Middle Ear Myoclonus
Spasms of the palatal (roof of the mouth) muscles
From Wikipedia, the free encyclopedia
Middle Ear Myoclonus is neuromuscular disorder, involving involuntary muscle contractions of the muscles of the middle ear. Symptoms are noises in the frequency of the muscle spasms and the sensation of muscle movement. Treatment can be conservative with medicaments or via surgery.
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Symptoms and diagnosis
The most prominent symptom are frequently occurring noises in the ear. These can have various forms depending on the frequency of the contractions and the involved muscles. Patients usually describe the noises as "buzzing", "crackling", "clicking" or in similar ways. These noises can happen in various frequencies ranging from a constant noise to distinctive sharp buzzing sounds which appear every few seconds for up to several hours. A sensation of muscle movement is also present.[1][2][3]
In some cases a movement of the eardrum is visible when inspected with an otoscope. Movement of the opening of the Eustachian Tube can sometimes also be visible when inspected with a laryngoscope. Occasionally other muscles in the face also show involuntary movements.[3][2][4]
The muscle contractions can also be observed via Tympanometry, usually showing up as "sawtooth pattern".[1]
An MRI can be used to detect possible anomalies in the brain or to check whether a compression of the nerves inervating the middle ear muscles (CN V and CN VII) is present.[1][2]
Palatal myoclonus is a similar condition which can cause similar symptoms. It involves a different set of muscles and should therefore be ruled out before beginning treatment.[1]
Cause
Involuntary spasms of the Tensor Tympani or the Stapedius muscle can cause movement to the ossicles, the eardrum or the Eustachian tube opening, which can lead to physical sensations and various kinds of sounds experienced by the patient.[1]
The underlying neurological reason causing the muscles to move can be hard to determine as various neurological disorders either in the brain or involving the innervating nerves can cause the myoclonus. Compression of the innervating nerves can lead to demyelination of the nerve, leading to erratic and hyperactive functioning resulting in involuntary muscle spasms. Brain lesions, tumors or degenerative neurological diseases such as Multiple Sclerosis can also lead to middle ear myoclonus.[2][3]
Treatment
Medication
Anticonvulsants such as Carbamazepine have shown to be effective in either resolving or reducing the severity of the symptoms. Other medicaments tested for treatment are muscle relaxants such as Baclofen or benzodiazepines such as Clonazepam, though these have been studied less with benzodiazepines only showing limited results.[2][3]
Botox
Experimental Botox treatments have been conducted in various studies. Various procedures have been suggested, usually the Botox is applied to the involving muscles by making an opening through the eardrum. While lasting cure has been described, the effect is often only temporary, requiring re-appliance every few months.[1][5]
Surgery
A tenotomy is a definitive procedure which cuts the tendons of the middle ear muscles. Resolution of the symptoms is usually immediately and success rate is very high. Failure to cut the tendons completely or an incorrect identification of the involved muscles (for example when the underlying condition is actually palatal myoclonus with one of the palatal muscles involved) lead to failure of the procedure. There have also been reports of the tendons re-connecting after the operation, requiring a repeat of the procedure.[2][4]