Evaluation of Olfactory Function by Iranian Smell Diagnostic Test in Patients with Parkinson's disease in North of Iran

Introduction: Parkinson's disease is a neurodegenerative and multisystem disorder affecting systems more than the motor system. The olfactory disorder is an early non-motor symptom of Parkinson's disease. Materials and Methods: The present study was conducted on ۱۱۰ patients aged ۵۰-۹۵ years with a diagnosis of Parkinson's disease referred to the Neurology Clinic of Babol University of Medical Sciences between  ۲۰۱۸-۲۰۱۹. The control group consisted of ۵۰-۹۵-year-old non-neurological patients who were matched for age and gender with patients with Parkinson's disease. Data were collected by examination, demographic and clinical information questionnaire (duration of disease, the severity of disease, symptom index), as well as Iranian smell diagnostic test. A p-value less than ۰.۰۵ was considered statistically significant. Results: The mean age scores of Parkinson's disease and control groups were obtained at ۶۹±۹ and ۶۶±۹ years, respectively. The mean duration of the disease was ۵ years. Patients with Parkinson's disease scored lower on the Iranian smell test, and olfactory function was significantly reduced in the case group (p <۰.۰۰۱). Based on the results, olfactory function in patients with Parkinson's disease was not significantly correlated with gender, marital status, education, place of residence, and occupation(p <۰.۰۵). Only olfactory dysfunction was increased with age (P=۰.۰۱). In addition, olfactory dysfunction showed no significant relationship with severity of disease, duration of disease, and clinical index sign. Rapid Iranian smell test with a cut-off of ۳.۵% had a sensitivity of ۸۷.۳% and a specificity of ۶۶.۴%. Conclusion: According to the obtained results,olfactory dysfunction is an important non-motor and a primary symptom in patients with Parkinson's disease and is not related to the duration and severity of motor symptoms and symptom index.

Keywords:

Olfactory dysfunction , Olfactory , Parkinson's disease , Severity of Parkinson's disease