Botulinum Toxin Can Abolish and/or Quiet Tinnitus Associated with Chronic Migraine: Serendipidous Observations.

INTRODUCTION It is well established that treatment of head and neck myofascial dysfunction can alleviate both tinnitus and chronic migraine (CM). Onabotulinumtoxin A (OnaA) has become a standard treatment for CM. In a recent systematic study a subject reported tinnitus improvement. This prompted a survey of the tinnitus in all study participants. METHODS Fifty-seven patients with CM at a tertiary headache referral center received intramuscular Onabotulinumtoxin A (OnaA) injections into craniocervical muscles using the "follow-the-pain" protocol for headache. Effectiveness of OnaA was assessed by changes in (i) tinnitus loudness and (ii) number of headache days. RESULTS Of the five patients with pre-existing tinnitus OnaA abolished the tinnitus in two, including one whose tinnitus of ten years' duration resolved permanently with one treatment. The tinnitus loudness of the other four was attenuated between 70 to 100 percent for about three months, which paralleled their headaches response. All were women who had (i) a significant improvement of their CM and (ii) headaches located fronto-temporally. None of the CM non-responders reported tinnitus. Analysis of injection sites revealed that the temporalis muscle injections were likely accounting for the tinnitus attenuation. CONCLUSION Tinnitus associated with chronic migraine is abolished/quieted by intramuscular craniocervical Onabotulinumtoxin A injections. These results are consistent with the dorsal cochlear nucleus hypothesis for craniocervical somatic tinnitus, as well as the association between migraine and tinnitus. This serendipitous result warrants further study of botulinum toxin for tinnitus.