BRAIN ATROPHY has become a significant factor in the evaluation of patients with multiple sclerosis (MS). Observed over time, there seems to be a progressive loss of brain tissue that may start very early in the disease. Studies of MS at postmortem1 have long recognized loss of brain tissue at the end of life. Recent magnetic resonance imaging (MRI) studies2 have reemphasized brain and spinal cord atrophy that can be measured in life, and sequential studies have shown that the tissue loss is a progressive one.