Natural history of bell's palsy: the salivary flow test and other prognostic indicators.

Fifty-one patients with Bell's palsy were evaluated within two days of onset and followed for six months without surgical intervention or effective medical treatment in order to observe the natural history of the disease. Sixty-three percent had a complete return while 37 percent had incomplete return. Age, the presence of pain, and taste alterations had no prognostic value. The progression of the palsy, response to maximal stimulation and salivary flow testing were approximately 80 percent accurate in predicting outcome. The salivary flow test was the most useful prognostic indicator since salivary flow became reduced within two days of onset in the patients likely to develop denervation while the other tests did not become altered until 3 to 14 days after onset. In patients with Bell's palsy, the salivation test seems to be the only method capable of predicting denervation before it begins; therefore, it should be ideal for selecting patients for appropriate treatment.