Background: Bell's palsy (BP) is a condition that causes a temporary
weakness or paralysis of the muscles in the face. Some patients with
BP experience rapid aggravation of facial weakness in the early
stage. The objective of this study was to identify the clinical and
radiologic characteristics of BP with early deterioration.

Methods: This retrospective study included 603 patients of BP from
July 2005 to December 2016. The clinical history, neurologic
examination, electrophysiological test and brain magnetic resonance
imaging (MRI) were all checked at the time of diagnosis. The
severity of facial palsy was assessed using House-Blackmann facial
nerve grading scale. Patients with early deterioration were
identified by clinical history and neurologic examination.
Comparisons of clinical characteristics, radiologic findings, and
prognosis were done between the early deterioration group (group 1)
and no deterioration group.

Results: Of 603 patients, 576 patients were included in this study.
Group 1 had 257 patients (44.6%) and group 2 had 319 patients
(55.4%). Between group 1 and 2, there were no significant tatistical
difference in past medical history including hypertension, diabetes
mellitus, family history, recurrence history, location of BP, and
prognosis. However, facial nerve enhancement on brain MRI was
observed in 254 patients (98.8%) with early deterioration and in 95
patient (35.4%) without deterioration.

Conclusions: Facial nerve enhancement on brain MRI is more common in
patients with early deterioration, but early deterioration does not
affect prognosis of BP.

KEYWORDS : Bell palsy, Magnetic resonance imaging, Prognosis