Tractography assessment, T2 relaxometry and hippocampal volume and its relation to the control of seizures and memory impairment in patients with mesial temporal lobe epilepsy underwent surgical treatment

Author(s)

Daniela Alves Fernandes

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2015-02-20

Examining board members

Fernando Cendes; Luiz Eduardo Betting; Veriano Alexandre Junior; Carlos Alberto Mantovani Guerreiro; Marcondes Cavalcante Franca Junior

• Advisor: Fernando Cendes

Abstract

The quantification of the atrophy of the mesial temporal structures by MR images in patients with TLE allows identification "in vivo" of the anatomical changes associated with this disease and its correlation with neuropsychological data, allowing for the establishment of a proper diagnosis. Despite the evidence of the effectiveness of surgical treatment for seizure control, it is not yet clear the effects of resection of the mesial temporal lobe structures in cognitive performance in the long-term follow up. The aim of this study was to evaluate prospectively of a series of patients with TLE undergoing epilepsy surgery, comparing pre/post-surgical results obtained from neuropsychological assessment (NPA). We included 119 subjects, 88 patients and 31 healthy controls. Of the 113 patients, 88 had two NPA and 60 underwent two MRIs after surgery. Patients were classified according to Engel¿s scale. We evaluated the estimated intelligence coefficient (eIQ), the verbal and non-verbal memories with tests used in preoperative routine. We use specific longitudinal analyzes with SPSS®22 software. We observed that 73.7% of patients were classified as Engel I; 17.1% were classified as Engel II; 8.0% were classified as Engel III and 1.1% classified as Engel IV after surgery with a mean follow up of 8.8 years. The NPA pre/postoperative showed a memory decline for these patients related to seizures control and side of surgery (p<0.0001). We found no significant difference between the postoperative NPAs carried out in two different times and separated in groups regarding seizure control and side of surgery; however, all tests indicated a trend towards improvement trend in memory performance and eIQ. We observed a larger hippocampal volume for the controls (mean=3706±842), in comparison with seizure free patients (mean=3602±711) and smaller hippocampal contralateral volumes for patients with persistent seizures after surgery (mean=3284±521). We observed a significant difference (p=0.005) in T2 signal between patients and controls (increase in patients). We also observed changes with a significant difference to the white matter tracts analyzed with diffusion tensor images, in the ipsilateral side of surgery compared to controls. Our results show good seizure control after surgery, even after a long period of follow up. However, our results showed that after surgery there is a decline in the performance on neuropsychological tests for most patients, regardless of the side of surgery. However, the long-term repeated analysis showed that there is partial recovery that may be associated with the interaction between learning effect and brain plasticity. We can hypothesize that the improvement in seizure control after surgery allows "recovery" of the long-term cognitive efficiency (AU)

• FAPESP's process: 11/20694-1 - Assessment of tractography, T2 relaxometry and hippocampal volumetry and its relationship to seizure control and memory impairment in patients with mesial temporal lobe epilepsy underwent surgical treatment
• Grantee: Daniela Alves Fernandes
• Support Opportunities: Scholarships in Brazil - Doctorate