Epileptic nystagmus: A case report and systematic review

EEG based oculographic analysis of epileptic nystagmus

Epileptic nystagmus (EN) is a subtle seizure semiology, most commonly seen in seizures originating in the posterior cortical regions. EN is broadly categorized into type I and type II. Type I EN consists of contralateral repetitive saccadic eye movements alternating with post-saccadic slow drifts with an overall contralateral deviation. Type II EN is characterized by ipsilateral slow drift alternating with contralateral corrective saccades. In this article, we report a method to perform oculographic analysis of eye movements using EEG only. We used this method to classify the type of EN in three patients with parieto-occipital seizures. In all three patients, the ictal EEG demonstrated repetitive saccadic eye movements, directed contralateral to the seizure onset zone. With prolonged time constant, we were able to identify this eye movement pattern as EN with distinct slow and fast phases. We were able to further characterize the type of EN as type I and type II. In all three patients, the direction of EN (direction of fast phase or saccades) was contralateral to the seizure onset zone. EN can be easily missed on video-electroencephalography (vEEG) recordings because of various reasons. Our study demonstrates a systematic method of eye movement analysis on EEG, which can be used to not only identify EN as seizure semiology but also classify it, without requiring additional electrodes.

Early Manifestation of Benign Paroxysmal Positional Vertigo: A Case Report

Introduction

Benign paroxysmal positional vertigo (BPPV) is an inner ear disorder with a heterogeneous etiology, often linked to preceding infections, head injuries, or vestibular neuronitis. While it is commonly observed in the elderly, its occurrence in the pediatric population is rare. To our knowledge, there have been no reported cases of BPPV in patients younger than 5 years.

Case Presentation

A 4.5-month-old female infant was admitted with episodes of paroxysmal nystagmus. Parents reported fast horizontal eye movements lasting up to 30 s, with one episode accompanied by vomiting. Comprehensive differential diagnosis was considered from epileptic nystagmus to intoxications and both central and peripheral vestibular etiologies. During the observation on ward, connection between the baby's positioning and nystagmus was identified. The diagnostic roll test confirmed a transient positional geotropic nystagmus. The diagnosis aligned with BPPV characteristics, pointing to the right lateral semicircular canal canalolithiasis. A successful Lempert roll maneuver was performed with prompt effect. To further support the diagnosis and research, we introduced a semiautomatic video-oculography method.

Conclusion

This case highlights a rare instance of BPPV in an infant. The clinical findings combined with the effectiveness of the repositioning maneuvers support the diagnosis of right lateral semicircular canal lithiasis. Despite the rarity of this condition in such a young-age group, the need for thorough diagnostic evaluations is emphasized. In order to document the case, we also present a semiautomatic video analysis pipeline for analyzing abnormal eye movements in a home setting.

Vestibular seizures and spontaneous downbeat nystagmus of ganglioglioma origin: a case report

BACKGROUND

Low-grade gangliogliomas (GGs) are typically epileptogenic intracranial neoplasms. Yet, the presentation of simplex vertiginous experience and spontaneous downbeat nystagmus (DBN) has not been reported to date.

CASE PRESENTATION

We present the case of a 26-year-old male with focal onset impaired awareness seizures, characterized by vertigo due to right temporal lobe epilepsy caused by ganglioglioma. As rare presentations, a spontaneous, consistent DBN in the absence of vertiginous experience was noticed. MRI suggested lesion in the right temporal pole. Twenty-four-hour continuous electroencephalogram (EEG) monitoring recorded periodic sharp and slow waves, originating from the right temporal lobe. The patient was completely relieved of the symptoms after surgical removal of the tumor, which was histologically confirmed as Grade I Ganglioglioma.

CONCLUSIONS

Asides from the cortical pathogenesis of epileptic vertigo, this case also provides insight into the DBN secondary to tumor of the temporal lobe. Moreover, the 24-h EEG is advantageous to recognize vestibular seizures and localize the ictal onset areas.

What does epileptic nystagmus show us in cases presenting acute neurological symptoms?

PURPOSE

This study aims to determine the clinical significance of epileptic nystagmus in patients with acute neurological symptoms.

METHOD

The clinical findings of patients with documented epileptic nystagmus, their original video and EEG data, and cranial imaging and laboratory tests were analyzed retrospectively.

RESULTS

20 patients were included in the study and 21 epileptic nystagmus attacks were determined from patients' clinical and video-EEG recordings. All recorded seizures with epileptic nystagmus were focal onset in nature. The ictal discharge pattern was rhythmic fast activity with a mean frequency of 15 Hz. The ictal discharges originated from the parieto-occipital (n = 8), temporo-occipital (n = 7), parieto-occipito-temporal (n = 3), temporal (n = 2), occipital (n = 1), and centroparietal (n = 1) areas. In the fast phase, the nystagmus was beating away from the side of ictal discharges. The origin of the ictal discharges on EEG images was compatible with the lesion localization at cranial MRI in all patients. Etiologies were epilepsy in seven patients, non-ketotic hyperglycemia in four, ketotic hyperglycemia in one, PRES in three, acute stroke in three, HSV encephalitis in one, and MELAS in one.

CONCLUSIONS

Epileptic nystagmus represents a guide to the lateralization and localization of the lesion in cases presenting with acute neurological symptoms. In these patients, the lesion is frequently in the posterior regions of the hemispheres. Although various diseases affect these regions in terms of etiology, such cases should be evaluated in terms of the presence of hyperglycemia.

Seizure semiology, localization, and the 2017 ILAE seizure classification

In the study of epilepsy, the term semiology is used to comprise the clinical characteristics of a seizure, both subjective symptoms and objective phenomena. It is produced by activation of the symptomagenic zone, and an accurate and comprehensive understanding of the localizing value of seizure semiology is crucial for presurgical evaluation and planning. Myriad publications in epilepsy journals detail correlations between various semiological features and activation of specific cortical regions. Traditionally these studies involved scalp EEG recorded in epilepsy monitoring units. The increasing use of invasive monitoring, and specifically the use of depth electrodes and stereo-electroencephalography, has advanced our understanding of the characteristics of seizures arising from ictal foci deep to the scalp, including the cingulate, insula and operculum. However, the distinction between seizure onset and symptomogenic zones is not always clear. In 2017 the International League Against Epilepsy (ILAE) published an operational classification of seizure types based heavily on seizure semiology. The current paper provides an updated review of the current body of knowledge relating to seizure semiology, incorporating both scalp EEG studies and more recent stereo-electroencephalography discoveries in the framework of the 2017 ILAE classification.

[Neurophysiological and functional neuroimaging methods in the assessment of migraines and epilepsy with vertigo]

A review of the current literature shows that the combined use of neurophysiological and structural-functional neuroimaging methods has significantly expanded the understanding of the mechanisms of migraine with vestibular dysfunction: functional and structural disorders were found in brain regions involved in multisensory vestibular control and Central vestibular processing. Analysis of numerous studies shows that epilepsy can also cause vestibular symptoms, they can occur both without epileptic markers, and in combination with epileptic paroxysms. In isolated epileptic vertigo, according to studies widely presented in the literature, epileptic activity was most often detected by EEG data in the temporal regions, to a lesser extent in the parietal regions. In these studies, neuroimaging findings of foci of reduced substance density were found, which could be a consequence of deafferentation, as well as violations of connections with the focus of neuronal activity. In the absence of structural abnormalities, numerous studies have shown using magnetic resonance spectroscopy, diffusion MRI, and PET that the physiological basis for impaired neuronal metabolism was a decrease in synaptic activity, a violation of maintaining the difference in membrane potentials on the surface of the hippocampus, or changes in neighboring tracts of the white matter of the brain.

Localisation in focal epilepsy: a practical guide

The semiology of epileptic seizures reflects activation, or dysfunction, of areas of brain (often termed the symptomatogenic zone) as a seizure begins and evolves. Specific semiologies in focal epilepsies provide an insight into the location of the seizure onset zone, which is particularly important for presurgical epilepsy assessment. The correct diagnosis of paroxysmal events also depends on the clinician being familiar with the spectrum of semiologies. Here, we summarise the current literature on localisation in focal epilepsies using illustrative cases and discussing possible pitfalls in localisation.

Moyamoya disease with epileptic nystagmus: A case report

Epileptic nystagmus is a quick, repetitive, jerky movement of the eyeball caused by seizure activity, which is unaccompanied by other ictal phenomena. We report a case of moyamoya disease with epileptic nystagmus. A 23-year-old woman presented with a headache and transient hemiparesis on her left side. Magnetic resonance imaging showed no ischemic or hemorrhagic stroke lesions. Digital subtraction angiography confirmed stenosis of the terminal portion of the right internal carotid artery and the formation of moyamoya vessels on the right side. ¹²³I-N-isopropyl-iodoamphetamine (¹²³I-IMP) single photon emission computed tomography (SPECT) showed decreased uptake in the right basal ganglia, frontal, and parietal regions. After electroencephalography (EEG) and a hyperventilation test were performed, nystagmus appeared and was accompanied with a declining level of consciousness. Ictal EEG during an attack showed no epileptiform discharge. Moreover, the patient sometimes experienced simultaneous upper limb-shaking and gelastic attacks. After superficial temporal artery to middle cerebral artery bypass surgery was performed on the right side, symptom frequency and duration gradually decreased. Decreased ¹²³I-IMP SPECT blood flow in the right frontal region is considered a mechanism that causes the onset of epileptic nystagmus. It is presumed that the attack was caused by an ischemic abnormality in the saccade region of the frontal eye field. Moreover, revascularization can effectively treat the symptoms of moyamoya disease.

Ipsiversive ictal eye deviation in inferioposterior temporal lobe epilepsy-Two SEEG cases report

Background

Versive seizure characterized by conjugate eye movement during epileptic seizure has been considered commonly as one of the most valuable semiological signs for epilepsy localization, especially for frontal lobe epilepsy. However, thelateralizing and localizing significance of ictaleye deviation has been questioned by clinical observation of a series of focal epilepsy studies, including frontal, central, temporal, parietal and occipital epilepsy.

Case presentation

Two epileptic cases characterized by ipsiversive eye deviation as initial clinical sign during the habitual epileptic seizures are presented in this paper. The localization of the epileptogenic zone of both of the cases has been confirmed as inferioposterior temporal region by the findings of ictalstereoelectroencephalography (SEEG) and a good result after epileptic surgery. Detailed analysis of the exact position of the key contacts of the SEEG electrodes identified the overlap between the location of the epileptogenic zone and human MT/MST complex, which play a crucial role in the control of smooth pursuit eye movement.

Conclusion

Ipsiversive eye deviation could be the initial clinical sign of inferioposterior temporal lobe epilepsy and attribute to the involvement of human MT/MST complex, especially human MST whichwas located on the anterior/dorsal bank of the anterior occipital sulcus (AOS).

Conjugate Eye Deviation on CT Associated With Worse Outcomes Despite IV Thrombolysis

INTRODUCTION

Rapid stroke management has significant implications in patient outcomes. Ipsilateral computed tomography conjugate eye deviation (CT-CED) has been associated with worse outcomes but has never been evaluated as predictive of vascular occlusion. To test the hypothesis that CT-CED is a marker for vascular occlusion, we evaluated patients treated with intravenous tissue plasminogen activator (IV tPA).

METHODS

We performed a retrospective analysis of patients with acute ischemic stroke treated with IV tPA at a large tertiary care hospital over an 18-month period. A waiver of informed consent was granted. Two examiners evaluated baseline brain CTs blinded to the location of infarct to assess the presence of CT-CED and follow-up imaging for the location of infarct and the presence of intracranial large vessel occlusion. Demographics, initial National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scales (mRSs), and hospital length of stay (LOS) were collected.

RESULTS

Among 104 patients treated with IV tPA, 36 had CT-CED. Inter-rater reliability for CT-CED was excellent (κ = 0.97; 95% confidence interval: 0.98-1.0). The CT-CED group was older (69.8 vs 64 years; P = .038), had higher initial NIHSS (14.6 vs 11; P = .01), worse mRS (3.2 vs 2.4; P = .03), and longer LOS (8.4 vs 6.4; P = .05) compared with those without CT-CED. A vascular occlusion in the territory of the infarct was seen in 58% of patients with CT-CED versus 32% without CT-CED (P < .01). Atrial fibrillation (AF) was diagnosed in 61% patients with CT-CED versus 22% without (P < .01).

CONCLUSION

The CT-CED is associated with higher initial NIHSS, large vessel occlusion, and AF. Prospective studies are needed to ascertain whether CT-CED may be utilized part of a screen for endovascular therapy.