Brain Atrophy and Physical and Cognitive Disability in Multiple Sclerosis

Introduction: Brain atrophy is associated with physical disability in multiple sclerosis (MS), but there is a great variability between different studies and methodologies, and its use is still limited to research projects. We aimed to analyze the relationship between several volumetric measurements and physical disability and cognitive functioning in MS patients in a clinical practice setting.

Methods: This is a cross-sectional study. A total of 41 patients (31 relapsing-remitting MS, 6 secondary-progressive MS, and 4 primary-progressive MS) were included. Whole brain volume (WBV), gray matter volume (GMV), and T2 lesion load (T2L) were obtained using Icometrix^® software. Physical disability was measured with the Expanded Disability Status Scale (EDSS), and cognitive status was evaluated with the brief repeatable battery of neuropsychological tests (BRB-N). The relationship between brain volumes and EDSS was analyzed through linear multivariate regression. The association between volumetry measurements and the number of affected cognitive domains was studied with negative binomial regression.

Results: GMV was associated with age (b=-1.7, P=0.014) and with EDSS (b=-7.55, P=0.013). T2L was associated with EDSS (b=2.29, P=0.032). The number of affected cognitive domains was associated with clinical phenotype, worse in primary progressive MS (PPMS). There was not correlations between cognitive impairment and cerebral volumes.

Conclusion: Brain atrophy measurement is feasible in clinical practice setting, and it is helpful in monitoring the EDSS progression. Primary progressive phenotype is associated with greater risk of cognitive dysfunction.

Highlights: The T2 lesion load is associated with physical disability in patients with multiple sclerosis (MS).The gray matter volume is associated with age and physical disability in patients with MS.There is no significant correlation between cognitive impairment and cerebral volumes in patients with MS.

Plain language summary: Conventional magnetic resonance imaging (MRI) is still used for diagnosing and monitoring multiple sclerosis (MS). Analysis of Brain volumes including Whole brain volume (WBV), gray matter volume (GMV), and T2 lesion load (T2L) allows the evaluation of its neurodegenerative mechanisms. Robust evidence links brain atrophy with disability in MS. This study aims to analyze the relationship between advanced MRI sequences and physical disability and cognitive functioning in MS patients. According to the results, T2L was associated with physical disability and GMV was associated with age and physical disability. There was no significant correlation between cognitive impairment and cerebral volumes in patients with MS.