Does cortical mapping protect naming if surgery includes hippocampal resection?
Article first published online: 27 OCT 2009
Copyright © 2010 American Neurological Association
Annals of Neurology
Volume 67, Issue 3, pages 345–352, March 2010
How to Cite
Hamberger, M. J., Seidel, W. T., Goodman, R. R. and McKhann, G. M. (2010), Does cortical mapping protect naming if surgery includes hippocampal resection?. Ann Neurol., 67: 345–352. doi: 10.1002/ana.21903
- Issue published online: 29 MAR 2010
- Article first published online: 27 OCT 2009
- Accepted manuscript online: 27 OCT 2009 12:00AM EST
- Manuscript Accepted: 20 OCT 2009
- Manuscript Revised: 16 SEP 2009
- Manuscript Received: 13 JUL 2009
- National Institutes of Health/the National Institute of Neurological Disorders and Stroke. Grant Number: NIH R01 NS35140
Preresection electrical stimulation mapping is frequently used to identify cortical sites critical for visual object naming. These sites are typically spared from surgical resection with the goal of preserving postoperative language. Recent studies, however, suggest a potential role of the hippocampus in naming, although this is inconsistent with neurocognitive models of language and memory. We sought to determine whether preservation of visual naming sites identified via cortical stimulation mapping protects against naming decline when resection includes the hippocampal region.
We assessed postoperative changes in visual naming in 33 patients, 14 who underwent left temporal resection including hippocampal removal and 19 who had left temporal resection without hippocampal removal. All patients had preresection cortical language mapping. Visual object naming sites identified via electrical stimulation were always preserved.
Patients without hippocampal resection showed no significant naming decline, suggesting a clinical benefit from cortical mapping. In contrast, patients who had hippocampal resection exhibited significant postoperative naming decline, despite preresection mapping and preservation of all visual naming sites (p ≤ 0.02). These group effects were also evident in individual patients (p = 0.02). More detailed, post hoc examination of patients who had hippocampal resection revealed that overall, patients who declined were those with a preoperative, structurally intact hippocampus, whereas patients with preoperative hippocampal sclerosis did not exhibit significant decline.
Despite cortical language mapping with preservation of visual naming sites from resection, removal of an intact dominant hippocampus will likely result in visual naming decline postoperatively. ANN NEUROL 2010;67:345–352