The systematic review protocol is registered through PROSERO (ID:533857). Among other criteria, articles were included if they discussed at least one longitudinal monitoring metric for neurosarcoidosis disease activity. Based on the results of the systematic review we propose definitions for levels of disease activity and inactivity.

Of the 387 articles in the original search, 67 studies were included in the systematic review.Most studies only evaluated domain-specific metrics (i.e clinical, imaging, CSF), and only six studies included a multi-domain monitoring metric. Often the definitions were not formally defined. Our proposed disease activity definition draws on prior standardization within multiple sclerosis clinical trials and integrates three domains: 1) clinical 2) imaging, and 3) laboratory. Assessment of disease activity within each domain occurs independently of the others, allowing for discordance. Among the clinical and imaging domains, within the active disease category there are three ordinal sub-levels of activity: “improved”, “stable” and “worsened”. In the event that clinical and imaging disease activity is discordant, laboratory evaluation can help clarify overall disease status. When all three domains are present, if two of the three domains reflect active disease then the overall disease status is considered active. If two of the three domains reflect inactive disease, then disease status is isolated for the only active domain.