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We present the main provisions and ideas of the quasi-particle description concept of the discrete time dynamics of complex non-physical systems, developed within the frameworks of Memory Functions Formalism. The initial signal generated by a complex system is represented as time variations of the quasiparticle movement coordinate in one-dimensional space. The novelty of the proposed concept lies in the derivation of analytical expressions for chains of finite-difference equations relating time correlation functions and statistical memory functions for a sequence of derivatives of the temporal dynamics of the quasiparticle coordinates: velocity, acceleration, energy, energy flow. The proposed concept was tested for the study of correlations and statistical memory effects, as well as relaxation patterns, in the dynamics of neuromagnetic responses of healthy subjects and a patient with photosensitive epilepsy in response to a red-blue flickering stimulus. The results obtained allow establishing informationally significant sensors and the corresponding zones of localization of the human cerebral cortex for the analysis and diagnosis of photosensitive epilepsy., Представлены основные положения и понятия концепции квазичастичного описания дискретной временной динамики сложных нефизических систем, развиваемой в рамках формализма функций памяти. На основе техники проекционных операторов Цванцига–Мори получено аналитическое выражение цепочки конечно-разностных уравнений для набора исходных временных корреляционных функций и функций статистической памяти временных вариаций характеристик перемещения квазичастицы в одномерном пространстве. Проведена апробация предложенной концепции к исследованию корреляций и эффектов статистической памяти, а также релаксационных закономерностей в динамике нейромагнитных откликов здоровых испытуемых и пациента с фоточувствительной эпилепсией в ответ на красно-голубой мерцающий стимул.

To determine and quantify the effect of blue lenses (Z1) on photosensitivity (PS) suppression in patients aged 5-18 years with and without epilepsy.The retrospective cohort study was carried out in 100 pediatric patients aged 5-18 years with grade 4 PS assessed with EEG for medical indications. All EEG procedures were carried out and recordings assessed by two independent researchers. The study cohort was divided into groups with and without the diagnosis of epilepsy. The overall effect of the Z1 lenses on photoparoxysmal response (PPR) was determined by directly comparing the maximum discharge values in each patient without and with Z1 lenses in a within-subject design yielding the index of overall improvement (IOI). The differences in PS suppression by brain region and side were assessed by an additional between-subject comparison of age groups (below and above 14 years). Then, overall findings were compared with the PPR change criteria developed in 2006 by Capovilla (PPR disappearance, persistence, or attenuation) which warranted another subset analysis. Finally, in a between-subject design, we assessed whether the presence of epilepsy affects the intensity of PPR in children with PS, compared to non-epilepsy children.The IOI in the entire cohort was 66.1±2.5% (P0.001). There were no significant differences in IOI between the left and right hemispheres, between the age groups, and between the epilepsy and non-epilepsy groups, despite some qualitative variation. With reference to literature findings, whereas median IOI were comparable in PPR disappearance and attenuation subsets, they differed significantly from the median IOI in the PPR persistence subset.Using Z1 lenses results in neither a complete PPR disappearance, nor a complete lack of effect. However, the correlation between the quantified PS suppression and the Z1 filter may be expected to become a valuable piece of information for both clinicians and manufacturers.

Introduction Both levetiracetam (LEV) and brivaracetam (BRV) eliminate the electroencephalogram photoparoxysmal response (PPR) in the human phase IIa photosensitivity model of epilepsy. The physiochemical properties of BRV differ from those of LEV, having higher potency and lipophilicity plus 10- to 15-fold greater affinity for synaptic vesicle glycoprotein 2A. Objective We compared the rapidity of the effects of both drugs in the central nervous system (CNS) of patients with photosensitive epilepsy using time to PPR elimination post-intravenous infusion as a pharmacodynamic endpoint. Methods Using a randomized, double-blind, two-period, balanced, crossover design, we tested patients with photosensitive epilepsy with equipotent milligram doses of intravenous LEV 1500 mg versus BRV 100 mg post-15-min intravenous infusion (part 1) and post-5-min intravenous infusion (part 2, same doses). Eight patients per part were deemed sufficient with 80% power to determine a 70% reduction for intravenous BRV:LEV intrapatient time ratio to PPR elimination, with a 0.05 two-sided significance level. Plasma antiseizure medicine concentrations were measured using liquid chromatography/mass spectrometry. Results Nine patients [six women; mean age 27.8 years (range 18–42)] completed the study; seven of these participated in both parts 1 and 2. In 31 of 32 instances, patients experienced PPR elimination. In mixed-effects model time analysis, BRV eliminated PPRs more quickly than did LEV (median 2 vs. 7.5 min, respectively). However, no statistically significant difference in BRV:LEV time ratio to PPR elimination was observed for two of our multiple primary outcomes: for the 15-min infusion alone (p = 0.22) or the 5-min infusion alone (p = 0.11). However, BRV was faster when we excluded an outlier patient in part 1 (p = 0.0016). For our remaining primary outcome, parts 1 and 2 data combined, the median intrapatient BRV:LEV time ratio was 0.39 [95% confidence interval (CI) 0.16–0.91], i.e., PPR elimination was 61% faster with BRV, p = 0.039. PPR was completely eliminated in ≤ 2 min in 11 patients with BRV and in four patients with LEV. No period or carryover effects were seen. No serious or severe adverse effects occurred. At PPR elimination (n = 16), median plasma [BRV] was 250 ng/mL (range 30–4100) and median plasma [LEV] was 28.35 μg/mL (range 1–86.7). Conclusion Outcome studies directly comparing LEV and BRV are needed to define the clinical utility of the response with BRV, which was several minutes faster than that with LEV. Clinical trials ClinTrials.gov Identifier = NCT03580707; registered 07-09-18 Electronic supplementary material The online version of this article (10.1007/s40263-020-00761-1) contains supplementary material, which is available to authorized users.

This review assesses the risk of a photic-induced seizure in a child during viewing of 3D (binocular 3 dimensional, stereoscopic) movies or games, either on standard video displays or when wearing a virtual reality (VR) headset. Studies published by pediatric epilepsy experts emphasize the low risk of 3D viewing even for children with known photosensitive epilepsy (PSE). The low incidence of PSE is noteworthy because the number of hours devoted to 2D or 3D screen viewing and/or VR headset use by children worldwide has increased markedly over the last decade. The medical literature does not support the notion that VR headset use poses a risk for PSE.

International Conference on Soft Computing Models in Industrial and Environmental Applications (SOCO 2021) (16th. 2021. Bilbao), This research has been funded by the Spanish Ministry of Science and Innovation under project MINECO-TIN2017-84804-R, PID2020-112726RB-I00 and from the State Research Agency (AEI, Spain) under grant agreement No RED2018-102312-T (IA-Biomed). Additionally, by the Council of Gijón through the University Institute of Industrial Technology of Asturias grant SV-21-GIJON-1-19.

Laser photocoagulation is a safe method for the treatment of retinal disorders. We present a case of a 21-year-old woman with high myopia, retinal detachment in the right eye, and bilateral lattice degeneration. She underwent surgical repair in the right eye followed by bilateral retinal laser therapy. During laser photocoagulation of the left eye, she experienced a generalized tonic-clonic seizure for the first time in her life. She had a positive family history of epilepsy. Neurological examination and brain magnetic resonance imaging findings were normal, but an electroencephalogram revealed epileptogenic discharges, more frequent during photostimulation. She avoided flickering lights during the 2-year follow-up, without seizure recurrence. Approximately 5% of patients with epilepsy have photosensitive epilepsy, of whom a considerable proportion will experience seizures only during exposition to flashing lights. Laser photocoagulation was already successfully employed in an animal model of photosensitive epilepsy. Personal or family history of photosensitivity warrants a neurological consultation before retinal treatment with laser therapy. RESUMO Fotocoagulação a laser é método seguro para tratamento de retinopatias. Apresentamos o caso de uma mulher de 21 anos com alta miopia e degeneração lattice bilateral que sofreu descolamento de retina no olho direito e foi submetida a tratamento cirúrgico e ulterior laserterapia. Durante a fotocoagulação no olho esquerdo, ela teve uma convulsão tônico-clônica generalizada, a primeira em sua vida. Havia história familiar de epilepsia. O exame neurológico e a ressonância magnética de en céfalo foram normais, mas o electroencefalograma revelou descargas epileptogênicas, mais frequentes durante a fotoesti mulação. Ela evitou luzes piscantes durante os 2 anos subsequentes, sem recorrência de convulsões. Cerca de 5% dos pacientes com epilepsia têm fotossensibilidade. Proporção considerável deles terá convulsões somente durante exposição à luz piscante. Fotocoagulação a laser já foi empregada como modelo animal de sucesso para epilepsia fotossensível. Presença de fotossensibilidade na história pessoal ou familiar deve merecer avaliação neurológica antes do tratamento retiniano.

A 15-year-old girl was admitted to the emergency room because of a bilateral tonic-clonic seizure. The family reported that the episode began with rapid hand movements in front of the patient's eyes while staring at the sun. The patient has a history of multiple admissions in the emergency department due to similar events since the age of eight. Most occurrences were associated with episodes of frustration. The review of the literature has shown that this type of phenomenon, designated in some studies by sunflower syndrome, may be overlooked in patients with photosensitive epilepsy. Despite the unknown etiology, there are several reasons why patients experience this type of behavior, and thus a multidisciplinary approach is needed.Uma jovem de 15 anos foi admitida no Serviço de Urgência após ter sofrido crise epiléptica tónico-clónica bilateral. A família relatou que o episódio surgiu na sequência de ter iniciado movimentos rápidos das mãos na frente dos olhos enquanto olhava para o sol. A doente havia sido assistida, por diversas vezes, no Serviço de Urgência, devido a eventos semelhantes, desde os oito anos de idade. A maioria dos episódios estava associada a episódios de frustração. A revisão da literatura mostrou que esse tipo de fenómeno, designado em alguns estudos por sunflower syndrome, pode ser desvalorizado em doentes com epilepsia fotossensível. Apesar da etiologia desconhecida, existem várias razões pelas quais os doentes apresentam este tipo de comportamento, enfatizando a necessidade de uma abordagem multidisciplinar.

The study aimed to review the clinical, radiological, and pathological findings and electroencephalogram (EEG) of pediatric epilepsy patients with temporal onset focal seizures induced by intermittent photic stimulation (IPS). Four patients with temporal onset photosensitivity focal seizures were analyzed. Three (75%) of the four patients were female. The average age of seizure-onset was 4.4 years. The interictal EEG showed both generalized and focal spike and waves in one patient and focal or multifocal spike and waves alone in three patients. Photoparoxysmal response (PPR) was evoked in all patients and showed generalized discharges (patients 2–4), both generalized and posterior discharges (patient 1). Both generalized and focal discharges could coexist in interictal discharges and PPR. The sensitive frequencies of PPR and photoconvulsive response (PCR) were 12–30 and 10–16 Hz, respectively, which were close to the occipital rhythm. In all patients, the onset of PCR was recorded, namely, the left anterior and mesial temporal lobe (TL), the left posterior TL, and the whole left TL, which showed two forms: the seizure of two patients was the onset of slow waves in the temporal area without spreading generalized discharges (patients 1 and 4), and the other one was fast rhythmic activities in the temporal area, spreading to the occipital area or gradually evolving into the generalized discharges (patients 2 and 3). During follow-up, except for patient 3 who had occasional seizures, the seizures of the remaining patients were under control. Temporal onset focal seizures could be induced by IPS. Temporal onset photosensitivity seizures were mostly easy to control with antiseizure drugs.

Fenfluramine hydrochloride, initially utilized as a weight loss drug in the 1970s and later removed from the market for adverse cardiopulmonary side effects, has since been repurposed as an antiseizure medicine (ASM). The potential antiseizure effects of fenfluramine were first identified in patients with photosensitive epilepsy in the 1980s but it was not rigorously explored as a treatment option until 30 years later. Compared with other ASMs, fenfluramine offers a novel mechanism by acting on serotonin and σ1 receptors, demonstrated in vitro and in vivo in animal models of Dravet syndrome. Results from a large double-blind, placebo-controlled trial demonstrated robust efficacy for seizure reduction in patients with Dravet syndrome, and met its primary endpoint with the 0.7 mg/kg/day fenfluramine treatment group experiencing a 62.3% or greater reduction in mean monthly convulsive seizure frequency (MCSF) compared with placebo. Here we provide a comprehensive review of the preclinical and clinical activity of fenfluramine, a recently approved drug for treatment of epilepsy in patients with Dravet syndrome.

Reflex seizure provoked by light or pattern stimulation are an interesting and, at times, difficult to treat entity. Such seizures occur in patients with a variety of well-described epileptic syndromes, although in most spontaneous seizures are also described. This paper attempts to describe epileptic syndromes with primarily light or pattern provoked seizures.

Background Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome. Methods In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0.2 mg/kg per day, or fenfluramine 0.7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0.7 mg/kg per day group versus placebo; 0.2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863. Findings Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9.0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0.2 mg/kg per day (39), fenfluramine 0.7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74.9% in the fenfluramine 0.7 mg/kg group (from median 20.7 seizures per 28 days to 4.7 seizures per 28 days), 42.3% in the fenfluramine 0.2 mg/kg group ( from median 17.5 seizures per 28 days to 12.6 per 28 days), and 19.2% in the placebo group ( from median 27.3 per 28 days to 22.0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0.7 mg/kg per day showing a 62.3% greater reduction in mean MCSF compared with placebo (95% CI 47.7-72.8, p

Photosensitive is probably caused by multiple factors including gender, familiar, etc. We aim to study the clinical and EEG features of Chinese Han patients with photosensitivity. A total of 5482 consecutive patients with possible epilepsy from 3 center in China. Of the 73 patients with PPR to IPS, 48 were female. 69.9% patients were evoked by frequency ranged 8 Hz–25 Hz, with accompanying seizures in 13 patients. 6 of 9 patients with eyes closure sensitivity experienced epileptic seizures during IPS. We found some new features: 1) The patients with eyes closure sensitivity apt to experience electro-clinical seizures provoked by IPS; 2) Female epilepsy patients with PPR and ECS maybe difficult to be seizure free. Preventive measures for related seizures should be performed to the patients with generalized PPR, upper threshold evoking frequency, and eyes closure sensitivity when they received the IPS.

ObjectiveTo evaluate the effect of cenobamate in patients with photoparoxysmal-EEG response (PPR) to intermittent photic stimulation (IPS) as proof of principle of efficacy in patients with epilepsy.MethodsIn this multicenter, single-blind study, adults with photosensitive epilepsy, with/without concomitant antiepileptic drug therapy, underwent IPS under 3 eye conditions after a single dose of placebo (day −1, day 2) or cenobamate (day 1; 100, 250, or 400 mg). Complete suppression was a standardized photosensitivity range reduction to 0 over ≥1 time points for all eye conditions. Partial suppression was a ≥3-point reduction over ≥3 testing times vs the same time points on day −1 in ≥1 eye condition. Pharmacokinetics and safety were assessed.ResultsOf 6 evaluable patients, 5 reentered to receive higher doses. Cenobamate 100 mg produced partial suppression in 1 of 3 patients; 250 mg produced complete suppression in 1 of 4 and partial suppression in 4 of 4 patients; and 400 mg produced complete suppression in 1 of 4 and partial suppression in 2 of 4 patients. PPR was consistently reduced on days 1 and 2 (>24 hours after cenobamate) vs day −1 (placebo) with the 250- and 400-mg doses. Area under the plasma concentration-time curve (before dose to last measurable concentration) values between 201 and 400 μg/h/mL resulted in partial suppression in 4 of 6 (66%) patients. Most common adverse events were dizziness and somnolence.ConclusionsThis proof-of-principle study demonstrated that cenobamate is a potentially effective product for epilepsy.ClinicalTrials.gov identifierNCT00616148.Classification of evidenceThis study provides Class III evidence that, for patients with photosensitive epilepsy, cenobamate suppresses IPS-induced PPR.

Photosensitive epilepsy is the most common subset of reflex epilepsy in humans. It is characterized by an abnormal electroencephalogram trait known as photoparoxysmal response (PPR) corresponding to ictal symptomology in response to intermittent photic stimulation. Increased exposure to photic stimulation through technological and societal advance has had a significant impact on the incidence and interest in photosensitive epilepsy. Paralleled scientific developments have deepened our understanding of the neurophysiology underlying photosensitivity, especially in the context of deep genomic sequencing and neuroimaging. Furthermore, given the relatively predictable nature of photosensitive epilepsy, there is substantial interest in translating advancements in this field to epilepsy as a whole. Herein, we comprehensively review the epidemiology, clinical features and novel insights into the mechanism behind photosensitive epilepsy with a focus on the clinical implications of new advancements.

Purpose: Recently, altered visual cortical processes i.e., lack of habituation to visual evoked potentials (VEP), has been highlighted in both photosensitive epilepsy and in a specific i.e., analytic mode of processing visual inputs. In this study we aimed at evaluating the relationship between photosensitivity (PS) and analytic style of processing visual information, in a sample of 30 patients with Idiopathic Generalized Epilepsy (IGE) and matched healthy controls. Methods: At our Epilepsy unit of the Sapienza University of Rome, we consecutively enrolled 15 patients with IGE with PSand matched them with 15 patients with IGE without PS and 15 Healthy Volunteers. All patients underwent EEG recording in basal conditions during hyperventilation (3 Min), and intermittent light stimulation. The most effective frequencies comprised from 12 to 16 Hz. The instruments used to gather psychological cognitive behavioral data, consisted of participation in two tests: the Sternberg-Wagner Self-Assessment Inventory and the Mariani Learning Style Questionnaire. Results: Compared to controls, both IGE groups show significantly higher scores for the analytic style (One-way ANOVA, F(2,44) = 110.3, p < 0.0001). Epilepsy groups thereby showed very distinctive cognitive styles as measured with the Sternberg test. In the visual style, scores of the photosensitive Individuals with IGE were significantly higher than the non-photosensitive individuals with IGE (p < 0.0001, Tukey's post hoc test). Conclusions: An association between analytic style of processing visual information and PS in IGE has been shown. The common neurophysiological features between these two factors, suggest the possibility to evaluate this cognitive behavior as a potential target for nonpharmacological therapeutic strategies in photosensitive epilepsy.

Objective Red-light filtering lenses represent an additional option to medication in photosensitive epilepsy. Blue lenses (Clarlet Z1 F133) can dramatically reduce seizure frequency, with a substantial restriction in luminance that can limit their applicability in daily life. We investigated the efficacy of 4 blue lenses with higher transmittance and reduced chromatic distortion in abolishing the photoparoxysmal EEG response (PPR) compared to the gold-standard Z1 lenses. Methods We reviewed EEG data during photic-and pattern stimulation in 19 consecutive patients (6–39 years) with photosensitivity (PS). Stimulation was performed at baseline and while wearing Z1 and the four new lenses. Lenses were tested in the same session by asking the patient to wear them in a sequentially randomized fashion while stimulating again with the most provocative photic/pattern stimuli. The primary outcome was the change in the initial PPR observed for each lens, categorized as no change, reduction, and abolition. Results Photosensitivity was detected in 17 subjects (89.5%); pattern sensitivity (PtS) was identified in 14 patients (73.7%). The highest percentages of PPR abolition/reduction were observed with Z1, for both PS and PtS. Regarding the new lenses, B1 + G1 offered the best rates, followed by B1 + G2. B1 + G3 and B1 showed lower efficacy rates, particularly for PtS. In the comparative analysis, no significant differences in PPR suppression were detected between the five lenses for PS. For PtS, the capacity of Z1 for PPR abolition was significantly higher compared with B1 + G3 and B1. Conclusions This preliminary study suggests efficacy of the new group of blue lenses with potentially greater tolerability, particularly in regions with fewer sunlight hours during winter. In line with the current trend for personalized approach to treatment, this study suggests that in some patients there might be scope in extending the testing to offer the lens with the higher transmittance effective in abolishing the PPR.

As shown in cases of photosensitive epilepsy, audio-visual stimuli can have various effects on the human body. However, until now, there have been no reports investigating the effect of television commercials on the human body. In this study, for which we obtained ethical approval, we are the first ones to investigate the effect of television commercials on the human cardiovascular and autonomic nervous systems. Cardiovascular and autonomic nervous functions were evaluated using the human face blood flow analyzing system invented in Tohoku University (Jpn.Pt. 4789203, 5161671, 5390851, 5408751). No epilepsy and no patho-physiological reactions were observed after viewing of soft TV commercials including commercials from the advertising awards. Autonomic nerve responses were shown to be altered depending on the interests and preferences of the viewer. Our results suggest that assessing the response of the human body to TV commercials will become a key aspect of the process of creating TV commercials.

Paroxysmal activity, namely “generalized EEG expressed spike wave discharges,” has been closely related to generalized epilepsies. However, it is known that focal discharging lesions can cause both focal and generalized seizures and that “auras”—the first prominent symptom giving a clear indication of localized seizure onset—were frequently found in patients with Generalized Tonic-Clonic Seizures (GTCS) or with Idiopathic Generalized Epilepsy (IGE). Also, focal EEG epileptiform events have been consistently found in long-lasting follow-up studies of patients with generalized seizures. This also applies to patients with photosensitive epilepsy in which visual aura is frequent. Studies on the transitions between brain activity at rest and during IPS showed that the transition to seizure activity in photosensitive patients is preceded by changes in the dynamics of brain systems in the course of intermittent photic stimulation. An enhancement of phase synchrony namely on gamma band EEG frequencies related to the frequency of stimulation, preceded the stimulation trials that evolve into PPRs. This is related to the physical characteristics of the stimuli: type and frequency. Such stimuli characteristics interfere with the generation of high frequency rhythms (gamma band) giving origin to local modifications within the visual cortex. In certain conditions, such rhythms could be phase synchronized by the persistence of IPS stimulation giving origin to a focal (photosensitive) epileptic event frequently followed by rapid generalization.

Photosensitive epilepsy is a rare reflex epilepsy characterized by seizures in photosensitive individuals. The incidence has been reported as 1.1/100,000 persons per year among the general population, representing about 2% of all new cases of epilepsy. This chapter focusses on the geographical distribution of scientific and medical studies on photosensitive epilepsy published across the world over the last 11 years (between November 1, 2008 and January 31, 2019). Searches were conducted in PubMed using the following key terms in the title/abstract: “photosensitivity” OR “photosensitive epilepsy”, with “HUMANS” as a filter. A total of 465 articles were identified from the initial search in PubMed. After reviewing all full-text articles and excluding papers about other reflex epilepsy, a total of 164 papers remained for analysis. The largest number of selected articles was produced by European authors (n = 96). The American continent (n = 31) followed, then papers from Asia (n = 29), and a modest contribution also came from the Oceanic continent (n = 8). This review clearly indicates the need for more research on photosensitive epilepsy in more diverse countries and in groups of persons of different ethnic backgrounds. Recommendations are also proposed in order to help facilitate an increase in the number of countries in which research is carried out on photosensitive epilepsy.

Photosensitive epilepsy occurs in a variety of epilepsy syndromes, with different degrees of severity. Management of provocative stimuli, as well as pharmacological treatment both play important roles in prevention and treatment. Non-pharmacologic methods for treatment and prevention of photosensitive seizures include stimulus control and specialized lenses, as well as limiting exposure to alcohol and sleep deprivation. Important factors for non-pharmacologic management include viewing television from a safe distance, limiting provocative factors such as extended viewing of television or playing of video games, and recognition of visual symptoms or myoclonic jerks to remove themselves from the provocative stimulus. For pharmacological management, valproic acid is supported by extensive past studies as first line treatment for photosensitive epilepsy. Levetiracetam shows suppression of the photoparoxysmal response (PPR) and is also an effective agent. Lamotrigine, vigabatrin, and carisbamate, all reduce the PPR, and are reasonable choices for treatment of photosensitive epilepsy, depending on other factors such as associated epilepsy syndrome. Other pharmacologic agents which may be useful include ethosuximide, carbamazepine, lacosamide (particularly in JME), and clobazam. In summary, there many useful preventative and pharmacological treatment possibilities for patients with photosensitive epilepsy. Careful management of provocative factors, as well as appropriate use of anti-seizure medications, will provide optimal management.

The presence of paroxysmal abnormalities of brain electrical activity provoked by intermittent photic stimulation, is an age-dependent EEG pattern usually first seen in childhood and adolescence. Indirect evidence suggests that this maps onto the time-course of the maturation of excitatory and inhibitory brain systems. Recent studies have confirmed the role of abnormal gating mechanisms in the abnormal susceptibility of the posterior cortex to visual stimuli in young patients with photosensitive epilepsy. Similarly, the later maturation of the parvocellular systems which has been associated with the photoparoxysmal EEG response might account for the low prevalence of photosensitivity in the very young patients. From the clinical perspective, while photosensitivity has a preferential onset in pediatric age, it tends to persist in adulthood, with two-thirds of the patients continuing to show the EEG trait even though 85% of them will no longer experience overt clinical seizures. The data presented in this chapter give an account of the role of maturational progression in the manifestations of photosensitivity at mesoscopic level and their integration with genetic data might provide a clearer account of the variability in genotype/phenotype association seen in photosensitive patients.

Photosensitive epilepsy is commoner in younger individuals, strongly inherited, more frequent in women, often time-limited, and closely but imperfectly related to generalised epilepsies, especially Juvenile Myoclonic Epilepsy (JME). EEG changes triggered by photic stimulation represent a useful marker of the trait. The genetics and pathophysiology of EEG photosensitivity are as yet incompletely understood but ongoing genetic searches and functional imaging studies continue to enhance our understanding. When EEG photic stimulation is carried out by utilising a consistent protocol, much more useful information is elicited than merely the presence or absence of photosensitivity. When executed carefully and consistently, quantification of the EEG photoparoxysmal response as a “Standardised Photoparoxysmal Response” (SPR) is possible. Although the SPR is non-linear, it is an ordinal single digit which quantitates the amount of photosensitivity as the “SPR”. The ability to quantitate photosensitivity then confers utility of the EEG PPR test as a predictor of likely AED efficacy and as a marker of longitudinal AED effectiveness.