Clinical and experimental neurology最新文献

Six cases of contrast neurotoxicity with cerebral visual disturbance following angiography are presented. The typical clinical features, putative mechanisms and usual outcome of this uncommon but distinctive syndrome are discussed.

Our experience of using video-audio/EEG monitoring in the diagnosis and management of epilepsy at The Queen Elizabeth Hospital Comprehensive Epilepsy Service from March 1987 to December 1990 is described. We performed 75 long term monitoring studies on a total of 66 patients. Following monitoring, a change in seizure diagnosis was made in 21 of 66 patients (32%). Pseudoseizures were diagnosed in 17 patients. A change in management as a consequence of monitoring occurred in 53 of the 66 patients (80%). The referring neurologists considered that 56 of the 75 studies (75%) were successful. The investigational technique is effective and is particularly useful for the diagnosis of pseudoseizures.

Mitochondrial DNA is a unique, maternally inherited molecule encoding several subunits of the respiratory enzyme chain. In several mitochondrial cytopathies mutations have been described in this genome viz. large-scale heteroplasmic deletions in syndromes with progressive external ophthalmoplegia and point mutations in MELAS and MERRF encephalomyopathies. We here report Southern blot analyses in the cases of CPEO we have seen and describe the search for point mutations in MELAS and MERRF. Mitochondrial genetic sequencing in normal and disease controls as well as in patients has confirmed the pathogenic nature of a tRNA Lys point mutation in MERRF. We propose a novel mitochondrial structural gene mutation in a MELAS--like encephalomyopathy: an A-->G substitution at position 11084 leading to a Thr to Ala replacement in the ND4 subunit of complex I.

Six cases of post-infectious encephalomyelitis are described. A preceding non-specific viral-like illness occurred 4 to 20 days before the onset of the neurological deficits. The clinical syndromes included transverse myelitis, focal encephalitis and encephalomyelitis (each in one case) and diffuse encephalitis in 3. Magnetic resonance imaging appeared to be the investigation of choice. High dose corticosteroids were given to 4 patients who recovered partially or fully. The patient with focal encephalitis had a spontaneous and complete recovery. The remaining patient with diffuse encephalitis died 3 days after the onset; autopsy showed prominent lymphocytic perivascular cuffing in the white matter and lymphocytic infiltration of the meninges.

Plasma concentrations of the [R]- and [S]- enantiomers of the new anticonvulsant vigabatrin were measured by an enantiospecific gas-liquid chromatographic assay in a group of therapy-resistant epileptic patients in whom racemic vigabatrin was added to their existing antiepileptic drug regimens. The peak plasma concentrations of the biologically active [S]-enantiomer of vigabatrin were correlated with those of the [R]-enantiomer, with drug dose, seizure frequency and change in score on various tests of psychological function administered prior to and when the subjects were under steady-state conditions following vigabatrin therapy. Plasma [S]-vigabatrin concentrations correlated with drug dose, [R]-vigabatrin concentration and change in score of certain psychological tests reflecting verbal memory, recall and speed of information processing. No definite pharmacokinetic interactions were detected, though plasma phenobarbitone concentrations tended to fall during vigabatrin administration. There were too few data to assess the relation between [S]-vigabatrin concentrations and seizure frequency.

Subcortical cerebral infarction is associated with impaired performance on tests of cognitive function which are sensitive to frontal lobe damage. In a cohort of 82 patients with multiple subcortical cerebral infarcts diagnosed on the basis of CT scan appearances, physical signs presumed to be sensitive to frontal lobe dysfunction were elicited. Associations between physical findings and CT scan changes were determined. The snout reflex was present in 38 patients and correlated significantly with the number of lesions, the presence of periventricular lucency and the presence of ventricular enlargement, while the grasp reflex occurred in 33 and correlated with the number of lesions and the presence of ventricular enlargement, and gait impairment in 54 correlated with the number of lesions and the presence of ventricular enlargement. It is assumed that multiple subcortical infarcts disrupt frontal association pathways, resulting in frontal disconnection which produces frontal cognitive dysfunction and frontal release signs.

Epileptic women may experience an increase in seizure frequency during pregnancy. To explore the relationship between seizures, simultaneous antiepileptic drug and sex hormone concentrations, 8 pregnant epileptic women collected saliva each week throughout their pregnancies and for up to 6 weeks after delivery. The ratio of the drug dose to the drug's body fluid concentration at steady state (dose:Css), as measured by high performance liquid chromatography (HPLC), increased throughout pregnancy and fell in the 3rd to 4th week postpartum. There was no correlation between the dose:Css ratio and the salivary oestradiol concentration, nor between the number of seizures and the antiepileptic drug or sex hormone concentrations, and there was only a weak positive correlation between the dose:Css ratio and the salivary progesterone concentration. The possible interactions between sex hormone concentrations, antiepileptic drug concentrations and seizures are complex, and warrant further study in a greater number of pregnant subjects.

Survival is the most fundamental measure of the outcome from stroke, the magnitude of the burden being strongly reflected in case-fatality and survival rates. Although the literature is rich with follow-up studies examining survival after stroke, most are based on selected series of patients and factors which correlated with time to death have usually been determined in univariate analyses. We examined the factors associated with a high risk of death during the acute phase of stroke. Analyses were based on data from a population based study of acute cerebrovascular disease undertaken in Perth, Western Australia, during an 18 month period 1989-1990. Using logistic regression modelling techniques only 2 factors, severe loss of consciousness, odds ratio 14.7 [95% confidence limits (CL), 4.0-53.6], and severe paresis, odds ratio 7.2 [95% CL, 1.6-32.0], independently predicted death by 28 days after the onset of stroke. The implication is that 2 simple measures, level of consciousness and motor power, may help direct management. Furthermore, age is not an independent risk factor for death early after stroke. Therefore the elderly should not be denied therapy purely on the basis of their age.

There have recently been reports that patients with motor neuropathy with multifocal conduction block have high circulating levels of antibodies to the ganglioside GM1. Other reports have described the presence of these antibodies in patients with inflammatory demyelinating neuropathy and patients with lower motor neurone forms of motor neurone disease. We have established an ELISA assay for IgG and IgM antibodies to asialo-GM1 (Sigma). We used this assay to measure such antibodies in serum from normal subjects and from patients with various neurological conditions. In normal subjects, antibodies to asialo-GM1 were present only in low levels. An arbitrary scale with an upper limit of normal was established. Initial studies have found that abnormally high levels of IgG antibodies to asialo-GM1 were present in 4 of 9 patients with inflammatory demyelinating neuropathies (Guillain-Barré syndrome or chronic inflammatory demyelinating polyradiculoneuropathy). We found one patient with a monoclonal IgM circulating paraprotein and a motor neuropathy who had a high titre of antibody to asialo-GM1. As yet we have found no patients with motor neurone disease with antibodies to asialo-GM1.