Background: Olfactory dysfunction is a predominant non - motor symptom in patients with Parkinson's disease. Indian studies on olfactory loss using standardized kits are lacking.
Objective: 1) To assess the olfactory impairment in patients with Parkinson's disease 2) To verify the applicability of UPSIT to Indian subjects 3) To assess the correlation between olfactory dysfunction and duration, stage and severity of the illness.
Materials and methods: Patients with Parkinson's disease attending Neurology outpatient and inpatient departments were taken for the study. The details of demographic data and illness were collected. Patients with other risk factors for hyposmia were excluded from the study. Detailed neurological examination and smell test were done using University of Pennsylvania Smell Identification Test (UPSIT) kit. 40 healthy individuals without any pre-morbid illness or risk factors for hyposmia were studied for the applicability of the British version of UPSIT to the Indian population, 20 of whom were age and sex matched with the Parkinson's disease patients. Statistical analysis was done using Wilcoxon matched-pair signed-ranks test (WSRT)) and Pearson correlation test.
Results: Parkinson's disease patients had a mean age 58.2 years and a mean duration of illness of 5.5 years. Parkinson's disease patients had a low score on UPSIT compared to controls which was statistically significant (p 0.000) and the loss spanned a variety of odorants in UPSIT. There was no correlation with the age, staging or duration of the illness.
Conclusions: Olfactory loss is a significant non motor symptom in Parkinson's disease patients and is probably not related to the disease duration, stage or severity of motor symptoms.