Cerebral venous thrombosis and subarachnoid haemorrhage in users of oral contraceptives.
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Biomedical subjects
Publications and source records attributed to P Rudge.
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The relative strengths of vertical canal and otolithic factors influencing downbeat nystagmus (DBN) were investigated in a patient whose nystagmus was of maximum intensity with the head in the upright position and abolished with the head in the supine position. The vestibuloocular reflex (VOR) was assessed by oscillating the patient about both the supine and upright positions. During oscillation about the supine position both the upward and downward VORs had equal gains in the dark (0.6) and unity gain in the light. In contrast, during oscillation about the upright, the upward VOR became hyperactive with a gain of 1.8 in the dark and 1.2 in the light, whereas the downward VOR became hypoactive with a maximum gain of 0.86 in the light. This degree of asymmetry of the VOR is greater than would be expected from a summation of spontaneous nystagmus with normal canal reflexes. We concluded that the DBN arose from an asymmetry of vertical canal function, which became manifest when the otoliths were tilted with respect to gravity. Contrasting findings are presented in a patient whose DBN was insensitive to tilt. It would seem that other cases of DBN lie on a continuum between these extreme examples.
Vestibular findings in a group of 35 patients with spasmodic torticollis without other otological or neurological symptoms were reviewed. The most consistent abnormality, present in more than 70% of cases, was a directional preponderance of vestibular nystagmus in the dark in a direction opposite to the head (chin) deviation. Rigidly clamping the head to a rotating chair did not abolish the directional preponderance. In the presence of optic fixation the directional preponderance was less frequent and its severity tended to diminish as a function of the duration of the disease. Smooth pursuit and optokinetic nystagmus were only occasionally affected. The results are indicative of primary involvement of the vestibular system in spasmodic torticollis and are discussed in terms of a break-down of the central mechanisms conveying sensory information responsible for head and eye orientation.
Twenty-seven patients with an isolated brain stem syndrome, thought to be due to demyelination, were examined by magnetic resonance imaging (MRI). A brain stem lesion was identified in 25, and clinically silent lesions outside the brain stem were demonstrated in 20. MRI was more sensitive than evoked potentials in detecting brain stem and other lesions. The scan findings were compared with those in 23 patients with multiple sclerosis, who had chronic brain stem dysfunction, with particular reference to the distribution of abnormalities and the MRI characteristics of the lesions. The relaxation times, T1 and T2, of the lesions were measured by MRI. These values were seen to fall in serial studies of acute lesions, but remained unchanged in the chronic lesions. MRI may therefore allow the age of lesions to be assessed.
The neuro-otological findings are described in 3 unrelated patients who had xeroderma pigmentosum. All had impaired hearing. Routine audiometric assessment suggested that the hearing loss was of cochlear origin; brainstem evoked potentials in 2 patients and electrocochleography in 1 support this conclusion. Two adult patients had a supranuclear ophthalmoplegia. Vestibular function was mildly deranged and visual suppression of the vestibulo-ocular reflex impaired.
4 patients with tuberculosis, 3 of whom had tuberculous meningitis, were noted to have tuberculomas on computed tomographic scanning. During antituberculous chemotherapy the intracranial lesions increased in size in all 4 patients at a time when the clinical state and cerebrospinal-fluid abnormalities were improving; in 2 of the patients the regional lymph nodes also enlarged greatly. Though the expansion of the cerebral lesions caused anxiety and led to some changes in chemotherapy, the lesions eventually diminished in size.
The records of 1428 neurological patients referred to a department of Clinical Neurophysiology for PRVER testing have been reviewed. Half field studies with multichannel recordings were carried out in the majority. 1186 of these patients had a provisional diagnosis of MS; 42% had abnormal PRVERs compared with 25% for those patients who did not have MS. Symmetrical latency increases from stimulation of either eye, interocular latency abnormalities and amplitude abnormalities were as frequent in the non-MS patients as the group with a provisional diagnosis of MS. A small proportion of patients had neurophysiological evidence of field defects; homonymous hemianopias occurred as frequently as "central" defects in the MS group. The PRVER abnormalities are considered in relation to the current models of conduction in demyelinated fibres.
Three members of a family were affected by an autosomal dominant disorder comprising cerebellar ataxia, sensorineural deafness, myoclonus, and peripheral neuropathy. This is the second kindred with this syndrome reported to date. Necropsy of the proband showed loss of cells in the dentate nuclei, a reduced amount of cerebellar white matter, and pallor of the gracile tracts in the spinal cord.
Ten patients with an accepted diagnosis of Friedreich's ataxia have been examined neuro-otologically, and oculomotor, vestibular and auditory function assessed. Brainstem auditory evoked potentials (BAEPs) were also recorded. A high incidence of various eye movement disorders was noted. Some of these were indicative of cerebellar dysfunction. Reduced vestibular function and impaired hearing were common to most of the patients. BAEPs were also abnormal in the majority; reasons underlying these abnormalities are discussed. Neuro-otologically, the patients did not constitute an homogeneous group. The findings cast doubt upon the accuracy and validity of the currently accepted criteria for the diagnosis and classification of the spinocerebellar degenerations.
We reviewed the clinical and oculomotor findings in 62 patients with downbeating nystagmus (DBN). Only those patients whose DBN was enhanced in lateral gaze were included. Apart from gait ataxia, few patients had additional neurologic signs. The two most common causes of DBN were cerebellar ectopia (25%) and cerebellar degeneration (25%) with another 10% having a variety of conditions. In about 40% the cause remained undiagnosed. In some patients with idiopathic DBN and in others with DBN due to cerebellar ectopia, the disease progressed slowly, if at all. In DBN the slow-phase velocity is dependent on vertical head position and head velocity in pitch; vertical pursuit, particularly downward pursuit, is defective and vertical vestibulo-ocular reflexes are intact. We concluded that at least some cases of DBN were due to an imbalance in otolithocular reflexes. The lesion causing DBN appears to be in the vestibulocerebellum, perhaps the nodulus, a structure that normally inhibits otolith-ocular reflexes.
92 patients thought to have a cerebello-pontine angle tumour on initial presentation were studied prospectively using standard neuro-otological techniques, brainstem evoked potential recording with a variety of montages, middle latency auditory evoked potentials and CT scanning. 64 patients had a tumour, 40 of which were acoustic neuromas. By analysing the data from all disciplines it has been possible to delineate clusters of variables that are of value in the differential diagnosis of cerebello-pontine angle lesions.
We report a collaborative study of 11 patients with upbeat nystagmus in the primary position of gaze. In most cases the nystagmus behaved in accordance with Alexander's Law; in 3 patients convergence enhanced the nystagmus. Lateral gaze was without effect in 7 instances. Static tilt to prone and supine positions altered the characteristics of the nystagmus in 7 patients. The effects were variable and, in one case, there was reversal of the direction of the nystagmus to downbeating. There was pathological or radiological confirmation of lesions in the pontomedullary junction (2 cases) and the pontomesencephalic junction (2 cases). The findings support previous reports that primary position upbeat nystagmus occurs predominately with intra-axial brainstem lesions. There is one report of its occurrence with an intrinsic cerebellar lesion. Modification of the amplitude of upbeat nystagmus by tilt of the head with respect to gravity in the majority of patients implies an otolith-related component in the genesis of the nystagmus.
A case of post-traumatic hypothalamic hypothermia is described. An unusually selective defect in thermoregulatory function was demonstrated together with a defect in thyroid function suggestive of impaired hypothalamic control.
The majority of patients with multiple sclerosis have an abnormality of their spinal fluid immunoglobulins. This alteration is manifested as patterns of diffuse protein bands in the gamma globulin region following electrophoresis. This pattern has been termed one of restricted heterogeneity, or an oligoclonal pattern. We have found changes in the banding pattern of some patients studied longitudinally. Since the significance of these findings may be relevant to the pathogenesis of this notoriously waxing and waning disease, we discuss the importance of methodologies as well as the concept that IgM and IgA may be relevant to the interpretation of these observations.
The majority of patients with multiple sclerosis have an abnormality of their spinal fluid immunoglobulins. This alteration is manifested as patterns of diffuse protein bands in the gamma globulin region following electrophoresis. This pattern has been termed one of restricted heterogeneity, or an oligoclonal pattern. We have found changes in the banding pattern of some patients studied longitudinally. Since the significance of these findings may be relevant to the pathogenesis of this notoriously waxing and waning disease, we discuss the importance of methodologies as well as the concept that IgM and IgA may be relevant to the interpretation of these observations.
In a double-blind controlled trial 43 patients with relapsing-remitting multiple sclerosis were treated either with anti-lymphocyte globulin, prednisolone, and azathioprine, or with placebo preparations. Treatment began with a combination of the three medicaments but after 1 month was continued for another 14 months with azathioprine (3 mg/kg dialy) only. There was a marginally beneficial effect of immunosuppression on the overall relapse rate and clinical progression. However, there were significant effects on in-vitro lymphocyte function and in the visual evoked potentials in favour of the group receiving suppressive treatment. Placebo-treated patients of the HLA A3 tissue type had significantly more relapses than placebo-treated patients who were not of type HLA A3. Nevertheless, HLA-A3-positive patients treated with immunosuppression had significantly fewer relapses than A3-positive placebo-treated patients.
We describe two patients with mitochondrial myopathies who presented with complex multisystem diseases predominantly affecting the central nervous system. In both cases the disease ran a fluctuating clinical course, eventually leading to profound impairment of intellectual function. In Case 1 dementia was associated with optic atrophy, absent pupillary responses, impaired eye movements and generalized dystonic rigidity without evidence of weakness or loss of muscle bulk. In Case 2 myoclonus preceded the onset of ataxia, generalized weakness and mental confusion by several years. Biochemical studies on isolated muscle mitochondria revealed defects in the mitochondrial respiratory chain which were located at NADH-CoQ reductase in Case 1, and at cytochrome b in Case 2. This study illustrates the potential value of muscle biopsy in the diagnosis of unusual and otherwise unexplained cerebral syndromes in man, even in the absence of muscle weakness.
The BSEPs elicited by monaural and binaural click stimuli were studied using a variety of monopolar and bipolar montages. The wave form of the evoked response was different on separate montages. Evidence is presented that there are multiple generators responsible for the evoked potential recorded. Furthermore binaural stimulation evoked activity in a generator not excited from either ear alone. A method of presentation of the data in terms of a vectogram is given and the use of this in disease illustrated. The implication of complex interactions of many generators upon the assessment of the record in patients is discussed.