Olfactory dysfunction in multiple sclerosis: evidence of a decrease in different aspects of olfactory function

Area of Science:

• Neurology
• Neuroscience
• Olfactory Research

Background:

• Olfactory dysfunction is increasingly recognized in multiple sclerosis (MS).
• Previous research highlights altered smell perception in MS patients.
• Understanding specific deficits is crucial for patient care.

Purpose of the Study:

• To pinpoint which aspects of olfactory perception are most impaired in MS.
• To investigate correlations between olfactory deficits and clinical, anatomical, and functional MS data.

Main Methods:

• Study included 50 patients with remitting or secondary progressive MS.
• Collected clinical data: medical history, disease characteristics, depression/disability scores, and brain lesion load.
• Utilized the Sniffin Sticks® test to assess olfactory function.

Main Results:

• Odor detection threshold (hyposmia) was the most sensitive marker, affecting 40% of patients.
• Odor identification ability was impaired later in the disease course.
• Impaired odor identification showed an inverse correlation with disability levels.

Conclusions:

• Multiple facets of olfactory function are altered in MS patients.
• Olfactory deficits, particularly in odor discrimination and identification, are linked to cognitive demands.
• These findings underscore the impact of MS on sensory and cognitive processing.