China's Modified Version of Sniffin' Sticks 12-Identification Test Used in Chinese Parkinson's Disease and Multiple System Patients: Comparison of Three Olfactory Testing Methods

Objectives. The aim of this study was to compare the Sniffin' Sticks 12-identification test (SIT-12), China-modified version of the SIT-12 test (Ch-SIT-12) and brief smell identification test for Chinese (B-SITC) in Chinese population of Parkinson's disease (PD) and multiple system atrophy (MSA). Methods. 36 patients with PD and 7 patients with MSA were enrolled in this study. Three olfactory testing methods (SIT-12, Ch-SIT-12, and B-SITC) were used to test the olfactory function in all participants. Furthermore, demographic and clinical data were collected. Results. There was no significant difference between three olfactory tests in patients with PD (B-SITC vs. SIT-12: P=0.508; Ch-SIT-12 vs. B-SITC: P=0.146; and SIT-12 vs. Ch-SIT-12: P=0.375). Tremor-dominant (TD) subtypes have better olfactory function than akinetic-rigid dominant (ARD) subtypes when using Ch-SIT-12 (77.8% vs. 29.6%, P=0.019) or B-SITC (55.6% vs. 14.8%, P=0.026). There was a statistical difference between the PD and MSA using Ch-SIT-12 to test the olfactory function (P=0.046). Conclusions. Our results indicated that SIT-12, Ch-SIT-12 and B-SITC can be used for the detection of olfactory dysfunction in Chinese population of PD. TD subtypes may have better olfactory function than ARD subtypes. In addition, Ch-SIT-12 may be used to differentiate PD from MSA, but that should be confirmed in a larger population.