Objectives: Previous studies suggest that the nigrostriatal dopaminergic transmission is impaired in patients with primary orthostatic tremor.
Methods: We used transcranial sonography (TCS) to examine the morphology of the substantia nigra (SN) in four patients with primary orthostatic tremor (OT).
Results: TCS revealed an SN echogenicity in all patients, in three patients unilaterally, in one patient bilaterally.
Conclusions: Our data suggest nigrostriatal dopaminergic deficits in OT patients. The exact impact of these dopaminergic deficits on OT generation is unclear.