title: Temporopolar blurring in temporal lobe epilepsy with hippocampal sclerosis and long-term prognosis after epilepsy surgery.
abstract: OBJECTIVE
  We conducted a retrospective study in order to investigate the clinical significance of temporopolar grey/white matter abnormalities (GWMA) in patients with temporal lobe epilepsy (TLE) and unilateral hippocampal sclerosis (HS) with a long post-surgical follow-up.
  
  
  METHODS
  The study comprised 122 consecutive patients with medically refractory TLE and unilateral HS who underwent epilepsy surgery and had a minimum postoperative follow-up of 5 years. Patients were divided into two groups, based on findings of pre-surgical MRI: group 1 with GWMA and 2 with normal signal and grey/white matter definition in temporal pole. Demographic and clinical data were reviewed and compared between groups.
  
  
  RESULTS
  GWMA were found in 52.5% of patients, always ipsilateral to HS. Compared with group 2, group 1 patients had earlier epilepsy onset (mean, 9.3 vs 14.4 years, P=0.001), a higher occurrence of first seizure ≤2 years of age (25.8% vs 10.5%, P=0.036; OR=2.96 [95% CI=1.07-8.19]), and greater prevalence of left HS (76.6% vs 43.1%, P<0.001; OR=4.31 [95% CI=1.98-9.38]). No differences were found in gender, presence or type of initial precipitating injury, history of secondary generalized seizures, duration of epilepsy, seizure frequency before surgery, neuropsychological evaluation and presence or lateralization of pre-surgical interictal epileptiform discharges. Postoperative follow-up varied from 5 to 11.5 years (mean 7.4) and was similar in both groups (P=0.155). The proportion of patients classified as seizure-free (Engel class I) at last follow-up in groups 1 and 2 were 73.4% and 69%, respectively (P=0.689). Similarly, the percentages of seizure-free patients with no antiepileptic drugs at last evaluation were not different between groups (P=0.817). In logistic regression analysis, left HS (P=0.001; OR=4.166 [95% CI=1.86-9.34]) and age at epilepsy onset ≤2 years (P=0.047; OR=3.885 [95% CI=1.86-17.50]) were independently associated with risk of having GWMA.
  
  
  CONCLUSIONS
  GWMA are frequent findings in patients with TLE and HS, and may help lateralize the epileptogenic zone. Our data support the hypothesis that GWMA are caused by seizure-related insults during the critical period of cerebral myelination. GWMA did not influence the postoperative seizure outcome of patients with TLE and HS, even after an extended duration of post-surgical follow-up.
authors.affiliation: Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo, São Paulo, Brazil. Electronic address: pevinaves@yahoo.com.br.
authors.forename: Pedro V F
authors.initials: PV
authors.lastname: Naves
authors.affiliation: Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo, São Paulo, Brazil; Department of Clinical Neurophysiology, Hospital Israelita Albert Einstein, São Paulo, Brazil.
authors.forename: Luís Otávio S F
authors.initials: LO
authors.lastname: Caboclo
authors.affiliation: Department of Radiology, Division of Neuroradiology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Henrique
authors.initials: H
authors.lastname: Carrete
authors.affiliation: Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Bruno V
authors.initials: BV
authors.lastname: Kelmann
authors.affiliation: Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Larissa B
authors.initials: LB
authors.lastname: Gaça
authors.affiliation: Department of Radiology, Division of Neuroradiology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Gabriel B
authors.initials: GB
authors.lastname: Sandim
authors.affiliation: Department of Neurology and Neurosurgery, Division of Neurosurgery, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Ricardo S
authors.initials: RS
authors.lastname: Centeno
authors.affiliation: Department of Neurology and Neurosurgery, Division of Neurology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Elza Márcia T
authors.initials: EM
authors.lastname: Yacubian
mesh_terms: D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000150:complications* / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D066128:Gray Matter / Q000473:pathology*; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000473:pathology; D012189:Retrospective Studies; D012598:Sclerosis / Q000209:etiology; D066127:White Matter / Q000473:pathology*; D055815:Young Adult
keywords: Epilepsy surgery; Grey/white matter abnormalities; MRI; Temporal lobe epilepsy; Temporal pole blurring