What is this nystagmus? What maybe the pathology?

This girl presented to our E.R with complaints of unsteady gait and abnormal eye movement for last 1 year.she can't tandem walk,sways to sides but does not have intention tremor, dysarthria, trunkal ataxia or pendular knee jerk and no other cranial nerve involvement seen. Please tell me about the type of nystagmus. Chief Complaints Nystagmus,unsteady tandem walk