In-vivo measurements of human brain tissue conductivity at body temperature were conducted using focal electrical currents injected through intracerebral multicontact electrodes. A total of 1,421 measurements in 15 epileptic patients (age: 28 ± 10) using a radiofrequency generator (50 kHz current injection) were analyzed. Each contact pair was classified as being from healthy (gray matter, n = ...

We compared 100 patients with temporal lobe epilepsy, who exhibited the running down phenomenon following temporal resections, with two groups of patients: 100 patients who became seizure-free, and 100 patients who continued to have frequent seizures following temporal resection. We found a significant correlation between prognosis and the size of the epileptogenic area as defined; patients wit...

PURPOSE AND METHODS During the intracarotid amobarbital procedure (IAP) at the University of Michigan, continuous scalp EEG monitoring guides the timing for presentation of memory items and postinjection testing. Most of our patients have undergone bilateral injections. The interval between injections varied from 22 to 60 min, depending on the test and recovery time, as well as the time to cath...

It is unclear whether focal epilepsies chronically influence the processing of cortex distant to the epileptogenic zone. Therefore, motor cortex excitability was analysed in patients with temporal and extratemporal epilepsies whose epileptogenic zones did not include the primary motor area. Single and paired-pulse transcranial magnetic stimulation (TMS) was applied to the primary motor cortex i...

Is it time to replace epileptic spikes with fast ripples? In well over a century of performing epilepsy surgery, only 60%–65% of patients are, on average, seizure-free postoperatively. 1 Despite multiple advances in neuroimaging and electrophysiologic techniques for localizing the epileptogenic zone and determining its boundaries, defining the exact amount of neuronal tissue required to resect ...

Pachygyria or incomplete lissencephaly is a developmental condition due to abnormal migration of neurons. The association of seizures in this condition warrants investigation like electroencephalogram (EEG) and magnetic resonance imaging (MRI). 18F-flurodeoxyglucose positron emission topography computed topography (18F-FDG PET/CT) has a potential role in commenting of wide...

We recently reported that epileptic seizures might be facilitated through the action of blood–proteins that leak into the CNS during the chronic epileptic phase in rats (Van Vliet et al., 2007). This was further supported by our mannitol experiments in epileptic rats which showed increased seizure progression in a subgroup of rats. Mannitol can be used to open the blood–brain barrier (BBB) by p...

Improved non-invasive localization of the epileptogenic foci prior to epilepsy surgery would improve surgical outcome in patients with partial seizure disorders. A critical component for the identification of the epileptogenic brain is the analysis of electrophysiological data obtained during ictal activity from prolonged intracranial recordings. The development of a noninvasive means to identi...