title: Long-term postoperative atrophy of contralateral hippocampus and cognitive function in unilateral refractory MTLE with unilateral hippocampal sclerosis.
abstract: OBJECTIVE
  This study aimed to evaluate long-term atrophy in contralateral hippocampal volume after surgery for unilateral MTLE, as well as the cognitive outcome for patients submitted to either selective transsylvian amygdalohippocampectomy (SelAH) or anterior temporal lobe resection (ATL).
  
  
  METHODS
  We performed a longitudinal study of 47 patients with MRI signs of unilateral hippocampal sclerosis (23 patients with right-sided hippocampal sclerosis) who underwent surgical treatment for MTLE. They underwent preoperative/postoperative high-resolution MRI as well as neuropsychological assessment for memory and estimated IQ. To investigate possible changes in the contralateral hippocampus of patients, we included 28 controls who underwent two MRIs at long-term intervals.
  
  
  RESULTS
  The volumetry using preoperative MRI showed significant hippocampal atrophy ipsilateral to the side of surgery when compared with controls (p<0.0001) but no differences in contralateral hippocampal volumes. The mean postoperative follow-up was 8.7 years (± 2.5 SD; median=8.0). Our patients were classified as Engel I (80%), Engel II (18.2%), and Engel III (1.8%). We observed a small but significant reduction in the contralateral hippocampus of patients but no volume changes in controls. Most of the patients presented small declines in both estimated IQ and memory, which were more pronounced in patients with left TLE and in those with persistent seizures. Different surgical approaches did not impose differences in seizure control or in cognitive outcome.
  
  
  CONCLUSIONS
  We observed small declines in cognitive scores with most of these patients, which were worse in patients with left-sided resection and in those who continued to suffer from postoperative seizures. We also demonstrated that manual volumetry can reveal a reduction in volume in the contralateral hippocampus, although this change was mild and could not be detected by visual analysis. These new findings suggest that dynamic processes continue to act after the removal of the hippocampus, and further studies with larger groups may help in understanding the underlying mechanisms.
authors.affiliation: Neuroimaging Laboratory, Hospital de Clínicas, 2° Floor, MRI Unit, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Daniela Alves
authors.initials: DA
authors.lastname: Fernandes
authors.affiliation: Neuroimaging Laboratory, Hospital de Clínicas, 2° Floor, MRI Unit, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil; Epilepsy Service, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Clarissa Lin
authors.initials: CL
authors.lastname: Yasuda
authors.affiliation: Neuroimaging Laboratory, Hospital de Clínicas, 2° Floor, MRI Unit, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Tátila Martins
authors.initials: TM
authors.lastname: Lopes
authors.affiliation: Neuroimaging Laboratory, Hospital de Clínicas, 2° Floor, MRI Unit, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil; Neurosurgery Division, Department of Neurology, Hospital de Clínicas, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Ghizoni
authors.initials: G
authors.lastname: Enrico
authors.affiliation: Neuroimaging Laboratory, Hospital de Clínicas, 2° Floor, MRI Unit, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Andréa
authors.initials: A
authors.lastname: Alessio
authors.affiliation: Neurosurgery Division, Department of Neurology, Hospital de Clínicas, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Helder
authors.initials: H
authors.lastname: Tedeschi
authors.affiliation: Neurosurgery Division, Department of Neurology, Hospital de Clínicas, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil.
authors.forename: Evandro
authors.initials: E
authors.lastname: de Oliveira
authors.affiliation: Neuroimaging Laboratory, Hospital de Clínicas, 2° Floor, MRI Unit, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil; Epilepsy Service, Rua Vital Brasil, 251, University of Campinas, UNICAMP, Cidade Universitária Zeferino Vaz, 13083-888 Campinas, SP, Brazil. Electronic address: fcendes@unicamp.br.
authors.forename: Fernando
authors.initials: F
authors.lastname: Cendes
mesh_terms: D000328:Adult; D001284:Atrophy / Q000209:etiology / Q000473:pathology; D004833:Epilepsy, Temporal Lobe / Q000150:complications / Q000601:surgery*; D005260:Female; D007839:Functional Laterality; D006624:Hippocampus / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000503:physiopathology*; D011446:Prospective Studies; D012598:Sclerosis / Q000209:etiology; D016896:Treatment Outcome
keywords: Cognition; Contralateral hippocampus atrophy; Epilepsy surgery; Hippocampal sclerosis; MRI; MTLE; Memory outcome; Volumetry