How eloquent is eloquent?

Abstract

Kim et al. [2] report on awake craniotomy for resective epilepsy surgery in eloquent areas of the brain. The study includes 55 (out of 71) patients in whom complete followup was available. All patients suffered from non-lesional, or cryptogenic, pharmaco-resistant epilepsy. They had complete epileptological work-up, including invasive diagnostics with extra-operative brain mapping via subdurally implanted electrodes, for the generation of the final resection plan. Preoperative and postoperative MRI was obtained and co-registered in order to create a "resection frequency map" summarizing and displaying all resection areas on a single view. Color coding was used on a normalized brain surface in order to indicate how often particular regions of the brain had been removed (i.e. red color indicating frequent resections). Twenty-seven resections were performed in the frontal lobes, the rest in parietal and temporal lobes, or multilobar. Resections close to the speech area were stopped at 1 cm distance. Neurological deficits occurred in 18%-transient in 13%, and permanent in 5%, respectively. Epileptological outcome was Engel class I or II in 49% and 16%, respectively, and moderate/poor in a total of 35%. They state that the resection frequency map allows for objectivation of resections in/around eloquent brain areas. Thereby, they had found that resection of Broca's area was followed by neurological deficits in 50%. They concluded that "awake resective surgery with intraoperative brain mapping is an effective and safe treatment option for nonlesional epilepsy involving eloquent areas".

Response to the authors’ response to Schaller’s comment, “How eloquent is eloquent?”

“…First of all, and in view of their anticipation of "harsh criticism and even disbelief" when they had submitted their original manuscript, I would like to stress that my editorial was never meant to be insulting [5]. As it has been the very European style of this journal to stimulate frank and intense discussion amongst authors, readers and reviewers, I felt free to follow this enlightening tradition.…”