Neurology
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We report on the prevalence of dementia in Canadians age 85 years and older. The purpose of this study was to determine whether the prevalence of dementia continued to increase in the very old, and to define the types of dementia and their relative proportions in this age group. We collected data as part of the Canadian Study of Health and Aging (1990 to 1992), which consisted of a sample of 1,835 subjects from a population of 283,510 Canadians who were 85 years of age and older residing in the community or in institutions. ⋯ The prevalence of dementia of 23% in the 85- to 89-years sample (n = 1,332) increased to 40% in the 90 to 94 years group (n = 371) and, in the 95 years and older sample (n = 104), reached 58%. Overall, Alzheimer's disease (AD; probable or possible) accounted for 75% of all dementias; a vascular etiology alone accounted for 13% of dementias. The proportion of clinically diagnosed AD cases to vascular dementia cases increased significantly after age 65 and was higher in the 85+ group than in a younger cohort (65 to 84 years).
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Dystonia is a rare consequence of head trauma. We describe 10 such cases and review 19 similar patients reported in the literature. Twenty-two of the 29 patients suffered head injury during the first or second decade of life. ⋯ Two cases remained as focal dystonias, but the others developed segmental, hemi-, multifocal, or generalized dystonia. On brain imaging studies (CT or MRI), the most frequent lesion site was in the contralateral basal ganglia or thalamus, but two cases had normal brain scans. Dysfunction of the lenticulothalamic neuronal circuit seems to be related to the development of dystonia following head trauma.
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Case Reports
Anti-Ri antibodies associated with opsoclonus and progressive encephalomyelitis with rigidity.
A 57-year-old woman without a known neoplasia developed opsoclonus, myoclonus, and ataxia. Positive anti-Ri antibodies were present in both serum and CSF. The patient also had progressive encephalomyelitis with rigidity, an association not previously described.
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We report the first study of carbamazepine and carbamazepine-10,11-epoxide concentrations determined by using intracerebral microdialysis in three patients undergoing depth electrode studies for the evaluation of medically intractable epilepsy. Very small microdialysis catheters, affixed to and inserted with the depth electrodes, sampled drug concentration in the extracellular environment. ⋯ The relation between dialysate and extracellular concentration (recovery fraction) depended, in vivo but not in vitro, on the relative lipophilicity of the compounds, suggesting that diffusion of the drug within the brain is a major determinant of microdialysate drug concentration. When this is taken into account, the steady-state extracellular concentrations of these compounds closely mirror their unbound serum concentrations.
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We treated nine refractory status epilepticus cases with high-dose intravenous lorazepam. We monitored the EEGs continuously, and lorazepam dosing was titrated to stop clinical and electrographic seizures. Lorazepam doses needed to terminate status epilepticus ranged from 0.3 to 9 mg/hr. ⋯ All patients survived. Outcome was complete recovery in two cases, moderate disability in four, and severe disability in three. These findings suggest high-dose intravenous lorazepam may be an effective alternative to pentobarbital for the treatment of severe status epilepticus.