Bell 面瘫完全形成后(即:发作后 72 小时内),面瘫程度是最能预测最终恢复结果的参数。在临床检查时存在不完全麻痹的患者中,94% 会完全恢复,而存在完全性麻痹的患者为 61%。[7]Peitersen E. Bell palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Otolaryngol Suppl. 2002;549:4-30.http://www.ncbi.nlm.nih.gov/pubmed/12482166?tool=bestpractice.com进一步的证据显示,如果症状发作 14 天内电神经描记 (ENoG) 显示两侧之间的差异>95%,则 Bell 面瘫后面部功能自发恢复到正常或接近正常(即:HBS I 或 II 级)会减少 50%。[16]Fisch U. Surgery for Bell's palsy. Arch Otolaryngol. 1981;107:1-11.http://www.ncbi.nlm.nih.gov/pubmed/7469872?tool=bestpractice.com其他不良预后因素包括高龄、糖尿病和就诊时存在味觉异常。[23]Gilden DH. Clinical practice. Bell's palsy. N Engl J Med. 2004;351:1323-1331.http://www.ncbi.nlm.nih.gov/pubmed/15385659?tool=bestpractice.com
有一些证据提示,与一般人群发生的病例相比,妊娠相关的 Bell 面瘫长期结果较差,[55]Gillman GS, Schaitkin BM, May M, et al. Bell palsy in pregnancy: a study of recovery outcomes. Otolaryngol Head Neck Surg. 2002;126:26-30.http://www.ncbi.nlm.nih.gov/pubmed/11821761?tool=bestpractice.com对于发生 Bell 面瘫的孕妇,应当密切监测是否发生妊娠高血压疾病。[55]Gillman GS, Schaitkin BM, May M, et al. Bell palsy in pregnancy: a study of recovery outcomes. Otolaryngol Head Neck Surg. 2002;126:26-30.http://www.ncbi.nlm.nih.gov/pubmed/11821761?tool=bestpractice.com[56]Shmorgun D, Chan WS, Ray JG. Association between Bell's palsy in pregnancy and pre-eclampsia. QJM. 2002;95:359-362.http://qjmed.oxfordjournals.org/content/95/6/359.fullhttp://www.ncbi.nlm.nih.gov/pubmed/12037243?tool=bestpractice.com