Photosensitive Occipital Lobe Epilepsy Research Articles

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.

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.

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.

Contribution of Cognitive Behavioral Therapy on Epilepsy Treatment, Case Report

Introduction: Andrews / Reiter method based cognitive behavioral therapy (CBT) has been applied to a 33-year-old female patient who was followed up for 28 years with the diagnosis of drug resistant epilepsy. Depression, anxiety, quality of life and seizure frequency were followed. Case Report: The patient has been followed up with idiopathic photosensitive occipital lobe epilepsy and has been used many antiepileptics for years could not be achieved seizure control completely. Interviews were designed for the patient based on the method developed by Andrews / Reiter for patients with epilepsy. After the first interview, a total of 13 sessions were held once every two weeks. The Quality of Life in Epilepsy Inventory (QOLIE-31), Beck Depression Scale (BDI), Beck Anxiety Scale (BAI), Medication Adherence Report Scale (MARS), and Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) were administered.The scales were administered at baseline, at the fifth interview, and after the end of therapy, totally 3 times. The patient had aura sensation 9 times throughout the entire process. Two of these had seizures with focal symptoms after the aura. There was no epileptic transformation after the other 7 aura sensations. When the patient's visual aura started, she started to do breathing exercises. In this way, she said, she was able to stop the aura's progress. During follow-up, the patient's quality of life, depression and anxiety scores improved. Drug incompatibility was very rare and the patient started to use her antiepileptics completely regularly after the 5th session. Discussion: Psychiatric treatments in epilepsy may contribute to quality of life and emotional well-being. The acquired behavior may be changing the underlying epileptic neural networks. In our patient, the addition of cognitive behavioral therapy to the antiepileptic treatment caused improvement in quality of life, anxiety and depression. Moreover, there was a decrease in the frequency of seizures in our patient. CBT is advantageous in epilepsy due to the lack of side effects and drug interactions and its low cost. In addition, in patients with drug-resistant epilepsy and in patients with difficulties in medical treatment CBT can be improved compliance of drugs, quality of life, anxiety and depression, as a result seizure frequency can be reduced and epilepsy can be coped better.

Electroclinical and prognostic characteristics of epilepsy patients with photosensitivity

Epilepsy with photosensitivity (PSE) is one of the reflex epilepsy types with pathophysiology still unexplained. In our study we aimed to evaluate the clinical, electroencephalogram (EEG) and prognosis of patients with PSE diagnosis. A total of 44 patients with PSE diagnosis according to international classification were included in this retrospective and cross-sectional study. The age, gender, syndrome, clinical and EEG characteristics of patients, and treatment response were investigated. The mean age was 22.09±6.49 years for 28 females and 16 males included in the study. Of patients, 17 had idiopathic photosensitive occipital lobe epilepsy (IPOLE), 11 had juvenile myoclonic epilepsy (JME), 11 had other PSE and 5 had juvenile absence epilepsy (JAE), with the most common visual trigger factors television and sunlight. In terms of seizure type, the most common was generalized tonic clonic seizure (GTCS), with myoclonus, absence and other seizure types observed. There was family history present in 17 patients and valproic acid was most commonly used for treatment. As noted in the literature, our data show that PSE has defined age group and clinical presentation, good prognosis but requires correct choice of medication for treatment. It is thought that good description of these epilepsy types will reduce misdiagnosis and mistreatment rates.

Investigation of the possible association of NEDD4-2 (NEDD4L) gene with idiopathic photosensitive epilepsy.

NEDD4-2 alias NEDD4L (neural precursor cell expressed, developmentally downregulated) gene was reported as a candidate gene for epileptic photo-sensitivity. We aimed to investigate this possible association of NEDD4-2 variants with idiopathic photosensitive epilepsy. Consecutive patients who had been followed up at our epilepsy center and diagnosed with idiopathic epilepsy according to ILAE criteria and clear-cut photoparoxysmal responses in their electroencephalograms and 100 ethnically matched healthy subjects were included in the study. The regions around previously reported three variants, namely, S233L, E271A and H515P were tracked with DHPLC and the samples showing variations were sequenced. 81 patients (63 females) aged between 12-63 years (45 had juvenile myoclonic epilepsy, 11 childhood absence epilepsy, 14 juvenile absence epilepsy, 7 late onset idiopathic generalized epilepsy, 1 unclassified idiopathic generalized epilepsy, and 3 patients with idiopathic photosensitive occipital lobe epilepsy) were included in this study. We found only one heterozygous S233L variant in a 23-year-old man who has photosensitive form of juvenile absence epilepsy and pattern sensitivity to striped carpets. Other two variants were not found in any of the other patients and controls. Our results suggest that three screened NEDD4-2 variants do not play a leading role in the pathogenesis of photosensitive epilepsy in the Turkish population.

Natural evolution from idiopathic photosensitive occipital lobe epilepsy to idiopathic generalized epilepsy in an untreated young patient

Idiopathic photosensitive occipital lobe epilepsy (IPOE) is an idiopathic localization-related epilepsy characterized by age-related onset, specific mode of precipitation, occipital photic-induced seizures – frequently consisting of visual symptoms – and good prognosis. This uncommon epilepsy, which usually starts in childhood or adolescence, has rarely been observed in families in which idiopathic generalized epilepsy also affects other members. We describe a nuclear family in which the proband showed electro-clinical features of idiopathic photosensitive occipital lobe epilepsy in childhood, which subsequently evolved into absences and a single generalized tonico-clonic seizure in early adolescence. His mother had features suggestive of juvenile myoclonic epilepsy. This case illustrates a continuum between focal and generalized entities in the spectrum of the so-called idiopathic (genetically determined) epileptic syndromes.

Idiopathic Photosensitive Occipital Epilepsy

Idiopathic photosensitive occipital lobe epilepsy is a reflex, age- and localization-related syndrome. We describe the clinical and electroencephalographic features, therapy, and outcome of 16 children/adolescents with this syndrome. The cohort included 2 sets of siblings and 7 patients with other first- or second-degree relatives with a seizure history. All patients had occipital onset seizures and 15 had secondarily generalized tonic-clonic seizures. Seizure frequency was relatively low in all patients but one. Myoclonic seizures later developed in 2 patients with juvenile myoclonic epilepsy. Eight patients achieved full seizure control with monotherapy, and 5 required a second drug; 3 patients had rare seizures and were not treated with antiepileptics. Seven patients required special education or developmental assistance. This interesting syndrome sheds light on the pathophysiology and genetic etiology of common phenomena such as photosensitivity and headache. Further large prospective studies are required to better define this unique syndrome and its implications.

Benign occipital lobe seizures: Natural progression and atypical evolution

Benign occipital seizure syndromes are benign childhood epilepsy syndromes and are mainly of two types, Panayiotopoulos syndrome, an autonomic epilepsy and idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) including the idiopathic photosensitive occipital lobe epilepsy. Although both these types are categorized as occipital seizures, they are distinct in presentation and management. They can also be tricky to diagnose as visual symptoms may not always be the presenting feature and it is also not very easy to elicit visual hallucinations during history taking. These seizures have a good response to treatment; however, there could be atypical evolution and refractoriness to treatment especially with ICOE-G. We describe three children who presented with visual and non-visual symptoms and the electroencephalography (EEG) in all the three cases showed occipital paroxysms. We have emphasized the clues in the clinical history and EEG leading to the diagnosis of these distinct epilepsy syndromes. We have also discussed the natural course of these epilepsy syndromes with some atypical evolution, which clinicians need to be aware of during treatment of these children.

Benign childhood focal epilepsies

The idiopathic focal epilepsies comprise a group of syndromes characterized by focal-onset seizures for which there is no detectable structural brain abnormality and for which there is a proposed functional mechanism for the epilepsy and electroencephalography (EEG) abnormalities. This group includes benign rolandic epilepsy (BRE), benign epilepsy with occipital paroxysms (both early onset and late-onset types), idiopathic photosensitive occipital lobe epilepsy, and some less well-defined syndromes. The limits of the early onset idiopathic occipital epilepsy syndrome are not clear, and perhaps this entity represents part of a larger syndrome group of "autonomic" age-related epilepsies. The term "idiopathic" implies absence of a structural brain lesion and a genetic propensity to seizures. The term "benign" implies that the epileptic seizures are easily treated or require no treatment, show remission without sequelae with ultimate and definitive remission before adulthood, do not have severe or exceedingly disturbing seizures, and have no associated serious intellectual or behavioral disturbances. It may be that a syndrome is benign only when it can be recognized early with reasonable certainty, thereby avoiding unnecessary investigations, overtreatment, and lifestyle restrictions. Although BRE has such characteristic clinical and EEG features to make early recognition possible, this is less constantly so in the other focal idiopathic epilepsy syndromes, where the term "benign" may be inappropriate. Mild and selective neuropsychological impairment may occur even in those with typical syndromes but it is unclear whether such selective deficits outlast the active phase of epilepsy. Sometimes the clinical course may be complicated by obvious cognitive and language impairments. In such cases, the term benign is obviously inappropriate, even when seizures are rare. In most patients with the typical focal idiopathic epilepsy syndromes, medication is not necessary.

Relationship among eye condition sensitivities, photosensitivity and epileptic syndromes

Electroencephalogram (EEG) activity in normal subjects and epileptic patients is often closely related to the eye's status such as eye opened (EO), eye closure (ECL) and eyes closed (EC). ECL is the period immediately after closing of the eyes and only lasts for less than 3 seconds if the eyes remain closed. EC is the period as long as the eyes are closed. Epileptiform changes on EEG induced by ECL or EC are called the changes of ECL sensitivity (ECLS) or EC sensitivity (ECS). ECLS occurs mainly but not exclusively in photosensitive patients and ECS has been seen rarely in photosensitive patients. This study aimed to investigate the relationships among ECLS, ECS, photosensitivity and epilepsy syndromes in children. EEG records from child patients in the EEG Department of Peking University First Hospital during the period of May 2005 to May 2007 were examined for the presence of ECLS or ECS. Open-close eye tests and intermittent photic stimulations were carried out during video-EEG monitoring for examining ECLS, ECS and photosensitivity. Based on ECLS and ECS on their EEGs, 30 patients were divided into ECLS group (16 cases) and ECS group (14 cases). There were more boys than girls in the two groups. The mean age of initial detection of ECLS and ECS was 10 years, and the average onset age of seizures was 9 years. The epilepsy syndromes in the ECLS group included idiopathic photosensitive occipital lobe epilepsy, Panayiotopoulos syndrome, symptomatic occipital lobe epilepsy, juvenile myoclonic epilepsy, juvenile absence epilepsy, eyelid myoclonia with absences, epilepsy with grand mal on awakening and pure photosensitive epilepsy with mainly generalized tonic clonic seizures. Those in the ECS group were juvenile myoclonic epilepsy, idiopathic photosensitive occipital lobe epilepsy, Panayiotopoulos syndrome and Gastaut type-idiopathic children occipital epilepsy. Photosensitivity was detected in 88% of patients with ECLS and 29% of patients with ECS. ECLS and ECS are relatively common in females. Comparing with ECS, ECLS is found in more epilepsy syndromes. However, ECS and ECLS could exist in the same epilepsy syndrome. ECLS and ECS can be associated or dissociated with photosensitivity. The rate of ECLS with photosensitivity is higher than that of ECS with photosensitivity, suggesting that mechanisms for ECLS, ECS and photosensitivity may be different but correlated.

Hot water epilepsy: Clinical and electroencephalographic features of 25 cases

The aim of this study was to analyze the clinical and electroencephalographic findings for 25 patients with hot water epilepsy. Personal and family history, neurological state, age at onset and types of seizures, provoking factors, bathing habits, EEGs, and neuroimages were all reviewed. Age at onset of seizures ranged from 6 months to 37 years. Twenty patients had complex partial seizures. Eight patients had spontaneous seizures as well; one was a typical case of idiopathic photosensitive occipital lobe epilepsy. One patient described an episode interpreted as nonconvulsive status. In our study group, the pouring of the water over the head and the temperature of the water were the most common triggering factors. A special kind of soap and entry of water into the mouth were determined to be unusual triggering factors. Interictal EEGs revealed epileptogenic abnormalities located over the temporal regions in nine patients. Seventeen patients underwent neuroimaging, mostly cranial magnetic resonance imaging. One had right mesial temporal sclerosis and one cortical atrophy; the others had normal findings. Sixteen patients received antiepileptic drugs, mainly carbamazepine, and remained seizure-free. The high rate of epileptogenic abnormalities localized in the temporal region and the complex partial seizures observed in most of our patients indicate the considerable role of the temporal lobe in hot water epilepsy.

Juvenile myoclonic epilepsy and idiopathic photosensitive occipital lobe epilepsy: is there overlap?

Although epileptic photosensitivity is well known, its genetics and syndromic associations are incompletely understood. Seizures triggered by photic stimulation are usually a manifestation of the idiopathic generalized epilepsies, especially juvenile myoclonic epilepsy (JME), or of the occipital epilepsies. Idiopathic photosensitive occipital epilepsy (IPOE) is a focal epilepsy with colourful elementary visual auras, often with conscious tonic head and eye version; myoclonus is not a feature. All seizures are induced by photic stimuli. We describe four families with phenotypic overlap between JME and IPOE. Families were identified if two or more affected individuals had visual auras and electro-clinical features of an idiopathic epilepsy. Family members underwent detailed electro-clinical assessment. In addition, 40 unrelated JME probands were investigated systematically for unrecognized features of IPOE (visual aura and conscious head version). There were 12 affected individuals in four families; 11 were female. Clinical onset was at 8-21 years of age. Of 10 patients with visual auras, six had conscious head version and five also experienced myoclonic jerks; eight had non-photic induced tonic-clonic seizures (TCS). Of the remaining individuals, one had myoclonic jerks and occipital spikes; the other had TCS without visual aura or myoclonic jerks. Of 10 patients with EEG studies, eight had generalized spike and wave (GSW) and six had occipital spikes. All had photosensitivity with GSW and four had additional occipital spikes. Of the 40 JME probands, six had visual aura and/or conscious head version; five of these were photosensitive. There is overlap between the clusters of clinical features used to diagnose IPOE and JME. Half of the affected individuals in our families with visual aura had myoclonic jerks; the former is characteristic of IPOE and the latter of JME. Importantly, visual aura is not regarded as part of JME, nor myoclonus part of IPOE, but our data emphasize that these symptoms may occur in both disorders. Moreover, two-thirds of individuals with visual aura had spontaneous TCS; the latter feature is not described in IPOE. Additionally, we demonstrate that visual aura and conscious head version are under-recognized features of JME, particularly among photosensitive patients. These findings could be explained by shared genetic determinants underlying IPOE and JME. Understanding the genetic basis of these disorders must account for the striking female predominance, the variable phenotypes associated with photosensitivity and the overlap of clinical features classically regarded as distinguishing focal and generalized syndromes.