Quantifiable Olfactory Dysfunction as a Diagnostic marker in Parkinson’s disease: A study from Central Kerala

Abstract

Olfactory dysfunctionwhich mayprecede motor dysfunction in Parkinson’s disease(PD), is often neglected in the clinical care setting. The present study aimed at assessing and quantitating olfactory function inPDpatients and comparing olfactory function between patients with young-onset Parkinson's disease (YOPD)and those with the later-onset disease.Patients diagnosed withPDhad their olfactory functiontested and compared with controls;tested olfactory parameters included Olfactory Recognition Threshold, Olfactory Identification Score and Olfactory Discrimination Score. 32 PD patients and 64 healthy controls were recruited for olfactory function assessment after obtaining informed consent.Our results revealed a statistically significant loss ofolfactory functionamong PD patients compared to age-matched controls(p-value <0.001). The correlation analysis showed a statistically significant negative correlation between olfactory scores with a duration of PD(p-value =0.029 and <0.001).Olfactory function was impaired in YOPD compared to controls but not as severely affected as in elderly patients. We concludethat olfactory dysfunction can be used as an easily tested,reliable, quantifiable and inexpensive biomarker for Parkinson’s disease.