Objective: It is to propose a psychophysical test of the olfactory function. Its originality is to use Moroccan odorous products belonging to our culture to study the preponderance of olfactory dysfunction in Parkinson’s disease.

Background: Parkinson’s disease (PD) is the second most common neurodegenerative pathology after Alzheimer’s disease. Bradykinesia, rigidity and tremor are his clinical signs; however, there are non-motor signs that affect other functions such as neuropsychiatric troubles, olfactory disorders, cognitive, or emotional impairments. Olfactory disorders are among the first non-motor signs that appear years before the onset of motor disorders. Several studies have be published to develop psychophysical olfactory tests in order to have a predictive diagnosis. Our study is the first experience on the Moroccan population in the country.

Method: An analytical case-control study carried out in the neurology department of the Mohammed VI university medical center in Marrakech, including 69 Parkinsonians and 66 healthy subjects, respecting the same conditions.It consists in studying three variables: the threshold, the identification and the discrimination of odors. The experiment exploits two essential oils known by their wide use in Morocco.

Results: Our study found that parkinsonians can detect odor at a concentration 16 times higher than healthy subjects. Our identification test results in control subjects indicate that more than 70% of our control subjects recognized at least one of the two products against 36% of Parkinson’s patients. For the discrimination test, we found that 54% of Parkinson’s patients, compared to 12% of healthy subjects, could not distinguish between the two products.

Conclusion: Analyzing the results of this test allowed us to confirm the initial hypothesis that our parkinsonians suffer from olfactory disorders. This test will therefore be useful for identifying individuals in the pre-motor and early stages of the disease, pending the likely success of future therapies aimed at slowing the prevention of the pathological progression of Parkinson’s disease.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/olfactory-dysfunction-in-parkinsons-disease/