Disclosures: Yulia Rivelis, MD: Nothing to disclose

Case Description: Patient with history of hypertension, hyperlipidemia, coronary artery disease, and myocardial infarction presented to acute inpatient rehabilitation after EVAR for juxtarenal AAA. Course was complicated by acute left dorsal pontine stroke, and subsequent imaging also revealed evidence of chronic right pontine infarct. On right horizontal gaze, exam revealed nystagmus and deficit in left eye adduction, with normal right eye abduction. With left horizontal gaze the left eye abducted, but the right eye was unable to adduct. Patient also had mild left facial weakness, all consistent with eight-and-a-half-syndrome.

Setting: Acute stand-alone rehabilitation facility.

Patient: 70-year-old male with acute dorsal pontine stroke.

Assessment/Results: Typical presentation of one-and-a-half syndrome in our patient would yield only right eye abduction given a left pontine lesion. However, he was able to abduct the left eye, signifying partial sparing of the left abducens and oculomotor nerves. With continued therapy focused on ocular movement and strengthening, patient showed improvement in right eye adduction and convergence. Facial nerve weakness also improved with therapeutic modalities.

Discussion: One-and-a-half syndrome refers to ipsilateral horizontal gaze palsy (“one”) combined with ipsilateral internuclear opthalmoplegia (INO) (“half”), due to lesions of paramedian pontine reticular formation and medial longitudinal fasciculus. In such cases only contralateral abduction typically remains. If the ipsilateral facial nerve is affected, it is termed eight-and-a-half syndrome, since it is one-and-a-half plus a 7th nerve palsy. Eight-and-a-half syndrome is a rare complication resulting from a pontine stroke occurring on the ipsilateral side of the lower motor neuron lesion. Our patient lost ability to adduct left eye due to INO from prior right pontine infarct but retained left eye abduction despite acute left sided pontine stroke.

Conclusion: There are few reports highlighting this rare syndrome, and our case emphasizes an even more unique presentation of a patient with eight-and-a-half syndrome, yet with retained ipsilateral abduction.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/bilateral-pontine-strokes-a-gaze-at-the-unusual-presentation-of-eight-and-a-half-syndrome/