Auditory brain-stem response audiometry in patients with Bell's palsy

Area of Science:

• Neuroscience
• Neurology
• Otolaryngology

Background:

• Bell's palsy is a common idiopathic peripheral facial nerve paralysis.
• The exact pathophysiology and potential central nervous system involvement remain debated.
• Auditory brain-stem responses (ABR) are utilized to assess the integrity of the auditory pathway and brainstem.

Purpose of the Study:

• To investigate the hypothesis of central nervous system (CNS) involvement in Bell's palsy.
• To evaluate auditory brain-stem responses (ABR) in patients diagnosed with Bell's palsy.
• To differentiate between peripheral and central nervous system dysfunction.

Main Methods:

• Auditory brain-stem responses (ABR) were recorded in 32 patients diagnosed with Bell's palsy.
• ABR results were analyzed for abnormalities, specifically focusing on conduction times.
• Site-of-lesion testing was performed to evaluate for eighth nerve dysfunction.

Main Results:

• Abnormalities in ABR were detected in 14 out of 32 patients (43.7%).
• The observed ABR deviations indicated prolonged brain-stem conduction time.
• These abnormalities were independent of the side or severity of the facial paralysis.
• Site-of-lesion tests did not reveal evidence of eighth nerve dysfunction.

Conclusions:

• The findings suggest a potential involvement of the central nervous system, specifically the brainstem, in Bell's palsy.
• Prolonged brain-stem conduction time in ABR supports a central origin or complication.
• The results do not support a theory of polyneuropathy affecting the auditory nerve in Bell's palsy.