Memory outcome one year after stereotactic interstitial radiosurgery in patients with epilepsy due to hypothalamic...

Epileptic seizures caused by hypothalamic hamartomas (HHs) are highly pharmacoresistant. Resective surgical approaches have shown some efficacy in controlling seizures; however, they bear a significant risk of postoperative mnemonic deterioration due to the close anatomical proximity of the HHs to structures essential for memory functions. We report on cognitive outcome in 26 patients with structural epilepsy due to HHs one year after interstitial radiosurgery. Individually, deteriorations occurred more frequently in declarative memory functions (in 20 to 50% of the patients), whereas more than 80% of the patients revealed stable or even improved performance in attentional functions. Preoperative better memory functions were associated with higher risk of postoperative performance decline. After radiosurgery, half of the patients showed more than 50%, and some up to 90%, of seizure reduction. Hypothalamic hamartoma volumes were significantly reduced at follow-up. Transient radiogenic edema found in 10/26 patients was not associated with further cognitive decline after radiosurgery. These results are highly relevant for therapeutic decisions and patient consultation on timing and choice of nonmedical treatment options for HHs.