DYSNOMIA AFTER LEFT ANTERIOR TEMPORAL LOBECTOMY WITHOUT FUNCTIONAL MAPPING - FREQUENCY AND CORRELATES

The integrity of language function after a left (dominant) anterior te mporal lobectomy performed without the use of functional mapping remai ns controversial. Much of the controversy concerns the degree to which analyses of group data obscure the identification of surgically induc ed dysnomia in individual patients. This study investigated postoperat ive language outcome in our entire series (n = 162) of nonretarded, le ft hemisphere speech dominant patients with intractable nonlesional ep ilepsy who underwent a left (n = 85) or right (n = 77) anterior tempor al lobectomy without functional mapping. A comparison of preoperative to (6 mo) postoperative performance on a standardized test of nominal speech revealed the following: 1) a statistically significant but clin ically modest difference in outcome between left and right anterior te mporal lobectomy groups; 2) a subgroup (7%) of left anterior temporal lobectomy patients exhibited a postoperative dysnomia (a decline in no minal speech that exceeded the worst performance in the right anterior temporal lobectomy group); and 3) a postoperative decline in nominal speech after left anterior temporal lobectomy was specifically associa ted with a later age at the onset of epilepsy. Within the context of g roup data suggesting minimal risk to language function when functional mapping is not used, a small subgroup of individuals characterized by a later onset of epilepsy can be identified who exhibit a surgically induced dysnomia after a standard left anterior temporal lobectomy. Wh ether these results differ from the outcome of functional mapping rema ins to be determined.