Smell functions in patients with multiple sclerosis: a prospective case-control study

Area of Science:

• Neurology
• Otolaryngology
• Neuroscience

Background:

• Multiple sclerosis (MS) is a chronic neurological disease affecting the central nervous system.
• Smell dysfunction is increasingly recognized as a potential symptom in MS patients.
• Understanding the impact of MS on olfactory pathways is crucial for comprehensive patient care.

Purpose of the Study:

• To evaluate and quantify smell function in patients diagnosed with multiple sclerosis (MS).
• To investigate the relationship between MS and olfactory pathway integrity using neuroimaging.
• To assess the utility of the Brief Smell Identification Test (BSIT) in MS-related smell disorders.

Main Methods:

• A case-control study involving 20 MS patients and 20 healthy controls.
• Smell identification was assessed using the 12-item Brief Smell Identification Test (BSIT).
• Cranial magnetic resonance (MR) imaging was used to examine central and peripheral olfactory regions for MS lesions.

Main Results:

• MS patients exhibited significantly lower total BSIT scores compared to controls (p<0.05).
• MS patients showed significantly altered measurements in central olfactory regions, including the corpus amygdala (p<0.05).
• MS lesions were detected in central olfactory regions (temporal lobe insular gyrus, corpus amygdala), but not in peripheral regions.

Conclusions:

• Multiple sclerosis is associated with a significant deterioration in smell function.
• The Brief Smell Identification Test (BSIT) is a reliable and accessible tool for diagnosing smell disorders in MS patients.
• ENT specialists are encouraged to incorporate the BSIT into their diagnostic protocols for patients with suspected olfactory dysfunction due to MS.