Predictive value of the smell identification test for nigrostriatal dopaminergic depletion in Korean tremor patients

Abstract

BackgroundThe predictive value of Cross-Cultural Smell Identification Test for nigrostriatal dopaminergic depletion in Korean tremor patients has yet to be assessed. MethodsThree hundred nineteen drug-naive patients who visited our clinic for the diagnosis of their tremor, and took both Cross-Cultural Smell Identification Test and dopamine transporter PET were included in the data analysis. Visual grading of each PET image was performed by two independent neurologists. ResultsSmell test scores were significantly correlated to the striatal dopaminergic activity (Kendall's τb = −0.291, p < 0.001). However, smell test score alone appeared to have relatively weak power for predicting dopaminergic depletion (area under the curve = 0.693). Multivariate logistic regression model with inclusion of the patient's age and symptom duration as independent variables enhanced predictive power for dopaminergic depletion (area under the curve = 0.812). ConclusionsThese results demonstrated that Cross-Cultural Smell Identification Test measurements alone may be insufficient to predict striatal dopaminergic depletion in Korean tremor patients.