Ear click in palatal tremor: its origin and treatment with botulinum toxin.

We report the successful treatment of a rhythmic, continuing ear click in a patient with palatal tremor with local injections of botulinum toxin into the tensor veli palatini muscle. We could demonstrate that the ear click occurred during contraction of the tensor veli palatini, which opens the eustachian tube. Therefore, we believe that the clicking noise is due to the sudden breakdown of the surface tension within the eustachian tube. Our observations suggest that the ear click is due to rhythmic discharges of the trigeminal nucleus rather than the ambiguous nucleus.