Ultrasonography for Assessment and Intervention With Botulinum Toxin Injection for Tremors.

[OBJECTIVE] Tremors are caused by contractions of reciprocally innervated muscles. The role of ultrasound in diagnosing tremors has not yet been investigated, although it appears to be promising because it can visualize muscle movements. In the present study, we report four cases of tremor (Holmes' tremor, extremity tremor associated with palatal myoclonus, dystonic tremor, and tremor associated with dystonia), which were evaluated using ultrasound and treated with botulinum toxin injections.

[METHODS] The muscles of patients with tremors were examined using B- or M-mode ultrasound while they were in the supine position. Tremor was determined by involuntary muscular contraction (B-mode) or fasciculation (M-mode) from recorded sonography clips. Thereafter, tremors were measured as frequency and amplitude of specific muscles. Ultrasound-guided botulinum toxin type A injection was administered, and follow-up ultrasonography was used to assess tremors.

[RESULTS] Tremors, which manifest as a specific set of muscle contractions, were measured using ultrasonography and treated with botulinum toxin injection. Follow-up ultrasonography revealed improved tremors as seen with decreased frequency and amplitude of specific muscle after the intervention, which included medication and botulinum toxin injections.

[CONCLUSION] Ultrasonography is an effective assessment tool for tremors, allowing further information regarding tremor characteristics with high sensitivity, playing a role in detecting specific muscles that are affected by tremors, and guiding an exact intervention with botulinum toxin.