Relevance of substantia nigra hyperechogenicity and reduced odor identification in idiopathic REM sleep behavior disorder

Value of combined midbrain sonography, olfactory and motor function assessment in the differential diagnosis of early Parkinson's disease

“…High intra- and inter-rater reliability of this TCS finding for the diagnosis of PD has been demonstrated, provided the investigator is adequately qualified 7 20. While SN hyperechogenicity alone has a good predictive value for PD,33 34 its diagnostic value was increased if combined with either other TCS findings7 35 or with the results of olfaction testing 28 29 32 36. Even though SN hyperechogenicity and (mild) motor asymmetry were found to coincide frequently in subjects without parkinsonism,37 38 assessment of both SN echogenicity and motor asymmetry improved the predictive value for the diagnosis of PD in the present study (table 2).…”

Developments in the Role of Transcranial Sonography for the Differential Diagnosis of Parkinsonism

“…In idiopathic REM behavioural disorder (iRBD), the most specific prodromal feature for an alpha-synucleinopathy to date, SN+ can be found in up to half of all cases [85,86]. In 2010, Iranzo and colleagues demonstrated that the combination of TCS and DAT SPECT can predict the conversion to parkinsonism in iRBD with a sensitivity of 100 % and a specificity of 55 % after 2.5 years [87].…”

Neuroimaging in Parkinson's Disease

“…This is thought by some authors to be specific for PD (or, more correctly, to be a trait marker, given that echogenicity may be increased in relatives of patients with PD [22], in normal individuals [23], and in those with other disorders thought to predispose to PD, such as rapid-eyemovement sleep behavior disorder and anosmia) [24,25]. Abnormal echogenicity in normal younger individuals may correspond to impaired dopaminergic function as assessed by positron emission tomography (PET) [26].…”