A prospective multicenter study of laser ablation for drug resistant epilepsy - One year outcomes.

OBJECTIVE: To report one-year seizure outcomes, procedural data, and quality of life scores following laser interstitial thermal therapy (LITT) of epileptogenic foci. METHODS: Data from an ongoing prospective, multi-center registry were assessed. Procedural information, Engel seizure outcomes, and quality of life (QoL) scores were analyzed. A responder analysis was performed to better understand potential clinical characteristics that could influence seizure outcome. RESULTS: Sixty patients have been enrolled into LAANTERN (Laser Ablation of Abnormal Neurological Tissue Using Robotic NeuroBlate System) specifically for epilepsy treatment, of which 42 reached one year follow up. Engel I outcome was achieved in 64.3 % at one year follow up. Patients with mesial temporal lobe epilepsy (MTLE) comprised 56.7 % of this cohort of multiple epilepsy types. Other significant etiologies included focal cortical dysplasia, hypothalamic hamartoma, cavernoma, heterotopias, and tuberous sclerosis. Median length of stay was 32.7 h. At discharge, head pain score averaged 1.4 ± 2.1 on a scale from 1 to 10. Five adverse events were reported, one categorized as serious. Seizure worry and social functioning scores improved significantly in quality of life measures. SIGNIFICANCE: Surgical treatment with LITT for epileptic foci is a safe and effective treatment option for people with drug resistant epilepsy. Our multicenter prospective seizure outcomes continue to expand published LITT experience in MTLE as well as non-MTLE epilepsies. The minimally invasive nature allows for short hospitalizations with minimal reported pain and discomfort.

Circadian-Like Rhythmicity of Extracellular Brain Glutamate in Epilepsy.

Seizures often exhibit striking circadian-like (~24-h) rhythms. While chronotherapy has shown promise in treating epilepsy, it is not widely used, in part because the patterns of seizure rhythmicity vary considerably among patients and types of epilepsy. A better understanding of the mechanisms underlying rhythmicity in epilepsy could be expected to result in more effective approaches which can be tailored to each individual patient. The excitatory neurotransmitter glutamate is an essential modulator of circadian rhythms, and changes in the extracellular levels of glutamate likely affect the threshold to seizures. We used a reverse translational rodent model of mesial temporal lobe epilepsy (MTLE) combined with long-term intracerebral microdialysis to monitor the hourly concentrations of glutamate in the seizure onset area (epileptogenic hippocampus) over several days. We observed significant 24-h oscillations of extracellular glutamate in the epileptogenic hippocampus (n = 4, JTK_CYCLE test, p < 0.05), but not in the hippocampus of control animals (n = 4). To our knowledge, circadian glutamate oscillations have not been observed in a seizure onset region, and we speculate that the oscillations contribute to the rhythmicity of seizures in MTLE.

Effect of an external responsive neurostimulator on seizures and electrographic discharges during subdural electrode monitoring.

PURPOSE: Approved neural-stimulation therapies for epilepsy use prolonged intermittent stimulation paradigms with no ability to respond automatically to seizures. METHODS: A responsive neurostimulator that can automatically analyze electrocortical potentials, detect electrographic seizures, and rapidly deliver targeted electrical stimuli to suppress them was evaluated in an open multicenter trial in 50 patients, 40 of whom received responsive cortical stimulation via subdural electrodes implanted for epilepsy surgery evaluations. RESULTS: Four patients, ages 15 to 28 years, monitored at three institutions, with clinical and electrographic response to neurostimulation, are described. Electrographic seizures were altered and suppressed in these patients during trials of neurostimulation lasting < or =68 h, with no major side effects. In one patient, stimulation appeared also to improve the baseline EEG. CONCLUSIONS: Responsive cortical neurostimulation may be a safe and effective treatment for partial epilepsy. This information was derived from a small group of patients in an observation study. A double-blind, controlled Food and Drug Administration (FDA)-approved study of a permanently implanted responsive neurostimulation system to treat medically refractory partial seizures is under way.

1H and 31P spectroscopic imaging of epilepsy: spectroscopic and histologic correlations.

Although MRS measurements are useful in assessing the biochemical alterations underlying human epilepsy, to date their use has been limited primarily by three factors: (a) the lack of widespread methods and appropriate hardware for acquiring high-resolution spectroscopic imaging data, (b) difficulties in spectral interpretation associated with metabolic heterogeneity, and (c) difficulties in biological interpretation due to a lack of correlative histologic studies. In this work, we (a) describe approaches to overcome these hurdles, and (b) discuss the biological interpretation of the spectroscopic findings in TLE.

Emerging surgical and radiotherapeutic techniques for treating epilepsy.

PURPOSE OF REVIEW: Recent advances in epilepsy surgery have developed a resurgence of interest in the use of surgical techniques for the treatment of intractable epilepsy. RECENT FINDINGS: More invasive procedures such as hemispherectomy and multiple subpial transection have become more popular. Disconnective techniques such as multiple subpial transection have provided a surgical option for patients whose epileptogenic zone resides in the eloquent cortex. Alternatively, new minimally invasive neurostimulation therapies have been introduced to preserve maximal cerebral tissue. Radiosurgery has been recently utilized in the treatment of epilepsy with preliminary promising results. SUMMARY: In this analysis, the authors will attempt to review the more recent surgical approaches and their indications for the treatment of medically intractable epilepsy. For patients with the epileptogenic zone in the noneloquent cortex, seizure focus resection remains the most reasonable approach to therapy.

1H and 31P spectroscopy and bioenergetics in the lateralization of seizures in temporal lobe epilepsy.

Over the past decade, (1)H and (31)P spectroscopy measurements have demonstrated that significant metabolic alterations occur in temporal lobe epilepsy. However, to most accurately interpret these changes, metabolic heterogeneity and differences between gray and white matter must be accounted for. These alterations, decreased NAA and the ratio of phosphocreatine/inorganic phosphate, can be reversed with successful treatment of seizures. The reversibility of these two measures is consistent with the localization of NAA synthesis to neuronal mitochondria and the important role for bioenergetics in the pathophysiology of temporal lobe epilepsy.