Fixation-off sensitivity in an adult with symptomatic occipital epilepsy.

An adult patient had EEG occipital spike fixation-off sensitivity and spontaneous occipital seizures due to perinatal asphyxia with bioccipital hemorrhage. EEG abnormalities consisted of repetitive posterior spikes that occurred when the eyes were closed and other conditions of fixation-off. Magnetic resonance imaging (MRI) documented severe posterior lesions with wallerian degeneration of the optic radiation. Electron capture detector single-photon emission computed tomography (ECD-SPECT) during the state of fixation-off showed regional hyperperfusion in the right posterior regions. We suggest that partial denervation of the primary visual cortex in this patient resulted in an increased cortical excitability and that the inhibitory effect of central vision and fixation leads to a suppression of spontaneous epileptic activity. This unusual symptomatic case may serve as a model for the pathophysiology in the more often reported cases of idiopathic benign epilepsy syndrome of childhood.

Risk assessment of alcohol withdrawal seizures with a Kohonen feature map.

Recently, it has been suggested that alcohol-induced hyperhomocysteinaemia in patients suffering from chronic alcoholism might be a risk factor for alcohol withdrawal seizures. In the present follow-up study 12 patients with chronic alcoholism who suffered from withdrawal seizures had significantly higher levels of homocysteine (Hcy) on admission (71.43 +/- 25.84 mol/l) than patients (n = 37) who did not develop seizures (32.60 +/- 24.87 mol/l; U = 37.50, p = 0.0003). Using a logistic regression analysis, withdrawal seizures were best predicted by a high Hcy level on admission (p < 0.01; odds ratio 2.07). Based on these findings we developed an artificial neural network system (Kohonen feature map, KFM) for an improved prediction of the risk of alcohol withdrawal seizures. Forty-nine patients with chronic alcoholism (12 with alcohol withdrawal seizures and 37 without seizures) were randomized into a training set and a test set. Best results for sensitivity of the KFM was 83.3% (five of six seizure patients were predicted correctly) with a specificity of 94.4% (one false positive prediction of 19 patients). We conclude that in patients with alcohol-induced hyperhomocysteinaemia the KFM is a useful tool to predict alcohol withdrawal seizures.

Persistently increased density of serotonin transporters in the frontal cortex of rats treated with fluoxetine during early juvenile life.

This experimental animal study was performed in order to assess possible long-term effects of the administration of the selective serotonin reuptake inhibitor fluoxetine (Prozac) during early periods of juvenile life on the developing central serotonergic and noradrenergic systems. Fluoxetine was administered via the drinking water (5 mg/kg/day) for a period of two weeks to very young (day 25) and somewhat older (day 50) rats. The effect of this treatment on the density of serotonin and noradrenaline transporters was measured by ligand-binding assays in various brain regions. The Bmax-values of [3H]-nisoxetine binding were not affected by either treatment schedule, but a significant increase of the Bmax-values of [3H]-paroxetine binding was found in the brains of early fluoxetine-treated rats. This increase was restricted to the frontal cortex and persisted long after the termination of the treatment into adulthood (day 90). The most likely explanation of this observation is a stimulatory effect of the fluoxetine treatment on the outgrowth of serotonergic projections in the frontal cortex of very young rats. This is the first empirical demonstration of long-lasting effects of the administration of a selective serotonin reuptake inhibitor during juvenile life on the maturation of the central serotonergic system.