Chronic bilateral subthalamic stimulation after anterior callosotomy in drug-resistant epilepsy: long-term clinical and functional outcome of two cases.

We explored the efficacy and safety of bilateral SubThalamic Nucleus (STN) stimulation in two subjects suffering from drug-resistant epilepsy even after anterior callosotomy. Case 1 had about 65% decrease of partial motor seizures and the complete disappearance of tonic-clonic generalized attacks. Case 2, with sudden drop (atonic) attacks, partial complex seizures, atypical absences and rare tonic-clonic seizures, showed no meaningful reduction of fits and a stimulation associated atypical absence rate increase.

Bimanual crossed-uncrossed difference and asynchrony of normal, anterior- and totally-split-brain individuals.

This study investigated interhemispheric transfer in ten normal, four anterior-, and four totally-split-brain individuals, through measures of manual asynchrony and bimanually-recorded crossed-uncrossed difference (CUD). The CUD relied on the difference between crossed and uncrossed responses whereas the asynchrony measure relied on the reaction time difference between the two responding hands. Manipulations of sensory and attentional factors were assessed for both measures. We found a normal CUD (3.8 ms) along with an exacerbated and more variable asynchrony for partial split-brain individuals (40.8 ms) compared to normal individuals (CUD: 0.4 ms, asynchrony: 13.8 ms). In turn, the CUD of total split-brain individuals (20.4 ms) was larger than that of partial split-brain and normal individuals. Also, the asynchrony of total split-brain individuals (57.6 ms) was larger and more variable than that of normal individuals, and more variable than that of partial split-brain individuals. We interpret these results as behavioural evidence of independent mechanisms underlying the CUD and bimanual synchronization, as well as evidence of the joint involvement of both the anterior and the posterior portions of the corpus callosum in bimanual coordination.

Sensory and motor involvement in the enhanced redundant target effect: a study comparing anterior- and totally split-brain individuals.

This study investigated the redundant target effect (RTE) in partial split-brain (anterior section sparing the splenium), total split-brain, and neurologically intact individuals. All completed an RTE protocol in which targets were presented on the midline or in an inter- or intrahemispheric manner. Stimuli of different nature (luminance, equiluminant colour, and global motion) were used separately in three experiments in order to investigate the contribution of subcortical versus cortical pathways. Despite the preservation of the splenium (the portion of the corpus callosum assumed to transfer visual information), partial split-brain individuals showed an enhanced RTE pattern as compared to neurologically intact individuals. Total split-brain individuals showed a tendency toward larger RTEs with the luminance stimuli than with the colour and motion stimuli, whereas this was not the case for partial split-brain individuals, suggesting a contribution of the posterior portion of the corpus callosum in the RTE. It is therefore likely that both sensory and motor processes contribute to the enhanced RTE in split-brain individuals.

Oxcarbazepine and adverse events: impact of age, dosage, metabolite serum concentrations and concomitant antiepileptic therapy.

The aim of this study was to investigate the relationships between oxcarbazepine (OXC) dosage, metabolite mono-hydroxy-derivative (MHD) serum concentrations, number of concomitant antiepileptic drugs, age and incidence of adverse events (AEs) in epileptic patients. A retrospective analysis was conducted of 414 consecutive epileptic patients on OXC alone or added-on to previous therapy. The sample was collected from the period 2001 to 2006. Statistical analysis was performed in two groups: with and without AEs. Eighty-seven patients (21%) experienced at least one AE. The most frequent was hyponatremia, reported in 9.2%. OXC was discontinued because of AEs in 27 cases. There were no important differences between patients with and without AEs, except for age (p=0.04). The categorization of patients into three different age ranges, <20, 20-59 and (3)60 years, disclosed that the risk of AEs is notably lower in young (<20 years) and adult (20-59 years) patients (OR 0.46 and 0.51, respectively). In particular, the patients who experienced hyponatremia were significantly older than those who did not (p=0.0045). The other variables showed no major changes according to age. The incidence of major AEs during OXC treatment, leading to withdrawal, was found to be low and influenced by age, but not by OXC dosage, MHD concentrations or number of concomitant antiepileptic drugs.