Unusual ocular motor findings in multiple sclerosis

In multiple sclerosis (MS), nystagmus or internuclear ophthalmoplegia (INO) are the usual ocular motor dysfunctions. However, in patients with focal brainstem lesions, other rare manifestations may be observed, such as an isolated ocular motor nerve palsy or complex ocular motor disturbances. We report five MS patients with unusual ocular motor disturbances (bilateral third nerve palsy [ n = 2], opsoclonus, Horner's syndrome and one-and-a-half syndrome). We discuss possible correlations between clinical disturbances and MRI abnormalities. Patients were seen in two MS centres. They had a confirmed diagnosis of MS and underwent a brain MRI and a complete neuro-ophthalmological work-up. In one case (opsoclonus), ocular motor manifestations were the first manifestation of MS. In the other four cases they occurred 3 months (Horner syndrome), 6 years and 12 years (bilateral third nerve palsy) and 2 years (one-and-a-half syndrome) after the disease onset, respectively. Four out of five patients were still in a relapsing-remitting form of MS. In the opsoclonus case, there was no evidence of a brainstem lesion. A gadolinium-enhanced lesion (2 cases) or a new T2-weighted lesion located in the brainstem correlated with the clinical presentation. All patients completely or partially recovered after corticosteroid infusions. Our study shows some rare or previously undescribed complex ocular motor symptoms in MS.