Tuberous sclerosis complex (TSC) is a genetic condition that affects 1/6,000 children born in the UK. It is a disorder that disrupts cell development, and causes distinct malformations to appear on one or more organs of the body. The effects of this are usually visible in infancy and are highly varied; whilst some children with TSC experience little or no clinical problems, others suffer multi-organ dysfunction.

Approximately 70% of people with TSC also have epilepsy, and this is thought to be due to the existence of abnormalities called tubers on the brain cortex. In cases where seizures are intractable (they cannot be controlled with anti-epileptic drugs (AEDs)), surgery to remove the affected part of the brain may be an option. Before surgery can take place, however, investigations are required to find out which tuber or tubers the seizures arise from. This may require electrodes to be implanted into the child's head to determine the area of the brain that should be removed. This invasive process is not only highly uncomfortable, but often requires longer hospital stays and can pose greater risks during surgery.

Researchers at the University of California in Los Angeles (UCLA) have now discovered a non-invasive pre-surgical technique which, along with early consideration of children for surgery, could offer the best epilepsy surgery outcome for children with TSC. The technique uses a combination of three imaging methods known as magnetic resonance imaging, fluoro-deoxyglucose positron emission tomography and magnetic source imaging, and this was the first trial to test its clinical potential.

The scientists recruited 28 children with TSC and intractable epilepsy, who were referred to UCLA between 2000 and 2007. All participants underwent standard pre-surgical evaluation, and the non-invasive imaging technique was used to map the brain and identify the region(s) that needed to be removed. None of the children had the invasive test described earlier.

18 (64%) of the 28 children actually underwent surgery and became seizure-free. This group was followed up for an average of 4.1 years, and the researchers found that 12 of the 18 (67%) remained seizure-free for this duration. Although more evidence needs to be collected, from larger study populations, this is higher than the expected seizure freedom after TSC epilepsy surgery using traditional pre-surgical methods (approximately 57%).

The team noted that a younger age at surgery and shorter seizure duration prior to surgery were associated with post-operative freedom of seizures. Ongoing seizures in intractable epilepsy can be very damaging to the brain, and can add to learning difficulties in those affected. In children whose seizures are stopped early, their chance of optimal cognitive development has been shown to increase.

The non-invasive imaging technique appeared to be as effective as the invasive approach in identifying the brain tissue to be removed. However as it is a lot less invasive, it is a far more attractive option to use in children who are a lot younger. Results from this study also suggest that an opportunity for earlier surgical treatment of children with TSC and intractable epilepsy could be the key to increasing their chances of seizure freedom and dramatically improving their lives.

The team will now study this approach in people with epilepsy alone (not TSC). If their findings are similar, they hope that these will encourage changes to the treatment of intractable epilepsy in the future; for example earlier considerations for surgery and closer assessment of long-term development.

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