Neurometabolic activity in the thalamic and frontal cortex and cognitive functions in adolescents with generalized epileptic syndromes

Abstract

The study aimed to analyse the mutual correlations between the metabolic activity of the brain evaluated by the magnetic resonance spectroscopy method (MRS) and intelligence and cognitive functions in adolescents with idiopathic generalised epilepsies (IGE). The focus of the study was placed on the activity of the thalamus and frontal cortex.Twenty newly diagnosed patients with juvenile absence epilepsy (JAE) and juvenile myoclonic epilepsy (JME) were included in the study. Adolescents underwent primary structural neuroimaging (1.5T) and advanced evaluation of the frontal cortex and thalamus by MRS. Concentrations of N-acetyl aspartate (NAA), creatine plus phosphocreatine (Cr) and choline (Cho) were measured and were expressed as ratios of NAA/Cr, NAA/Ch and NAA/Cr+Ch. Patients also completed a panel of IQ and cognitive tests (e.g., FePsy Battery – classification test, verbal fluency test, RAVLT memory test). The correlation between the level of metabolites and the results of intellectual and cognitive tests was examined.Strong correlations were found between IQ and some cognitive functions and metabolic ratios in the IGEs group. Overall the patients whose NAA/Cr, NAA/Ch, NAA/Cr+Ch ratios were lower, obtained worse results in IQ and in some of the neuropsychological tests.The metabolite activity in the thalamus and frontal cortex impacts the results of neuropsychological tests in the group of patients with IGE.