Diagnostic value of vietnamese smell identification test in Parkinson's disease

The Vietnamese Smell Identification Test (VSIT) has been validated in determining olfactory dysfunction in the Vietnamese population; however, its value in diagnosing Parkinson's disease (PD) has not been established.

This case-control study was conducted at University Medical Center HCMC, Ho Chi Minh City, Vietnam. The study sample included non-demented PD patients and healthy controls (HC) who were gender- and age-matched. All participants were evaluated for odor identification ability using the VSIT and the Brief Smell Identification Test (BSIT).

A total of 218 HCs and 218 PD patients participated in the study. The median VSIT and BSIT scores were significantly different between PD and HC groups (VSIT, 5 (3) vs. 9 (2), P < 0.0001; BSIT, 6 (3) vs 8 (2), P < 0.0001). Using the cut-off of <8 for correct answers out of 12 odorants, the VSIT had higher sensitivity (84.4%) and specificity (86.2%) than those of the BSIT (sensitivity of 81.7% and specificity of 69.3%) for the diagnosis of PD. The area under the curve (AUC) value was greater for the VSIT than for the BSIT (0.909 vs 0.818). The smell identification scores were not significantly correlated with disease duration, disease severity, or LEDD (all p > 0.05).

The VSIT can be a valuable ancillary tool for supporting the diagnosis of PD in Vietnam. Olfactory dysfunction in PD was unrelated to the disease duration and severity. The VSIT can be applied to improve the accuracy of clinical PD diagnosis.