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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although epilepsy remains an unsolved medical problem, there is a type of epilepsy known as 'photosensitive epilepsy' described in the medical literature that could serve as the window to understanding the pathophysiology of all epilepsies. Photosensitive epilepsy is a seizure phenomenon caused by exposure to bright and/or flickering light. This type of epilepsy has been estimated to occur in one of every 10,000 people. The nurse's role in this pathological state includes meticulous notations of seizure activity, adverse medication reactions, and psychological assessment of the photosensitive epileptic client.
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PMID:Photosensitive epilepsy. 286 78

Since 1968, annual EEG recordings during photic stimulation using a standardised technique have been made on photosensitive patients and siblings. In 1983, 72 were aged greater than or equal to 20 years and 14 were aged 16-19 years. Mean duration of follow-up was 9.8 +/- 4.8 years. Seventy-five patients were treated with sodium valproate (VPA), which was withdrawn in 15 but restarted in eight because of return of photosensitivity. Eighty-two patients had seizures at some time; at follow-up 58 were receiving monotherapy with VPA, seven were receiving comedication, and three were taking other drugs. Fifty-four of them were seizure free, as were 10 of the 15 who were not being treated with drugs. Photosensitivity disappeared in 44 of 65 patients at a mean dosage of VPA at 21.5 +/- 6 mg/kg day. In 55 of 86 patients photosensitivity was no longer present at follow-up; in 18, slight abnormality was evoked by intermittent photic stimulation, and in 13, photoconvulsive responses were still present. Eighteen patients were not receiving drugs, 10 of them being no longer photosensitive at the mean age of 24.5 +/- 4.9 years. Thirty-one treated and untreated patients were still photosensitive at age 21.5 +/- 3.4 years. Photosensitivity disappeared earlier in those treated with VPA than in the untreated. Spontaneous remission in the treated cases may have occurred at 22.9 +/- 2.5 years of age. Photosensitivity appears around puberty and may disappear around 24 years of age. Photosensitive epilepsy is easily and rapidly controlled by VPA.
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PMID:The prognosis of photosensitivity. 309 15

Reflex epilepsy (RE) is characterised by seizures that are regularly elicited by some specific stimulus or event mediated by neural pathways. In a prospective study of 1287 epileptic patients seen at Peradeniya, 223 (17.3%) were found to have RE, eating being the commonest stimulus (191 patients, 85.7%). Photosensitive epilepsy (PSE) was relatively rare. Intermittent photic stimulation on 874 unselected epileptic patients produced a positive photoconvulsive response in 60 (6.9%). None had photosensitive seizures, but 3 had a higher frequency of seizures while watching television. Eating epilepsy (EE) had the highest prevalence at Peradeniya (148/1000 epileptic patients). This group was male predominant, and the onset of epilepsy in most cases was in the second decade. The majority experienced partial complex seizures. Repetitive and chronic stimulation of the amygdala during eating is suggested as the mechanism underlying EE. Twenty-one patients had seizures evoked by calculation, problem solving or spatial tasks. Juvenile myoclonic epilepsy was the commonest form of seizure disorder in them. Although PSE itself is rare, self-induced epilepsy (SIE) was common. There were 8 patients who self-induced seizures. The majority were photosensitive and they induced seizures by gazing at the sun and waving a hand in front of the eyes. In the management of REs, clobazam produced impressive results. As for possible seizure-inhibitory mechanisms, our studies on a "Sathi" mediator showed definite EEG changes during mediation. Can mediation increase the seizure-threshold and abort or prevent the propagation of the epileptic discharge? The answer, apart from its possible therapeutic applications, may provide insight into the mechanisms of seizure generation.
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PMID:Reflex epilepsies: experience in Sri Lanka. 792 53

The recognition of photosensitivity depends upon the finding of an abnormal EEG response to intermittent photic stimulation (IPS). Photosensitive epilepsy being the most common form of reflex epilepsy, has been studied most extensively and is reported to account for 5-10% of the epileptic population in general. One thousand unselected epileptics hailing from different parts of Northern India were screened for photosensitivity, both clinically and on a standard protocol of IPS-provoked EEG recordings. Six patients (mean age 14.5 +/- 3.56 yr) were found to be photosensitive: 4 had generalized, 1 had complex partial and 1 mixed seizures; 3 had history of seizures provoked by visual stimuli. The baseline EEG in 4 patients showed generalized and 2 partial, with secondary generalized, epileptiform discharges. On IPS, similar EEG findings were obtained with a wide range of stimulus frequency (6-60 cycles/s). There is a low incidence of photosensitivity in our epileptic population, for which we believe, genetic factors are responsible.
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PMID:Incidence of photosensitive epilepsy in unselected Indian epileptic population. 817 29

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.
Seizure 1998 Apr
PMID:Photosensitivity--better informing patients with epilepsy of their individual risk. 962 98

Photosensitive epilepsy is a type of reflex epilepsy. Five percent of epileptics are photosensitive, i.e. they show photoconvulsive response (PCR) during intermittent photic stimulation. Patients with photogenic or photosensitive epilepsy have seizures with flickering light. They also exhibit heliotaxis. Sodium valproate and ethosuximide are the common drugs used. Even though benzodiazepines are useful, the specific effect of lorazepam is not mentioned. We report 5 cases of photosensitive epilepsy with inadequate response to usual antiepileptic drugs who had complete or near complete remission with lorazepam.
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PMID:Lorazepam: an adjuvant therapy in patients with seizure and heliotaxis. 1159 56

Photosensitive epilepsy (PSE) is the most common form of human reflex epilepsy, appearing in up to 10% of epileptic children. It also offers a highly reproducible model to investigate whether changes in neuronal activity preceding the transition to an epileptic photoparoxysmal response (PPR) may be detected. We studied 10 patients with idiopathic PSE (eight female, mean age 26 years, range 9-51 years) using magnetoencephalography. In addition, we also studied the responses of five normal controls (mean age 24 years, age range 9-35 years) and three non-photosensitive epileptic patients (mean age 10 years, range 8-11 years). Spectral analysis of the MEG signals recorded during intermittent photic stimulation revealed relevant information in the phase spectrum. To quantify this effect, we introduced a second order response feature of the stimulus-triggered visual response preceding the PPR: the phase clustering index, which measures how close the phases of successive periods are grouped for each frequency component for all periods of the stimuli applied. We recorded a total of 86 PPRs, including several absence seizures, in nine of the 10 patients. We found that an enhancement of phase synchrony in the gamma-band (30-120 Hz), harmonically related to the frequency of stimulation, preceded the stimulation trials that evolved into PPRs, and differed significantly from that encountered in trials not followed by PPR or in control subjects. This novel finding leads us to postulate that a pathological deviation of normally occurring synchronization of gamma oscillations, underlying perceptional processes, mediates the epileptic transition in PSE.
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PMID:Gamma-band phase clustering and photosensitivity: is there an underlying mechanism common to photosensitive epilepsy and visual perception? 1269 55

Photosensitive epilepsy is a well-known condition characterized by seizures in patients who show photoparoxysmal responses on electroencephalography (EEG) elicited by intermittent photic stimulation. Photoparoxysmal responses can be defined as epileptiform EEG responses to intermittent photic stimulation or to other visual stimuli of everyday life and are frequently found in nonepileptic children. The modern technologic environment has led to a dramatic increase in exposure to potential trigger stimuli; nowadays, television and video games are among the most common triggers in daily life. There is ample evidence for genetic transmission of photoparoxysmal responses; systematic family studies have provided data for an autosomal dominant mode of inheritance with age-dependent penetrance for photosensitivity. The age of maximum penetrance is between 5 and 15 years. The prognosis for control of seizures induced by visual stimulation is generally very good. The large majority of patients do not need anticonvulsant therapy, but, when needed, the drug of choice is valproate. Stimulus avoidance and stimulus modification can be an effective treatment in some patients and can sometimes be combined with antiepileptic drug treatment.
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PMID:Photosensitivity and epilepsy. 1560 65

Photosensitivity is a condition detected on the electroencephalography (EEG) as a paroxysmal reaction to Intermittent Photic Stimulation (IPS). This EEG response, elicited by IPS or by other visual stimuli of daily life, is called Photo Paroxysmal Response (PPR). PPRs are well documented in epileptic and non-epileptic subjects. Photosensitivity rarely in normal individuals evolves into epilepsy. Photosensitive epilepsy is a rare refex epilepsy characterized by seizures in photosensitive individuals. The development of modern technology has increased the exposition to potential seizure precipitants in people of all ages, but especially in children and adolescents. Actually, videogames, computers and televisions are the most common triggers in daily life of susceptible persons. The mechanisms of generation of PPR are poorly understood, but genetic factors play an important rule. The control of visually induced seizures has, generally a good prognosis. In patients known to be visually sensitive, avoidance of obvious source and stimulus modifications are very important and useful to seizure prevention, but in the large majority of patients with epilepsy and photosensitivity antiepileptic drugs are needed.
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PMID:Human photosensitivity: from pathophysiology to treatment. 1624 71

The classification of epilepsy includes a group of generalized idiopathic epilepsies that are triggered by a specific mode of activation, known as reflex epilepsies. Photosensitive epilepsy is the most common type. Some patients with photosensitive epilepsy use this sensitivity to induce seizures or epileptiform discharges on the electroencephalogram. In some patients, psychopharmacological treatment, for instance with selective serotonin reuptake inhibitors and neuroleptics, has demonstrated benefit insofar as self-induction of seizures is concerned. However, so far as we know, there are no documented cases of treatment with methylphenidate in patients with this type of seizure. Our purpose is to report the case of an 8-year-old girl with attention-deficit hyperactivity disorder (ADHD) and self-induced photosensitive epilepsy whose behavior in general, and self-inducing behavior in particular, improved dramatically following treatment with methylphenidate.
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PMID:Clinical response to methylphenidate in a patient with self-induced photosensitive epilepsy. 2142 45


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