Herpes simplex virus type 1 is the major etiologic agent in Bell palsy.

Although the antiviral agent acyclovir is currently used for the treatment of Ramsay Hunt syndrome, its effects on facial nerve and hearing recovery remain controversial. We retrospectively analyzed the effects of acyclovir-prednisone treatment in 80 Ramsay Hunt patients. Of 28 patients for whom treatment was begun within 3 days of the onset of facial paralysis, the recovery from paralysis was complete in 21 (75%). By comparison, of 23 patients for whom treatment was begun more than 7 days after onset, recovery from facial paralysis was complete in only 7 (30%). A significant difference in facial nerve recovery was found between these groups. Early administration of acyclovir-prednisone was proved to reduce nerve degeneration by nerve excitability testing. Hearing recovery also tended to be better in patients with early treatment. There was no significant difference in facial nerve outcome between intravenous and oral acyclovir treatment.

Acoustic Analysis and synthesis of hoarseness by sound spectrography suggests that the acoustic properties of hoarseness are mainly determined by the interactions of the following three factors: 1) noise components in the main formant of each vowel, 2) high frequency noise components above 3000 Hz, and 3) the loss of high frequency harmonic components. These three findings are more pronounced in the vowels /α/, /ε/, and /i/ than in /u/ and /ɔ/. With the progression of the severity of hoarseness, these three abnormal patterns become more prominent and exaggerated. On the basis of these findings, a classification of four types of hoarseness was presented using sonagram tracings.

These results suggest that early diagnosis and treatment within 3 days of the onset of paralysis are necessary for maximal efficacy of combined acyclovir and prednisolone therapy for Bell's palsy.

The annual incidence of Bell's palsy in three consecutive years — 1984, 1985, and 1986 — was investigated in Ehime Prefecture in Japan, which has a population of 1,530,000. The number of new patients with Bell's palsy was solicited from 1,377 medical institutions and their referral hospitals. The clinical records of the 15 main hospitals were examined personally by the author to confirm the exact numbers. Special care was taken to ensure minimal error in the present epidemiologic investigation. The annual incidence of Bell's palsy per 100,000 population was found to be 30, and no annual variation was noted. The ratio of male to female patients was 48:52 in all cases. There was no geographic difference in incidence.