Abstracts

Introduction: We recently reported that patients with juvenile myoclonic epilepsy (JME) have reduced frontal lobe levels of N-acetyl aspartate (NAA). The present study was undertaken to investigate whether similar changes exist in subjects A further issue was to analyze whether possible NAA-abnormalities are related to frontallobe dysfunctions who only manifest primarily generalized tonic clonic seizures (GM). Method: Eighteen patients with GM, 17 with JME, and 10 matched healthy controls were investigated with quantitative single voxel magnetic resonance spectroscopy (MRS) measurements of N-acetyl aspartate (NAA), Choline (Cho), Creatine (Cr) and myo--Inositol (mI) according to previously described method. The voxels were placed over cerebellum thalamus, the prefrontal and occipital cortex. The two groups of patients were matched for the antiepileptic medication, age, age at seizure onset, duration, frequency and and the total number of seizures. The frontallobe function was assessed with a battery of commercial neuropsychological tests. Results: Patients with GM had normal regional metabolites. In contrast, significantly lower frontallobe NAA (mmol/l) was found in subjects with JME, both in relation to GM-patients (9.4 1.0 vs 10.9 1.1, p=0.009), and controls (9.4 1.0 vs. 10.3 0.7, p=0.013). Seven of the JME patients had reduced frontallobe NAA. Only 60% of them had abnormal neuropsychological tests, and no correlation was found with the frontal lobe NAA (simple regression). Conclusion: The observed frontallobe abnormality in JME may be syndrome related. Among patients with JME, the distribution of subjects with reduced frontal lobe NAA may, however, be bimodal. The present preliminary findings, therefore, need further attention.