Critical area for memory decline after mesial temporal resection in epilepsy patients

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Mesial temporal lobe epilepsy (MTLE) surgery is associated with a risk of memory decline after surgery, but the effect of the extent and locus of temporal resection on postoperative memory function are controversial. The authors’ aim in this study was to confirm if selective resection is effective in preserving memory function and identify critical areas for specific memory decline after temporal resection.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>In this single-center retrospective study, the authors investigated data from patients who underwent unilateral MTLE surgery between 2005 and 2015. Data from 74 MTLE patients (60.8% of whom were female; mean [SD] age at surgery 32 years [8.91 years] and duration of epilepsy 16 years [9.65 years]) with histologically proven hippocampal sclerosis were included. Forty-two patients underwent left-sided surgery. The resection area was manually delineated on each patient’s postoperative T1-weighted images. Mapping was performed to see if the resected group, compared with the nonresected group, had worse postoperative memory in various memory domains, including verbal item, verbal associative, and figural memory.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Overall, 95.9% had a favorable epilepsy outcome. In verbal item memory, resection of the left lateral temporal area was related to postoperative decline in immediate and delayed recall scores of word lists. In verbal associative memory, resection of the anterior part of the left hippocampus, left parahippocampal area, and left lateral temporal area was related to postoperative decline in immediate recall scores of word pairs. Resection of the posterior part of the left hippocampus, left parahippocampal area, and left lateral temporal area was related to delayed recall scores of the same task. Similarly, in the figural memory, postoperative decline of immediate recall scores was associated with the resection of the anterior part of the right hippocampus, amygdala, parahippocampal area, and superior temporal area, and decline of delayed recall scores was related to resection of the posterior part of the right hippocampus and parahippocampal area.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Using voxel-based analysis, which accounts for the individual differences in the resection, the authors found a critical region for postoperative memory decline that is not revealed in the region-of-interest or groupwise comparison. Particularly, resection of the hippocampus was related to associative memory. In both verbal and visual memory, resection of the anterior part of the hippocampus was associated with immediate recall, and resection of the posterior part of the hippocampus was associated with delayed recall. Therefore, the authors’ results suggest that selective resection may be effective in preserving postoperative memory decline.</jats:p></jats:sec>

Global and Regional Changes in Perivascular Space in Idiopathic and Familial Parkinson's Disease

“…However, there was no significant difference between FPD and NMC or between IPD and HC in this region. The superior temporal area is a region known to subserve memory, which is also commonly affected in PD 63‐68 . Volume loss in the superior temporal region has been reported to be associated with cognitive decline in PD 64,69‐71 .…”

Transsylvian amygdalohippocampectomy for mesial temporal lobe epilepsy: Comparison of three different approaches

“…Additionally, the improvement of postoperative visual memory and IQ following TP-AH is evidence that the resection of the temporal pole is less impactful on neurocognitive performance than a combined impact of other factors such as preoperative functional reserve, age at seizure onset, resection of critical temporal areas, the magnitude of epilepsy network disconnection, and seizure control. 7,42,43 A major concern related to epilepsy surgical treatment is whether reducing the resection of nonpathological tissue may affect seizure control and postoperative side effects simultaneously. In a cohort of 95 patients with HS, McIntosh et al reported an Engel I rate of 54.2% 5 years after standard ATL.…”

“…The contralateral hemifield was evaluated, and the result was classified as (1) normal perimetry or visual field not attributable to surgery, (2) quadrant VFD F I G U R E 1 Drawings illustrating the transsylvian amygdalohippocampectomy at the right hemisphere. After the Sylvian fissure is dissected, anatomical landmarks are observed: frontal lobe (1), temporal pole (2), internal carotid artery (3), M1 segment of the middle cerebral artery (4), oculomotor nerve (5), limen insula (6), and uncus (7). The topography of the amygdala and the hippocampus (A) correspond to the regions surrounded by small dots and highlighted in yellow and blue, respectively.…”

“…Selective approaches are used worldwide once they are thought to be effective and to result in better postoperative neuropsychological performance than anterior temporal lobectomy (ATL) 6–8 . There is also evidence supporting that selective approaches lead to a lower rate of VFDs than nonselective ones 9–11 .…”

“…[3][4][5] Selective approaches are used worldwide once they are thought to be effective and to result in better postoperative neuropsychological performance than anterior temporal lobectomy (ATL). [6][7][8] There is also evidence supporting that selective approaches lead to a lower rate of VFDs than nonselective ones. [9][10][11] It is also intuitive to think that minimizing the resection volume of nonpathological tissue during an amygdalohippocampectomy would better preserve the temporal neocortex and the TS, which explains the preference for selective procedures in many centers.…”