Ultrasonography Evaluation of Bilateral Focal Auricular Dyskinesia

Abstract

An otherwise healthy woman inherlate20spresentedwitha1-week history of almost continuous bilateral ear twitching. Onset was spontaneous. There was no previous exposure to neuroleptics nor history of neuropsychiatric disorders. The ear movements were not within voluntary control nor distractible under cognitive load. These movements caused significant distress including poor sleep and headaches.Shedeniedfeelingstressedoranxious.Themovementsstopped during sleep. She denied any tinnitus.Examination revealed semirhythmic, asymmetrical movement of bilateral ears and the frontalis muscle. The character of muscle movement was observed on ultrasonography. Muscle contraction and shortening generally began as quick and jerky movements, and the degree of contraction ranged from complete to partial. Muscle relaxation and lengthening occurredatvariablespeed,fromquickandjerky to slow and sinuous. Neurologic examination results were otherwise normal with no tremors or dyskinesias in thelimbs.TheVideodemonstratestheclinicalpresentationandmuscle movements visualized under ultrasonography examination.Full blood cell count and inflammatory markers were within normal limits. Electrolyte levels including calcium, magnesium, and phosphate were normal. Magnetic resonance imaging results of the brain were normal.The patient was diagnosed as having auricular dyskinesia with no obvious precipitating factor and started taking baclofen, 10 mg, 3 times adaywithnoimprovement.Thiswaschangedtoclonazepam,0.25mg, 3 times a day. She was able to sleep better with clonazepam, but it had no effect on the frequency or intensity of the twitching.The patient was offered a trial of botulinum toxin injection in view of her poor response to oral medications. Ultrasonography (Aixplorer Mach 30 with a high-frequency linear transducer SLH20-6 using musculoskeletal preset [resolution mode; depth, 1 cm] with focus set at the structure of interest) was used for muscle examination. Bilateral auricularis superior and posterior muscles were injected with 10 units of onabotulinum toxin type A. A further 10 units were injected into the frontal bellies of the occipitofrontalis muscle bilaterally in the area with the most active muscle movements seen under ultrasonography. The Figure shows a pictorial representation of the muscles. At follow-up 2 weeks later, all spontaneous movements had ceased. She did not experience any adverse events apart from worsening of the existing headache for a few days.