Suppressive Efficacy by a Commercially Available Blue Lens on PPR in 610 Photosensitive Epilepsy Patients

Photosensitivity and self-induction in patients aged 50 and older

OBJECTIVE

Photosensitivity is known to occur predominantly in children and adolescents and with a clear female predominance. Little is known on the prevalence of photosensitivity in older patients (50+) and its phenotypical appearance.

METHODS

A retrospective observational study was performed investigating the prevalence of a photoparoxysmal EEG response (PPR) on at least one EEG during the period 2015-2021. Data were gathered from patients aged 50 years and older by retrieving clinical and EEG characteristics from existing medical records. Data on photosensitivity-related symptoms in daily life were gathered with telephone interviewing.

RESULTS

In 248 patients a PPR had been elicited, of whom 16 patients (6.5%) were 50 years or older. In older patients, photosensitivity was a persistent feature of childhood-onset epilepsy (n = 8), of adult-onset epilepsy (n = 7), or an incidental finding (n = 1). In the 50+ group, 56% of photosensitive patients was female, whereas 72% in the total PPR-group. In six of 16 older patients, eye closure sensitivity was observed; two of these patients reported self-induction. Symptoms of photosensitivity in daily life were present in eight out of nine patients who consented in a telephone interview. For seven of these patients, wearing sunglasses was helpful.

SIGNIFICANCE

Female preponderance for photosensitivity was not found in epilepsy patients of 50 years and older. In 44% of the older photosensitive patients in this series, the PPR was a feature of adult-onset epilepsy. Symptoms of photosensitivity in daily life in older patients with epilepsy seem comparable to those in younger patients, and thus worthwhile to diagnose and treat them equally.

Evaluating the Potential of Light Exposure on Reducing the Frequency of Epileptic Seizures

Epilepsy is one of the most common and devastating neurological disorders that causes unprovoked, recurrent seizures arising from excessive synchronized neuronal discharging. Although antiepileptic drugs (AEDs) reduce the frequency of epilepsy seizures, drug-refractory epileptic patients exert resistance to AEDs, resulting in treatment difficulty. Moreover, pharmacological treatments do not show satisfactory results in response to photosensitive epilepsy. In the recent era, light therapy emerged as a potential non-pharmacological approach for treating various diseases, including depression, seasonal affective disorders, migraine, pain, and others. Several studies have also shown the potential of light therapy in treating epilepsy. In addition, Red light evokes epilepsy seizures. Blue lenses filter the red light and significantly suppress the frequency of epilepsy seizures. However, the effects of green light on the frequency of epileptic seizures are not studied yet. In addition, light-activated gene therapy or optogenetics also emerged as a possible option for epilepsy treatment. Animal models have shown the therapeutic possibilities of optogenetics and light therapy; however, human studies addressing this possibility are still vague. This review provides the beneficial effects of light in reducing seizure frequency in epilepsy patients. A limited number of studies have been reported so far; therefore, light therapy for treating epilepsy requires more studies on animal models to provide precise results of light effects on seizures.

A comprehensive narrative review of epilepsy with eyelid myoclonia

Epilepsy with eyelid myoclonia (EEM) is a generalized epilepsy syndrome with childhood-onset and 2:1 female predominance that consists of: 1. eyelid myoclonia with or without absence seizures, 2. eye closure induced seizures or EEG paroxysms, 3. clinical or EEG photosensitivity. While eyelid myoclonia is the disease hallmark, other seizure types, including absence seizures and generalized tonic-clonic seizures, may be present. It is thought to have a genetic etiology, and around one-third of patients may have a positive family history of epilepsy. Recently, specific genetic mutations have been recognized in a minority patients, including in SYNGAP1, NEXMIF, RORB, and CHD2 genes. There are no randomized controlled trials in EEM, and the management literature is largely restricted to small retrospective studies. Broad-spectrum antiseizure medications such as valproate, levetiracetam, lamotrigine, and benzodiazepines are typically used. Seizures typically persist into adulthood, and drug-resistant epilepsy is reported in over 50%.

Electroclinical characteristics of photosensitive epilepsy: A retrospective study of 31 Chinese children and literature review

Objective

The objective of this study was to better understand the clinical features of photosensitive epilepsy (PSE) in Chinese children.

Methods

Thirty-one children with PSE were screened out of 398 children with epilepsy who were consecutively diagnosed by the video-electroencephalogram (VEEG) monitoring method and by using an intermittent photic stimulation (IPS) test. Their EEGs and clinical features were retrospectively analyzed, and their treatment outcomes were followed up.

Results

PSE accounted for 7.79% (31/398) of children with epilepsy during the observation period in our single epilepsy center. The male to female ratio of PSE was 1:3.43, and the average seizure onset age was 7.8 ± 3.28 years. The highest range of frequency sensitivity of the IPS test for the induction of EEG epileptic discharge or electroclinical seizures was within 10-20 Hz. Electroclinical seizures were induced in 41.94% (13/31) of PSE patients by using the IPS test, while EEG discharge without clinical seizures was induced in 58.06% (18/31) of PSE patients. Among all PSE patients, an IPS-positive reaction in the eye-closure state was induced in 83.87% of patients, and this rate was significantly higher than that in the eye-opened state (41.94%) or eye-closed state (35.48%). (Eye-closure IPS stimulation means: make the subjects close their eyes at the beginning of each stimulation, open their eyes at the end of the stimulation, and close their eyes again at the beginning of the next stimulation, and so on. While Eye-closed IPS stimulation means the stimulation is started after 5 s of eye closure, and the subjects are kept closed throughout the whole process.) The common and effective drugs used for single or combined therapy in PSE children were valproic acid and levetiracetam.

Conclusion

This study provides some useful information about electroclinical characteristics in a cohort of 31 PSE children. It may be beneficial for pediatric neurologists in terms of paying more attention to PSE and correctly dealing with it.

Visually sensitive seizures: An updated review by the Epilepsy Foundation

Light flashes, patterns, or color changes can provoke seizures in up to 1 in 4000 persons. Prevalence may be higher because of selection bias. The Epilepsy Foundation reviewed light-induced seizures in 2005. Since then, images on social media, virtual reality, three-dimensional (3D) movies, and the Internet have proliferated. Hundreds of studies have explored the mechanisms and presentations of photosensitive seizures, justifying an updated review. This literature summary derives from a nonsystematic literature review via PubMed using the terms "photosensitive" and "epilepsy." The photoparoxysmal response (PPR) is an electroencephalography (EEG) phenomenon, and photosensitive seizures (PS) are seizures provoked by visual stimulation. Photosensitivity is more common in the young and in specific forms of generalized epilepsy. PS can coexist with spontaneous seizures. PS are hereditable and linked to recently identified genes. Brain imaging usually is normal, but special studies imaging white matter tracts demonstrate abnormal connectivity. Occipital cortex and connected regions are hyperexcitable in subjects with light-provoked seizures. Mechanisms remain unclear. Video games, social media clips, occasional movies, and natural stimuli can provoke PS. Virtual reality and 3D images so far appear benign unless they contain specific provocative content, for example, flashes. Images with flashes brighter than 20 candelas/m² at 3-60 (particularly 15-20) Hz occupying at least 10 to 25% of the visual field are a risk, as are red color flashes or oscillating stripes. Equipment to assay for these characteristics is probably underutilized. Prevention of seizures includes avoiding provocative stimuli, covering one eye, wearing dark glasses, sitting at least two meters from screens, reducing contrast, and taking certain antiseizure drugs. Measurement of PPR suppression in a photosensitivity model can screen putative antiseizure drugs. Some countries regulate media to reduce risk. Visually-induced seizures remain significant public health hazards so they warrant ongoing scientific and regulatory efforts and public education.

Successful use of perampanel in GABRA1-related myoclonic epilepsy with photosensitivity

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Generalized epilepsies with variants in GABRA1 may be a treatment challenge when myoclonus remains drug-resistant.

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Photosensitivity may be particularly disabling and is without feature-specific treatments.

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We describe an adolescent with GABRA1 mutation and photosensitivity who improved with PER.

Pathogenic variants in gamma-aminobutyric acid type A receptor subunit alpha1 (GABRA1) is a protein coding gene that has been associated with a broad phenotypic spectrum of epilepsies. These have ranged from mild generalized forms to early-onset severe epileptic encephalopathies. Both in mild and in severe forms, tonic-clonic and myoclonic seizures with generalized spike and wave discharges and photoparoxysmal responses are common clinical manifestations. We present the case of a 14-year-old girl referred to our clinic with uncontrolled epilepsy. She was found to carry a heterozygous variant (c.335G > A) in GABRA1, already described in the literature and classified as “pathogenic” according to ACMG guidelines. The patient showed severe drug resistance with seizures often triggered by photic stimulation. The introduction of perampanel therapy led to overall reduction of the focal and generalized myoclonic seizures and complete clinical control of the light-triggered seizures.

To our knowledge this is the first report of perampanel efficacy in photosensitive epilepsy, and in particular in the presence of a GABRA1 variant. New evidence is needed to confirm our findings in this case.

The quantitative effect of blue lenses on pediatric photoparoxysmal response - An electroencephalographic cohort study

PURPOSE

To determine and quantify the effect of blue lenses (Z1) on photosensitivity (PS) suppression in patients aged 5-18 years with and without epilepsy.

METHODS

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.

RESULTS

The IOI in the entire cohort was 66.1±2.5% (P<0.001). 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.

CONCLUSION

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.

Efficacy of color lenses in abolishing photosensitivity: Beyond the one-type-fits-all approach?

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.

Epilepsy in "Sunflower syndrome": electroclinical features, therapeutic response, and long-term follow-up

BACKGROUND

Sunflower syndrome (SFS) is a rare childhood-onset generalized epilepsy characterized by photosensitivity, heliotropism, and drug-resistant stereotyped seizures maybe self-induced by hand-waving maneuvers. Data on the long-term prognosis are scantly and evidence over best treatment strategies is lacking.

METHODS

We retrospectively describe the electroclinical features, and therapeutic response in a group of 21 patients with SFS, without intellectual disability.

RESULTS

16 patients were female (67%), with a median age at onset of 7 years. In all patients, ictal episodes began with sun-staring, and hand-waving in front of the sunlight, accompanied by brief typical absence seizures. 17 patients (81%) showed interictal EEG abnormalities, mainly characterized by spike and polyspike-and-wave discharges. Ictal epileptiform activity occurred approximately less than one second after the start of hand-waving. At the last follow-up (median length 8.2 years), 12 patients (57%) were drug-resistant. Nine of them (75%) achieved seizure control with the use of tainted lenses, either alone or compared with anti-seizure medications (ASM). Disappearance of seizures was associated with EEG improvement/normalization when tinted glasses were used during EEG recordings.

CONCLUSION

While the clinical and EEG characteristics of SFS are well defined, the best therapeutic approaches are still under debate. Our data confirms a high rate of drug-resistance and frequent need of polytherapy. Of note, in drug-resistant patients, lenses (but not ASM) were able to suppress PPR in our patients while wearing lenses. Regarding the role of lenses, we do not only rely on the PPR reduction but also clinically by the reduction of seizures. Although additional data are needed, lenses seem to have a powerful potential role for the management of SFS.

Epilepsy With Eyelid Myoclonia (Jeavons Syndrome)

The purpose of this review is to provide a comprehensive update and highlight the distinct electroclinical features and discuss recent advances in the etiology, pathophysiology, and management strategies of epilepsy with eyelid myoclonia. Recent studies indicate that variations of certain genes including CHD2 (chromodomain helicase DNA-binding protein 2), KCNB1, KIAA2022, and NAA10 may occur in these patients. It has been postulated that the occipital cortex may play a role in the pathophysiology. Recent studies of functional imaging and connectivity of neuronal electrical activity have provided additional evidence to support this hypothesis. The frontal cortex has additionally been implicated, and it has been suggested that the epileptic cortex may extend beyond the occipital cortex to involve the posterior temporal cortex. We update the management strategies and describe tools that may predict seizure persistence. Epilepsy with eyelid myoclonias, or Jeavons syndrome, is an idiopathic generalized epilepsy characterized by the triad of eyelid myoclonia with or without absence seizures, eyelid closure-elicited electroencephalographic (EEG) paroxysms (epileptiform discharges and/or seizures), and photosensitivity. This condition may account for up to 13% of generalized epilepsies. However, it is frequently under-reported and under-recognized. Many of the patients develop medically refractory epilepsy, and seizures tend to persist throughout life.

Photoparoxysmal response and its characteristics in a large EEG database using the SCORE system

OBJECTIVE

To characterize photoparoxysmal EEG response (PPR) using a standardized protocol of intermittent photic stimulation (IPS) and standardized definitions for PPR, classified into six types.

METHODS

Using the SCORE system (Standardized Computer-Based Organized Reporting of EEG) we prospectively built a large database of standardized EEG annotations. In this study, we extracted the features related to PPR from the structured dataset consisting of 10,671 EEG recordings with IPS, from 7,188 patients.

RESULTS

The standardized IPS protocol elicited PPR in 375 recordings (3.5%), in 288 patients (4%), with a preponderance among young (11-20 years) and female patients (67%). PPR was persistent in patients with multiple recordings. The most frequent type of PPR was activation of preexisting epileptogenic area (58%), followed by generalized-PPR limited to the stimulus train (22%). We could not find any recording with self-sustained posterior response. Seizures were elicited in 27% of patients with PPR, most often myoclonic seizures and absences, in patients with self-sustained generalized PPR.

CONCLUSIONS

The most common type of PPR was accentuation of preexisting epileptogenic area. Self-sustained posterior response could not be documented. Self-sustained generalized-PPR had the highest association with seizures.

SIGNIFICANCE

Using standardized stimulation protocol and definitions for PPR types, IPS provides high diagnostic yield.

Dealing with the storm: An overview of seizure precipitants and spontaneous seizure worsening in drug-resistant epilepsy

In drug-resistant epilepsy, periods of seizure stability may alternate with abrupt worsening, with frequent seizures limiting the individual's independence and physical, social, and psychological well-being. Here, we review the literature focusing on different clinical scenarios related to seizure aggravation in people with drug-resistant epilepsy. The role of antiseizure medication (ASM) changes is examined, especially focusing on paradoxical seizure aggravation after increased treatment. The external provocative factors that unbalance the brittle equilibrium of seizure control are reviewed, distinguishing between unspecific triggering factors, specific precipitants, and 'reflex' mechanisms. The chance of intervening surgical or medical conditions, including somatic comorbidities and epilepsy surgery failure, causing increased seizures is discussed. Spontaneous exacerbation is also explored, emphasizing recent findings on subject-specific circadian and ultradian rhythms. Awareness of external precipitants and understanding the subject-specific spontaneous epilepsy course may allow individuals to modify their lifestyles. It also allows clinicians to counsel appropriately and to institute suitable medical treatment to avoid sudden loss of seizure control.

Jeavons Syndrome: Clinical Features and Response to Treatment

BACKGROUND

Jeavons syndrome is an underreported epileptic syndrome characterized by eyelid myoclonia, eyelid closure-induced seizures or electroencephalography paroxysms, and photosensitivity. Drug-resistant epilepsy is common, but the prognostic factors and clinical course leading to drug resistance have not been well characterized.

METHODS

We identified 30 patients who met the diagnostic criteria of Jeavons syndrome at a single institution between January 1, 2000 and December 15, 2016. Criteria for Jeavons syndrome included all of the following: (1) eyelid myoclonia with or without absences, (2) eye-closure-induced seizures or electroencephalography paroxysms, and (3) seizure onset after 12 months of age. We reviewed and described the epilepsy history, antiepileptic drug trials, and response to treatments.

RESULTS

Mean age at seizure onset was 7.3 years, and 80% were female. Absence seizures (63%) and generalized tonic-clonic seizures (23%) were most common at onset. Diagnosis was delayed by an average of 9.6 years. After a median follow-up of two years, 80% of patients had drug resistant epilepsy and 70% experienced generalized tonic-clonic seizures. Generalized tonic-clonic seizures and seizure types other than absence seizures increased the risk of drug-resistant epilepsy (P values 0.049 and 0.03, respectively). Valproic acid, lamotrigine, ethosuximide, and levetiracetam were the most effective in reducing seizures by more than 50%.

CONCLUSIONS

The diagnosis of Jeavons syndrome is often delayed. Generalized tonic-clonic seizures and seizure types other than absence seizures may be predictors of drug-resistant epilepsy among patients with Jeavons syndrome.

Clinical and electrographic features of sunflower syndrome

BACKGROUND

Sunflower Syndrome describes reflex seizures - typically eyelid myoclonia with or without absence seizures - triggered when patients wave their hands in front of the sun. While valproate has been recognized as the best treatment for photosensitive epilepsy, many clinicians now initially treat with newer medications; the efficacy of these medications in Sunflower Syndrome has not been investigated. We reviewed all cases of Sunflower Syndrome seen at our institution over 15 years to describe the clinical course, electroencephalogram (EEG), and treatment response in these patients.

METHODS

Search of the electronic medical record and EEG database, as well as survey of epilepsy providers at our institution, yielded 13 cases of Sunflower Syndrome between 2002 and 2017. We reviewed the records and EEG tracings.

RESULTS

Patients were mostly young females, with an average age of onset of 5.5 years. Seven had intellectual, attentional or academic problems. Self-induced seizures were predominantly eyelid myoclonia ± absences and 6 subjects also had spontaneous seizures. EEG demonstrated a normal background with 3-4 Hz spike waves ± polyspike waves as well as a photoparoxysmal response. Based on both clinical and EEG response, valproate was the most effective treatment for reducing or eliminating seizures and improving the EEG; 9 patients tried valproate and 66% had significant improvement or resolution of seizures. None of the nine patients on levetiracetam or seven patients on lamotrigine monotherapy achieved seizure control, though three patients had improvement with polypharmacy.

CONCLUSIONS

Valproate monotherapy continues to be the most effective treatment for Sunflower Syndrome and should be considered early. For patients who cannot tolerate valproate, higher doses of lamotrigine or polypharmacy should be considered. Levetiracetam monotherapy, even at high doses, is unlikely to be effective.

Photosensitivity in generalized epilepsies

Photosensitivity, which is the hallmark of photosensitive epilepsy (PSE), is described as an abnormal EEG response to visual stimuli known as a photoparoxysmal response (PPR). The PPR is a well-recognized phenomenon, occurring in 2-14% of patients with epilepsy but its pathophysiology is not clearly understood. PPR is electrographically described as 2-5Hz spike, spike-wave, or slow wave complexes with frontal and paracentral prevalence. Diagnosis of PPR is confirmed using intermittent photic stimulation (IPS) as well as video monitoring. The PPR can be elicited by certain types of visual stimuli including flicker, high contrast gratings, moving patterns, and rapidly modulating luminance patterns which may be encountered during e.g., watching television, playing video games, or attending discotheques. Photosensitivity may present in different idiopathic (genetic) epilepsy syndromes e.g. juvenile myoclonic epilepsy (JME) as well as non-IGE syndromes e.g. severe myoclonic epilepsy of infancy. Consequently, PPR is present in patients with diverse seizure types including absence, myoclonic, and generalized tonic-clonic (GTC) seizures. Across syndromes, abnormalities in structural connectivity, functional connectivity, cortical excitability, cortical morphology, and behavioral and neuropsychological function have been reported. Treatment of photosensitivity includes antiepileptic drug administration, and the use of non-pharmacological agents, e.g. tinted or polarizing glasses, as well as occupational measures, e.g. avoidance of certain stimuli.

Electroclinical aspects and therapy of Han patients with juvenile myoclonic epilepsy in northern China

OBJECTIVE

The objective of this study was to assess the electroclinical aspects and treatment of Han patients with juvenile myoclonic epilepsy (JME) in northern China.

METHODS

One hundred fifty-six outpatients with JME from six epilepsy centers, between January 2011 and June 2012, were followed up for at least two years. They underwent twenty-four-hour video-EEG recording. Brain imaging was performed using magnetic resonance imaging (MRI). Clinical aspects, electroencephalographic (EEG) features, and antiepileptic drugs (AEDs) received were reviewed.

RESULTS

Generalized tonic-clonic seizures (GTCS) were found in 150/156 patients. Delay of diagnosis was 4.60±9.92years. Photosensitivity was more common in eye closure condition during IPS in patients with JME; in addition, patients with JME with myoclonic seizures (MS) and GTCS as seizure types were likely to present photoparoxysmal responses (PPRs). The 82 nontreated patients showed a median latency to first interictal or ictal generalized spike-wave discharge (GSWD) of 50min (IQR: 22-102min). The first GSWDs were recorded in 63%, 76%, 90%, and 98% patients within one, two, three, and 4h, respectively; only 2% of patients had first GSWDs after 4h. One hundred eleven patients (111/156) chose extended-release valproate (VPA) at daily doses ≤1000mg. The percentages of seizure-free patients among MS, GTCS, and absence seizure (AS) groups were 88.3%, 99.0%, and 94.9%, respectively.

CONCLUSION

Photoparoxysmal responses were more common in patients with JME with MS and GTCS and rare in patients with JME with MS and AS in northern Chinese Han patients. Most patients with JME in northern China chose VPA as first therapeutic choice, and low dose (500 to 1000mg daily) of extended-release VPA may be an optimal choice for them. Video-EEG monitoring for at least 4h may be helpful in detecting the first interictal or ictal GSWD in patients with potential JME. Moreover, video-EEG monitoring performed at about 9 o'clock in the morning with patients in the awake state might be useful to find the first GSWD. For JME diagnosis, Class II criteria are more helpful than Class I counterparts, the latter yielding more missed diagnoses.

Reflex epileptic mechanisms in ictogenesis and therapeutic consequences

Recent studies of reflex epileptic mechanisms in human epilepsy using advanced methods of neurophysiology and functional neuroimaging have contributed much to elucidate pathophysiological processes of seizure generation. Whereas in lesional focal epilepsies reflex mechanisms usually relate directly to the anatomical focus, in system epilepsies they have helped to define which functional anatomical systems serving physiological function are recruited by the ictogenic mechanisms. Reflex epileptic seizures can often be prevented by avoidance or modification of triggers or by prophylactic benzodiazepine administration. Surgical options apply to focal cases. According to restricted experiences with pharmacotherapy, without controlled studies and little information on new AEDs, reflex seizures in system epilepsies appear to respond best to valproic acid and in focal epilepsies, to carbamazepine.

Generalized versus partial reflex seizures: a review

In this review we assess our currently available knowledge about reflex seizures with special emphasis on the difference between "generalized" reflex seizures induced by visual stimuli, thinking, praxis and language tasks, and "focal" seizures induced by startle, eating, music, hot water, somatosensory stimuli and orgasm. We discuss in particular evidence from animal, clinical, neurophysiological and neuroimaging studies supporting the concept that "generalized" reflex seizures, usually occurring in the setting of IGE, should be considered as focal seizures with quick secondary generalization. We also review recent advances in genetic and therapeutic approach of reflex seizures.

Reexamining the added value of intermittent photic stimulation and hyperventilation in routine EEG practice

OBJECTIVE

Investigate the added value of hyperventilation (HV) and intermittent photic stimulation (IPS) to the routine electroencephalogram (EEG).

METHOD

This is a retrospective review of 1,172 successive EEGs. The records with evidence of epileptogenic activity were identified and further analyzed to identify if the activation techniques could trigger the expression of epileptic activity not seen otherwise in the nonactivated tracing.

RESULTS

Activation procedures provided additional information in 9.5% of the abnormal EEG files. They helped establish the diagnosis of an epileptic disorder or further characterize the epileptic syndrome. This occurred exclusively in the younger age group (age <36 years), and predominantly in women.

CONCLUSION

IPS and HV are easy to perform and remain important adjuncts to routine EEG. They may trigger the expression of epileptogenic activity in an otherwise uneventful EEG. Whereas their diagnostic value was obvious in the younger age group, we found no evidence to support their usefulness in the middle-age and elderly groups.

Management of juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a common form of epilepsy and a fairly lifelong disorder that may significantly lower a patient's expectations and potential for a full life. Luckily, it is also a highly treatable disorder, and up to 85% of patients with JME will enjoy satisfactory seizure control. Among anticonvulsants, valproate still stands out as the most efficacious drug, but may be poorly tolerated by some, and is considered unsafe for the fetuses of pregnant women. Alternatives have emerged in recent years, especially levetiracetam, but also topiramate, zonisamide or lamotrigine. In some cases, combination therapy may be useful or even required. One should not forget the potential aggravation induced not only by some commonly used anticonvulsants, especially carbamazepine and oxcarbazepine, but also, in some patients, by lamotrigine. In special settings, older drugs like benzodiazepines and barbiturates may be useful. But the management of JME should also include intervention in lifestyle, with strict avoidance of sleep deprivation and the management of copathologies, including the cognitive and psychiatric problems that are often encountered. With adequate management, there will only remain a small proportion of patients with uncontrolled epilepsy and all of its related problems. Juvenile myoclonic epilepsy is a condition in which the clinician has a fair chance of significantly helping the patient with medication and counseling.

Diagnosing photosensitive epilepsy: fancy new versus old fashioned techniques in patients with different epileptic syndromes

PURPOSE

To demonstrate the clinical importance of using a high quality photic stimulator for recording EEGs to diagnose photosensitivity.

METHODS

We performed EEG examinations on 2 adult and 2 paediatric patients with a history of visually induced seizures; routinely we used a Grass PS 40 photic stimulator (rectangular Xenon lamp giving flashes of 10 μs duration, 0.7J, 1-30 Hz, width 7 cm, length 12 cm). We repeated the IPS with a Grass PS 33 plus stimulator (round Xenon lamp giving flashes of 10 μs duration, 1J, 1-60 Hz, diameter 14 cm).

RESULTS

Patients were affected by both benign and catastrophic epilepsies. They complained about episodes of dizziness (case 1), dizziness accompanied by a sensation in the arms and fear (case 2), absences (case 3), and myoclonic jerks (case 4). These symptoms occurred when working with neon lights, computers or ironing striped clothes (case 1), while driving (case 2), whenever there was sunlight (case 3 and 4). Only IPS performed with the Grass PS 33 plus stimulator evoked PPRs accompanied by their typical complaints. In all cases, the revised diagnosis led to changes in their treatment and the disappearance or diminishment of their complaints and PPR range.

CONCLUSION

A PPR can occur in various types of epilepsy, can have a different meaning, and requires a different therapeutic intervention. Only an appropriate photic stimulator with diffuse white light and a flash intensity level of 1J/flash, can reliably demonstrate whether a patient is photosensitive, or equally important exclude it.

[Is there a bridge between migraine and familial mesial temporal lobe epilepsy?]

Numerous reviews have emphasized the links between certain types of epilepsy and migraine. Historically, Gowers was one of the first, in 1907, to have drawn attention to a possible relationship between migraine headache and epilepsy in a period when no additional examination was available. In the last two decades, progress in molecular biology, electrophysiology, and neuro-imaging has enabled a better approach to the fundamental elements underlying the interrelationship between these two nosological domains. During this same time, a new term "channelopathy" has appeared in the literature. This term groups together affections involving a dysfunction of ion channels. In this article, the links between the different types of migraine and familial mesial temporal lobe epilepsy are illustrated by two case reports. This association does not appear to occur at random but would undoubtedly depend on a common genetic substratum, leading to a direct comorbidity. These occasional recurring symptoms would lie within the framework of a more general concept of "Primary Brain Channelopathies".

Ictal Headache and Visual Sensitivity

Migrainous headache is reported by patients with photosensitive epilepsy, whereas their relatives complain more often about headache than the relatives of patients with other types of epilepsy. We therefore investigated whether headache itself could be an epileptic symptom related to photosensitivity Four probands with headache and photosensitive epilepsy were selected. Their first-degree family members were studied using video-EEG with extensive intermittent photic stimulation and pattern stimulation. Nine of the 12 subjects (10 female and two male, mean age 30 years, range 14–46 years) proved to be photosensitive with either focal ( n = 5) or generalized ( n = 4) epileptiform discharges. In two subjects an ictal recording of headache occurred after visual stimulation. We found evidence that, in specific patients, headache could be an ictal sign of epilepsy. Photic stimulation during EEG recording can contribute to correct diagnosis and lead to the best care and management of the patient.

The photoparoxysmal response: the probable cause of attacks during video games

Photic stimulation is part of a typical EEG in most countries, especially to check on the photoparoxysmal response (PPR). Interest in this response was enhanced in 1997 when hundreds of Japanese children had attacks while viewing a TV cartoon called "Pokemon." The overall prevalence of the PPR among patients requiring an EEG is approximately 0.8%, but 1.7% in children and 8.87% in patients with epilepsy, more often in Caucasians and females. Autosomal dominant inheritance is indicated, and this response is seen especially at the wavelength of 700 nm or at the flicker frequency of 15-18 Hz. The PPR extending beyond the stimulus carries no increased risk of seizures. Prognosis is generally good, especially after 20 years of age. Attention to PPR has been increased with the advent of video games, and the evoked seizures from these games are likely a manifestation of photosensitive epilepsy. Drug therapy has emphasized valproic acid, but Levetiracetam has also been successful in eliminating the PPR.

Usefulness of a morning routine EEG recording in patients with juvenile myoclonic epilepsy

OBJECTIVE

To evaluate if a standard awake EEG recording in the morning is superior to afternoon awake EEG session in detecting generalized epileptiform discharges (GEDs) in patients with juvenile myoclonic epilepsy (JME).

METHODS

The study group included 29 consecutive patients (23 women; mean age 22.3+/-6.3 years; age at onset of JME 15.4+/-3.4 years) with JME. Out of 29 patients 5 were untreated, 9 patients were treated with valproate, 8 with lamotrigine, 6 with levetiracetam and 1 patient with valproate plus phenobarbital. Two routine consecutive interictal EEG recordings were performed at 9a.m. and at 3p.m., respectively, while the subject was awake, on the same day after a a regular nocturnal sleep at own home.

RESULTS

The morning EEG recording showed GEDs (i.e., generalized polispike and waves, photoparoxysmal response, or both). in 20/29 patients. In 15 of these 20 patients, the afternoon recording was normal and this difference was statistically significant (p < or = 0.001). Moreover, there was a striking reduction of GEDs in three of the remaining five patients. Nine/29 patients had both morning and afternoon EEG recording normal.

CONCLUSIONS

The results of this study have illustrated a significant greater rate of detection of generalized epileptiform abnormalities by performing standard awake EEG in the morning in comparison with an afternoon session.

Is colour modulation an independent factor in human visual photosensitivity?

Considering that the role of colour in photosensitive epilepsy (PSE) remains unclear, we designed a study to determine the potential of different colours, colour combinations and white light to trigger photoparoxysmal responses (PPRs) under stringent controlled conditions. After assessing their photosensitivity to stroboscopic white light and black and white patterns, we studied 43 consecutive PSE patients (mean age 19 years, 34 women), using a specially designed colour stimulator. Stimuli included: pulse trains between 10 and 30 Hz of white light and of all primary colours, and also isoluminant alternating time-sequences of colours. Illuminance was kept constant at 100 lux. A progressive stepwise increase of the modulation-depth (MD) of the stimuli was used to determine PPRs threshold. Whereas all the 43 patients were found to be sensitive during the stroboscopic and pattern protocol, only 25 showed PPRs (Waltz's score >2) at least in one session when studied with the colour stimulator. Coloured stimuli elicited PPRs in all these patients, whereas white light did so only in 17 patients. Of the primary colours, red elicited more PPRs (54 in 22 patients) and at a lower MD (max Z-score 0.93 at 10 Hz). Of the alternating sequences, the red-blue was the most provocative stimulus, especially below 30 Hz (100% of patients, max Z-score: 1.65 at 15 Hz). Blue-green was the least provocative stimulus, since it elicited only seven PPRs in seven (28%) patients (max Z-score 0.44 at 10 Hz). Sensitivity to alternating colours was not correlated to sensitivity to individual colours. We conclude that colour sensitivity follows two different mechanisms: one, dependent on colour modulation, plays a role at lower frequencies (<30 Hz). Another, dependent on single-colour light intensity modulation correlates to white light sensitivity and is activated at higher frequencies. Our results suggest that the prescription of spectacles with coloured lenses, tailored to the patient, can be an effective preventative measure against visually induced seizures.