Morphometric MRI features and surgical outcome in patients with epilepsy related to hippocampal sclerosis and low intellectual quotient

• Published in: Epilepsy & behavior Vol. 82; pp. 144 - 149
• Main Authors: Gaça, Larissa Botelho, Garcia, Maria Teresa Fernandes Castilho, Sandim, Gabriel Barbosa, Assumption Leme, Idaiane Batista, Noffs, Maria Helena Silva, Carrete, Henrique, Centeno, Ricardo Silva, Sato, João Ricardo, Yacubian, Elza Márcia Targas
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2018
• Subjects: FreeSurfer analysis; Hippocampal sclerosis; Low IQ; Mesial temporal lobe epilepsy; Surgical outcome; Hippocampal sclerosis; FreeSurfer analysis; Mesial temporal lobe epilepsy; Surgical outcome; Low IQ
• ISSN: 1525-5050; 1525-5069
• DOI: 10.1016/j.yebeh.2018.03.011

The objectives of this study were to verify in a series of patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) if those with low intellectual quotient (IQ) levels have more extended areas of atrophy compared with those with higher IQ levels and to analyze whether IQ could be a variable implicated on a surgical outcome.
Patients (n=106) with refractory MTLE-HS submitted to corticoamygdalohippocampectomy (CAH) (57 left mesial temporal lobe epilepsy (MTLE); 45 males) were enrolled. To determine if the IQ was a predictor of seizure outcome, totally seizure-free (SF) versus nonseizure-free (NSF) patients were evaluated. FreeSurfer was used for cortical thickness and volume estimation, comparing groups with lower (<80) and higher IQ (90–109) levels.
In the whole series, 42.45% of patients were SF (Engel Class 1a; n=45), and 57.54% were NSF (n=61). Total cortical volume was significantly reduced in the group with lower IQ (p=0.01). Significant reductions in the left hemisphere included the following: rostral middle frontal (p=0.001), insula (p=0.002), superior temporal gyrus (p=0.003), thalamus (p=0.004), and precentral gyrus (p=0.02); and those in the right hemisphere included the following: rostral middle frontal (p=0.003), pars orbitalis (p=0.01), and insula (p=0.02). Cortical thickness analysis also showed reductions in the right superior parietal gyrus in patients with lower IQ. No significant relationship between IQ and seizure outcome was found.
This is the first study of a series of patients with pure MTLE-HS, including those with low IQ and their morphometric magnetic resonance imaging (MRI) features using FreeSurfer. Although patients with lower intellectual scores presented more areas of brain atrophy, IQ was not a predictor of surgical outcome. Therefore, when evaluating seizure follow-up, low IQ in patients with MTLE-HS might not contraindicate resective surgery.
•Total cortical volume was reduced in patients with lower IQ and MTLE-HS.•Patients with lower IQ presented more areas of brain volume reduction.•In this pure series, IQ was not a predictor of surgical outcome.