Background and Objective: Visual object naming traditionally has been used
to identify cortical areas essential for naming (i.e., word retrieval), and
investigators have found critical naming sites in the middle and posterior
temporal region in most patients. Based. on clinical observation, empirica
l findings, and the pathophysiology of temporal lobe epilepsy, the authors
hypothesized that naming sites identified from auditory cues might also be
relevant, and that within the temporal region, these sites would be anatomi
cally distinct and located anterior to naming sites based on visual cues. M
ethods: Twenty patients requiring resective surgery involving the left (lan
guage dominant) temporal lobe underwent pre-resection language mapping usin
g direct cortical stimulation. Visual and auditory naming were tested at la
teral temporal sites extending from 1 cm from the anterior tip to the parie
tal operculum. Results: Auditory naming was consistently disrupted by stimu
lation in the anterior temporal lobe, whereas both auditory and visual nami
ng were impaired by stimulation in the posterior temporal region. Conclusio
ns: This pattern may explain why word finding difficulties sometimes arise
or worsen following surgical procedures in which the anterior temporal regi
on is resected without language mapping, or when resection is based on mapp
ing that identifies language cortex exclusively using visual tasks. These r
esults suggest that utilization of auditory based naming tasks might improv
e pre-resection identification of essential language cortex during direct s
timulation cortical mapping, as well as noninvasive localization of dysfunc
tion during presurgical cognitive testing.