Correspondence and reprint requests to: L.F. Dell’Osso, Ph.D. Ocular Motor Neurophysiology Laboratory Veterans Affairs Medical Center (127A) 10701 East Boulevard Cleveland, OH 44106 USA Tel: (216) 421-3224 Fax: (216) 231-3461 E-mail: lfd@po.cwru.edu Acknowledgements: This work was supported in part by the Office of Research and Development, Medical Research Service, Department of Veterans Affairs. Abstract An observer with horizontal/torsional congenital nystag- mus (CN) made two unique observations. One occurred during a migrainous aura and the other during a decompensated vertical phoria. The otherwise typical migraine aura was perceived as oscillating hori- zontally over a stable visual field – an oscillating scintillating scotoma. The vertical diplopia secondary to a decompensated phoria oscillated vertically – a diplopic oscillopsia. The implications raised by these observations strengthen the role of efference copy in the usual sup- pression of oscillopsia in CN. Retinal rivalry is proposed to explain the possible perception of vertical oscillopsia without vertical nystagmus. Key words Congenital nystagmus; migraine; scotoma; oscillopsia; diplopia Introduction Clinical phenomena are ‘experiments of nature’ and, when properly analyzed, may be the source of considerable knowledge of human neurophysiology. This is especially true of ocular motor research in general and of congenital and other types of nystagmus in particular. Migraine auras are usually visual and consist of scintillating lights (photopsias) and scotomata (fortification spectrum). The aura’s position may be stationary, but usually migrates slowly across the visual field, with a typical duration of approximately 20 minutes or less. The scintillating aura may be thought to be ‘moving’ since it might be per- ceived to move with voluntary eye movements, but it will not continu- ally oscillate. Many auras, particularly in the middle-aged or elderly, are not associated with a headache. 1 Diplopia is the appearance of two static images of the visual scene, usually caused by the misalignment of the eyes in one or more planes. CN is usually a horizontal-torsional oscillation of the eyes that, in its purest form, is not associated with an afferent deficit or strabismus, not accompanied by oscillopsia, and does Oscillating scintillating scotoma and diplopic oscillopsia 79 Neuro-Ophthalmology 0165-8107/01/US$16.00 Neuro-Ophthalmology – 2001, Vol. 26, No. 2, pp. 79–83 © Swets & Zeitlinger 2002 Accepted 30 April 2002 Migraine aura and diplopia phenomenology associated with congenital nystagmus L.F. Dell’Osso 1–3 R.B. Daroff 1,2 R.L. Tomsak 2 1 Ocular Motor Neurophysiology Laboratory, Veterans Affairs Medical Center, and the Departments of 2 Neurology and 3 Biomedical Engineering, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH, USA Original paper