fairly long follow-up. The one No. 170 E.S., male, aged 55, presented with a 20-year case that had persisted had given evidence during history of increasing tremor and rigidity on the right side. operation of such movement and if we had realized The left arm had been removed for an accidental injury its significance and had not made a further lesion as a child but three years after the onset of tremor this might have resulted in a similarly happy out- involuntary movements were noticed in the left arm stump come. During the course of routine follow-up and have continued since, getting slowly worse. It was examinations of these patients, however, three difficult to assess the true nature of these movements for patients came to light in whom ballismus had they were confined to the shoulder muscles and the short on the side treated for Parkinsonism some stump, but they appeared to be true ballismic movements. appeared Left thalamotomy was carried out which abolished time after operation. tremor and rigidity in the right limbs. The ballismus was unchanged. No. 61 J.Hd., female, aged 36, was the first to be identified. Tremor and mild rigidity had appeared in the left limbs at the age of 25 and had gradually progressed. THE LOCATION OF LESIONS As with all stereotactic Operation was carried out on the right side with excellent surgery the exact position of the lesions made in results. Six months later she had a fall without serious these cases can only be predicted approximately. injury and immediately afterwards developed coarse Inaccuracy derives from three sources: that in- ballismic movements in the left wrist and hand. These herent in the machine used, that resulting from relat- might well have been described in the early stages as ing coordinates of the machine to structures in the athetosis but over the ensuing months they gradually brain, and, lastly, variations in the relationship http://jnnp.bmj.com/ spread to the whole arm and then appeared in the foot between these reference and nuclear masses and ankle and became frankly ballismic. Two and a half points years later, with some trepidation, further lesions were and tracts in an individual brain. made in the ventro-lateral thalamus extending the original The machine used is capable of locating an elec- lesions further forwards and backwards. This resulted in a trode in space with an accuracy of 1 mm. at the very temporary improvement in her movements which electrode tip, all coordinate settings are double- lasted only a few weeks and since then they have gradually checked and written down at the time of operation become more and more severe. and further checked after operation to ensure that no arithmetical error has been made. on September 24, 2021 by No. 30 J.H., female, aged 46. Onset of tremor and The relating of the frame coordinates to the brain rigidity 36 years previously at the age of 10. Advanced is accomplished by means of a pair of radiographs. rigidity and severe tremor and numerous tics, the most taken at right angles in constant relationship to the of which was a scream. Left frequent high-pitched to thalamotomy was carried out with excellent control frame and the x-ray tube which are coupled of tremor and rigidity on the right side. Two and a half together on a special table. Standard allowance is. years later there was no tremor on the right and no rigidity. made by mathematical means for x-ray magnifica- Akinesis and tics were not changed. At this time, however, tion. These figures seem to be beyond reproach, and J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

298 Brodie Hughes in a number of cases early in the series a droplet of sequently of other causes, usually a terminal Myodil was used as a marker and post-operative bronchopneumonia. Of these five, two necropsies check radiographs showed that this was exactly have been obtained but neither of them has been less where it had been presumed to be. than a year after operation and the appearance of the Some error may appear when the machine frame acute lesion remains unknown. In these cases gliosis is not exactly parallel to the sagittal plane or at right and contraction of tissues distorts adjacent struc- angles to this. When the frame was obviously out of tures so that the exact coordinate position of the alignment it was re-applied or direct allowance made lesion is difficult to determine. Brain blocks were for the angle of inclination according to the method sectioned serially in the coronal plane, at right angles described by Mark, McPherson, and Sweet (1954). to the AC-PC line and at known distances along it. Mathematical calculations showed, however, that In these specimens the lesions appeared to be in the when the angle of inclination was quite small and the correct coordinate position. One can presume, target points close to the reference points, as is the therefore, that error from the first two factors is case in this method, then the possible deviation was slight and probably not more than 2 mm. so small as not to constitute any gross error. Geographical error, however, may be considerable Fortunately, no patient in this series has died as a and no satisfactory method of overcoming the vari- result of operation and only five have died sub- ability of nuclear position has yet been devised. guest. Protected by copyright.

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FIG. 1. The estimatedposition oflesions in somepatients developing hemiballismus after thalamotomy. In each illustration the lateral view ofthe lesion is on the left and the antero-posterior view on the right. The horizontal solid line, marked A.P. in the first illustration, represents the intercommissural plane and the vertical from it, marked 500, represents the mid- point ofthis plane. In each illustration theposition ofthe subthalamic nucleus (cross-hatched) is indicated below the intercommissural line. J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

Involuntary movements following stereotactic operations for Parkinsonism 299 The percentage system described above would following facts. First, that the continuity of move- seem to reduce this error to a minimum and it is ment is related to the type and extent of pathology thought that the adjustment of electrode position and not intrinsic in the type of movement. In many from stimulation and recording data further reduces cases here and in the literature the movements were this error. Nevertheless, one cannot be certain in all not constantly present, tended to be absent when the probability that more than 70% of such lesions will patient was relaxed and occupied with other matters be wholly within a nucleus of the size of the ventro- but became aggravated under stress or when his oralis anterior or posterior. Certain reference points, attention was directed towards them. Denny-Brown however, have greater validity. In considering (1962) has considered in great detail the reflexcharac- ballismus one is naturally concerned with possible ter of involuntary movements and their relationship damage to the subthalamic nucleus and in all brains to attention and especially visual, tactile, and this lies wholly below the anterior-posterior com- positional stimuli. missure line. This is a plane that can be ascertained Secondly, there is a clear topographic relationship with accuracy from radiological data and if the to pathology. The shoulder, hand, or foot may be lesion is certainly above this line then the sub- involved alone, whilst, as the disease progresses, it thalamic nucleus cannot have been damaged directly. does so in an orderly manner spreading from its In only two cases in this series did the lesion appear initial site to involve the whole limb or side of the to extend below the line, in one even the sub- body. Many authors have described this topographic thalamic nucleus itself may have been damaged, but relationship in the subthalamic nucleus, the face in both these cases the ballismus was slight and being represented anteriorly and the hind limb transient (Fig. 1). posteriorly (Martin and Alcock, 1934; Whittier,

It was considered, in the light of the above argu- 1947; Dierssen et al., 1961). guest. Protected by copyright. ments, reasonable to think that 70% of the lesions Thirdly, that there are progressions and regres- made were in the ventro-oralis nucleus whilst the sions in the disease, most of the surgical cases having remainder may have involved adjacent structures, recovered completely within a few days. It was especially the medial portion of the internal capsule probably post-lesion oedema in these cases which had and lateral areas of the ventro-oralis internus. The impaired function rather than destruction of cells or meagre post-mortem material available would fibres and it may be noted that in the only case in confirm this supposition. which ballismus persisted there was E.E.G. evidence of abnormal function within a few seconds ofmaking DISCUSSION a lesion and overt ballismus appeared before the end of the operation. SITES OF LESIONS CAUSING HEMI-CHOREA In a series Fourthly, that one physical insult at least may of 200 cases of Parkinsonism lesions in the ventro- antedate the appearance of ballismus by at least lateral thalamus have resulted in involuntary move- two and a half years. It hardly seems possible that ments in 12 cases, either immediate or delayed by a progressive gliosis from this lesion could continue period of up to two and a half years. In seven, the for so long a period and one must presume the movements were choreiform or ballismic, in two interposition of one or more further lesions on the athetotic, in two myoclonic, and in two rhythmic first surgical one, presumably due to the progres- blinking. It may seem unreal to class all these sion of the disease itself. together and, indeed, the rhythmic blinking would The major and over-riding concern of the surgeon http://jnnp.bmj.com/ seem to be quite different from the others and is to ascertain the cause of such a complication possibly a manifestation of post-encephalitic disease and avoid it in future operations. If the cause could akin to oculogyric crises. Close examination, be ascertained it might well throw some light on the however, both of the evolution in individual patients neurophysiological basis of involuntary movements. and of extra-slow motion film, shows that the other Most authors have assumed, even in the early three types of movement merge imperceptibly into papers, that ballismus results from damage to the each other. In particular, the very early stage of subthalamic nucleus or its tracts. There can be ballismus is indistinguishable from athetosis. little doubt that in the animal such damage usually on September 24, 2021 by To the purist hemiballismus constitutes a disease results in ballismus, and that in most of the human entity in which the whole of one side of the body is cases of vascular aetiology this nucleus is involved affected, the onset is acute, and so forth. It must be (Papez, Bennett, and Cash, 1942; Thurel and Grenier, realized now that such a concept is a special one and 1947; Carpenter, 1955; Bedwell, 1960). An increas- probably related to a particular vascular pathology. ing body of evidence has accumulated, however, The present series of cases and innumerable to show that ballismus can occur from lesions not examples from the literature make quite clear the affecting this nucleus or its tracts and, indeed, from J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

300 Brodie Hughes lesions in quite a remote part of the brain (Wilson, nucleus Hyland and Forman (1957) suggest that 1954; Martin, 1957; Schwarz and Barrows, 1960). recovery in spontaneous cases is more likely when The sites of lesions, though usually in the basal the lesion involves the afferent tracts than the nucleus ganglia, are so widespread that it is difficult to accept itself. Whether this is true in these cases can only be this type of involuntary movement as resulting from speculation but it would be reasonable to assume damage to a single neural circuit. that the onset and recovery in these cases was most The first concern of the surgeon in considering likely to be due to the onset and resolution of trau- this problem is the site of the lesion. Has he reason- matic oedema rather than the particular area able evidence of its site and is it involving the sub- affected. The only evidence against this hypothesis thalamic nucleus? In this series, for the reasons is the case of J.Hd. quoted above. Here deliberate explained above, the exact geographical site in the surgical extension of the first lesion resulted in some antero-posterior and lateral planes cannot be pre- improvement in movements; one might have ex- dicted with certainty, that is to say, with respect to pected it to make them worse if the surgical lesion particular nuclei, probably not more than 70% of can be incriminated in this case. lesions being wholly within the ventrolateral The second matter for consideration is the small thalamus. One can predict with certainty, however, number of cases in which this complication occurs. the relationship to the intercommissural plane and Though there may be some small variations in the in 10 of the 12 it would be a justifiable assumption coordinate position of lesions and rather more that the subthalamic nucleus was not damaged. geographical variation with respect to nuclei, In the one case in which this nucleus may have been surgical lesions of this nature are, in comparison damaged the movements were mild and transient. with the size of nuclei in the area, relatively large and

One would feel justified in saying, therefore, that one would not expect such variations from patientguest. Protected by copyright. direct damage to this nucleus was not the cause of to patient to provide the explanation of this pheno- abnormal movements in this series. Indirect damage, menon. Some indication of the reason may be de- however, cannot be excluded and it is possible that duced from the three patients in whom ballismus damage to vessels may have occasioned lesions re- appeared some time after the surgical lesion and on mote from the primary surgical one. A study of the the same side as that treated. This may have been disposition and direction of feeding vessels in this fortuitous and indeed, as in the case of E.S. quoted area, however, would make one think that a lesion above, such abnormal movements do occur spon- lying superior to the subthalamic nucleus would be taneously in Parkinsonism. That in all the cases in very unlikely to interfere with its blood supply. which this has occurred it appeared on the same side The many cases in the literature when the nucleus as the surgical lesion would seem to make coincidence has been undamaged make it unnecessary, of course, unlikely. to assume damage to this area to produce ballismus. The probable explanation is that in such cases at It seems clear from the literature, and probably least two lesions are necessary to produce ballismus. from evidence in this. series, that lesions outside the One of these is in the ventrolateral thalamus; subthalamic nucleus can cause ballismus. The where the other may be we do not know. Both caudate, lenticular nucleus, portions of the internal these lesions can be produced by the disease itself, capsule, zona incerta, Forel's fields, and the parietal as in the case of I.S. In other cases the unknown cortex have all been invoked as a site of origin and in lesion is already present and the second, the thalamic,

a number of cases the ventrolateral thalamic area is provided by the surgeon. In another group the http://jnnp.bmj.com/ (Martin, 1957; Dierssen et al., 1961). Whilst in many thalamic lesion is provided by the surgeon and, at a cases occurring spontaneously multiple lesions have later date, the progress of the disease provides the been present, or a single lesion has involved a second lesion. The logical evidence here, of course, number of structures, in the present cases and that of only infers that at least two lesions are necessary; Dierssen et al. the lesions were confined to the in fact it may be many more than this. ventrolateral thalamus. One must accept this site, Since this is a rare occurrence it may be worth- therefore, as one capable of inducing ballismus. while to look into the pattern of disease in these

Two further matters have to be taken into considera- patients to see if it differs from the general spectrum on September 24, 2021 by tion here. First, though the lesions in most cases of disease in Parkinsonism. Anyone who sees a large involved a large area of the ventro-oral nucleus the number of these patients over a short period of time movements in all but one case were mild and tran- realizes that there are many patterns of clinical sient. This suggests that they result from lesion disease. Tremor may occur almost as an isolated oedema involving adjacent structures, and sub- factor with little or no rigidity, akinesis, or speech sequently subsiding, rather than involvement of this defect. Akinesis may appear in similar manner, nucleus itself. In talking about the subthalamic often proceeding to mental deterioration and minimal J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

Involuntary movements following stereotactic operations for Parkinsonism 301 rigidity and hardly any tremor. There are many ventrolateral thalamic lesions that it would seem other groupings which may be made on a clinical reasonable to continue this safeguard. basis. It seems likely, therefore, that Parkinsonism The treatment of established ballismus provides comprises a number of different disease entities, an interesting and difficult problem. Most of the possibly with differing aetiology. cases reported are of the 'spontaneous' variety; they In the present series no clear clinical picture are in elderly people, with a poor life expectancy and emerges: most were the usual combination ofrigidity, already with advanced cerebrovascular degeneration. tremor, moderate akinesis, speech defect, and so It must also be taken into account that the prog- forth. The evolution of the disease in this group, nosis in these cases, as far as involuntary movements however, was markedly different from the group is concerned, is not bad, probably as many as half as a whole. The average age at treatment was much remitting spontaneously (Hyland and Forman, lower than the group, being 47-5 years as against 1957). In many reports the alleviation has been only 54-6 (P = > 0-01). But the age of onset of disease partial and therefore the assessment of surgical was significantly lower than the group, being 32-1 results is extremely difficult. as against 46-0 (P = > 0-001). The evolution of the Many records date from the time before stereo- disorder appeared to be slower than usual with an tactic surgery was commonplace and involve open average length of history of nearly twice that of the operations on the motor pathways. Operations on whole group, 15-6 years as against 8-4, but this was the cortex (Russell Meyers et al., 1949; Alpers and not significant statistically (P = > 0-05). As a Jaeger, 1950; Talairach, Paillas, and David, 1950) group, therefore, it would seem that this complica- have been well-documented as have those on the tion occurred in people whose disease started at a cerebral peduncle (Walker, 1949; Bucy, Keplinger, much younger age and ran a slower course. The and Siqueira, 1964). The report by Bucy et al. guest. Protected by copyright. suggestion may be that all these cases were of the is a most carefully documented one in which a close post-encephalitic variety. study was made of the post-mortem pathology, the patient dying two and a half years after operation TREATMENT OF POST-OPERATIVE HEMI-CHOREA The during which he had been quite free of involuntary considerable literature on hemiballismus combined movements. Some degree of motor loss seems in- with recent clinical experience in stereotactic evitable fromsuch operations but such isthe nature of surgery offers little help in planning avoidance of these gross and exhausting movements that even a this complication or in treating it when established. severe degree of paralysis may be preferable, pro- The data given above would suggest that such a vided that no better treatment is available. complication should be anticipated when treating Operations on the ventral quadrant of the spinal patients in the post-encephalitic group, or who cord have also been successful and in some relief of start Parkinsonism at an early age with slow evolu- involuntary movements has been achieved without tion. Such patients should be treated with extreme any motor deficit (Brown and Walsh, 1954; Strain care and most probably warned before operation and Perlmutter, 1957). that this is a possible complication. Placing the lesion Stereotactic operations have also been well should be most rigidly controlled and continuous documented in recent years though there seems to be E.E.G. monitoring from scalp and depth electrodes wide variation in the site of election for such lesions. should be carried out during operation. It has been Hassler (1959) did not achieve much success from my practice to confine all lesions to the area above lesions in the ventrolateral thalamus (ventro-oralis http://jnnp.bmj.com/ the anterior-posterior commissure line, thus ensuring anterior) but suggested that lesions in the internal that the subthalamic nucleus is not directly damaged. capsule rostral to the main pyramidal tract were Certainly this manoeuvre has not prevented the effective in two of his cases. Andy (1962) recom- complication occurring, though the incidence in mended lesions in the 'diencephalic' area, largely this series is lower than in most. Furthermore, below the inter-commissural plane. In one case recent work has suggested that lesions in the sub- movements were improved and in three others they thalamic area are most probably those most suitable stopped, though the survival periods were short in for the control of tremor (Andy et al., 1963; Spiegel two of them (10 days and four and a half months). on September 24, 2021 by et al., 1963). Nevertheless, the incidence of ballismus The sites of his lesions were varied, and from the in the cases treated with subthalamic lesions (Andy illustrations the subthalamic nucleus itself may have et aL, 1963) was much higher than in other series been involved in two. In some cases lesions in the with more conventional lesions (five cases in 58 ventrolateral thalamus have been successful (Martin patients, 8 6 y). My own experience of such lesions and McCaul, 1959). Though case reports are few, has not been very impressive and such excellent conversations and correspondence with other neuro- results on tremor have been obtained from standard surgeons suggest that such lesions are as successful J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

302 Brodie Hughes as any. What should be the treatment, therefore, globus pallidus would be most likely to modify or when a lesion already made in this area has been the abolish ballismic movements and it would seem cause of ballismus ? There can be little doubt that the reasonable to attempt this as a first step in the situation is modified considerably by the pre-existing treatment of the post-operative cases. Capsular disease. Dierssen et al. (1961) in one case extended a lesions rostral to the main pyramidal tract would lesion in the ventrolateral thalamic area a little also seem effective in the human and if the medial deeper and this made the ballismus worse in the leg. pallidal lesion proved ineffective, or only partially In one case above (J.Hd.) the thalamic lesion was so, it would seem also reasonable to extend the lesion extended both anteriorly and posteriorly with only into the capsular area adjacent to the medial palli- transient improvement. The very wealth of sites for dus. If neither of these lesions were effective in successful operations indicates both the variability stopping the movements it would probably indicate of the disease and the lack of a universally effective that some motor deficit must be accepted and a operation for this condition. The position was well pedunculotomy on the lines suggested by Bucy summarized by Dierssen et al. as follows: 'Hemi- should be undertaken. ballismus represents a physiological expression of a functional state of the nervous system produced by SUMMARY a combination of pre-existent pathological alterations with a releasing lesion. We cannot assume In most reported series of stereotactic operations for that either the underlying alterations or the releasing Parkinsonism involuntary movements resembling lesion is necessarily located identically in all cases. athetosis or chorea have been noted post-operatively Consequently, we should not expect that the same in a small percentage (2 %). In the majority of cases

acute lesion will yield identical clinical effects in all these are mild and transient. In rare cases theyguest. Protected by copyright. instances.' persist for months or years. In the present series of In recent years a view has circulated amongst 200 cases the incidence of immediate movements stereotactic surgeons, though I have never seen it was 3%. expressed in print, that ballismus is associated with The types of movement encountered are described partial lesions of the subthalamic nucleus, or its and the nomenclature of involuntary movements in tracts. This probably derives from the work of general is discussed. Aggravation of Parkinsonian Carpenter, Whittier, and Mettler (1950) who tremor was not encountered. Two cases had inten- described the effects of subthalamic lesions in 48 tion tremor slightly aggravated by operation. Two rhesus monkeys. They noted that ballismus de- developed athetosis and four hemi-chorea. Two veloped if more than 20% of the nucleus was des- patientsdevelopedmyoclonusandtworhythmicblink- troyed but that thereafter lesion size had little effect ing. It is suggested that athetosis is a definite entity on the severity of movements. In lesions that were and conforms to the description given by Denny- 'too large' ballismus did not develop, nor did it if Brown (1962) as a regular alternation of posture. the number of adjacent structures involved by the Where there is a continual flow of movement and lesions was more than six. The implication was that there is alternation between many different postures partial lesions of the nucleus were most successful in a random manner the term chorea should be in producing ballismus, whereas, ifthe whole nucleus, used. Ballismus can be used to designate the wild together with a number of adjacent structures were flinging movements seen in these patients but is

destroyed ballismus did not develop. In another probably better used to define a special clinical http://jnnp.bmj.com/ report on this material (Mettler and Carpenter, 1949) syndrome of spontaneous sudden onset in elderly they analysed lesions which had modified ballismus and atherosclerotic patients. produced in this way. They indicated that lesions The method of operation is described and the in the medial globus pallidus were most effective in technical procedures of locating lesions in individual stopping ballismus, though in some animals major patients. The location of lesions was determined portions of the adjacent internal capsule were primarily by anatomical coordinates based on involved as well and in one a ventrolateral thalamic percentages of measurable distances, anterior- lesion stopped the movements. The implication posterior commissure separation, height of thalamus, on September 24, 2021 by read into this work has been that total destruction and width of lateral ventricle. The final position of of the nucleus together with adjacent structures lesions was guided by information from E.E.G. might be the best form of treatment. No one, so scalp and depth recordings, stimulation, and local far as I am aware, has yet put this idea into practice. cooling. The available theoretical and practical evidence The clinical material is discussed in detail and would suggest that destruction of the fibre pathway summaries given of the case histories of individual between the subthalamic nucleus and the medial patients. Three cases are then discussed in which J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.28.4.291 on 1 August 1965. Downloaded from

Involuntary movements following stereotactic operations for Parkinsonism 303 chorea appeared on the side treated for Parkinson- Gillingham, Watson, W. S., Donaldson, A. A., and Naughton, J. A. L. (1960). The surgical treatment of Parkinsonism. Ibid., 2, ism at some interval from the time of operation, 1395-1402. six months in one and two and a half years in the Gros, C., Serrats, A. F., Adib-Yazdi, I. S., and Parker, S. A. (1963). Les limites de l'indication chirurgicale dans la maladie de may occur spon- others. It is indicated that chorea Parkinson. Neuro-chirurgie, 9, 3-1 1. taneously in Parkinsonism and one case is cited. Hassler, R. (1959). Anatomy of the thalamus. In Schaltenbrandt and Bailey's Introduction to Stereotaxis, Vol. 1, pp. 230-290, The probable anatomical location of the lesions ed. G. Schaltenbrandt and P. Bailey. Thieme, Stuttgart, and in these patients is discussed with special reference Grune and Stratton, New York. to their relation to the subthalamic nucleus. Hughes, B. (1961a). Stereotactic surgery. In British Surgical Practice: Surgical Progress, 1961, pp. 129-158. Butterworths, London. The nature and significance of this complication (1961b). A method of using information from stereotactic is discussed and the literature on the subject re- atlases for the location of targets in the brain. Excerpta med. (Amst.), Int. Congr. Series. No. 36, p. 88. viewed. It is stressed that such a complication usually Hyland, H. H., and Forman, D. M. (1957). Prognosis in hemiballis- follows lateral thalamic lesions and is rare with those mus. Neurology (Minneap.), 7, 381-391. Kelman, H. (1945). Hemiballismus. J. nerv. ment. Dis., 101, 363-371. of the globus pallidus. It is significantly related to Lea-Plaza, H., and Uiberall, E. (1945). Hemilbalismo. Rev. med. Chile, Parkinsonism which is post-encephalitic or where 73, 938-944. the onset has been early in life and the progression Mark, V. H., McPherson, P. M., and Sweet, W. H. (1954). new method for correcting distortion in cranial roentgenograms. slow. The incidence of delayed onset suggests that Amer. J. Roentgenol., 71, 435-444. at least two lesions are necessary to produce hemi- Martin, J. P. (1927). Hemichorea resulting from a local lesion of the brain. Brain, 50, 637-650. chorea from a lateral thalamic lesion. One is provided (1957). Hemichorea (hemiballismus) without lesions in the corpus by the surgical lesion and the other, which may post- Luysii. Ibid., 80, 1-10. date the surgical lesion, by the disease process of and Alcock, N. S. (1934). Hemichorea associated with a lesion of the corpus Luysii. Ibid., 57, 504.516. Parkinsonism. The anatomical location of lesions, -, and McCaul, I. R. (1959). Acute hemiballismus treated by ventrolateral thalamolysis. Ibid., 82, 104.108. therefore, is probably different from the cases of guest. Protected by copyright. Mettler, F. A., and Carpenter, M. B. (1949). The modification of spontaneous hemi-ballismus. subthalamic hyperkinesia in primates. Trans. Amer. neurol. Forms of treatment are reviewed and suggestions Ass., pp. 81-88. Meyers, R., Fry, F. J., Fry, W. J., Eggleton, R. C., and Schultz, D. F. made as to the lines of treatment which may be (1960). Determination oftopologic human brain representations adopted in the post-operative cases. and modification of signs and symptoms of some neurologic diseases by the use of high level ultrasound. Neurology (Min- neap.), 10, 271-277. REFERENCES Sweeney, D. B., and Schwidde, J. T. (1949). Hemiballismus: an extrapyramidal disorder in which early surgery is indicated. Trans. Amer. neurol. Ass., pp. 79-81. Alpers, B. J., and Jaeger, R. (1950). Hemiballism and its control by Papez, J. W., Bennett, A. E., and Cash, P. T. (1942). Hemichorea ablation of the motor cortex. Arch. Neurol. Psychiat. (Chic.), (hemiballismus). Arch. Neurol. Psychiat. (Chic.), 47, 667-676. 64, 285-287. Schwab, R. S., and England, A. C. (1958). In The Pathogenesis and Andy, 0. J. (1962). Diencephalic coagulation in the treatment of Treatment ofParkinsonism, ch. 8. Thomas, Springfield, Illinois. hemiballismus. Confin. neurol. (Basel), 22, 346-350. Schwarz, G. A., and Barrows, L. J. (1960). Hemiballism without , Jurko, M. F., and Sias, F. R. (1963). Subthalamotomy in treat- involvement of Luys' body. A.M.A., Arch. Neurol., 2, 420-434. ment ofParkinsonian tremor. J. Neurosurg., 20, 860-870. Spiegel, E. A., and Wycis, H. T. (1958). Long-range effects of electro- Bedwell, S. F. (1960). Some observations on hemiballismus. Neurology pallidoansotomy in extrapyramidal and convulsive disorders. (Minneap.), 10, 619-622. Neurology (Minneap.), 8, 734-740.

Brown, M. H., and Walsh, N. M. (1954). The effect of ventral quadrant , Szekely, E. G., Adams, J., Flanagan, M., and Baird, H. W. section of the cervical cord on hemiballismus. J. Neurosurg., (1963). Campotomy in various extrapyramidal disorders. 11, 409-412. J. Neurosurg., 20, 871-884. Bucy, P. C., Keplinger, J. E., and Siqueira, E. B. (1964). Destruction Strain, R. E., and Perlmutter, I. (1957). Hemiballismus relieved by of the 'pyramidal tract' in man. Ibid., 21, 385-398. ventral quadrant section of the cervical spinal cord without Carpenter, M. B. (1955). Ballism associated with partial destruction of paralysis. Ibid., 14, 332-336.

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