Dataset Information

Volumetric Changes in Hippocampal Subregions and Memory Performance in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

ABSTRACT: In the present study we explored the different patterns of volumetric atrophy in hippocampal subregions of patients with left and right mesial temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Meanwhile, the memory impairment patterns in Chinese-speaking TLE-HS patients and potential influencing factors were also determined. TLE-HS patients (21 left and 17 right) and 21 healthy controls were recruited to complete T2-weighted imaging and verbal/nonverbal memory assessment. The results showed that both left and right TLE-HS patients had overall reduced hippocampal subregion volumes on the sclerotic side, and cornu ammonis sectors (CA1) exhibited maximum atrophy. The verbal memory of left TLE-HS patients was significantly impaired (P < 0.001) and was not associated with the volumes of the left hippocampal subregions. Verbal or nonverbal memory impairment was not found in the patients with right TLE-HS. These results suggested that the atrophy of hippocampal subregion volumes cannot account for the verbal memory impairment, which might be related to the functional network.

SUBMITTER: Ji C

PROVIDER: S-EPMC5856714 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

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Volumetric Changes in Hippocampal Subregions and Memory Performance in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

Ji Caihong C Zhu Lujia L Chen Cong C Wang Shuang S Zheng Leilei L Li Hong H

Neuroscience bulletin 20171101 2

In the present study we explored the different patterns of volumetric atrophy in hippocampal subregions of patients with left and right mesial temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Meanwhile, the memory impairment patterns in Chinese-speaking TLE-HS patients and potential influencing factors were also determined. TLE-HS patients (21 left and 17 right) and 21 healthy controls were recruited to complete T2-weighted imaging and verbal/nonverbal memory assessment. The results s ...[more]

PMID: 29094314

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Project description:The Wada test is widely used in the presurgical evaluation of potential temporal lobectomy patients to predict postoperative memory function. Expected asymmetry (EA), defined as Wada memory lateralized to the nonsurgical hemisphere, or a higher score after injection of the surgical hemisphere would be considered favorable in terms of postoperative memory outcome. However, in some cases, nonlateralized memory (NM) results, with no appreciable asymmetry, may occur because of impaired scores after both injections, often leading to denial of surgery. The reason for such nonlateralized Wada memory in patients with intractable temporal lobe epilepsy (TLE) remains unclear. Given that quantitative morphometric magnetic resonance imaging studies in TLE patients have shown bilateral regional atrophy in temporal and extratemporal structures, we hypothesized that the volume loss in contralateral temporal structures could contribute to nonlateralized Wada memory performance. To investigate this, we examined the relationship between the volume changes of temporal structures and Wada memory scores in patients with intractable TLE with mesial temporal sclerosis (MTS) using an age- and gender-matched control group. Memory was considered nonlateralized if the absolute difference in the total correct recall scores between ipsilateral and contralateral injections was <11%. Among 21 patients, Wada memory was lateralized in 15 and nonlateralized in 6 patients, with all the nonlateralized scores being observed in left TLE. The recall scores after ipsilateral injection were significantly lower in patients with an NM profile than an EA profile (23 ± 14% vs. 59 ± 18% correct recall, p ? 0.001). However, the recall scores after contralateral injection were low but similar between the two groups (25 ± 17% vs. 25 ± 15% correct recall, p=0.97). Compared to controls, all the patients showed greater volume loss in the temporal regions. However, patients with a NM profile showed significantly more volume loss than those with a lateralized memory profile in both contralateral and ipsilateral temporal regions (p<0.05). Left hemispheric Wada memory performance correlated positively with the size of the left mesial and neocortical temporal structures (r=0.49-0.63, p=0.005-0.04). Our study suggests that volume loss in the nonsurgical temporal structures is associated with nonlateralized Wada memory results in patients with intractable TLE.

Project description:BACKGROUND:Epilepsy surgery often causes changes in cognition and cerebral glucose metabolism. Our aim was to explore relationships between pre- and postoperative cerebral metabolism as measured with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and neuropsychological test scores in patients with left mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), who were rendered seizure-free after epilepsy surgery. RESULTS:Thirteen patients were included. All had neuropsychological testing and an interictal FDG-PET scan of the brain pre- and postoperative. Correlations between changes in neuropsychological test scores and metabolism were examined using statistical parametric mapping (SPM). There were no significant changes in the neuropsychological test scores pre- and postoperatively at the group level. Decreased metabolism was observed in the left mesial temporal regions and occipital lobe. Increased metabolism was observed in the bi-frontal and right parietal lobes, temporal lobes, occipital lobes, thalamus, cerebellum, and vermis. In these regions, we did not find a correlation between changes in metabolism and neuropsychological test scores. A significant negative correlation, however, was found between metabolic changes in the precuneus and Boston Naming Test (BNT) scores. CONCLUSIONS:There are significant metabolic decreases in the left mesial temporal regions and increases in the bi-frontal lobes; right parietal, temporal, and occipital lobes; right thalamus; cerebellum; and vermis in patients with left MTLE-HS who were rendered seizure-free after epilepsy surgery. We could not confirm that these changes translate into significant cognitive changes. A significant negative correlation was found between changes in confrontation naming and changes in metabolism in the precuneus. We speculate that the precuneus may play a compensatory role in patients with postoperative naming difficulties after left TLE surgery. Understanding of these neural mechanisms may aid in designing cognitive rehabilitation strategies.

Dataset Information

Volumetric Changes in Hippocampal Subregions and Memory Performance in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

Publications

Volumetric Changes in Hippocampal Subregions and Memory Performance in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

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