[2025 Round-up] Multiple sclerosis research in 2025: earlier diagnosis and halting progression

In 2025, substantial breakthroughs were made with respect to earlier diagnosis, improved mechanistic understanding, and new hope for delaying progression of multiple sclerosis. Over successive refinements, the McDonald criteria have enabled earlier diagnosis of multiple sclerosis, with the 2017 update allowing diagnosis at the initial clinical event.1 The newly revised 2024 criteria allow for identification of asymptomatic disease with biological and radiological biomarkers.2 Because optic neuritis is the initial clinical event in about 25% of people with multiple sclerosis, inclusion of the optic nerve as a fifth anatomical location for demonstrating dissemination in space, incorporation of optical coherence tomography, visual evoked potentials, and orbital MRI as supportive paraclinical tests are welcome additions to the diagnostic criteria.