Palpebrale Variante des Blepharospasmus – Abgrenzung zur Lidöffnungsapraxie und zur Inhibitionsstörung durch synchrone EMG-Ableitungen

Abstract

Eyelid movements are mediated mainly by the orbicularis oculi and the levator palpebrae superioris muscles. In blinking they show a strictly reciprocal innervation. Blepharospasm manifests as involuntary eyelid closure, however, there are also a number other diseases resulting in the inability to open the eyelid. We analysed clinical and electromyographical findings in 81 patients with disturbances of eyelid opening. Among these were 63 with tonic or clonic dystonic activity only in the orbicular part of orbicularis oculi muscle, 43 with additional dystonic activity in the palpebral part of orbicularis oculi muscle = idiopathic blepharospasm. Ten showed isolated activity in the palpebral part of orbicularis oculi muscle = palpebral variant of blepharospasm. Four exhibited synchronous activity in the orbicularis oculi and the levator palpebrae superioris muscles = disturbance of the antagonistic inhibition. Another four had no activity in the levator palpebrae superioris muscle while activity in the palpebral part of orbicularis oculi muscle was normal = apraxia of eyelid opening. A distinction is relevant for the therapeutic modality and the exact spot as which to inject botulinum toxin. In apraxia of eyelid opening after manual opening the eyelid remains open up to the next contraction of the orbicularis oculi muscle (Zwickau's eye sign).