'Macro square wave jerks' and 'down beat nystagmus'. A clinic oculographic study of the simultaneous onset in the same patient

A female patient is presented with a progressive ataxia, lateropulsion to the right side and decreased visual acuity. The diagnosis was Klippel Feil malformation. Clinically the existence was shown of a 'down beat nystagmus' and in the course of the electrooculographic study several volleys of macro square waves were recorded. A terminologic assessment is made and a review of the literature shows the extreme rarity of this manifestation. Further, a physiopathological assessment is made in the discussion and the conclusion stresses emphasizing that this finding of the simultaneous association of both abnormal ocular movements is described for first time in the world's literature.