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Alternating ictal and postictal nystagmus Salman Bhai Athar N. Malik, PhD Khamidulla Bakhadirov, MD Sashank Prasad, MD

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65-year-old man presented with intermittent spells of unresponsiveness. EEG monitoring demonstrated seizures originating in the left temporo-occipital lobe attributed to hyperglycemia (.300 mg/dL).

At the onset of each seizure, the patient developed a rightward head turn and became unresponsive to verbal commands and tactile stimulation. He then developed primary-position horizontal jerk nystagmus (video at Neurology.org/cp). During the ictal period, the fast phases of the nystagmus were contraversive to the seizure focus and the eyes did not cross midline. In the postictal period, he became responsive again, and the direction of nystagmus transiently reversed, with low-amplitude ipsiversive fast phases (video). The patient denied ictal sensory symptoms, auras, or vertigo. He did not take nystagmusprovoking medications. Brain MRI at presentation demonstrated left subcortical T2 hypointensity. The changes were attributed to the seizures and resolved after 1 month (figure). Ictal nystagmus is usually characterized by contraversive fast phases and may result from various mechanisms.1,2 When the intervening slow phases decrease in velocity and the eyes approach but do not cross the midline, it is postulated that the nystagmus is the result of spontaneous activation of cortical saccade regions. This mechanism most likely accounts for the nystagmus exhibited by our patient. In contrast, epileptic discharges that activate cortical pursuit or optokinetic mechanisms may produce ipsiversive slow phase eye movements that cross the midline and are followed by reflexive contraversive fast phases.1,2 Spontaneous reversal of the direction of nystagmus in the postictal phase relates to transiently depressed activation in the affected networks.

REFERENCES 1. Kaplan PW, Tusa RJ. Neurophysiologic and clinical correlations of epileptic nystagmus. Neurology 1993;43:2508–2514. 2. Weber YG, Roesche J, Lerche H. Epileptic nystagmus: two case reports, clinical and pathophysiological review of the literature. J Neurol 2006;253:767–717.

STUDY FUNDING No targeted funding reported. Harvard Medical School (SB, ANM) and Department of Neurology (KB, SP), Brigham and Women’s Hospital, Boston, MA. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of General Medical Sciences or the NIH. Funding information and disclosures are provided at the end of the article. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp. Correspondence to: [email protected] 522

© 2014 American Academy of Neurology

Alternating ictal and postictal nystagmus

Figure

T2–fluid-attenuated inversion recovery MRI

Axial brain T2–fluid-attenuated inversion recovery MRI at presentation (A) shows left temporo-occipital subcortical hypointensity (arrows) and at 1-month follow-up (B) shows near-complete resolution.

DISCLOSURES S. Bhai reports no disclosures. A. Malik is supported by award number T32GM007753 from the National Institute of General Medical Sciences. K. Bakhadirov reports no disclosures. S. Prasad is supported by an American Academy of Neurology Clinical Research Training Fellowship. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp.

Neurology: Clinical Practice

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December 2014

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Alternating ictal and postictal nystagmus Salman Bhai, Athar N. Malik, Khamidulla Bakhadirov, et al. Neurol Clin Pract 2014;4;522-523 Published Online before print October 15, 2014 DOI 10.1212/CPJ.0000000000000073 This information is current as of October 15, 2014 Updated Information & Services

including high resolution figures, can be found at: http://cp.neurology.org/content/4/6/522.full.html

Supplementary Material

Supplementary material can be found at: http://cp.neurology.org/content/suppl/2014/10/15/CPJ.0000000000000 073.DC1.html

References

This article cites 2 articles, 0 of which you can access for free at: http://cp.neurology.org/content/4/6/522.full.html##ref-list-1

Subspecialty Collections

This article, along with others on similar topics, appears in the following collection(s): All Epilepsy/Seizures http://cp.neurology.org//cgi/collection/all_epilepsy_seizures All Neuro-ophthalmology http://cp.neurology.org//cgi/collection/all_neuroophthalmology EEG http://cp.neurology.org//cgi/collection/eeg_ Nystagmus http://cp.neurology.org//cgi/collection/nystagmus Video/ EEG use in epilepsy http://cp.neurology.org//cgi/collection/video__eeg_use_in_epilepsy

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Neurol Clin Pract is an official journal of the American Academy of Neurology. Published continuously since 2011, it is now a bimonthly with 6 issues per year. Copyright © 2014 American Academy of Neurology. All rights reserved. Print ISSN: 2163-0402. Online ISSN: 2163-0933.