Abstracts

Rationale: We examined one-year outcome of patients undergoing stereotactic laser amygdalohippocampotomy (SLAH) on a standard measure of visual naming. Busch et al.1 recently highlighted the substantial risk of naming decline in patients undergoing anterior temporal lobe (ATL) resection of the language dominant hemisphere for seizure control, and offered decision trees for predicting risk of decline. A meaningful decline on the Boston Naming Test (BNT) occurred in more than 40% of their clinical sample undergoing left ATL and 5% of those undergoing right ATL. They established criteria for gauging the relative risk of post-surgical decline for left TLE patients, finding patients at high risk had a 75% chance of meaningful decline. We compared our BNT outcome data to the Busch et al. study sample and also applied their risk criteria analysis to our patients with left SLAH. Methods: We present outcome data using reliable change scores for 44 SLAH patients (20 left-sided/24 right-sided) who reached one-year follow-up. We used chi square analyses to compare outcomes of our cohort with the large, recently published sample of ATL patients.1 We also applied the Busch et al. algorithm to determine if patients at a moderate or higher risk of decline experienced a worse outcome. This formula suggests the risk of naming decline is greatest for patients with a late age of seizure onset (>18 years) who are more than 50 years of age and/or have a high baseline score on the BNT (≥50). All patients underwent presurgical evaluation at Emory University, which included video-EEG monitoring, neuropsychological testing, MRI and PET scans, and sometimes intracranial monitoring (n=13). We also include data on 4 comparable TLE patients from the same consecutive series who underwent open resection rather than SLAH.  Results: Only one of 20 left TLE patients experienced a meaningful decline on the BNT after undergoing SLAH, and this was an older patient, with mild dementia who experienced global cognitive decline, believed to be due a primary systemic disease. Based on the study by Busch et al., we expected at least 8 of 20 patients from our left TLE sample to decline; rather, 8 of the 20 left TLE patients experienced significant improvement on the BNT demonstrating a far superior outcome after SLAH. Only one of 12 left TLE patients who were deemed to be at moderate or high risk for a poor outcome declined following SLAH (i.e., dementia patient). None of 24 right TLE patients declined significantly on the BNT, while 3 showed significant gains. Of note, 3 of 3 left TLE patients undergoing open resection declined meaningfully on the BNT, with a mean decline of 11.7 points (SD=7.3). Conclusions: Results indicate: 1) naming outcome is better for TLE patients following SLAH compared to standard ATL, even in patients at high risk for decline, 2) the amygdalohippocampal complex is not an essential component of neural networks underlying name retrieval for man-made objects, and 3) patients undergoing SLAH may exhibit naming improvement.   1Busch, R. M., Floden, D. P., Prayson, B., Chaping, J. S., Kim, K. H., et al. (2016). Estimating risk of word-finding problems in adults undergoing epilepsy surgery. Neurology, 87, 2363-2369. Funding: NIH/NINDS (K02 NS070960 & R01NS088748); Medtronic, Inc. (A1225797BFN:1056035)