A decade after scientists identified an over-the-counter antihistamine as a treatment for multiple sclerosis, researchers have developed an approach to measure the drug's effectiveness in repairing the brain. The researchers, led by Ari Green, used MRI scans to study the drug's impact on the brain of 50 participants in a clinical study. In MS, patients lose myelin, the protective insulation around nerve fibers. This myelin loss triggers delays in nerve signals, leading to weakness and spasticity, and other symptoms. In the brain, water trapped between the thin layers of myelin that wrap nerve fibers cannot move as freely as water...