Pattern-reversal visual evoked potentials in photosensitive epilepsy

VEPs to checkerboard pattern-reversal were recorded from 18 epileptic patients who had EEG photoparoxysmal responses to stroboscopic light. Patients were grouped according to whether seizures were precipitated by environmental light stimuli, or television viewing. Longitudinal studies were conducted on 8 patients treated with valproic acid. We concluded the following: (1) Latency of the major positive peak (P2) of the pattern-reversal VEP was shorter among photosensitive patients than among normal controls. This was especially true of television-sensitive patients. (2) Valproic acid, when effective in controlling seizures, lengthened the P2 latency and decreased VEP amplitude. Studies of drug effects on VEPs may help to elucidate neurochemical mechanisms of the visual cortex. (3) Because of overlap of values with normals, VEP measurements are not at present very sensitive in the diagnosis of photosensitivity. However, longitudinal studies in individuals parallel clinical changes and may be useful as objective measures of improvement.

Late-onset variant of Huntington's chorea

We identified a large Georgia kinship in which a hereditary autosomal dominant chorea appeared at an average age of 65 years, much later than usual for Huntington's chorea. Progression was slow. Dementia was not an obvious initial feature. Family members denied that affected persons became demented, and those affected cognitively intact with bedside testing. However, deficits of memory were apparent on formal psychologic testing. In the propositus' generation, five of 12 siblings were affected during their 60s. Of 23 persons in a younger generation, aged 30 to 60 years, none was yet affected. A number of variants of Huntington's chorea have been proposed. In elderly patients without obvious dementia, psychologic testing may be of diagnostic importance, revealing characteristic memory deficits. When the disorder consistently occurs at an advanced age and progresses slowly, the implications for the family may be less grave than with Huntington's chorea of earlier onset.

Cerebral complications of angiography for transient ischemia and stroke: prediction of risk

We examined the records of 147 consecutive patients studied by femoral catheterization to identify factors contributing to angiographic risk in cerebrovascular disease. Cerebral complications occurred in 12.2 percent and were permanent in 5.2 percent. Computer-assisted multivariate analysis of 21 possible risk factors was done. Two of these risk factors correlated strongly with increased risk: number of previous transient ischemic attacks (TIAs) (p less than 0.001), and the presence of arterial stenosis of greater than 90 percent (p less than 0.03). Risk factors of marginal significance were: diabetes, female sex, and number of selective injections. A discriminant function for estimation of risk was derived: D = [8 X number of TIAs] + [6 x number of arteries catheterized] + [14 if diabetic, 0 if not] + [11 if female, 0 if male]. When D was greater than 55, 77 percent of patients had a complication. When D was less than 55, 98 percent of patients had no complication. Unfortunately, patients in whom the study is most indicated tend to be those at greatest risk.