Brain reserve and physical disability in secondary progressive multiple sclerosis

Area of Science:

• Neurology
• Neuroscience
• Medical Research

Background:

• The brain reserve hypothesis suggests greater maximal lifetime brain growth (MLBG) may protect against physical disability in multiple sclerosis (MS).
• Previous studies linked larger MLBG to slower disability progression in early MS.
• The association between MLBG and disability progression in secondary progressive MS (SPMS) remained unclear.

Purpose of the Study:

• To investigate if larger MLBG is associated with decreased physical disability progression in patients with SPMS.
• To determine if the protective effect of brain reserve extends into the progressive phase of MS.

Main Methods:

• Post hoc analysis of the MS-Secondary Progressive Multi-Arm Randomisation Trial (NCT01910259).
• Physical disability assessed using Expanded Disability Status Scale (EDSS), 9-hole peg test (9HPT), and 25-foot timed walk test (T25FW).
• Maximal lifetime brain growth (MLBG) estimated by baseline intracranial volume (ICV); Cox regression models used to analyze associations.

Main Results:

• Larger MLBG was independently associated with a reduced risk of EDSS progression over 96 weeks (HR 0.84, p=0.04).
• No independent association was found between MLBG and progression measured by 9HPT or T25FW.
• The study included 383 participants with a median baseline EDSS of 6.0.

Conclusions:

• Larger MLBG is independently associated with slower physical disability progression, as measured by EDSS, in SPMS.
• Maximal lifetime brain growth (MLBG) may act as a brain reserve, offering protection against disability progression even in the secondary progressive stage of MS.