Hyperacusis and peripheral facial paralysis correlation (Bell's palsy)

Abstract

Bell's palsy is a unilateral facial paralysis of sudden onset and unknown causes. It may affect salivation, taste and lacrimation depending on the site of facial nerve involvement. Patients can report supersensitive hearing. The stapedius reflex is absent in-patients with Bell's palsy. Aim: The objective of this study was to check if patients with Bell's palsy present hyperacusis. Study design: Clinical prospective. Material and Method: Eighteen patients with peripheral facial paralysis were randomly selected and examined. A complete ENT evaluation was performed, including Hilger facial nerve stimulator, Schirmer's test, electrogustometry, pure tone testing, speech audiometry, immitance testing and uncomfortable loudness levels. The group aged 31-40 years was the most affected by peripheral facial paralysis in this sample. Results: The incidence was higher in females (61%). The right side of the face was involved in 56% of patients. As to local involvement, grade IV was observed in 44% of cases and grades III and V in 28% of patients each. Only one patient (5.5%) complained of hyperacusis. All patients studied presented reduced tolerance threshold in the audiometric graphs, and the stapedius reflex protects these patients, in average, by 16dB. Conclusion: Therefore, we could conclude that the frequency of complaints of hyperacusis in-patients with Bell's palsy is similar to that of the general population; however, in audiometric terms, the tolerance threshold in the paralyzed side is lower as compared with the normal side.