ABSTRACT
BACKGROUND: Low- and high-frequency stimulation (LFS and HFS, respectively) have been, reported to modify seizure characteristics in rats. We here report effects of hippocampal LFS and HFS, applied at two or four sites in fully kindled rats. METHODS: Rats were kindled through a hippocampal tetrode until the fully kindled state. Animals with, stable afterdischarge (AD) threshold were randomly assigned to 5 groups; stimulation at 1Hz (LFS) or, 130Hz (HFS) was continuously applied for 7 days at 2 or 4 intrahippocampal sites; a control, group received no stimulation. Four-contact stimulation was performed in a rotating fashion. Stimulation effects on AD threshold, AD duration and behavioral seizures were assessed. KEY FINDINGS: Four-contact LFS consistently increased AD threshold for a period of 2 days to 2 weeks, whereas 4-contact HFS significantly decreased AD duration 24hours following the stimulation period. No significant AD modification was observed with either 2-contact stimulation paradigms. No, behavioral alteration occurred in any group. SIGNIFICANCE: These findings suggest that effects of hippocampal stimulation depend on frequency and topography of stimulus application. LFS and HFS had anti-epileptic effect on afterdischarges when applied in a rotating pattern. This supports concepts on patterned stimulation to result in desynchronization and anti-kindling effects.
Subject(s)
Hippocampus/physiology , Kindling, Neurologic/physiology , Animals , Electric Stimulation/adverse effects , Electric Stimulation/methods , Female , Random Allocation , Rats , Rats, Wistar , Reaction Time , Seizures/physiopathologyABSTRACT
We revised 16 patients submitted to epilepsy surgery using a new method of digital, real-time, portable electrocorticography. Patients were operated upon over a period of 28 months. There were no complications. The exam was useful in 13 cases. The low installation and operational costs, the reliability and simplicity of the method, indicate it may be useful for defining the epileptogenic regions in a variety of circumnstances, including surgery for tumors, vascular malformations, and other cortical lesions associated with seizure disorders.
Subject(s)
Humans , Male , Female , Infant , Child, Preschool , Child , Adult , Electroencephalography/methods , Epilepsy/surgery , Cost-Benefit AnalysisABSTRACT
A total of 42 patients were submitted to a clinical, behavioural and neuropsychological evaluation with the objective of eventual surgical treatment of epilepsy refractory to the usual clinical therapies. Prolonged video-EEG monitoring, MRI hippocampal volume measurement, lateralization of speech and memory using the amobarbital (Wada) test were used. Of 18 operated cases, 12 were submitted to temporal lobectomy, with a follow-up of 6-30 months; 8 patients had significant improvement in seizures control; 2 patients had partial improvement in seizure frequency and intensity; 2 patients had no improvement in seizure control. One patient underwent right frontal lobectomy with total remission of seizures and 5 had callosotomy with varying degrees of success. There was no mortality. Morbidity included one subdural hematoma, one transient hemiparesis, one episode of mania, one lobar pneumonia and frequent immediately post-operative muscular tension headaches. These early results indicate good results of temporal lobectomy patients investigated through a non-invasive presurgical evaluation.
