Does cortical mapping protect naming if surgery includes hippocampal resection?
OBJECTIVE
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.


METHODS
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.


RESULTS
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 < or = 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.


CONCLUSIONS
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.
Hamberger
Marla J
MJ
Department of Neurology, College of Physicians and Surgeons, Columbia University, 710 West 168th Street, New York, NY 10032, USA. mhamberger@neuro.columbia.edu
Seidel
William T
WT
Goodman
Robert R
RR
McKhann
Guy M
GM
D000328:Adult; D000377:Agnosia / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery; D004185:Disability Evaluation; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006624:Hippocampus / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures / Q000009:adverse effects* / Q000379:methods; D010364:Pattern Recognition, Visual / Q000502:physiology; D011183:Postoperative Complications / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D011300:Preoperative Care / Q000379:methods*; D021641:Recognition, Psychology / Q000502:physiology; D013702:Temporal Lobe / Q000473:pathology / Q000601:surgery