안면마비와 동반된 1과 1/2 증후군

One and a Half Syndrome with Facial Palsy: Eight and a Half Syndrome

Purpose: We report a rare case of eight and a half syndrome after pons infarction. Case summary: An 80 year old woman had a sudden onset of dizziness, horizontal diplopia after wake-up. She had bilateral limited movement into left gaze, in right gaze there was an adduction deficit in the left eye and abducting nystagmus in the right eye. In primary position, there was slight exophoria at distance increasing in right gaze. Vertical ocular movements were normal and ptosis was absent. vestibular-ocular reflex was absent and convergence was relatively spared. Pupils were equal in size and normally reactive to light and near stimulus. She had left sided facial palsy including left side flattening of the nasolavial fold and absent forehead wrinkling. A Diffusion-weighted magnetic resonance imaging scan obtained and demonstrated a well-defined focus of increased signal character localized to the left paramedian aspect of the dorsal pontine tegmentum, just ventral to the fourth ventricle. 5 months after the onset of the symptoms, the patient showed complete recovery of her ocular movements in all gaze but still remained facial palsy. Conclusions: One-and-a half syndrome is caused by a single unilateral lesion of the paramedian pontine reticular formation or the abducens nucleus, with interruption of medial longitudinal fasciculus. When this lesion involves the nucleus and faciculus of facial nerve, thus called eight-and-a-half syndrome.