E-Pearl of the Week: Eight-and-a-half-syndrome

April 11, 2011



The Eight-and-a-half-syndrome, the combination of a facial nerve palsy + one-and-a-half-syndrome, was first coined by Eggenberger. It is caused by a lesion (often vascular or demyelinating) in the dorsal tegmentum of the caudal pons involving the parapontine-reticular formation or abducens nucleus and the medial longitudinal fasciculus, as well as the nucleus and the fasciculus of the facial nerve. Clinically the following signs are noted:

  1. Internuclear ophthalmoplegia (INO) in addition to horizontal gaze palsy (one-and-a-half-syndrome)
  2. Ipsilateral lower motor neuron-type facial palsy.


  1. Eggenberger E. Eight-and-a-half syndrome: one-and-a-half syndrome plus cranial nerve VII palsy. J Neuroophthalmol 1998;18:114-116.

Submitted by:
Partha S Ghosh, MD, Cleveland Clinic

Dr. Ghosh reports no disclosures.

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