Abstracts

Studies in animals models and epileptic patients have suggested that circuits of the basal ganglia may control epileptic seizures and that striatal dopaminergic neurotransmission plays a key role in seizure interruption. The aim of this study was to analyze if long lasting and seizures frequency are associated with reduction of striatal dopamine in drug resistant patients using positron emission tomography (PET) with [¹⁸F]fluoro-L-DOPA.
PET [¹⁸F]fluoro-L-DOPA studies were performed in adult patients with drug resistant epilepsy. The epileptic patients were divided in three groups: group 1 patients with ring chromosome 20 (r20) epilepsy (n=15; 21.8[plusmn]5.4 years old); group 2 patients with resistant generalized absence epilepsy (n=10; 32.3[plusmn]11.4 years old) and group 3 patients with pharmacoresistant temporal lobe epilepsy with hippocampal sclerosis (n=9; 35.2[plusmn]10.3 years old). The [¹⁸F]fluoro-L-DOPA uptake constant (Ki, min^-1) in the caudate and putamen nuclei was calculated using a multiple-time graphical analysis. For each nucleus, Ki values were average between both hemispheres and expressed as mean[plusmn]SD. The Ki values for each epileptic group were compared to a group of healthy volunteers (n=10; 45.1[plusmn]16.5 years old) using a ANOVA test with repeated measures.
A decrease of mean Ki values were observed in the caudate and putamen in all group of patients with refractory epilepsy.[table1]This decrease of [¹⁸F]fluoro-L-DOPA uptake is more marked for r20 epilepsy, where epilepsy is characterized by repeated and long lasting seizure the (group 1: p[lt]0,0001 for both nucleus). In group 2, where seizure occurs one or two times a day, a significant decrease uptake was also found (p[lt]0,001 and p=0.02, for caudate and putamen respectively). In the last group, where seizure event frequent occurs less than once a day, no significant differences were observed (group 3: p[gt]0.05, for both nucleus).
The decrease of [¹⁸F]fluoro-L-DOPA uptake observed in the striatum of patients with refractory epilepsy seems to be related to the seizure frequency suggesting that dopaminergic striatal dysfunction may impairs the mechanisms controlling seizures. We cannot exclude the possibility that the antiepileptic drugs had some consequences on [¹⁸F]fluoro-L-DOPA uptake. However, considering that the number of treatments was similar in the three groups, the influence of antiepileptic drugs doesn[rsquo]t not seem predominant in the decrease of Ki.