Journal of the Neurological Sciences 352 (2015) 112–114

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Letter to the Editor Delayed diagnosis of vestibular epilepsy due to temporal cavernous malformation

Dear Editor, Vestibular epilepsy refers to recurrent seizures that cause dizziness/ vertigo as a sole or predominant symptom [1]. It is due to epileptic discharges from the vestibular cortices mostly residing in the temporal [2] or temporo-parietal areas [3–5] but also in the frontal cortex [6]. Cerebral cavernous malformations, an enlarged collection of vascular channels invading adjacent brain tissue, mostly present with recurrent seizures in the supratentorial areas. Vestibular epilepsy has been reported in oligodendroglioma [7] and astrocytoma [6], but has not been described in association with a cavernous malformation. Herein, we describe a patient with recurrent spontaneous vertigo from a small temporal cavernous malformation that had escaped detection for several years. A 46-year-old man had suffered from recurrent internal vertigo of brief duration for 10 years. The spinning sensation developed in the yaw plane spontaneously without a noticeable provoking factor. During the first 6 years, the vertigo tended to occur once every other day and usually resolved within 1 min. He denied nausea/vomiting, auditory symptoms, and any postictal symptoms such as fatigue or headache in association with the vertigo attacks. The events tended to occur more frequently during the change of seasons. About 4 years before the presentation to our Dizziness Clinic, however, the duration of vertigo began to increase to about 5 min and accompany fumbling in the right hand, twitching of the left face, and occasional loss of consciousness. He had evaluation several times elsewhere including repeated EEGs and brain MRIs that had been reported normal. Between the attacks, findings of general physical, neurological, and neurotological examinations were all normal. Recording of eye movements using video-oculography (SMI, Teltow, Germany) showed normal saccades and smooth pursuit without spontaneous or evoked nystagmus. Results of bithermal caloric tests, cervical and ocular vestibular-evoked myogenic potentials, and audiometry were also normal. Given the normal results of previous EEGs and MRIs, he was arranged for a 24 h video-EEG monitoring with the most probable diagnosis of temporal lobe epilepsy (TLE). During the monitoring, the patient developed a seizure that started with vertigo followed by hand automatism and facial twitching. During the seizure, rhythmic spike discharges were documented maximal over the right temporal region (Fig. 1D). Unfortunately, however, we cannot make a statement on the presence of any eye movements including nystagmus during the attack because the trace of electro-oculography was too noisy. Review of the previous MRIs revealed an indistinct small nodular lesion in the posterior part of right supramarginal gyrus, and repeated MRIs including coronal T2- and susceptibility-weighted imaging confirmed a cavernous 0022-510X/© 2015 Elsevier B.V. All rights reserved.

malformation in the corresponding area (Fig. 1A and B, arrows). Subsequent CT demonstrated a calcification in the corresponding area (Fig. 1C, arrow). These findings were mostly consistent with a cavernous malformation. The patient was placed on the stepwise multiregimen of anti-epileptic drugs that included lacosamide, pregabalin, topiramate, and clobazam. The frequency of seizure decreased to once or twice per month with the medication. Vestibular epilepsy may be ascribed to epileptic discharges from the cerebral cortices with vestibular representation [1]. Thus, the patients with vestibular epilepsy may show nystagmus during the attacks [1,5]. The areas that receive vestibular inputs are distributed over the temporo-parietal cortices in animal studies [8]. Even though not identical, the posterior part of the insula, and the superior temporal, precentral, and prefrontal gyri correspond to the multimodal vestibular cortices in human [8]. Therefore, epileptic discharges originating from these areas can elicit vertigo during the seizure. A prior study by the authors supports this idea in that epileptic nystagmus is mostly due to epileptic discharges arising from the cortices responsible for saccades, smooth pursuits, or optokinetic eye movements, especially in the posterior part of the cerebral cortex [5]. The spinning sensation in the yaw plane reported in our patient is also consistent with the findings observed during electrical stimulation of the posterior part of the superior and middle temporal gyri in patients with focal epilepsy [9]. Indeed, dizziness is not a rare symptom among the patients with epilepsy, and is reported in up to 20% of TLEs [10]. However, less than 1% of epilepsy present with isolated vertigo [2], and only several anecdotal reports have described dizziness/vertigo as a sole manifestation of epilepsy [1–4,6,10]. In contrast to vestibular epilepsy, “vestibulogenic epilepsy” refers a form of reflex epilepsy in which the seizures are initiated by vestibular stimulation such as caloric tests or body rotation, and should be distinguished from vestibular epilepsy [1,2]. Vestibulogenic epilepsy is explained by the cerebral cortical neurons that have connections with the neurons in the brainstem and peripheral vestibular system [1]. However, the terminology of “vestibulogenic epilepsy” should be used with caution since the seizures also occur spontaneously, and vestibular stimulation provokes seizure only occasionally in this condition [1]. Furthermore, vertigo is not a typical manifestation of seizure in vestibulogenic epilepsy. In our patient, the epilepsy also started with recurrent brief vertigo in isolation, and then 6 years later began to accompany other symptoms suggestive of TLE. This progression of symptoms may be attributed to possible growth of the cavernous malformation over the period and/or intracortical spreads of the ictal discharges. In view of the brief and recurrent attacks of vertigo in isolation initially, vestibular paroxysmia as well as vestibular epilepsy should have been considered in differential diagnosis in our patient [1]. Even though vestibular paroxysmia is usually precipitated by a specific head position change and is frequently accompanied by cochlear symptoms such as hyperacusis or tinnitus [1], a definite differentiation would not be possible without associated symptoms and signs indicative of a seizure, or epileptiform discharges

Letter to the Editor


Fig. 1. (A) T2-weighted coronal and (B) susceptibility-weighted axial MRIs disclosed a small nodular lesion with mixed signal intensities surrounded by a hemosiderin rim on the area of right supramarginal gyrus (arrows). (C) CT demonstrated a calcification in the corresponding area (arrow). These findings are mostly consistent with a cavernous malformation. (D) Ictal EEG shows a build-up of rhythmic spike discharges that arise from the right temporal region.

on EEG or imaging abnormalities that may be localized to the vestibular cortices. Of relief, though, anti-epileptic medication is effective for both disorders. Even though vertigo mostly indicates a lesion involving the peripheral labyrinth, brainstem or cerebellum, it is noteworthy that cerebral lesions can be a rare cause of recurrent spontaneous vertigo. Indeed, the diagnosis of epilepsy and identification of the causative lesion had been delayed in our patient until the vertigo was accompanied by the signs suggestive of TLE. Vestibular epilepsy should be included in the differential diagnosis of isolated recurrent spontaneous vertigo. Author contributions Dr. Lee wrote the manuscript, and analyzed and interpreted the data. Dr. Yun analyzed and interpreted the data, and revised the manuscript. Dr. Kim conducted the design and conceptualization of the study, interpretation of the data, and revising the manuscript. Conflict of interest Drs. Lee and Yun report no disclosures. Dr. Kim serves as an associate editor of Frontiers in Neuro-otology and on the editorial boards of the Journal of Korean Society of Clinical

Neurophysiology, Journal of Clinical Neurology, Frontiers in Neuroophthalmology, Journal of Neuro-ophthalmology, Journal of Vestibular Research, Journal of Neurology, and Medicine; and received research support from SK Chemicals, Co. Ltd. Acknowledgments This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (HI10C2020). References [1] Brandt T. Vestibular epilepsy. Vertigo: its multisensory syndromes. London: Springer; 1991 91–7. [2] Kogeorgos J, Scott DF, Swash M. Epileptic dizziness. Br Med J (Clin Res Ed) 1981;282: 687–9. [3] Altay EE, Serdaroglu A, Gucuyener K, Bilir E, Karabacak N, Thio L. Rotational vestibular epilepsy from the temporo-parieto-occipital junction. Neurology 2005;65: 1675–6. [4] Hewett R, Guye M, Gavaret M, Bartolomei F. Benign temporo-parieto-occipital junction epilepsy with vestibular disturbance: an underrecognized form of epilepsy? Epilepsy Behav 2011;21:412–6. [5] Lee SU, Suh HI, Choi JY, Huh K, Kim HJ, Kim JS. Epileptic nystagmus: a case report and systematic review. Epilepsy Behav Case Rep 2014;2:156–60. [6] Kluge M, Beyenburg S, Fernández G, Elger CE. Epileptic vertigo: evidence for vestibular representation in human frontal cortex. Neurology 2000;55:1906–8.


Letter to the Editor

[7] Lopez C, Heydrich L, Seeck M, Blanke O. Abnormal self-location and vestibular vertigo in a patient with right frontal lobe epilepsy. Epilepsy Behav 2010;17: 289–92. [8] Brandt T, Dieterich M. The vestibular cortex: its locations, functions, and disorders. Ann N Y Acad Sci 1999;871:293–312. [9] Kahane P, Hoffmann D, Minotti L, Berthoz A. Reappraisal of the human vestibular cortex by cortical electrical stimulation study. Ann Neurol 2003;54: 615–24. [10] Currie S, Heathfield KW, Henson RA, Scott DF. Clinical course and prognosis of temporal lobe epilepsy. A survey of 666 patients. Brain 1971;94:173–90.

Sun-Uk Lee Department of Neurology, Ajou University School of Medicine, Ajou University Hospital, Suwon, South Korea

Chang-Ho Yun Ji-Soo Kim⁎ Department of Neurology, Seoul National University School of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea ⁎Corresponding author at: Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, South Korea. Tel.: +82 31 787 7463; fax: +82 31 719 6828. E-mail address: [email protected] (J.-S. Kim). 21 January 2015

Delayed diagnosis of vestibular epilepsy due to temporal cavernous malformation.

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