Occipital Lobe Epilepsy Research Articles

Occipital lobe epilepsy surgery: treating seizures in the posterior cortex.

Occipital lobe epilepsy (OLE) is an uncommon type of extratemporal epilepsy constituting roughly 2-13% of symptomatic partial epilepsies and epilepsy surgery cases. Over two-thirds of patients with OLE present with two characteristics: (1) ictal semiology compatible with an occipital seizure focus (e.g., ictal blindness, visual perceptual disturbance, eye blinking, nystagmus), and (2) lateralizing features referable to the posterior cortex (e.g., visual field defects, contralateral head deviation). The remaining one-third of patients present with ≥ 2 seizure types, indicative of spread to other lobes. A common representation of this cortical spread is the altered mental status and generalized tonic-clonic activity seen in patient with OLE. While the key clinical symptoms include visual hallucinations, it may be difficult to elicit on history, especially from children, and are not always present.

Familial occipital lobe epilepsy associated with GABAA receptor variants

Familial occipital lobe epilepsy associated with GABAA receptor variants

Structural brain network analysis in occipital lobe epilepsy

BackgroundThis study aimed to analyze the structural brain network in patients with occipital lobe epilepsy (OLE) and investigate the differences in structural brain networks between patients with OLE and healthy controls.MethodsPatients with OLE and healthy controls with normal brain MRI findings were enrolled. They underwent diffusion tensor imaging using a 3.0T MRI scanner, and we computed the network measures of global and local structural networks in patients with OLE and healthy controls using the DSI studio program. We compared network measures between the groups.ResultsWe enrolled 23 patients with OLE and 42 healthy controls. There were significant differences in the global structural network between patients with OLE and healthy controls. The assortativity coefficient (-0.0864 vs. -0.0814, p = 0.0214), mean clustering coefficient (0.0061 vs. 0.0064, p = 0.0203), global efficiency (0.0315 vs. 0.0353, p = 0.0086), and small-worldness index (0.0001 vs. 0.0001, p = 0.0175) were lower, whereas the characteristic path length (59.2724 vs. 53.4684, p = 0.0120) was higher in patients with OLE than those in the healthy controls. There were several nodes beyond the occipital lobe that showed significant differences in the local structural network between the groups. In addition, the assortativity coefficient was negatively correlated with the duration of epilepsy (r=-0.676, p = 0.001).

Deep brain stimulation for patients with refractory epilepsy: nuclei selection and surgical outcome.

By studying the surgical outcome of deep brain stimulation (DBS) of different target nuclei for patients with refractory epilepsy, we aimed to explore a clinically feasible target nucleus selection strategy. We selected patients with refractory epilepsy who were not eligible for resective surgery. For each patient, we performed DBS on a thalamic nucleus [anterior nucleus of the thalamus (ANT), subthalamic nucleus (STN), centromedian nucleus (CMN), or pulvinar nucleus (PN)] selected based on the location of the patient's epileptogenic zone (EZ) and the possible epileptic network involved. We monitored the clinical outcomes for at least 12 months and analyzed the clinical characteristics and seizure frequency changes to assess the postoperative efficacy of DBS on the different target nuclei. Out of the 65 included patients, 46 (70.8%) responded to DBS. Among the 65 patients, 45 underwent ANT-DBS, 29 (64.4%) responded to the treatment, and four (8.9%) of them reported being seizure-free for at least 1 year. Among the patients with temporal lobe epilepsy (TLE, n = 36) and extratemporal lobe epilepsy (ETLE, n = 9), 22 (61.1%) and 7 (77.8%) responded to the treatment, respectively. Among the 45 patients who underwent ANT-DBS, 28 (62%) had focal to bilateral tonic-clonic seizures (FBTCS). Of these 28 patients, 18 (64%) responded to the treatment. Out of the 65 included patients, 16 had EZ related to the sensorimotor cortex and underwent STN-DBS. Among them, 13 (81.3%) responded to the treatment, and two (12.5%) were seizure-free for at least 6 months. Three patients had Lennox-Gastaut syndrome (LGS)-like epilepsy and underwent CMN-DBS; all of them responded to the treatment (seizure frequency reductions: 51.6%, 79.6%, and 79.5%). Finally, one patient with bilateral occipital lobe epilepsy underwent PN-DBS, reducing the seizure frequency by 69.7%. ANT-DBS is effective for patients with TLE or ETLE. In addition, ANT-DBS is effective for patients with FBTCS. STN-DBS might be an optimal treatment for patients with motor seizures, especially when the EZ overlaps the sensorimotor cortex. CMN and PN may be considered modulating targets for patients with LGS-like epilepsy or occipital lobe epilepsy, respectively.

A Narrative Review of Visual Hallucinations in Migraine and Epilepsy: Similarities and Differences in Children and Adolescents.

Since the earliest descriptions of the simple visual hallucinations in migraine patients and in subjects suffering from occipital lobe epilepsy, several important issues have arisen in recognizing epileptic seizures of the occipital lobe, which often present with symptoms mimicking migraine. A detailed quantitative and qualitative clinical scrutiny of timing and characteristics of visual impairment can contribute to avoiding mistakes. Differential diagnosis, in children, might be challenging because of the partial clinical, therapeutic, and pathophysiological overlaps between the two diseases that often coexist. Ictal elementary visual hallucinations are defined by color, shape, size, location, movement, speed of appearance and duration, frequency, and associated symptoms and their progression. The evaluation of the distinctive clinical features of visual aura in migraine and visual hallucinations in occipital epilepsy could contribute to understanding the pathogenetic mechanisms of these two conditions. This paper aims to critically review the available scientific evidence on the main clinical criteria that address diagnosis, as well as similarities and differences in the pathophysiological mechanisms underlying the visual impairment in epilepsy and migraine.

Photosensitive occipital lobe epilepsy: Delineation of an under-recognized reflex epilepsy syndrome according to the new ILAE criteria and long-term follow-up.

Photosensitive occipital lobe epilepsy (POLE) should be suspected in patients with occipital lobe seizures triggered by photic stimuli, who have normal motor-mental development and brain imaging. We aimed to examine the clinical, electrophysiological, and prognostic features of POLE, which is a rare and under-investigated syndrome. Archives from two tertiary epilepsy centers were retrospectively scanned and patients with normal neurological examination and cranial imaging were identified with POLE if they had: (1) seizures consistently triggered by photic stimuli; (2) non-motor seizures with visual symptoms; and (3) photosensitivity documented on EEG. The clinical and electrophysiological features and prognostic factors were evaluated for patients who had follow-up ≥5 years. We identified 29 patients diagnosed with POLE with a mean age of 20.1± 7.6 years. In one-third of the patients, POLE syndrome overlapped with genetic generalized epilepsy (GGE). The overlap group had higher rates of febrile seizure history and self-induction; when compared to pure POLE patients, their EEGs showed more frequent interictal generalized epileptic discharges and posterior multiple spikes during intermittent photic stimulation. During long-term follow-up, the remission rate for POLE was 80%, but EEG photosensitivity persisted in three quarters of patients despite clinical remission, and more than half had relapsed after clinical remission. This first long-term follow-up study, utilizing newly suggested criteria of the International League Against Epilepsy, showed that POLE syndrome shows a notable overlap with GGE but also has distinctive features. POLE has a good prognosis; however, relapses are common, and photosensitivity persists as an EEG finding in the majority of patients.

Thalamic nuclei volumes and intrinsic thalamic network in patients with occipital lobe epilepsy.

This study aimed to investigate the alterations in individual thalamic nuclei volumes in patients with occipital lobe epilepsy (OLE) compared with those of healthy controls, and to analyze the intrinsic thalamic network based on these volumes using graph theory. Thirty adult patients with newly diagnosed OLE and 42 healthy controls were retrospectively enrolled (mean age, 33.8±17.0 and 32.2±6.6years, respectively). The study participants underwent brain magnetic resonance imaging with three-dimensional T1-weighted imaging. The right and left total thalamic and individual thalamic nuclei volumes were obtained using the FreeSurfer program. Then, the intrinsic thalamic network was calculated based on the individual thalamic nuclei volumes and graph theory using a BRAPH program. There were no differences in the right and left whole-thalamic volumes between the two groups (0.445%vs. 0.469%, p=.142 and 0.481%vs. 0.490%, p=.575, respectively). However, significant differences were observed in the volumes of several thalamic nuclei between the two groups. The right medial geniculate and right suprageniculate nuclei volumes were increased (0.0077%vs. 0.0064%, p=.0003 and 0.0013%vs. 0.0010%, p=.0004, respectively), whereas the right and left parafascicular nuclei volumes were decreased in patients with OLE compared with those in healthy controls (0.0038%vs. 0.0048%, p<.0001 and 0.0037%vs. 0.0045%, p=.0001, respectively). There were no differences in the network measures regarding intrinsic thalamic network between the two groups. We successfully demonstrated the alterations in individual thalamic nuclei volumes, especially the increased medial geniculate and suprageniculate, and decreased parafascicular nuclei volumes in patients with OLE compared with those of healthy controls despite no changes in the whole-thalamic volumes. These findings suggest an important role of the thalamus in the epileptic network of OLE.

An epileptogenic intracranial cystic lesion lined with fallopian tube-type epithelium: illustrative case.

Intracranial cystic lesions are often a trigger for epileptic seizures. However, there has never been a report of a cystic lesion lined with fallopian tube-type epithelium. A 48-year-old female presented with a cystic lesion in the right occipital lobe, which gradually grew over 8 years. Right occipital lobe epilepsy was diagnosed based on visual aura, convulsive seizures, and electroencephalogram findings and the cyst was surgically removed. Further examination revealed the cyst was lined with ciliated cells, which had morphological and immunohistochemical features similar to those of fallopian tube epithelium. The characteristics of the cyst did not conform to any known types of benign cystic lesion. To the authors' knowledge, no such cyst has been reported before. The authors discuss the origins and pathogenesis of this unfamiliar cystic lesion.

Glymphatic system dysfunction in patients with occipital lobe epilepsy.

We aimed to investigate the glymphatic system function in patients with occipital lobe epilepsy (OLE) and healthy controls using diffusion tensor image analysis along the perivascular space (DTI-ALPS) index. We retrospectively included 23 patients with OLE and 30 healthy controls. The participants underwent brain MRI, which was normal, and diffusion tensor imaging. We used the DSI Studio for data preprocessing, obtained the fiber orientation and diffusivities, and calculated the DTI-ALPS index from the diffusivity values associated with the projection and association fibers in the left hemisphere. There were no differences in mean age (31.6 years [range: 13-58] vs. 31.3 years [range: 20-57], p=.912) and male sex ratio (10/23 [43.5%] vs. 15/30 [50.0%]) between the groups. Compared to healthy controls, the diffusivities in patients with OLE were higher along the Y-axis in the projection fiber and along the Z-axis in the association fiber and lower along the Y-axis in the association fiber. The DTI-ALPS index in patients with OLE was lower than that in the healthy controls (1.421±0.171vs. 1.667±0.271, p<.001, 95% confidence interval of difference=0.117-0.376, Test statistic t=3.823). We found no association between the DTI-ALPS index and clinical characteristics in OLE. The DTI-ALPS index in patients with OLE was significantly lower than that in healthy controls, suggesting glymphatic system dysfunction in OLE. The DTI-ALPS index could help assess the glymphatic system function in patients with epilepsy.

Prevalence of headache disorders in patients living with epilepsy in rural region in western part of India

Background and aimsHeadache disorders cause significant distress in patients living with epilepsy (PWE) and are underreported. This study aimed to evaluate the prevalence of various forms of headache in PWE. MethodologyTwo hundred and three PWE were evaluated for the presence and type of headache as per the International Classification of Headache Disorders (ICHD)-3 classification criteria. The severity was graded using the Headache Under Response to Treatment (HURT)–3. A subgroup analysis of headache and epilepsy was done. The World Health Organization-5 (WHO-5) questionnaire was used to assess mental well-being. The Mini International Neuropsychiatric Interview (MINI) questionnaire was used to study the psychiatric comorbidities, which were classified according to the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV classification. ResultsThe prevalence of headaches in PWE was 45% [60% females]. Female gender and younger age were significantly associated with migraine (p values of 0.03 and 0.05, respectively). Migraine was the most common type of headache (71%), followed by tension-type headache (TTH) (23%) in PWE. The headache was inter-ictal in 80% of PWE. In PWE with migraine, both juvenile myoclonic epilepsy (JME) and frontal lobe epilepsy (FLE) had a 28% prevalence. In PWE with TTH, FLE was more common (43%). The prevalence of migralepsy in PWE was 4% [n = 4; 2 each of occipital lobe epilepsy (OLE) and idiopathic generalized epilepsy (IGE)]. A psychiatric illness was more than two times more likely in PWE with headache (n = 34; 37%) as compared to PWE without headache (n = 19; 17%). Patients living with epilepsy with headaches and psychiatric comorbidities had significantly lower mental well-being (p = 0.001). Forty five percent of PWE with headaches required acute management, and 35% required prophylactic management for their headache. ConclusionHeadache is frequently ignored in PWE. It can affect their mental health and quality of life. Evaluation and management of headache in PWE is very important.

International League Against Epilepsy classification and definition of epilepsy syndromes with onset in childhood: Position paper by the ILAE Task Force on Nosology and Definitions

The 2017 International League Against Epilepsy classification has defined a three-tier system with epilepsy syndrome identification at the third level. Although a syndrome cannot be determined in all children with epilepsy, identification of a specific syndrome provides guidance on management and prognosis. In this paper, we describe the childhood onset epilepsy syndromes, most of which have both mandatory seizure type(s) and interictal electroencephalographic (EEG) features. Based on the 2017 Classification of Seizures and Epilepsies, some syndrome names have been updated using terms directly describing the seizure semiology. Epilepsy syndromes beginning in childhood have been divided into three categories: (1) self-limited focal epilepsies, comprising four syndromes: self-limited epilepsy with centrotemporal spikes, self-limited epilepsy with autonomic seizures, childhood occipital visual epilepsy, and photosensitive occipital lobe epilepsy; (2) generalized epilepsies, comprising three syndromes: childhood absence epilepsy, epilepsy with myoclonic absence, and epilepsy with eyelid myoclonia; and (3) developmental and/or epileptic encephalopathies, comprising five syndromes: epilepsy with myoclonic-atonic seizures, Lennox-Gastaut syndrome, developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, and febrile infection-related epilepsy syndrome. We define each, highlighting the mandatory seizure(s), EEG features, phenotypic variations, and findings from key investigations.

Genetic Epilepsy Syndromes.

This article reviews the clinical features, typical EEG findings, treatment, prognosis, and underlying molecular etiologies of the more common genetic epilepsy syndromes. Genetic generalized epilepsy, self-limited focal epilepsy of childhood, self-limited neonatal and infantile epilepsy, select developmental and epileptic encephalopathies, progressive myoclonus epilepsies, sleep-related hypermotor epilepsy, photosensitive occipital lobe epilepsy, and focal epilepsy with auditory features are discussed. Also reviewed are two familial epilepsy syndromes: genetic epilepsy with febrile seizures plus and familial focal epilepsy with variable foci. Recent years have seen considerable advances in our understanding of the genetic factors underlying genetic epilepsy syndromes. New therapies are emerging for some of these conditions; in some cases, these precision medicine approaches may dramatically improve the prognosis. Many recognizable genetic epilepsy syndromes exist, the identification of which is a crucial skill for neurologists, particularly those who work with children. Proper diagnosis of the electroclinical syndrome allows for appropriate treatment choices and counseling regarding prognosis and possible comorbidities.

High frequency oscillation analysis of intracranial 14 and 6 Hz-positive spikes and interictal epileptiform discharges in a patient with occipital lobe epilepsy

High frequency oscillation analysis of intracranial 14 and 6 Hz-positive spikes and interictal epileptiform discharges in a patient with occipital lobe epilepsy

Visual Illusion as a Main Presenting Symptom of Occipital Lobe Epilepsy: A Case Report

Visual Illusion as a Main Presenting Symptom of Occipital Lobe Epilepsy: A Case Report

Resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy.

BACKGROUNDNeurosurgical treatment of severe bilateral occipital lobe epilepsy usually involves two operations several mos apart. AIMTo evaluate surgical resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy. METHODSThis retrospective case series included patients with drug-refractory bilateral occipital lobe epilepsy treated surgically between March 2006 and November 2015.RESULTSPreoperative evaluation included scalp video-electroencephalography (EEG), magnetic resonance imaging, and PET-CT. During surgery (bilateral occipital craniotomy), epileptic foci and important functional areas were identified by EEG (intracranial cortical electrodes) and cortical functional mapping, respectively. Patients were followed up for at least 5 years to evaluate treatment outcome (Engel grade) and visual function. The 20 patients (12 males) were aged 4-30 years (median age, 12 years). Time since onset was 3-20 years (median, 8 years), and episode frequency was 4-270/mo (median, 15/mo). Common manifestations were elementary visual hallucinations (65.0%), flashing lights (30.0%), blurred vision (20.0%) and visual field defects (20.0%). Most patients were free of disabling seizures (Engel grade I) postoperatively (18/20, 90.0%) and at 1 year (18/20, 90.0%), 3 years (17/20, 85.0%) and ≥ 5 years (17/20, 85.0%). No patients were classified Engel grade IV (no worthwhile improvement). After surgery, there was no change in visual function in 13/20 (65.0%), development of a new visual field defect in 3/20 (15.0%), and worsening of a preexisting defect in 4/20 (20.0%). CONCLUSIONResection of bilateral occipital lobe lesions during a single operation may be applicable in bilateral occipital lobe epilepsy.

SY6.5. Temporal plus epilepsies

Temporal plus epilepsies are characterized by the epileptogenic foci outside the temporal lobe and a mix of temporal and extratemporal features. They have a wide spectrum of semiological presentation depending on the extent of network. They can arise from frontal, parietal, occipital lobes along with temporal lobe networks. We discuss in this review the semiology of different types. Lateralizing and localizing features are mentioned in the table below the review is not exhaustive and it is recommended to read large descriptive semiology’s in journals. Temporal plus epilepsies will have red flags for temporal lobe in that there will be extratemporal auras or signs. These would suggest wider networks more than temporal. So if a typical temporal lobe seizure has amnesia, arrest, lack of awareness, aphasia, etc. Presence of a visual aura would favor a temporal plus network. CL = Contralateral, IL = ipsilateral, NonLAT = Nonlateralizing, FLE = Frontal lobe epilepsy, PLE = Parietal lobe epilepsy, OLE = Occipital lobe epilepsy, SSMA = Supplementary sensorimotor area, IPSI = Ipsilateral.

ÇOCUKLUK ÇAĞI OKSİPİTAL EPİLEPSİ: 19 HASTANIN KLİNİK DEĞERLENDİRİLMESİ

OBJECTIVE: Childhood occipital epilepsy (COE) can mainly be divided into idiopathic (IOLE) or symptomatic occipital lobe epilepsy (SOLE). Idiopathic occipital lobe epilepsy consists of Panayiotopoulos (PS) and Gastaut syndromes (GS). In this study, we aimed to classify COE and investigate the segregations between the groups according to clinical features.MATERIAL AND METHODS: Nineteen patients with COE were enrolled. Medical records of the patients were evaluated. Demographic data, ictal symptoms, neurological examination, brain magnetic resonance imaging (MRI) and electroencephalography (EEG) findings, family history, febrile seizure, and treatment response were analyzed.RESULTS: There were 6 patients diagnosed with idiopathic occipital lobe epilepsy and 13 patients diagnosed with SOLE. Compared to the SOLE, all patients of the IOLE had a normal neurological examination and MRI findings (p=0.044 and p=0.009). The most frequent ictal symptom was generalized seizures in all groups (100% IOLE, 75% SOLE). However, ictal vomiting was the most frequent autonomic seizure in IOLE and PS (2/6, 2/4; 33%, 50%). Nocturnal seizures were observed more frequently in IOLE than SOLE (1/13, 3/6; 8%, 50%). The rate of family history (1 patient, 25%) and febrile seizures (1 patient, 25%) were found in only PS group. Psychomotor/mental retardation was more common in SOLE than IOLE (8/13, 2/6; 62%, 33%). According to treatment outcomes, the seizures were controlled with one antiepileptic drug (AED) in all patients of PS and two AEDs in all patients of GS. On the other hand, 38% of patients in SOLE were treated with three or more AEDs.CONCLUSIONS: Normal neurologic examination and neuroimaging are substantial features due to discrimination between IOLE and SOLE. Ictal vomiting is a remarkable autonomic seizure in IOLE and PS. Although psychomotor/mental retardation is observed higher in SOLE than IOLE, the patients of COE should be followed up carefully. IOLE has better treatment outcomes than SOLE and PS has better than GS.

Adult occipital lobe epilepsy: 12-years on.

Occipital lobe epilepsies (OLE) comprise 5-10% of focal epilepsies in surgical and paediatric series; with little data from adult medical cohorts. This longitudinal study examined OLE patients, to characterise prevalence, semiology, co-morbidity and prognosis in a neurology outpatient setting. 24 adult OLE patients identified over 12months from 1548 patients in a neurologist's service were followed over 12years. 92% of these OLE patients had simple visual hallucinations, misdiagnosed in 40% of cases. 75% had co-morbid interictal migraine and 38% had visual field defects. Only 33% achieved long-term remission, and only 2 /10 (20%) of OLE patients with a structural aetiology were seizure-free. The two patients with migralepsy achieved remission. Adult OLE accounted for 7.7% of focal epilepsies in this cohort, misdiagnosed or misclassified in 40%. Most patients had co-existing migraine. A minority had migralepsy characterised by a longer aura and good prognosis. Remission rates were lower than that of childhood OLE and general adult epilepsy populations, strengthening the argument for considering epilepsy surgery in drug-resistant OLE patients with a structural cause. Precision medicine will potentially refine diagnosis and management in those OLE patients without an identified cause but is predicated on accurate clinical phenotyping.

Reflex Epilepsy

Reflex seizures (RS) are epileptic events that are objectively and consistently elicited in response to a specific afferent stimulus or by an activity of the patient. The specific stimulus can be a variety of heterogenous intrinsic or extrinsic factors, ranging from the simple to the complex, such as flashing lights or reading a book. These seizures can take a variety of forms, comprising either general or focal onset, with or without secondary generalization. Reflex epilepsies (RE) are classified as a specific syndrome in which all epileptic seizures are precipitated by sensory stimuli. The few designated RE include idiopathic photosensitive occipital lobe epilepsy, other visual sensitive epilepsies, primary reading epilepsy, and startle epilepsy. RS that occurs within other focal or generalized epilepsy syndromes that are associated with distinct spontaneous seizures are classified by the overarching seizure type. Most patients experience spontaneous seizures along with their provoked events. RS originate from stimulation of functional anatomic networks normally functioning for physiological activities, that overlap or coincide with regions of cortical hyperexcitability. Generalized RS typically occur within the setting of IGEs and should be considered as focal seizures with quick secondary generalization via cortico-cortical or cortico-reticular pathways. In aggregate, activation of a critical neuronal mass, supported and sustained by cortico-subcortical and thalamocortical pathways eventually result in a seizure. Treatment includes antiseizure medication, commonly valproate or levetiracetam, along with lifestyle modifications, and when amenable, surgical intervention. High clinical suspicion and careful history taking must be employed in all epilepsy patients to identify reflex triggers.

A 16-year-old male case of post-ictal headache due to occipital lobe epilepsy with ulegyria that required differentiation from migraine with aura

A 16-year-old male case of post-ictal headache due to occipital lobe epilepsy with ulegyria that required differentiation from migraine with aura