The thalamus is among the first brain areas to atrophy in multiple sclerosis (MS); this study wanted to know if measuring this loss can predict future disability.
The progression of multiple sclerosis (MS) leading to reduced or eliminated workforce participation or productivity is a significant problem, and even those without high physical burdens still face a steep economic price. A recent study sought to determine if atrophy in the thalamus region of the brain is linked to later disability.
The authors said that prior work has shown that brain atrophy, particularly in the thalamus, is a marker of MS progression.
Their own research, published last year, showed that patients with isolated thalamic atrophy, measured just once, had an increased risk of disability, as measured by the Expanded Disability Status Scale (EDSS), and of not reaching a status of no evidence of disability activity (NEDA-3) at 2 years.
Early intervention with disease-modifying therapy (DMT) is critical, they said, but measuring brain volume is not typical in everyday practice. In MS, the thalamus and other deep gray matter are among the first to be affected.
In this study, the authors returned to the same group of patients they previously investigated to determine their disability progression 5 years after baseline.
Global and regional brain volumes were measured from 24 patients with newly diagnosed relapsing MS (RMS) 6 months after starting first-line immunomodulatory therapy and from 36 patients with secondary progressive MS (SPMS).
For the new patients with RMS, inclusion criteria were meeting McDonald 2010 criteria, an EDSS score of 0 to 3.5, as well as either type of glatiramer acetate of interferon-beta treatment begun within 12 months as the first DMT.
In the SPMS group, patients were required to be in the secondary progressive stage of MS and have more pronounced disability scores (EDSS of 4 to 6.5).
Researchers conducted MRIs from all of the patients, using the same machine and having the images read by the same neuroradiologist, to determine total brain parenchyma volume, lesion volumes, total white and gray matter volumes, cerebellum, and deep gray matter volumes.
The patients were divided by baseline brain parenchymal and thalamic atrophy. Standard scores (z scores) were computed by comparing individual brain volumes with healthy controls. A z score cutoff of –1.96 separated atrophic from normal brain volumes.
Patients with thalamic atrophy at baseline were at a higher risk for 5-year EDSS increase than those without identified brain atrophy.
"Brain volume measurement at a single time point could help predict disability progression in MS and complement clinical and routine MRI evaluation in therapeutic decision-making," the authors concluded.
Hänninen K, Viitala M, Paavilainen T, et al. Thalamic atrophy predicts 5-year disability progression in multiple sclerosis. Front Neurol. Published online July 15, 2020. doi: 10.3389/fneur.2020.00606