[Essential blepharospasm and botulinum toxin. An electrophysiologic study].

Thirty-five patients with essential blepharospasm were investigated electrophysiologically after local treatment with subcutaneous periocular injections of botulinum toxin. In all patients the blink reflex was measured on both sides. The results showed in some cases reproducible changes in the reflexes, indicating a central supranuclear origin for the spasm. Furthermore, an influence of afferent information on the "spasm threshold" via the trigeminal nerve is suggested.