| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[1] Prednisone, oral (adults: within 72 hours): Madhok VB, Gagyor I, Daly F, Somasundara D, Sullivan M, Gammie F, Sullivan F. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2016 Jul 18;7:CD001942. https://www.ncbi.nlm.nih.gov/pubmed/27428352
Prednisone, oral (adults: within 48 hours): Axelsson S, Berg T, Jonsson L, Engström M, Kanerva M, Pitkäranta A, Stjernquist-Desatnik A. Prednisolone in Bell's palsy related to treatment start and age. Otol Neurotol. 2011 Jan;32(1):141-6. https://www.ncbi.nlm.nih.gov/pubmed/21099725