Hearing loss
The most common cause of hearing loss associated with facial palsy is due to a benign tumour on the vestibular nerve. This is commonly called an acoustic neuroma or vestibular schwannoma (these labels are interchangeable).
Hearing loss is not a symptom associated with a diagnosis of Bell’s palsy.
Causes
The nerve responsible for hearing is called the vestibulocochlear nerve/vestibular nerve. It is also referred to as the eighth cranial nerve. It follows a very similar pathway to the facial nerve whilst it travels within the skull. As the two nerves travel very closely together sometimes injury, swelling or pressure of the facial nerve may impact on the vestibular nerve and vice versa.
An acoustic neuroma or vestibular schwannoma is a benign tumour on the vestibular nerve. The term benign means that it is not cancerous. It is commonly a very slow-growing tumour which can go undiagnosed for many months and years. It does not spread to any other parts of the body.
Symptoms
The vestibular nerve also controls balance so early symptoms may be hearing loss in one ear and problems with balance or unsteadiness.
Early symptoms
- Hearing loss that usually affects one ear
- Hearing sounds that come from inside the body, for example, tinnitus (ringing in the ears) or sounds feeling muffled.
- Vertigo (unsteadiness or a sensation that you are spinning)
If the tumour has gone undetected for several years it can become very large and cause a range of other symptoms, for example:
- Facial palsy
- Headaches
- Double vision or blurred vision
- Facial numbness
- Difficulty coordinating movements (ataxia)
- Difficulty swallowing
- Hoarse voice
Treatment
Report any of these symptoms to your GP which should prompt further investigations to exclude the possibility of an acoustic neuroma. Investigations will include a range of hearing tests (audiology assessment), an MRI scan (Magnetic Resonance Imaging) which can look inside the brain, and a CT scan (Computerised Tomography), a series of detailed x-rays which give very clear information about the location of the tumour.
For further information about symptoms, diagnosis and treatment of acoustic neuroma visit https://www.nhs.uk/Conditions/Acoustic-neuroma/
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