Relationship between substantia nigra echogenicity and olfactory dysfunction in idiopathic PD and vascular Parkinsonism

Introduction: Olfactory function deficit is a robust finding in about 90% of idiopathic Parkinson's disease (PD) patients. Degree of smell-loss has been reported to be unrelated to the magnitude of motor and cognitive symptoms in some studies. Hyposmia has also been described as premotor PD sign. Abnormal hyperechogenicity of substantia nigra (SN) is a characteristic and stable transcranial sonography (TCS) finding in PD while healthy adults with marked SN hyperechogenicity often have a subclinical functional impairment of the nigrostriatal dopaminergic system. Here, we wanted to find out whether SN echogenicity…