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Studies with electrocochleography and auditory brainstem response in Ramsay Hunt syndrome
J Kusakari1, M Takeyama, T Kawase
1Department of Otolaryngology, Tohoku University School of Medicine, Sendai, Japan.
Acta Oto-Laryngologica. Supplementum
|January 1, 1988
Summary
Ramsay Hunt syndrome can cause sensorineural hearing loss due to cochlear damage, not retrocochlear lesions. This study used electrocochleography and auditory brainstem response to identify the primary site of auditory dysfunction.
Area of Science:
- Neurology
- Otolaryngology
- Audiology
Background:
- Ramsay Hunt syndrome (herpes zoster oticus) is a viral infection affecting the facial nerve.
- Previous histopathological studies suggested retrocochlear lesions in the internal auditory canal as the primary cause of auditory dysfunction.
Purpose of the Study:
- To investigate the site of auditory pathway involvement in Ramsay Hunt syndrome.
- To determine if hearing loss is due to cochlear or retrocochlear pathology.
Main Methods:
- Electrocochleography (ECoG) and auditory brainstem response (ABR) were performed on 18 patients with Ramsay Hunt syndrome.
- Audiometric evaluation was conducted to assess hearing levels and characteristics of hearing loss.
Main Results:
- Four patients had normal hearing; 14 exhibited mild to moderate sensorineural hearing loss.
- While I-V interwave latency was mostly normal, N1 latency was significantly prolonged in 8 cases, correlating with hearing loss severity at 4 and 8 kHz.
- Findings indicate cochlear pathology, not retrocochlear lesions, as the primary cause of hearing loss.
Conclusions:
- The cochlea, not the retrocochlear region, is the main site responsible for hearing loss in Ramsay Hunt syndrome.
- The study challenges previous assumptions about the pathology in this syndrome.
- Further investigation into the mechanisms of cochlear involvement is warranted.