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Episode 2: The Child's Brain - Epilepsy and Rasmussen's Syndrome FAQ

photo of a young boy

Scan of Michael's brain
The after-effects of seizures vary greatly depending on the individual. These include fatigue, aphasia, disorientation and, in some cases, aggression.

How does Rasmussen's syndrome differ from other seizure disorders?

A scan of Michael's brain after the hemispherectomy.

Scans of intact brain and Michael's brain
Scans of an intact brain (left) and Michael Rehbein's brain (right).

Rasmussen's syndrome is a unilateral, progressive, inflammatory disease characterized by normal early development and relatively late onset seizures. In contrast to other childhood seizure disorders, these children develop normally until at least 5 years of age and even until 13-15 years of age before they start having seizures. Another difference with other childhood seizure disorders is that Rasmussen's syndrome is unilateral: it affects only one hemisphere. Rasmussen's syndrome is also one of the rarest seizure disorders.

Is there a known cause of Rasmussen's syndrome?
A definitive cause has not yet been identified. There has been speculation that Rasmussen's Syndrome is viral in origin, but that hypothesis has been challenged.

What is a hemispherectomy? How is a hemispherectomy performed? How many are performed each year?
A hemispherectomy is a radical surgical procedure that involves the removal of one cerebral hemisphere. To date, hemispherectomy is the most effective treatment for Rasmussen's syndrome (the seizures are progressive in nature and do not respond over time to medication). In most cases, our patients are seizure free after hemispherectomy.

There are different types of hemispherectomies: partial, functional, and full/complete. Partial and functional hemispherectomies do not involve removal of the entire cerebral hemisphere, but typically leave one or more cortical lobes in place. At Hopkins, the procedure is characterized as a full/complete hemispherectomy, which involves removal of all four cortical lobes (temporal, frontal, parietal, and occipital lobes), the insular cortex, and much of the underlying white matter tracts leaving intact the basal ganglia, thalamus, and ventricles intact.

There are a number of different centers in the country that perform hemispherectomies, so it's hard to estimate the total number performed each year. At Hopkins, the number has ranged from three to six per year.

Answer to this FAQ provided by Dr. Dana Boatman of Johns Hopkins School of Medicine and Dr. John Freeman of Johns Hopkins School of Medicine.

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