Olfactory impairment in Parkinson disease using culture-relevant products: making the case for a Moroccan Smell Identification Test (MoroSIT)

Introduction: Olfactory problems are frequent in Parkinson disease. Their early onset relative to motor problems makes them a potential biomarker for the disease, yet no culture-specific standardized tests exist in Morocco. Aim: To use indigenous plant extracts generated in our laboratory to investigate olfactory impairment in patients with Parkinson disease. Method: Our study is a cross-sectional case-controlled analytical investigation in a group of 69 patients with Parkinson disease and another group of 66 healthy volunteers in order to assess odor threshold, odor identification, and odor discrimination in these two groups using Mentha pulegium and Lavandula latifolia extracts. Results: We found a marked decrease of the threshold of odor detection in patients compared to controls (p<0.001). A statistically significant difference was found between the ability to discriminate odors, with more patients with Parkinson disease unable to distinguish between odors (p<0.001). For the odor identification test, 70% of control subjects versus 36% of patients were able to correctly identify the test products. The difference was statistically significant (p<0.001). Conclusions: Our study points to the potential for the elaboration of a standardized smell identification screening battery using indigenous products with which patients are familiar.