Naming Decline After Left Anterior Temporal Lobectomy Correlates with Pathological Status of Resected Hippocampus

Abstract

Summary: Purpose:To evaluate the determinants of postoperative change in visual confrontation naming ability and the differential sensitivity of two common tests of confrontation naming.Methods: In a group of 99 patients undergoing lobectomy of the left, language-dominant anterior temporal lobe, we examined naming ability using two measures: the 60 item Boston Naming Test (BNT), and the Visual Naming (VN) subtest of the Multilingual Aphasia Examination (MAE). ATL entailed resection of lateral temporal lobe followed by microsurgical complete removal of hippocampus. Language mapping was not performed. The status of the resected hippocampus was graded on a scale 0-4 of hippocampal sclerosis (HS). A dichotomous grouping HS-(grades 0 and 1, n = 34) and HS+ (grades 3 and 4, n = 61) was effected. Age at surgery, age of epilepsy onset, sex, extent of lateral temporal resection, Full-Scale IQ (FSIQ), and preoperative naming scores were also examined as potential predictors of pre-versus postoperative naming change.Results: Preoperative BNT and VN scores were significantly worse for HS+ than for HS-(BNT, p c 0.05; VN, p = 0.001).Postoperatively, BNT and VN scores significantly declined for HS-as compared with HS+ patients (p c 0.001). For individual risk, the 90th centile of reliable change index (RCI) was used. By this criterion, of the total sample, 39% evidenced decline on the BNT and 17% evidenced decline on the VN. Logistic regression analysis with backward elimination showed HS to be the only predictor of decline in BNT and HS and sex to be the only predictors of VN decline. Males were more at risk than females. Age, age at onset, extent of lateral resection, preoperative scores, and FSIQ were not predictors. Using age at onset as a proxy for HS+/HS-we calculated probabilities for naming decline for given onset age. Conclusions: Both preoperative and postoperative change in naming ability are associated with the pathological status of the hippocampus. The potential interpretations and implications of these findings are discussed.

Intracarotid Amobarbital Procedure and Prediction of Postoperative Memory in Patients with Left Temporal Lobe Epilepsy and Hippocampal Sclerosis

“…Regarding the word list, 17 patients were tested on the 16-item California Verbal Learning Test (22), and five patients were administered the 15-item Rey Auditory Verbal Learning Test (23). We included the naming (semantic memory) tests as possible outcome measures in addition to the episodic memory tests because a relationship between ipsilateral hippocampal integrity and postoperative object naming change had previously been identified (24).…”

Language activation distributions revealed by fMRI in post-operative epilepsy patients: Differences between left- and right-sided resections

“…The resection may disturb or damage cortex eloquent for memory and language functioning. Despite extensive non-invasive and invasive pre-operative hemispheric language and memory testing, subtle problems may arise in post-operative language functioning after left ATL (Hermann et al, 1994;Davies et al, 1998;Langfitt and Rausch, 1996;Clusmann et al, 2002). More frequently difficulties in verbal memory are found post-operatively (Rausch et al, 2003;Lee et al, 2002;Bell and Davies, 1998).…”

Prediction of neuropsychological outcome after resection of temporal and extratemporal seizure foci

“…58 Postoperative word-finding difficulties are more likely to occur with more extensive resection of lateral temporal cortex, 29 which is one area that stores semantic knowledge. 24 Other predictors of postoperative word-finding difficulties include an absence of hippocampal sclerosis or other imaging abnormalities before surgery, 11 MR tractography showing more lateralized white matter tracts in the language-dominant hemisphere, 48 fMRI temporal lobe laterality index, 51 the absence of risk factors for seizures (for example, febrile seizures in childhood), 56 cessation of language in tissue to be resected during intraoperative electrical stimulation mapping, 23 and better presurgical naming ability. 10 Semantic knowledge acquired later in life is the most vulnerable to loss after surgery.…”