Nine syndrome: Case report and review of clinical signs in internuclear ophthalmoplegia

The pathologic involvement of brainstem and midbrain nuclei and white matter tracts in various combinations may result in a spectrum of arithmetically derived syndromes. They include ‘one and a half syndrome’, ‘eight and a half syndrome’ and ‘fifteen and a half syndrome’. We report a case of ‘nine syndrome’, which has been reported more recently, caused by caused by acute pontine infarcts and characterised clinically by a combination of internuclear ophthalmolplegia, ipsilateral horizontal gaze palsy, lower motor neuron type of facial palsy, contralateral hemiparesis and hemianesthesia. We highlight the genesis of this combination of clinical signs , revisit the different variants of INO and review the literature on ‘Nine syndrome’.