Wallenberg syndrome

Horizontal gaze-evoked nystagmusWallenberg syndrome is caused by an ischemia of the dorsolateral medulla oblongata, which belongs to the vascular territory of the vertebral artery or posterior inferior cerebellar artery (PICA). Like other forms of stroke, this condition should always be treated as an emergency.

Signs and Symptoms

The leading symptom of Wallenberg syndrome is acute vertigo with a tendency to fall toward the affected side. In addition there are often double vision, impaired sensation in the face and body, dysphagia, hoarseness, slurred speech or hemiataxia. The torso and extremities on the opposite side of the infarction and/or the face and cranial nerves on the same side as the infarction may be affected by sensory deficits including loss of pain and temperature sensitivity and cerebellar ataxia. Patients also often present with a Horner’s syndrome (unilateral ptosis, miosis and enophthalmus).

Observable ocular motor disorders

  • Ocular tilt reaction, i.e. skew deviation/vertical divergence, head tilt, ocular torsion and a deviation of subjective visual vertical
  • Nystagmus toward the non-affected side
  • Hypermetric saccades to the side of the lesion, hypometric saccades towards the non-affected side
  • “Lateropulsion” of vertical saccades
  • Horizontal gaze-evoked nystagmus


Strupp M, et al. Central ocular motor disorders, including gaze palsy and nystagmus. J Neurol 2014, 261(2):542-558. PubMed