The association between olfactory bulb volume, cognitive dysfunction, physical disability and depression in multiple...

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Olfactory bulb atrophy is linked to cognitive issues in Parkinson's, Alzheimer's, and depression, suggesting it as a neurodegeneration marker.
• Multiple sclerosis (MS) exhibits neurodegenerative characteristics, prompting investigation into olfactory bulb volume in MS patients.

Purpose of the Study:

• To explore the relationship between olfactory bulb volume and physical/cognitive disability, and depression in MS patients.
• To determine if olfactory bulb volume serves as a neurodegeneration marker in multiple sclerosis.

Main Methods:

• 146 MS patients and 27 healthy controls underwent neurological exams, neuropsychological testing, and MRI.
• High-resolution 3D T1-weighted MRI scans were used for semi-automatic olfactory bulb segmentation.
• Expanded Disability Status Scale (EDSS) scores and white matter lesion volumes were assessed.

Main Results:

• MS patients exhibited significantly lower mean olfactory bulb volume compared to healthy controls (183.9 ± 40.1 vs. 209.2 ± 59.3 μl).
• Olfactory bulb volume did not correlate with cognitive performance, EDSS scores, or white matter lesion volume across all MS patients.
• In progressive MS, olfactory bulb volume showed a negative correlation with depression scores (Spearman's rho = -0.38, P < 0.05).

Conclusions:

• Olfactory bulb volume is reduced in individuals with multiple sclerosis compared to healthy controls.
• Olfactory bulb volume does not appear to reflect cognitive impairment in MS.
• A significant association exists between lower olfactory bulb volume and higher depression scores specifically in the progressive MS subgroup.