Standard versus tailored left temporal lobe resections: Differences in cognitive outcome?

This study explores differences in cognitive outcome after a standard resection (SR) or tailored (TR) in 100 patients with left temporal lobe epilepsy, controlling for extent in the three lateral gyri. Comparing preoperative to 6-month postoperative performance on a battery of intelligence, language and verbal memory tests revealed the following: a differential effect of the procedure was found for digit span, a short-term memory and attention task, the SR group showing a gain and the TR group a loss postoperatively. This could be explained by a rather large improvement of the SR group with below average resection sizes in the superior temporal gyrus (STG) (<2.8 cm), which small resections are nearly absent in TR resections. Effect of larger extent on the STG in the SR group was related to a decrease in verbal intelligence and a tendency in auditory comprehension which poses a risk in 'large' standard resections. Differences in extent of resection on the other gyri did not cause differences in effects on language functioning or verbal memory. Conclusions: In standard anterior temporal lobe resections only (without intraoperative language mapping) up to a limit of 4.5 cm, large resections on the STG pose a risk for declining on verbal IQ and auditory comprehension. In general, tailored resections (with language mapping) result in decline on a task measuring short-term memory and attention. (C) 2007 Elsevier Ltd. All rights reserved.