Light therapies for focal epilepsy

Epilepsy is more common in people who have hydrocephalus. The likelihood of developing epilepsy varies depending on the type of hydrocephalus someone has. In this blog, we look at two different approaches to treating focal epilepsy: one that is newly available through the NHS and one that is in development in the United States.

Laser Interstitial Thermal Therapy (LITT)

Earlier this year, the NHS announced the introduction of a cutting-edge laser-beam therapy to help reduce seizures in people with focal epilepsy that cannot be controlled with medication. Laser Interstitial Thermal Therapy (LITT) uses fibre optic lasers to target the areas of the brain causing seizures. It is a less invasive alternative to existing surgeries.

A small hole is drilled in the skull so a 1.5mm-wide probe with a fibre optic laser at the tip can be inserted. An MRI scanner helps surgeons move the probe safely through the brain, avoiding blood vessels and other vital parts. Once the probe reaches the area of the brain causing the seizures the laser is used to destroy the target tissue with heat. The temperature of the surrounding tissue is carefully monitored to prevent damage to healthy brain tissue from overheating.

Because the wound is small and heals quickly, patients can go home within 48 hours of surgery, usually the next day. Most will be able to return to their usual daily activities within a week.

The treatment is being offered to adults and children at specialist national hubs at King’s College Hospital in London and The Walton Centre in Liverpool. It has also been successfully performed at Alder Hey Children’s Hospital. You can read the detailed service specification here.

James Palmer, NHS England’s Medical Director for Specialised Services and a Consultant Neurosurgeon said: “Not only will this world-leading technology help replace invasive surgery for patients, which can have a huge impact and take months to recover from, it will also allow clinicians to target the parts of the brain better causing the epilepsy, which dramatically reduces the risks and helps cut patients’ recovery time both in and out of hospital.”

Optogenetics

A new method for treating seizures is being developed at the University of California. The approach is called optogenetics, and the idea is to make it possible to control specific brain cells (neurons) with pulses of light.

To do this, light-sensitive genes need to be delivered to the target nerve cells, and this is achieved using a specially engineered (harmless) virus. Once incorporated into the target neurons, the genes make it possible to switch the brain cells on and off using pulses of light. The light pulses are delivered by remote control using software that also enables the electrical activity of the neurons to be recorded.

This approach has now been demonstrated in human brain tissue for the first time in research published in Nature Neuroscience. For the study ,the researchers used brain tissue that had been surgically removed from patients to treat their epilepsy. The hope is that with further research and development, optogenetics could be an alternative to invasive surgery for people with focal seizures that resist other treatments.

Dr Tomasz Nowakowski, who authored the study, said: “This represents a giant step toward a powerful new way of treating epilepsy and likely other conditions.”