An FDOPA PET study in patients with periodic limb movement disorder and restless legs syndrome.

The authors investigated nine drug-naive patients with periodic limb movement disorder and restless legs syndrome (PLMD-RLS) and 27 healthy controls with PET using 6-[18F]fluoro-L-dopa (FDOPA). In the patients, the FDOPA uptake (Ki(occ)) in the caudate nucleus was 88% and in the putamen 89% of the control mean values. This equal affection of the caudate and the putamen differs, for example, from the dopaminergic dysfunction in Parkinson's disease, which affects the putamen earlier and more severely than the caudate. The current results indicate mild nigrostriatal presynaptic dopaminergic hypofunction in PLMD-RLS.