Teaching video NeuroImage: acquired or congenital gaze-evoked nystagmus?

Matthew J. Thurtell, MBBS Konrad P. Weber, MD G. Michael Halmagyi, MD A 40-year-old female migraineur reported intermittent unsteadiness with headache. On examination, she had gaze-evoked horizontal-torsional nystagmus that was also evident during pursuit (video). Nystagmus recordings showed increasing-velocity slow phases typical for congenital nystagmus (CN) (figure 1). A relative subsequently confirmed that the nystagmus was long-standing. While usually isolated, CN can be associated with visual system abnormalities or strabismus.1 It is usually conjugate, horizontal with a subtle torsional component,2 andminimized in a certain “null” position. Eye movement recordings help differentiate it from other nystagmus types (figure 2).1 Confirmation that it is long-standing supports the diagnosis, helping to avoid unnecessary investigations.