Hemispherectomy for dominant hemisphere Rasmussen's Encephalitis - how late is too late?

It is unclear whether a dominant hemispherectomy/hemispherotomy in someone with Rasmussen's Encephalitis (RE) may produce a satisfactory outcome when performed over the age of 40 years. Important questions include whether RE may continue to evolve three decades after onset, and whether a hemispherectomy may adequately shift language function when performed in older ages. Two cases illustrate seizure, language, motor and functional outcomes after dominant hemispherotomies. The cases were selected from an epilepsy surgery database of procedures performed at a private hospital in Cape Town, South Africa, spanning the period 1998-2023. A man in his 40s with epilepsy since childhood and dominant hemisphere RE partially regained impaired comprehension and ambulation, while expressive language function did not recover post-hemispherotomy. By contrast, a young teenage patient with dominant hemisphere RE demonstrated considerable recovery of expressive and receptive language and ambulation post-surgery. Both remain seizure-free. These two cases demonstrate that a dominant hemispherotomy, when performed on a quadragenarian, may produce a satisfactory, albeit inferior, functional outcome in comparison to when performed in childhood. RE may cause progressive neurological dysfunction in the late thirties and older and should be considered in patients presenting with functional decline decades after disease onset.