Showing papers in "Journal of Neurology, Neurosurgery, and Psychiatry in 1971"

Focal dysplasia of the cerebral cortex in epilepsy

Abstract: An unusual microscopic abnormality has been identified in the lobectomy specimens removed surgically from the brains of 10 epileptic patients. The abnormality could seldom be identified by palpation or with the naked eye. Histologically, it consisted of congregations of large, bizarre neurones which were littered through all but the first cortical layer. In most, but not in all cases, grotesque cells, probably of glial origin, were also present in the depths of the affected cortex and in the subjacent white matter. This kind of abnormality appears to be a malformation. The picture is reminiscent of tuberous sclerosis but too many distinguishing features, both in the clinical and in the pathological aspects, make this diagnosis untenable. The cases are therefore looked on provisionally (since all but one are still alive) as comprising a distinct form of cortical dysplasia in which localized, exotic populations of nerve cells underlie the electrical and clinical manifestations of certain focal forms of epilepsy.

Electrophysiological estimation of the number of motor units within a human muscle.

Abstract: An electrophysiological method is described for estimating the numbers of motor units in the extensor digitorum brevis muscle in man. The results obtained are compared with counts of axons in the nerve to the muscle. The significance of the sizes of the evoked motor unit potentials is discussed.

Potentiation of `late' responses evoked in muscles during effort

Abstract: A study has been made of the effect of voluntary contraction on the `late' responses which can be recorded in muscles after indirect stimulation. Two late responses have been described of which the first was shown to consist mainly of a potentiated H-reflex. The potentiation of this wave was greatest in the abductor pollicis brevis muscle and depended largely on `direct' descending pathways to motoneurones. In addition, a later evoked muscle response appeared during effort; the nature of this wave was uncertain. Simple formulae have been devised to express the excitability of motoneurones to inputs from muscle nerves during effort.

Human flexor reflexes

Abstract: One type of flexor reflex, that recorded from the tibialis anterior muscle in response to electrical stimulation of the sole of the foot, was studied in normal subjects and patients with several neurological disorders. Normally this reflex consists of two components, the second of which is related to the actual withdrawal. The first component, normally of lower threshold, is difficult to evoke in patients with chronic spinal cord or discrete cerebral lesions, whereas it has an unusually low threshold and is very clearly seen in those with Parkinson's disease. In patients with spinal cord disease, the exaggerated flexor reflexes are seen at long latencies after relatively small stimuli. During the early phase of recovery from spinal transection, both components may be seen and are, therefore, spinal in origin. Studies of patients with the sensory neuropathy of Friedreich's ataxia suggest that the afferent fibres responsible for these flexor reflexes are the small myelinated fibres. Recovery curves demonstrate very long-lasting changes in flexor reflex excitability in normal subjects and patients with `spasticity' from spinal lesions. This differs in patients with `spasticity' from lesions rostral to the brain-stem. Examples in man of such physiological phenomena as reciprocal inhibition, local sign, habituation, temporal and spatial summation are discussed.

Epidemiology of headache and migraine in women

Abstract: During a survey of a defined community, 2,933 women aged 20 to 64 years were asked standard questions about headaches. Overall, 78·7% had headaches during the year immediately preceding the survey and this proportion decreased significantly with age. Random samples of subgroups with unilateral headaches, headaches preceded by a warning, and headaches accompanied by nausea were examined clinically. From these clinical diagnoses the prevalence of women with migraine during the previous year was estimated as 19%. Nearly half of those diagnosed as having migraine had never consulted a doctor because of headaches. Women with migraine and non-migrainous headaches kept diaries of all headaches and data are presented for the time and day of onset, severity, duration and relation of menstruation for both types of headache.

Functional compensation in partially denervated muscles

Abstract: In patients with various types of chronic motor denervation, the numbers of surviving motor units have been compared with the twitch tensions developed by the same muscle (extensor digitorum brevis). It was found that functional compensation in partially denervated muscles was often marked; in most patients abnormally small twitches occurred only when fewer than 10% of motor axons remained. The factors responsible for this compensation are considered. The twitch speeds of partially denervated muscles differed markedly, even among patients with the same disorder; there was evidence to suggest that the twitches of some motor units might become slower than those found in normal muscles.

Normal sensory conduction in the nerves of the leg in man

Abstract: For comparison with findings in neuropathy, sensory conduction was studied along distal and proximal segments of the superficial peroneal, sural, and posterior tibial nerves in 71 healthy subjects 15 to 72 years of age and normal values were established (Table 2). In the distal segments of the nerves of the leg the amplitudes of the sensory potentials were one tenth those in the nerves of the upper extremity; the potentials were split up into several components, and electronic averaging was used routinely to analyse the shape of the potentials. The maximum sensory conduction velocity was 56·5 m/sec, SD 3·4 m/sec, in proximal; and 46·1 m/sec, SD 3·7 m/sec, in distal segments of the nerves (subjects 15 to 30 years, 34 to 36°C). Slowing of conduction with increasing age was the same proximally and distally (subjects 40 to 65 years: proximally 53·1 m/sec, SD 4·6 m/sec; distally 42·5 m/sec, SD 5·5 m/sec, 34 to 36°C). The velocity in the slowest components of the sensory potentials averaged 20 m/sec. The sensory velocity was 3 to 6 m/sec faster than the motor. The error arising from measuring the conduction distance on the surface across the capitulum fibulae was evaluated.

Diagnosis and treatment of thoracic intervertebral disc protrusions.

Abstract: A series of 14 patients with a protruded thoracic intervertebral disc is reported. We believe that the true incidence may be as high as one patient per million population per annum. Trauma, sometimes mild, seems to have played a significant role in this series. This fact coupled with pronounced numbness and disagreeable paraesthesiae should suggest the diagnosis with thoracic spinal lesions. Armed with clinical suspicion, radiological verification of the lesion can be expected using a thorough myelographic technique supported if necessary by tomography. A posterolateral approach which combines laminectomy, complete excision of the ligamentum flavum, and the extradural removal of protruded disc is described. The technique is safe and effective.

Sensory conduction from digit to palm and from palm to wrist in the carpal tunnel syndrome.

Abstract: In normal subjects the maximum and minimum conduction velocity along sensory nerve was the same from digit to palm and from palm to wrist. Severe slowing from palm to wrist in patients with the carpal tunnel syndrome was often associated with only slight slowing from digit to palm. The distal slowing is attributed to a reversible constriction of nerve fibres, an assumption supported by the recovery in distal conduction velocity as early as two and a half months after decompression. The sensory velocity from wrist to elbow was normal or supernormal, whereas the motor velocity was often slightly decreased. The exclusion of the normal segment of the median nerve distal to the flexor retinaculum made it possible to demonstrate abnormalities across the flexor retinaculum in patients with clinical signs of carpal tunnel syndrome in whom distal motor latency and sensory conduction from digit to wrist were normal.

Bancroft's introduction to biostatistics

Abstract: ever in doubt, of the ageing of the population in hospitals for the mentally subnormal, and in particular of the I onger survival rate of the severely subnormal. Although this volume has only 254 pages and an index, the lay-out is compact, making it the equivalent of a larger volume. It is printed by photolithography; the type is clear and the many Figures and Tables are well produced. It has a paper cover, but is well bound and is good value for money.

Fast and slow twitch units in a human muscle

Abstract: A study has been made of the isometric twitches of single motor units in the extensor hallucis brevis (EHB) muscle in man. The twitch contraction times ranged from 35 to 98 msec and the pooled results indicated the presence of at least two types of unit. The recorded twitch tensions also varied considerably (from 2 to 14 g) but were not related to the twitch speeds. The twitch tension developed by the whole EHB muscle depended on the initial length of the muscle and on the age of the subject. The EHB muscle was estimated to contain approximately 56 motor units.

Closed head trauma and aphasia

Abstract: A prospective study has been done on the relationship between closed head trauma and aphasia. The most frequent type of aphasia seen after closed head injury is an anomic aphasia. This aphasia is often associated with other defects of higher cortical function. The second most common type of aphasia is a Wernicke's aphasia. Other types of aphasia were not seen in this study. The areas of the head which when injured produce aphasia are the right orbitofrontal region and the left temporoparietal region. The prognosis for recovery appeared highly variable.

Judgment of spatial orientation in patients with focal brain damage

Abstract: Thirty control and 121 brain-damaged patients with injury restricted to one hemisphere were presented with a test requiring the placing of a rod, fixed on a support by a hinged joint, in the same position as a model. Two versions of the test were given, one to be performed with the aid of vision and the other only by touch. The brain-damaged patients were subdivided into the following groups: right hemisphere patients without visual field defect (VFD): 30; right hemisphere patients with VFD: 20; left hemisphere patients without VFD: 46; left hemisphere patients with VFD: 25. The test modality did not differentially affect the performance of the groups. Both on the visually and on the tactually guided version of the test the right hemisphere group with VFD did significantly worse not only with respect to controls but also with respect to the three other braindamaged groups. The latter, in turn, were not significantly inferior to patients without cerebral damage. It appears, therefore, that when spatial perception is tested at a very basic and simple level, such as the detection of orientation in space of a rod, there is an almost complete dominance of the posterior region of the so-called minor hemisphere. This result must be contrasted with the less striking asymmetry of functions shown in more complex spatial tasks-for example, route finding, copying drawings, block designs-that are failed also by patients with damage to the left posterior area. Normal subjects reproduced the orientation of the rod on the horizontal plane with a constant error which was found to be dependent on the position of the model. Clockwise deviations were made when the model was on the left and counterclockwise deviations when the model was on the right. The constant error was present in left brain-damaged patients too, while it was not significantly different from zero in right brain-damaged patients. A systematic error was also found on the vertical plane and it consisted in the tendency to stop the rod below the level of the standard.

Altered thermal sensitivity in injured and demyelinated nerve. A possible model of temperature effects in multiple sclerosis

Abstract: Electrophysiological studies were performed on frog and guinea-pig peripheral nerves to determine the effect of temperature on conduction at the site of pressure and demyelinating lesions. An increased susceptibility to thermally-induced conduction blockade has been demonstrated. In pressure-injured frog and guinea-pig nerves, conduction blocks occur at temperatures approximately 6°C lower than in normal nerves. A similar phenomenon occurs in guinea-pig demyelinated nerve (experimental allergic neuritis) and in some cases at temperatures around 15°C lower than in controls. It is suggested that these effects are the result of a critical lowering by temperature of an already markedly depressed conduction safety factor. In support of this, it has been shown that calcium ion depletion, which would be expected to increase the conduction safety factor by lowering the threshold for excitation, counteracts the increased thermal sensitivity of frog pressure-injured nerve. These findings are discussed in relation to well-known temperature effects in multiple sclerosis. They add support to an earlier proposed hypothesis that the changes in signs and symptoms with a change of body temperature in multiple sclerosis may be caused by an effect of temperature on axonal conduction.

Electrophysiological study of dystrophia myotonica

Abstract: A comprehensive electrophysiological study has been made of the extensor digitorum brevis muscle and its motor innervation in 17 patients with dystrophia myotonica. The mean contraction and half-relaxation times were prolonged in the isometric twitches of dystrophic muscles. Decremental responses to repetitive motor nerve stimulation were found in two patients. All the terminal latency measurements were normal and only one patient had a reduced nerve conduction velocity. As the patients aged their muscles became weaker, due to a progressive loss of motor units. This finding, and the normal sizes of many surviving motor units, suggested that the muscle changes resulted from a primary defect of motor innervation.

Analysis of l-dopa induced dyskinesias in 51 patients with Parkinsonism

Abstract: An analysis of 51 patients with Parkinsonism who have developed L-dopa induced dyskinesias is presented. The cause has not been proven, although various hypotheses are discussed. One third of the total number of patients treated developed dyskinesia. These patients tend to respond better to L-dopa than the other group. There is a tendency for the older patient or the patient with long-standing disease to develop dyskinesias. There appears to be no way of predicting which patients will develop dyskinesia by analysis of the symptoms or the aetiology of the Parkinsonism syndrome. The unilateral characteristic of the dyskinesia in patients with hemi-Parkinsonism and patients with unilateral thalamotomies suggests that structural abnormalities are critical in determining the presence and localization of dyskinesias. This is supported by non-occurrence of similarly treated patients without Parkinsonism.

Blink reflex studies in patients with Parkinsonism before and during therapy

Abstract: Electrophysiological analysis of the blink reflex makes it possible to quantitate the reflex changes observed in pathology. The authors therefore propose a `habituation index' to be determined by recording the electromyographic reflex response during stimulation at controlled frequencies. Several populations of subjects were tested. It was confirmed that marked differences in blink reflex habituation exist between normals and patients with Parkinson's disease. It was also found that when patients with Parkinsonism were treated with the classical anticholinergic drugs their habituation index remained virtually unchanged. However, treatment with either l-dopa or amantadine caused a rise in the index in almost all patients tested. On the basis of these findings it is suggested that these two new drugs have a highly similar mechanism of action.

An electrophysiological study of Duchenne dystrophy

Abstract: An electrophysiological study has been made of extensor digitorum brevis muscles in 19 boys with Duchenne dystrophy. The isometric twitches of the dystrophic muscles developed less tension and were usually slower than those in controls. Impulse conduction velocity appeared to be reduced in distal regions of nerve axons but was normal proximally. The most interesting finding was a reduction in the number of functioning units in all but one of the patients. The sizes of the surviving units suggested that the results could be explained more easily in terms of a neurogenic process than a primary myopathic one.

Permeability and function of biological membranes

Abstract: Dawson, the technique became less esoteric with the introduction of small digital computers. The anticipated flood of papers studying the variation ofevoked responses in cerebral diseases has not appeared. A major difficulty is that there is not one evoked wave but many. These vary sufficiently from one individual to another in temporal amplitude and distribution parameters to such an extent that there is no agreed nomenclature. This makes it extremely difficult to identify abnormalities, though changes in time in one subject are relatively easy. Possibly more interesting than the primary response in receiving areas of cortex are the secondary responses. These are of wider distribution and correlated with activity of nonspecific afferent systems. Slow potential shifts, such as the negative variation discovered by Grey Walter, are certainly connected with psychological set and expectancy of particular events. Legitimate correlations between EEG activity and psychical responses seem at last to be possible. Evoked potentials and contingent negative variation are certainly valid techniques for the investigation of deafness and perception in non-communicating subjects, including children. Differences between hemispheres are also promising in the study of migraine and hemianopia. This book is the proceedings of a conference sponsored by NASA and the American Institute for Biological Sciences in San Francisco in 1968. It is an excellent production, appearing with commendable speed and few errors. The seven chapters and six supplements provide an admirable introduction to the subject and the unusually lucid discussions highlight the areas of controversy. The price indicated is correct. It is a wonderful bargain.

Craniopharyngiomas—a summary of 85 cases

Abstract: The results of treating 85 patients suffering from craniopharyngioma are reviewed. The recurrence of the tumour after 20 symptom-free years after radical excision is reported. Claims for successful treatment of this illness should be reviewed in this light.

Psychiatric aspects in Parkinsonism treated with L-dopa

Abstract: Psychiatric aspects of patients with Parkinsonism treated with L-dopa are described. These include acute psychosis in patients with or without previous psychiatric illness and worsening or improvement of pre-existing psychiatric conditions. Therapeutic management is discussed The relevance of these studies to the understanding of the psychiatric aspects of Parkinsonism in general is discussed.

Visual reactions in a case of long-lasting cortical blindness

Abstract: A case is described of long-lasting cortical blindness in a 71 year old man showing no other visual reactions than pupillary narrowing to light and (only after some months) optokinetic nystagmus of the `passive' type. Necropsy demonstrated total bilateral destruction of the striate area of the cortex caused by bilateral softening in the territory of the posterior cerebral artery, and nearly total loss of ganglion cells in both lateral geniculate bodies.

Cerebral arachnoid cysts in children.

Abstract: The case histories of 14 children are described in which hydrocephalus was found on investigation to be associated with a cyst of the posterior fossa or subarachnoid cisterns. The neuroradiological and histological findings are described. The cysts are considered to be developmental in origin. Their recognition and management are discussed.

Motor and sensory nerve conduction velocity in the baboon: normal values and changes during acrylamide neuropathy

Abstract: Nerve conduction velocity and the amplitude of nerve and muscle action potentials have been measured in the median and anterior tibial nerves of normal adult and infant baboons. The effect of altered temperature on velocity has also been investigated. Seven adult baboons were intoxicated with acrylamide. In animals given 10-15 mg/kg/day, the gradual development of a peripheral neuropathy was accompanied by a decline in the amplitude of both muscle and nerve action potentials. There was also a gradual fall in conduction velocity. In some cases maximal motor velocity in the median nerve fell by as much as 34%, and in the anterior tibial nerve by as much as 49%, the largest falls being seen in animals showing the greatest reductions in response amplitude. Histological studies, reported elsewhere, have shown that the main pathological change in our animals was a degeneration of the peripheral nerves, with little demyelination. Fibre diameter histograms indicated that large fibres were particularly severely affected, and it seems likely that the reduced maximal conduction velocities were due to this selective loss of large-diameter fibres.

Mechanical properties of dystrophic mouse muscle

Abstract: A physiological method of estimating the number of motor units in normal and dystrophic muscles has revealed a large reduction in the number of motor units in dystrophic muscles Anatomical confirmation of the results has been obtained Dystrophic muscles also exhibit a `myasthenic-like' response to high frequency stimulation It is suggested that the nerve fibre is primarily affected in murine dystrophy

An electrophysiological investigation of limb-girdle and facioscapulohumeral dystrophy

Abstract: A detailed electrophysiological study has been made of the extensor digitorum brevis muscle and its motor innervation in 11 patients with limb-girdle or facioscapulohumeral dystrophy. In nine patients there were reductions in the populations of motor units and many surviving units appeared to be abnormally large. Most of the investigated muscles had slowed isometric twitches and decremental evoked potentials after repetitive nerve stimulation. The experimental observations have been interpreted in terms of a neuropathic process.

Recognition and naming of object-drawings by men with focal brain wounds

Abstract: The ability to name object-drawings, measured by score and response latency, was examined in men with chronic, focal brain lesions due to missile injury. The group with left hemisphere lesions was significantly impaired on both measures and this impairment was clearly related to the incidence of clinically detectable dysphasia. In contrast, the impairment of the bilateral group was not closely associated with dysphasia; it was characterized by long response latencies which exceeded the sum of unilateral deficits in the task. Analysis of response errors showed that both misnaming and misidentification occurred but were often dissociated. Difficulty in naming was noted in men with lesions involving the left temporal lobe. Misidentification was not common; it occured more frequently in the bilateral group, in men with lesions of the occipital areas of the brain. Dissociated deficits were also noted within the group of men with residual dysphasia.

Visually evoked responses in multiple sclerosis

Abstract: Visually evoked cerebral responses (VERs) from the occipital and central areas were compared between 50 patients with multiple sclerosis and 50 control subjects. The average peak latencies of four occipital components (OII-OV) and two central ones (CIV and CV) were significantly delayed. In no instance was the amplitude significantly different. Routine EEGs were either entirely normal (16) or showed only minor findings (10) in 26 patients. Of this group, nine showed abnormal VERs. Seventeen patients had clinical symptoms or signs which pointed to spinal cord involvement only; nonetheless, eight in this group had abnormal responses. Inasmuch as changes in visually evoked potentials are not directly dependent upon the presence of a demonstrable field defect, the technique may be useful in detecting otherwise occult cerebral lesions.

Neuropathy associated with lymphoma.

Abstract: Electrophysiological studies have been performed on 62 subjects with malignant lymphoma and the results compared with those of 35 control subjects matched for age. There was evidence of impairment of conduction consistent with a generalized peripheral neuropathy in 22 subjects (35%). Histological and electronmicroscopic studies were performed on sural nerve biopsy material from five subjects, and the pathological abnormalities of the myelinated fibres were those of axonal degeneration and segmental demyelination. The unmyelinated fibres were not affected.