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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.

To prospectively study the prevalence of photoparoxysmal response (PPR) and its determinants in epilepsy patients.Consecutive patients, older than 2 years, undergoing EEG from January 2016 to December 2019 were prospectively studied for the presence of PPR. Patients with emergent EEG and those with only sleep record were excluded. Intermittent photic stimulation was performed as per standard techniques with frequencies from 1-30 Hz.Of the 1893 subjects included, 1492 (78%) patients had epilepsy while 401 (22%) had other diagnoses. In epilepsy group, 1028 (68.7%) had focal epilepsy, 343 (21.6%) had generalized epilepsy, while (9.7%) patients had unclassified epilepsy. Overall, 36 (2.2%) patients with epilepsy had PPR. The mean age of these patients was 19.5 ± 9.4 years and 75% were females. PPR was noted in 5 (0.5%) patients with focal epilepsy and 31 (9%) patients with generalized epilepsies [p0.0001; Odds ratio: 20.3 (95% CI, 7.8 - 52.7)]. PPR was noted in 1.5% of treated and 18% of untreated patients with genetic generalized epilepsy (n = 145) and 22% of untreated patients with juvenile myoclonic epilepsy (n = 86). Patients with untreated epilepsy had 17 times higher odds of having PPR [p0.0001; Odds ratio: 17.6 (95% CI, 4.1 - 75.6)].Underlying epilepsy syndrome and treatment status are the two most important determinants of PPR. Variability in these two factors is largely responsible for the variable reported prevalence of PPR.

The authors review the influence of photic stimuli on the generation of epileptic seizures, addressing the first descriptions of the phenomenon and its subsequent exploration. Initially defined in the 1950's, links between intermittent photic stimulation (IPS) and seizures were well understood by the 1970. Since then the increasing exposure to photic stimuli associated with modern life (for instance through TVs, patterns, computer games and electronic instruments with flickering displays) has led to an increased interest in this issue. Diverse stimulation procedures have been described and difference in the effects of stimulation frequencies and types, colour and lighting have been recognised. Approximately 5% of patients with epilepsy have photosensitive epilepsy (PSE). PSE is commoner in younger individuals, more frequent in women, often time-limited, generally easy to treat and closely related to generalised epilepsies, especially Juvenile Myoclonic Epilepsy (JME). Structural and functional studies of PSE indicate abnormalities beyond the frontal lobes and evidence for the role of the visual cortex in human PSE. A reduction in connectivity between prefrontal and frontopolar regions and increased connectivity between occipital cortex and the supplementary motor area may be the basis for triggering motor seizures in JME. Due to the changes observed in such areas, it is hypothesised that photoparoxysmal responses (PPR) could be a final expression of pathogenic phenomena in the striato-thalamocortical system, and possibly a core feature of JME as system epilepsy. The familial transmission of epileptiform responses to IPS is well-recognised, but no clear relation between PSE and specific genes has emerged. Although the influence of ethnic factors on PSE has been widely studied, clear conclusions are still lacking. Pharmacological therapeutic approaches are beyond the scope of this review although preventive measures allowing patients to avoid PS seizure initiation and/or generalisation are discussed. Given the gender/age group most commonly affected by PSE, the risks and benefits of drug treatment need to be carefully weighed up.

Recent changes in the understanding and classification of reflex seizures have fuelled a debate on triggering mechanisms of seizures and their conceptual organization. Previous studies and patient reports have listed extrinsic and intrinsic triggers, albeit their multifactorial and dynamic nature is poorly understood. This paper aims to review literature on extrinsic and intrinsic seizure triggers and to discuss common mechanisms among them. Among self-reported seizure triggers, emotional stress is most frequently named. Reflex seizures are typically associated with extrinsic sensory triggers; however, intrinsic cognitive or proprioceptive triggers have also been assessed. The identification of a trigger underlying a seizure may be more difficult if it is intrinsic and complex, and if triggering mechanisms are multifactorial. Therefore, since observability of triggers varies and triggers are also found in non-reflex seizures, the present concept of reflex seizures may be questioned. We suggest the possibility of a conceptual continuum between reflex and spontaneous seizures rather than a dichotomy and discuss evidence to the notion that to some extent most seizures might be triggered.

Photosensitivity is a typical feature of photosensitive epilepsy which is usually considered a form of idiopathic generalized epilepsy. Partial seizures featuring visual symptoms are rarely reported in photosensitive epilepsy. In this study, we describe 13 neurologically normal patients in whom daytime seizures were always induced by television and began with elementary visual hallucinations, followed frequently by vomiting, headache and then secondary generalization. Three patients additionally reported nocturnal seizures, which have not been described in previous studies. Two of these latter patients had generalized tonic–clonic seizures, the other always awoke from sleep and could describe typical visual hallucinations at the beginning of the seizure. EEG features included normal background activity and occipital spikes or spike-waves in all but two patients. Eight patients also showed generalized epileptiform activity during intermittent photic stimulation. Seizure frequency was low in all. Apart from two patients, who refused treatment, all patients received antiepileptic drugs. Only one patient continued to have rare seizures after treatment; in the others seizure control was achieved with monotherapy. We conclude that reflex occipital lobe epilepsy is an idiopathic form of the benign partial epilepsies, which may overlap with one another.

A recently introduced optometric technique, colorimetry, enables the perceptual effects of ophthalmic tints to be evaluated subjectively, optimized, and then prescribed in tinted spectacles. The new technique is beneficial in reducing visual stress in patients with dyslexia and migraine. We describe an open trial designed to ascertain: (1) whether the colorimetry assessment, as it is now given, is safe for the investigation of photosensitive patients in optometry clinics where colorimetry equipment is most readily available, but where EEG control is not practical; (2) what proportion of patients with photosensitive epilepsy is likely to benefit to the extent already described in individual cases ; (3) whether a tint selected by colorimetry could be shown to reduce the incidence of paroxysmal epileptiform EEG activity in response to flicker and patterns, thereby validating the subjective methods and corroborating the reported seizure reduction. Twenty-four females and nine males (aged 12–43 years) took part. All the patients had suffered visually-provoked seizures, had exhibited a photoparoxysmal response on at least one previous EEG recording, and had received a diagnosis of photosensitive epilepsy. Twenty-two were currently experiencing seizures. A further EEG was recorded in all except seven cases: a routine resting record, followed by hyperventilation. Colorimetry was performed after hyperventilation and before photic stimulation. Twenty-three (70%) reported beneficial effects during colorimetry and were prescribed glasses. There was a preponderance of lenses with a rose or purple colour, in contrast to patients with dyslexia. Seventeen of the 23 patients were available at follow-up, an average of 2.4 years later. Thirteen (57%) reported benefits, and said they were still using the lenses. In six of the 13 the benefits were pronounced, including a reduction of dizziness from fluorescent lighting, elimination of aura when using computer screens etc. Only in three cases was there a reduction in seizures that could reasonably be attributed to the use of lenses; in two of these cases no medications were prescribed, and in the third the medications remained unchanged for four years, two before and two after the introduction of the glasses. In an additional four cases a reduction in seizures was observed but medication had been changed. There was a modest reduction in EEG photosensitivity with the coloured lenses but also to an equivalent or lesser extent with grey in all of the eight patients examined in this way. One patient had seizures during colorimetry, but the seizures were not accompanied by scalp EEG changes.

We performed a retrospective analysis of 17 children with photosensitive seizures (PSS) who had been followed for more than 3 years (mean: 9 years). PSS were verified in all patients by simultaneous video-EEG monitoring. The seizures were precipitated by flickering stroboscopes (14 patients) or were induced by patients themselves (3) with head-nodding in front of illumination, blinking at television or close viewing of striped patterns. PSS consisted of myoclonic seizures (eight patients), generalized tonic-clonic convulsions (5), partial seizures (3) or atypical absence (1). According to the International Classification of Epileptic Syndrome, three patients were classified as having severe myoclonic epilepsy in infancy and five as having juvenile myoclonic epilepsy. The remaining nine could not be categorized as any specific epileptic syndrome. Children with age of the onset of epilepsy at 7 years or younger tended to suffer intellectual deficit in addition to intractable seizures.

s 81 Treatment of photosensitive epilepsy using glasses tinted individually according to their effects on visual perception and asthenopia A.J. Wilkins*, A. Baker*, D. Amin*, S. Smith*, J. Bradford*, S. Boniface”, Z. Zaiwalla¶, C.D. Binnies & D. Fish+ * Medical Research Council Applied Psychology Unit, Cambridge, UK, f National Hospital for Neurology Queen Square, London, UK, * Maudsley Hospital, Denmark Hill, London, UK, SAddenbrookes Hospital, Cambridge, UK and * Park Hospital for Children, Oxford, UK Intuitive calorimetry is a recently introduced technique that enables the perceptual effects of ophthalmic tints to be evaluated subjectively, optimized, and then prescribed in tinted spectacles. The system has proved of benefit in reducing visual stress in patients with dyslexia and migraine. We describe an open trial designed to ascertain: (1) whether the calorimetry assessment, as it is now given, is safe for the investigation of photosensitive patients in optometry clinics where calorimetry equipment is most readily available, but where electroencephalogram (EEG) control is not practical; (2) what proportion of patients are likely to benefit to the extent already described in individual cases of photosensitive epilepsy; (3) whether a tint selected by calorimetry could be shown to reduce the incidence of paroxysmal epileptiform EEG activity in response to flicker and patterns, thereby validating the subjective methods and corroborating the reported seizure reduction. Twenty-four females and nine males (aged 1243 years) took part. All the patients had suffered visually provoked seizures, exhibited a photoconvulsive response on at least one previous EEG recording, and received a diagnosis of photosensitive epilepsy. Twenty-two were currently experiencing seizures. An EEG was recorded in all except seven cases: a routine resting record, followed by hyperventilation. Colorimetry was performed after hyperventilation and before photic stimulation. Twenty-three (70%) reported beneficial effects during calorimetry and were prescribed glasses. Seventeen of these patients were available at follow-up, an average of 2.4 years later. Thirteen (57%) reported benefits, and said they were still using the lenses. In 6 of the 13 the benefits were pronounced, including a reduction of dizziness from fluorescent lighting, elimination of aura when using computer screens, etc. Only in three cases was there a reduction in seizures that could reasonably be attributed to the use of lenses; in two of these cases no medications were prescribed, and in the third the medications remained unchanged for 4 years, two before and two after the introduction of the glasses. In an additional four cases a reduction in seizures was observed but medication had been changed. There was a preponderance of lenses with a rose or purple colour in contradistinction to patients with dyslexia. In 8/S patients there was a modest reduction in photosensitivity with the coloured lenses but also to an equivalent or lesser extent with grey. Only in one case was the reduction clearly greater with the coloured than that with the grey. In another patient lenses of the selected colour were compared with those of other similar colours and reduced the photosensitivity frequency range by a greater amount. One patient had seizures during calorimetry, but the seizures were not accompanied by scalp EEG changes. Reflections on a phrase in King Lear ‘A plague upon your epileptic visage’ Tim Betts* & Hannah Betts’ *Birmingham University Seizure Clinic, Queen Elizabeth Psychiatric Hospital, Birmingham, UK and 7 Lincoln College, Oxford, UK The phrase ‘a plague upon your epileptic visage’ in Shakespeare’s King Lear is considered to be the first use of the word ‘epilepsy’ in the English language (OED) although we have found an earlier reference to the word. The phrase is used by Kent against Oswald: it is clearly meant to be derogatory and raises the interesting question as to whether a particular facial appearance was already equated with epilepsy before the days of Lombroso and phenytoin! However, textual analysis of the following lines after the phrase suggests that the reference may have been to syphilitic sores on the face rather than to epilepsy itself. In King Lear there are clear descriptions of dissociation (‘The Mother’), feigned madness and actual madness (delirium brought on by exposure to the elements). ‘The Mother’, a mixed bag of emotional symptoms which often included nonepileptic seizures (‘Fits of the Mother’) was considered to be an exclusively female disorder and Shakespeare has been credited with first describing it in a male: his source was a polemical report of court proceedings (Samuel Harsnett’s) from which he also obtained his description of feigned madness (the case involved prosecution for carrying out exorcisms).

We describe a 16-year-old female patient affected by photo-induced temporal lobe epilepsy. During intermittent photic stimulation she showed a photoparoxysmal response in the EEG. This case was diagnosed from clinical symptoms, single photon emission computer tomography, and EEG data. The clinical symptoms were relieved by the administration of carbamazepine. As these photoparoxysmal responses were observed not only during photic stimulation, but also when patient was closing her eyes during an eye-opening test in complete darkness, we propose the existence of an alternative pathway such as from the extraocular muscles or orbicularis oculi, or activation of cortical activity due to the change of consciousness by closing eyes in inducing photosensitive epilepsy. We describe an additional case and discuss a novel aspect of photo-induced temporal lobe epilepsy.

Purpose Human photosensitive epilepsy models have been used as proof of principle (POP) trials for epilepsy. Photosensitive patients are exposed to intermittent photic stimulation and the reduction in sensitivity to the number of standard visual stimulation frequencies is used as an endpoint. The aim of this research was to quantify the predictive capabilities of photosensitive POP trials, through a survey of current literature. Methods A literature search was undertaken to identify articles describing photosensitive POP trials. Minimally efficacious doses (MEDs) in epilepsy were compared to doses in the POP trials that produced 50–100% response (ED 50–100 ). Ratios of these doses were calculated and summarised statistically. Results The search identified ten articles describing a total of 17 anti-epileptic drugs. Of these, data for both MED and ED 50–100 were available for 13 anti-epileptic drugs. The average ratio of MED to ED 50–100 was 0.95 (95% CI 0.60–1.30). The difference in MED to ED 50–100 ratios between partial epilepsy (0.82) was not significantly different from that of generalised epilepsy (1.08) ( p =0.51). Conclusion Photosensitive POP trials are a useful tool to quantitatively predict efficacy in epilepsy, and can be useful as early and informative indicators in anti-epileptic drug discovery and development.

Photosensitive epilepsy is relatively rare. However, a large proportion of individuals with epilepsy perceive that they are at an increased risk of a seizure whilst exposed to specific photic material. The difference between perceived and real risk may be due to inadequate education and misinformation. One half of the participants in the present survey could not recall being informed of the result of the 'gold standard' test for photosensitivity--intermittent photic stimulation during an electroencephalogram. Furthermore, approximately one-third of our sample were apparently given inaccurate and overcautious advice about their everyday exposure to photic material. Better information and advice is crucial to improve this situation in the future. The majority of people with epilepsy (>95%) who are not photosensitive can pursue activities that involve flickering or patterned light, encompassing educational, employment and leisure opportunities, without undue concern.

Purpose Photosensitive epilepsy (PSE) is a form of reflex epilepsy characterized by seizures triggered by light. Genetic factors play an important role and some studies have indicated a possible role of the Bromodomain-Containing Protein 2 (BRD2) gene. Our aim was to investigate the relationship between PSE and mutations of the BRD2 gene. Methods Fifty-four PSE patients with normal findings on neurological examination and neuro-imaging studies were included. All had a clear photoparoxysmal response in the EEG as reported by 2 experienced EEG interpreters. We investigated the BRD2 gene by denaturing high performance liquid chromatography followed by direct DNA sequencing. Results We failed to detect any mutations of the BRD2 gene. However, several single-nucleotide polymorphisms (SNPs) were observed in the gene; three of them were novel SNPs. The comparison of the patients showing these SNP changes with the remaining patients suggested a link between carrier status and prognosis. Conclusion Our study did not confirm the presence of the genetic variants previously found to link the BRD2 gene to the idiopathic form of photosensitive epilepsy. SNP changes of the BRD2 gene may be clinically relevant but these findings need to be verified by larger studies.

3D television (TV) and cinema have experienced a recent surge in popularity aided in part by the success of films such as "Toy Story 3" and "Avatar". In parallel with this trend there have been increasing concerns about the safety of 3D TV and cinema for patients with photosensitive epilepsy. General practitioners, paediatricians and neurologists are being consulted about their opinions on the risk of triggering a seizure. Photosensitive epilepsy occurs in 1 in 4000 of the population but the incidence is higher in people aged 7–19 years. We found little evidence in the literature and confusing advice on various websites. We discuss this evidence in an attempt to clarify the advice that health professionals should be giving on this issue. We conclude that 3D cinema and television are only unlikely to trigger seizures in patients with non-photosensitive epilepsy. In young people with photosensitive epilepsy the risk of triggering a seizure is not greater with 3D TV or cinema than with conventional television, and we suggest means by which this risk can be minimised. We suggest removing 3D glasses when watching conventional TV to prevent the eyes from picking up flicker. Unfortunately there is currently insufficient evidence to draw more formal conclusions and clinical trials would be of great benefit.