lapsing MS, worsening occurs in most patients during acute attacks with incomplete recovery. In progressive MS, the dominant pattern is a gradual accumulation of neurologic deficits, with slow clinical worsening.
Disease activity and progression have both clinical and subclinical components. Clinical disease activity and progression are judged by observation and neurologic examination. Subclinical components refer to pathological changes that are not observable in a clinical examination but are observed using a variety of laboratory tests, predominantly neuroimaging parameters.
Relapses. Relapses are variously referred to as acute attacks, exacerbations, or disease flare-ups. They involve the acute, or sudden onset, of focal neurologi-