Propranolol and Botulinum Toxin for Essential Vocal Tremor

Essential tremor is the most common adult-onset movement disorder, and essential voice tremor is the vocal manifestation of essential tremor. While nearly all essential tremor patients experience hand tremor, many also manifest head tremor and voice tremor. Essential voice tremor can lead to increased vocal effort, decreased intelligibility, and misconstrued emotional state. Only one medication, propranolol, is FDA-approved to treat essential tremor. Propranolol is not felt to be nearly as effective for axial tremors (head, trunk, neck) as it is for extremity tremors. However, this has not been studied with any objective assessment in a prospective way for EVT. For patients with essential voice tremor, the limited published data suggests that botulinum toxin has been shown to lead to functional voice improvement. Botulinum toxin, though also not well-studied with objective voice outcomes, is a commonly used clinical therapy for treatment of essential voice tremor. While it is used more often for essential voice tremor than propranolol therapy, botulinum toxin also has not been prospectively studied with validated, objective voice outcome measures. The investigators would like to determine if propranolol has any significant effect on vocal tremor. The investigators would also like to determine, in an objective way, the effect of botulinum toxin on vocal tremor. If effective, propranolol would provide an affordable and non-invasive alternative or addition to botulinum toxin injections for patients with essential voice tremor.