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Updated: Nov 9, 2025
A Free-breathing fMRI Method to Study Human Olfactory Function
Published on: July 30, 2017
Olfactory Dysfunction and Cognition in Radiologically Isolated Syndrome and Relapsing-Remitting Multiple Sclerosis
Ozge Arici Duz1, Ozlem Saatci2, Ece Zeynep Karakulak3
1Department of Neurology, Istanbul Medipol University, Istanbul, Turkey.
Background:
Multiple Sclerosis (MS) is a neuroinflammatory, neurodegenerative, demyelinating disease that causes cognitive, olfactory, and other neurological dysfunctions. Radiologically Isolated Syndrome (RIS), in which only radiological findings are monitored, is accepted as the preclinical stage of demyelinating disease and is considered an important period for disease pathology. Therefore, in this study, we aimed to evaluate the olfactory and cognitive functions and their clinical correlation in RIS and Relapsing-Remitting MS (RRMS) patients and a healthy control group.
Methods:
Our study included 10 RRMS patients, 10 RIS patients, and 10 healthy controls. We conducted an olfactor evaluation via the "Sniffin' Sticks" test. The subjects underwent a neuropsychometric test battery to evaluate cognitive functions, including memory, visuospatial, and executive functions. Depression was evaluated using the Beck depression scale. Fatigue and daily life activity were evaluated using the Fatigue Severity Scale (FSS) and the 36-Item Short Form Survey (SF-36), respectively. Disability assessment was done with the Expanded Disability Status Scale (EDSS).
Results:
RRMS and RIS patients' olfactory test scores were significantly different from those in the control group (p < 0.05). There was a significant difference between the odor threshold scores of patients in the RRMS and RIS groups. There was a significant correlation between memory-oriented cognitive tests and olfactory tests in the RRMS and RIS groups.
Conclusion:
Olfactory dysfunction can be seen in RIS patients, like in RRMS patients. Cognitive and olfactory dysfunction may be together a sign of degeneration in demyelinating diseases.
Insights
Olfactory dysfunction is present in early Multiple Sclerosis (MS) stages, including Radiologically Isolated Syndrome (RIS). Cognitive and olfactory impairments may indicate neurodegeneration in demyelinating diseases.
Area of Science:
- Neuroscience
- Neurology
- Demyelinating Diseases
Background:
- Multiple Sclerosis (MS) is a complex neuroinflammatory and neurodegenerative disease.
- Radiologically Isolated Syndrome (RIS) represents a preclinical stage of MS.
- Early detection of pathology in RIS is crucial for understanding disease progression.
Purpose of the Study:
- To investigate olfactory and cognitive functions in RIS and Relapsing-Remitting MS (RRMS) patients.
- To assess the correlation between olfactory and cognitive deficits in these patient groups.
- To compare these functions against a healthy control group.
Main Methods:
- Included 10 RRMS patients, 10 RIS patients, and 10 healthy controls.
- Utilized the "Sniffin' Sticks" test for olfactory evaluation.
- Administered a neuropsychometric test battery for cognitive functions (memory, visuospatial, executive).
- Assessed depression, fatigue, daily activity, and disability.
Main Results:
- Significant differences in olfactory test scores were observed between RRMS/RIS patients and controls (p < 0.05).
- A significant difference in odor threshold was found between RRMS and RIS groups.
- A significant correlation was identified between memory tests and olfactory tests in RRMS and RIS patients.
Conclusions:
- Olfactory dysfunction is evident in RIS patients, similar to RRMS patients.
- Combined cognitive and olfactory dysfunction may signal neurodegeneration in demyelinating diseases.
- Early functional deficits are important indicators in the preclinical stages of MS.
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