Parasomnia as an occasion for the diagnosis of Parkinson's disease

We report a case of Parkinson's disease (PD) diagnosed by REM sleep behavio r disorder (RBD). The patient was a 68-year-old man. On admission, rigidity in the left upper and lower extremities, bradykinesia, and gait disturbanc e were noted. In addition, polysomnography revealed REM sleep without atoni a (RWA), and a diagnosis of untreated PD associated with RED was made. Poly somnographic data showed that REM density decreased and RWA tended to incre ase after administration of a combination of L-DOPA and DCI (L-DOPA/DCI). T hus, we considered that the pathophysiological mechanism of RED in this cas e was based not only on the dysfunction of the brainstem mechanism of RWA, but also on the impairment of dopaminergic neuron.