Conceptual distinctions between reflex and nonreflex precipitated seizures in the epilepsies: a systematic review of definitions employed in the research literature.

Seizure precipitation is a defining characteristic of reflex seizures and epilepsies, but seizure precipitants are also commonly reported for patients with epilepsies not considered to be reflex in nature. This raises the questions of exactly how reflex and nonreflex epilepsies with seizure precipitants are defined, and how these concepts are differentiated from one another in current practice. In this systematic literature review, definitions of reflex seizures, reflex epilepsies, and precipitation in a nonreflex context were extracted from published primary research papers. Content analysis was applied to these definitions to identify their main features, allowing comparisons to be made between definitions of the different concepts. Results indicated that there was little consistency within definitions of a given term, and that although some differences in definition content were found between terms, it was evident that clear defining characteristics to differentiate them from one another were lacking. These findings are discussed in the context of current debates regarding classification of the reflex epilepsies and the extent to which the distinction between reflex and nonreflex epilepsies is a meaningful one. Suggestions are made for how clarity might be increased in ongoing research in this area.

Provoked and reflex seizures: surprising or common?

Most patients with epilepsy report that seizures are sometimes, or exclusively, provoked by general internal precipitants (such as stress, fatigue, fever, sleep, and menstrual cycle) and by external precipitants (such as excess alcohol, heat, bathing, eating, reading, and flashing lights). Some patients describe very exotic and precise triggers, like tooth brushing or listening to a particular melody. Nevertheless, the most commonly noticed seizure increasers by far are stress, lack of sleep, and fatigue. Recognized reflex seizure triggers are usually sensory and visual, such as television, discotheques, and video games. Visually evoked seizures comprise 5% of the total of 6% reflex seizures. The distinction between provocative and reflex factors and seizures seems artificial, and in many patients, maybe all, there is a combination of these. It seems plausible that all of the above-mentioned factors can misbalance the actual brain network; at times, accumulation of factors leads then to primary generalized, partial, or secondarily generalized seizures. If the provoking factors are too exotic, patients may be sent to the psychiatrist. Conversely, if the seizure-provoking fluctuating mechanisms include common habits and environmental factors, these may hardly be considered as provocative factors. Awareness of precipitating factors and its possible interactions might help us to unravel the pathophysiology of epilepsy and to change the notion that seizure occurrence is unpredictable. This article provides an overview of the epidemiology, classification, diagnosis, treatment, and especially similarities in the variety of provocative and reflex factors with resulting general hypotheses.

Reflex seizures and reflex epilepsy.

Reflex seizures are evoked by a specific afferent stimulus or by activity of the patient and are divided into those characterized by generalized seizures and those principally manifested by focal seizures. Reflex epilepsies are syndromes in which all epileptic seizures are precipitated by sensory stimuli. Three categories of reflex seizures encountered clinically include pure reflex epilepsies, reflex seizures that occur in generalized or focal epilepsy syndromes that are also associated with spontaneous seizures, and isolated reflex seizures occurring in situations that do not necessarily require a diagnosis of epilepsy. Generalized reflex seizures are precipitated by visual light stimulation, thinking, and decision making. These seizures usually respond to valproate treatment. Numerous triggers can induce focal reflex seizures. The triggers include reading, writing, other language functions, startle, somatosensory stimulation, proprioception, auditory stimuli, immersion in hot water, eating, and vestibular stimulation. The classification and characteristics of reflex seizures and epilepsies are described in this review. Findings on EEG and advanced neuroimaging in the reflex seizures and epilepsies, treatment and preventive options, and animal models and mechanisms are also discussed.

Visual-sensitive epilepsies: classification and review.

Photosensitivity, photosensitive seizures, and photosensitive epilepsy are discussed. The International League against Epilepsy has suggested the term "visual-sensitive" replace "photosensitive". Visual-sensitive seizures may be more common than is realized. A classification for visual-sensitive epilepsies is presented. Chromosomal and DNA testing may help to refine the classification further. A standardized approach for neurophysiologic testing, such as that proposed by European experts, is recommended. These steps should promote evidenced-based management for this group of disorders.

Favorable outcome of epileptic blindness in children.

Acute blindness is a rare presentation of epileptic seizures, referring to loss of sight without loss of consciousness associated with electroencephalographic (EEG) epileptic discharges, mainly representing an ictal phase but also either pre- or postictal. We report a series of 14 children with documented epileptic blindness, describing the accompanying fits and thereafter the response to therapy to resolve the blindness and control associated seizures. All patients experienced episodes of acute complete visual obscuration lasting for 1 to 10 minutes. Seven patients hadaccompanying generalized seizures, with a photosensitive response recorded in three of them. All of these seven children were treated with valproic acid, regaining full vision, and six of them became seizure free. Three patients with acute blindness who had accompanying focal motor seizures and unilateral temporooccipital posterior epileptic discharges were treated with carbamazepine regained full vision and complete seizure control. Four additional children had the constellation of migrainous headaches, focal motor phenomena, and complete blindness, along with occipital discharges compatible with Gastaut syndrome, benign childhood epilepsy with occipital paroxysms. All four patients were started on carbamazepine and became asymptomatic. Our overall experience suggests that epileptic blindness in children is associated with a favorable outcome when promptly diagnosed and treated appropriately, resulting in complete resolution of blindness in all children and satisfactory control of seizures in most of them. We therefore recommend performing a prompt EEG in any child presenting with acute visual obscuration, even in the absence of other epileptic phenomena.

Seizures induced by nursery rhymes and children's games.

We report the case of a 20 years aged male patient with seizures induced by nursery rhymes and children's games. Seizures were precipitated by various triggers, including thinking to a children's rhyme, to a children's game, to the action of giving a kiss with a hand. Among the above triggers, only the last one was able to induce a seizure during our observation, characterised by jerking of the upper limbs and loss of consciousness with a quick recovery. The electroclinical features were of a brief paroxysm and diffuse theta/delta activity on electroencephalogram, with frontal maximal expression. The playful aspect and the reference to childhood intrinsically associated with an emotional component seem to be the true feature all the stimuli have in common and therefore this form could be classified as an emotional one. To our knowledge seizures precipitated by these kind of stimuli have never before been reported.

Reading epilepsy in a patient with previous idiopathic focal epilepsy with centrotemporal spikes.

RATIONALE: Reading epilepsy (RE) is a form of reflex epilepsy currently classified as an idiopathic localization-related epilepsy (ILAE, 1989). METHODS: We describe a 30 year-old right-handed male who suffered since the age of 8 from nocturnal partial motor seizures. Clinical features were typical of BECT. We reviewed the EEG recorded at that time which showed centrotemporal spike and waves. He was seizure-free from the age of 12 to the age of 17 when seizures evoked only by reading appeared. No other stimuli provoked seizures. Neurological and neuroradiological (CT and MR) investigations were normal. Baseline video-polygraphic EEG recordings were normal while reading aloud provoked myoclonic jerks in the facial muscles related to bilateral spike and wave discharges. Therapy with carbamazepine and valproic acid strongly reduced seizure frequency. CONCLUSION: Recent papers have debated the difficulties in classifying RE among the generalized or focal syndromes. Literature reports describe an association with RE and juvenile myoclonic epilepsy, supporting the hypothesis of an idiopathic generalized form. We report the first documented case with a clear-cut idiopathic localization-related epilepsy evolving to a primary reading epilepsy.

[Photosensitive epilepsies of children]. / Epilepsias fotosensibles del niño.

INTRODUCTION: Reflex epileptic seizures are caused by a specific sensorial stimulus which determines their classification. Photosensitive epilepsies are the commonest forms and are included with the idiopathic generalized epilepsies. DEVELOPMENT AND CONCLUSIONS: We analyze the different responses to intermittent light stimulation, in both normal and epileptic persons, and study the various epileptic syndromes in which photosensitivity is seen. The purely photosensitive (photogenic) epilepsies are characterized by seizures caused only by light as compared with the epilepsies with photosensitivity which also present spontaneous seizures. Special mention is made of seizures induced by the television screen, computer screen and video-games. The palpebral myoclonias with absences may be considered to be reflex seizures, since they are induced by eyelid closure, and include the vary rare self-induced epileptic seizures. Finally we study the epileptic seizures induced by pattern and exclusively due to intermittent light stimulation.

Genetics of epilepsy syndromes in families with photosensitivity.

OBJECTIVE: To use family studies to investigate the clinical genetics of photosensitivity to understand the interrelationship of different photosensitive epilepsy syndromes. METHODS: Twenty-nine families were recruited in which at least 2 members had idiopathic epilepsy and either clinical or electrical photosensitivity on EEG studies. We performed electroclinical analysis of these individuals and all other affected family members and analyzed the phenotypic patterns in families. RESULTS: An earlier age at seizure onset was observed in photosensitive patients compared with nonphotosensitive individuals. A significant female bias for photosensitivity was confirmed. All subjects with visual seizures were photosensitive. Subjects could be classified into 3 main photosensitive phenotypes: genetic (idiopathic) generalized epilepsies (GGE), idiopathic photosensitive occipital epilepsy (IPOE), and mixed GGE/IPOE. Within each category, subjects with purely photosensitive seizures were observed. We report a distinctive syndrome of early-onset photosensitive absence epilepsy, with onset beginning by 4 years of age, which was more refractory than childhood absence epilepsy. CONCLUSIONS: The clinical genetics of the idiopathic photosensitive epilepsies show a phenotypic spectrum from the GGEs to IPOE with overlap between the focal features of IPOE and all the GGE syndromes. Shared genetic determinants are likely to contribute to the complex inheritance pattern of photosensitivity, IPOE, and the GGEs.

Suppressive efficacy by a commercially available blue lens on PPR in 610 photosensitive epilepsy patients.

PURPOSE: Photosensitivity can represent a serious problem in epilepsy patients, also because pharmacologic treatment is often ineffective. Nonpharmacologic treatment using blue sunglasses is effective and safe in controlling photosensitivity, but large series of patients have never been studied. METHODS: This multicenter study was conducted in 12 epilepsy centers in northern, central, southern, and insular Italy. A commercially available lens, named Z1, obtained in a previous trial, was used to test consecutively enrolled pediatric and adult epilepsy patients with photosensitivity. Only type 4 photosensitivity (photoparoxysmal response, PPR) was considered in the study. A standardized method was used for photostimulation. RESULTS: Six hundred ten epilepsy patients were tested. Four hundred (66%) were female patients; 396 (65%) were younger than 14 years. Three hundred eighty-one (62%) subjects were pharmacologically treated at the time of investigation. Z1 lenses made PPR disappear in 463 (75.9%) patients, and PPR was considerably reduced in an additional 109 (17.9%) of them. PPR remained unchanged only in the remaining 38 (6.2%) patients. The response of PPR to Z1 lenses was not significantly influenced by the patients' age, sex, or type of epilepsy. No difference was found between pharmacologically treated and untreated patients. CONCLUSIONS: The Z1 lens is highly effective in controlling PPR in a very large number of photosensitive epilepsy patients irrespective of their epilepsy or antiepileptic drug treatment. The lens might become a valid resource in the daily activity of any clinician who cares for patients with epilepsy.

Telephone-induced seizures: a new type of reflex epilepsy.

PURPOSE: To report a new form of reflex epilepsy in which the seizures are repeatedly and exclusively triggered by answering the telephone. METHODS: Three patients with a history of telephone-induced seizures were studied in detail by means of clinical, EEG, and neuroradiologic investigations. Intensive video-EEG monitoring to record the reflex seizures also was performed in all cases. RESULTS: The patients (two men, one woman, aged 21 to 30 years) had the onset during early adulthood of complex partial and secondarily generalized seizures exclusively triggered by answering the telephone. The seizures were stereotyped, with subjective auditory or vertiginous auras and inability to speak or understand the spoken voices. In one patient, a telephone-induced seizure arising from the dominant temporal lobe was recorded by means of video-EEG technique. In the interictal EEGs, temporal abnormalities were detected in all cases. The patients had a normal neurologic examination and normal magnetic resonance imaging or computed tomography scans. CONCLUSIONS: We suggest that telephone epilepsy is a previously unrecognized form of reflex epilepsy induced by a complex auditory stimulus involving the lateral temporal areas.