Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or synchronous neuronal activity in the brain. While more likely to occur in young children or people over the age of 65 years, epilepsy can occur at any age. Epilepsy is usually controlled, but cannot be cured, with medication or special diets.
About 50 million people worldwide suffer from epilepsy.
There are several classifications of epilepsy depending on the type of the seizures, (generalized, focal or mixed), the cause of the epilepsy and the location of the focal in the brain.
Mesial temporal lobe epilepsy (TLE) is the most frequent cause of medically intractable epilepsy in adults. TLE consists of neuronal loss, atrophy and gliosis within the amygdala-hippocampus and limbic system.
Epilepsy surgery is an option for patients whose seizures remain resistant to treatment with anticonvulsant medications and who also have symptomatic localization-related epilepsy: a focal abnormality that can be located and therefore removed or inactivated.
There are two main types of epilepsy surgery, the first removes the area of the brain producing seizures, and the second interrupts the nerve pathways through which seizure impulses spread within the brain.
The most common type of epilepsy surgery is the anterior temporal lobectomy, or the removal of the front portion of the temporal lobe including the amygdala and hippocampus. Surgery for temporal lobe epilepsy is effective and durable. However, invasive brain surgery entails small but real risks of hemorrhage, infection and other complications despite contemporary MR-guided techniques.
Potential Benefits of Focused Ultrasound
As a non-invasive modality for thermal ablation of tissue, focused ultrasound may someday be used in the treatment of temporal lobe epilepsy (TLE) thereby providing a low morbidity means to target and destroy a specific area in the brain while sparing healthy tissue adjacent to the target or along the beam path.
If some technical hurdles can be overcome, a clinical trial of focused ultrasound for temporal lobe epilepsy may be indicated. Given the significant risk of loss of verbal fluency after dominant temporal resections, the ROSE trial has been devised to compare selective temporal lobe resections with Gamma knife radiosurgery in the treatment of TLE. Results of that study may impact the design of a focused ultrasound trial. Focused ultrasound would have a distinct advantage over Gamma knife radiosurgery in causing a fairly rapid cessation of seizures and avoiding ionizing radiation.
In addition, research on focused ultrasound has demonstrated that with the right set of parameters focused ultrasound can be used for neuro-modulation to stimulate or block brain activity in a transient and focalized manner. Using the blocking effect, research has shown it is possible to use focused ultrasound as a means to block an on-going seizure
To date, there are no active clinical trials evaluating the safety and efficacy of Focused Ultrasound for the treatment of epilepsy.
Regulatory Approval and Reimbursement
To date there is no regulatory approval or reimbursement for a commercial focused ultrasound device for the treatment of epilepsy, anywhere in the world.
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