From: Combination of olfactory test and substantia nigra transcranial sonopraphy in the differential diagnosis of Parkinson’s disease: a pilot study from China
Diagnostic feature
Sensitivity(%)
Specificity(%)
PPV(%)
NPV(%)
(1) Hyposmia
62.2
96.2
95.8
64.1
(2) SN hyperechogenicity
48.6
84.6
81.8
53.7
(3) Either (1) or (2) present
78.4
80.8
85.3
72.4
(4) Both (1) and (2) present
29.7
100
50.0