A systematic literature review of the association between global brain atrophy and the Expanded Disability Status

Robert Zivadinov1,2, Hoa H Le3, Alexander Keenan4

  • 1Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA.

Abstract

Insights

Brain atrophy predicts outcomes in multiple sclerosis. A 1% yearly decrease in brain volume correlates with disability progression, but definitions vary.

Area of Science:

  • Neurology
  • Radiology
  • Clinical Trials

Background:

  • Brain atrophy (BA) is a key indicator of clinical outcomes in people with multiple sclerosis (PwMS).
  • Global brain volume loss (BVL) is recommended as a secondary outcome in clinical trials for PwMS.
  • Recent evidence on the association between BA and disability in PwMS requires updated review.

Purpose of the Study:

  • To systematically review studies from 2013 onwards examining the relationship between brain volume loss (BVL) and disability in PwMS.
  • To assess associations between percentage of brain volume loss (PBVL), normalized brain volumes (NBV), or normalized brain parenchymal volume (NBPV) and the Expanded Disability Status Scale (EDSS) or disability progression (DP).

Main Methods:

  • Systematic review of observational studies, clinical trials, and modeling studies.
  • Searched major databases (Medline, Embase, Cochrane Library, CINAHL) for relevant literature.
  • Included studies on clinically isolated syndrome and limited primary progressive MS (≤20%).

Main Results:

  • 58 studies were eligible.
  • Most longitudinal studies (19/23) found a significant association between BVL and EDSS score changes or DP.
  • Most cross-sectional studies (26/29) found an association between baseline brain volume measures and EDSS.
  • Few studies (4/15) found baseline brain volume to be a predictor of future disability.

Conclusions:

  • A decrease of approximately 1% in global brain volume per year is associated with disability progression in PwMS.
  • Variations in the definition of disability progression necessitate caution when comparing study results.