Persistence of photosensitivity.

PURPOSE: One hundred patients with photosensitive epilepsy were investigated as part of an ongoing follow-up study. Average duration of follow-up was 14 years; mean age at follow-up was 27 years. METHODS: All patients were EEG investigated using a standard technique of intermittent photic stimulation (IPS). The presence of a photoparoxysmal response (PPR) or a degraded PPR indicated the presence of photosensitivity. RESULTS: Seventy-seven patients became seizure free. Of the untreated patients, photosensitivity disappeared in 14 patients but was present in 32 patients. Of the patients who were treated, 31 showed evidence of PPRs or degraded PPRs, but 23 patients no longer showed evidence of photosensitivity. Thirty-two mothers had 67 children during the follow-up period. Thirteen have so far proved to be sensitive to IPS in the laboratory and four have also had photosensitive seizures induced in the outside environment. Nine of the children have been found not to be photosensitive nor have they had seizures. CONCLUSIONS: This study suggests that photosensitivity persists in at least two thirds of patients with photosensitive epilepsy and that valproate is effective in controlling this photosensitivity.

'Telephillic syndrome' in pattern and photosensitive epilepsy: report of three cases.

The incidence of 'telephillic syndrome' (impulsive attraction to television), in three photosensitive epileptic patients who were referred to our neurophysiology clinic because they were having seizures is reported. Two were females, aged fourteen and eight respectively, one was a male aged twenty-five years. All the patients had a family history of epilepsy. The age range of onset of photosensitivity was 3.5-12 years and the most common seizure inducing factor was flickering light from the television (TV) viewing. They were all 'telephillic'. The predominant seizure type found in these patients was tonic-clonic seizure. Comprehensive electroencephalographic (EEG) investigation was carried out including hyperventilation. The basic EEG showed abnormal spike and wave activity on eye opening and eye closure in all the patients. Intermittent photic stimulation (IPS) evoked occipital spikes and photoparoxysmal response (PPRs) at a photosensitivity range of 758 flashes per second (fps). Pattern sensitivity test using a Gratings pattern revealed a sensitivity range of 1.03-3.5 cycles per second (cpd). And the predominant area of brain activity was the right mid-post temporal regions. Binocular stimulation offered no protection in one patient.

Video material and epilepsy.

Nine patients who had epileptic attacks while playing computer games were studied in the laboratory. Patients had an EEG recorded as well as their response to intermittent photic stimulation (IPS) at flash rates of 1-60 fps. In addition, pattern sensitivity was assessed in all patients by a gratings pattern. Only 2 patients had no previous history of convulsions, and only 2 had a normal basic EEG. All but 1 were sensitive to IPS, and all but 1 were pattern sensitive. Most patients were male, but although this appears to conflict with previously published literature results regarding the sex ratio in photosensitivity, it was due to the male predominance of video game usage. We compared our results with those reported in the literature. Diagnosing video game epilepsy requires performing an EEG with IPS and pattern stimulation. We propose a standard method of testing.

The prognosis of photosensitivity.

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.

Complex partial seizures: EEG foci and response to carbamazepine and sodium valproate.

The EEG and clinical records were reviewed of 85 subjects who had been treated for complex partial seizures with carbamazepine alone or with a combination of carbamazepine and sodium valproate. There was a correlation between the site of the EEG abnormality and the therapeutic response to anticonvulsant therapy. Subjects who had a left sided temporal lobe EEG abnormality responded better to carbamazepine alone, while those who had an abnormality on the right responded to a combination of carbamazepine and sodium valproate.

Non-dose-related side effects of valproate.

The clinical and histological findings in 88 patients in whom hepatotoxicity with valproate has been reported were reviewed. The characteristic lesion is microvesicular steatosis. Hepatotoxicity appears to be an idiosyncratic reaction and is most likely to appear within 6 months from the start of therapy, especially in young patients on comedication. The condition may be reversible if the drug is immediately withdrawn in patients who show acute gastrointestinal symptoms, drowsiness or lethargy, jaundice, or change in seizure pattern. Clinical monitoring is more important than laboratory monitoring. The outcome of pregnancies in 344 women who received valproate in the first trimester was reviewed. There were 225 normal babies and 68 abnormal babies. The role of valproate in the aetiology of neural tube defects remains uncertain, but mothers treated with valproate should receive prenatal counselling.

Aura in temporal lobe epilepsy: clinical and electroencephalographic correlation.

Patients with temporal lobe epilepsy were evaluated for their aura and the site of EEG abnormality. Autonomic and psychic auras were more frequently associated with right-sided temporal lobe lesions in 290 patients.

Sodium valproate: monotherapy and polytherapy.

Of the 605 patients seen since 1973, 336 patients have been treated with sodium valproate (VPA) alone or in combination with drugs other than carbamazepine (CBZ). Of these 336, 240 have been on monotherapy, of whom 200 are seizure-free. Follow up has been longer than 3 years in 78%. Complete control of seizures has been achieved in more than 80% of patients with absence, myoclonic, and primary tonic-clonic seizures, in 72% of those with photosensitive epilepsy including eyelid myoclonia, and in 47% of partial epilepsies, for which carbamazepine was the initial drug of choice. Only 21% of those with myoclonic astatic epilepsy have become free from seizures. At first VPA was given twice daily, but in recent years it was given once daily, as this was more effective. Reasons for failure of VPA therapy are given. Side effects in 436 patients (100 more patients were added for this assessment only) were uncommon, though where they did occur, weight increase was the most frequent. Platelets were reduced without clinical problems. There were no severe hepatic disorders. Serum levels were assessed in seizure-free patients, and the optimum level was between 60 and 120 mg/L (most patients received between 20 and 30 mg/kg). VPA was given during 30 pregnancies, and there was no evidence of teratogenicity on monotherapy. VPA is most effective in primary generalized epilepsy, especially if given as the sole antiepileptic drug. If the daily dose does not exceed 40 mg/kg or 2.5 g, it is singularly free from serious side effects.

Once-daily sodium valproate in the treatment of epilepsy.

Using monotherapy with enteric-coated sodium valproate, seizures have been completely controlled in 35 patients with administration of the drug once daily, usually at night. The mean serum levels in seven patients were the same whether the drug was taken once or twice daily. The mean serum level was 65.4 mg/l on a mean daily dose of 19.4 mg/kg. Drowsiness in the morning occurred in four patients, but only one had to return to twice-daily administration. Compliance improves with once-daily administration.

Television epilepsy--the role of pattern.

Patients with photosensitive epilepsy were asked to view normally functioning 625-line televisions while the EEG was monitored. In the first of two studies paroxysmal EEG activity was reliably induced by television at a viewing distance related to a patient's sensitivity to intermittent photic stimulation (IPS); patients who were sensitive to diffuse IPS at 50 Hz were sensitive to the television at greater viewing distances than those who were not. No such relationship was obtained with patterned IPS. On the other hand, patterned IPS was generally more epileptogenic than diffuse IPS with the same luminance. In the second study, where the angular subtense of the television screen and the subtense of its lines were manipulated independently, the convulsive response was found to be a function of both factors, the relative contribution of each depending on the viewing distance at which the patient was sensitive. For patients sensitive at normal viewing distances, where 50 Hz diffuse flicker appeared to be responsible for the induction of paroxysmal activity, the probability with which paroxysmal activity was induced was closely related to the subtense of the screen. For patients sensitive only at closer viewing distances the probability was influenced not by the subtense of the screen but by the subtense of its lines, suggesting that the paroxysmal activity was induced by the 25 Hz pattern alternation produced by the scan. A television with a small screen was considerably less epileptogenic than one with a large screen for all patients, presumably due to the reduced contribution of both diffuse flicker and pattern alternation.

A controlled study of the effect of sodium valproate on photosensitive epilepsy and its prognosis.

The effect of sodium valproate on photosensitive epilepsy was studied. The range of flash rates of intermittent photic stimulation to which patients were sensitive (photosensitive range) was tested prior to treatment, and the reliability of this measure established by repeated tests on 70 patients. The photosensitive range was measured on 50 patients prior to and during treatment with sodium valproate. In 27 patients photosensitivity was abolished and in a further 12 patients photosensitivity was significantly reduced. A group of 167 patients followed without treatment did not show significant improvement over a 7 year period. Sixteen patients had drug treatment withdrawn, and in 7 months their photosensitive range had returned to its predrug level.

Nosological problems of myoclonic epilepsies in childhood and adolescence.

An attempt is made to clarify the confusion over the classification of the myoclonic epilepsies of childhood. Six types of seizure are described, the classification being based on clinical and electroencephalographic findings. The types of myoclonic epilepsy are infantile spasms, myoclonic astatic epilepsy, myoclonic absence, myoclonic epilepsy of childhood, myoclonic epilepsy of adolescence and photomyoclonic epilepsy, the last being subdivided into myoclonic jerks and eyelid myoclonia. Synonyms are given for all types, based on the major papers in the literature over the last 16 years. The similarity of infantile spasms and myoclonic astatic epilepsy is discussed, as are the so-called 'Lennox' and 'Lennox-Gastaut' syndromes.

Treatment of generalized epilepsies of childhood and adolescence with sodium valproate ("epilim").

A total of 142 patients (84 per cent aged less than 20 years) with various forms of generalized epilepsy have been treated with sodium valproate alone or in combination with other drugs. The mean duration of symptoms was six years, and half the patients had daily seizures. Nine patients had typical absences, 33 had absences with automatisms, 28 had tonic-clonic seizures with or without photosensitivity, and 72 had various forms of myoclonic epilepsy. Dosage varied from 23 to 54mg/kg and twice-daily administration was usual. Estimation of serum levels did not assist in management. Fits ceased in 63 per cent of all cases and a further 18 per cent showed improvement greater than 50 per cent. Of the 69 with 3c/sec spike-and-wave discharges, 81 per cent became free from all fits, as did 77 percent of those with myoclonic jerks. Fits ceased in eight of the 32 patients with myoclonic astatic epilepsy and there was improvement greater than 50 per cent in a further eight patients. Other anticonvulsants were often withdrawn and always reduced. 21 patients received sodium valproate alone from the start of treatment and all other drugs were withdrawn in another 38. Sodium valproate alone controlled all fits in four children with absences, in 18 with absences with automatisms, 10 with tonic-clonic seizures and 22 with myoclonic epilepsy. Side-effects were rare, mild and often temporary. Potentiation of barbiturates and benzodiazepines occurred, especially clonazepam, which should be avoided. Many patients were more alert. Sodium valproate appears to be the drug of choice for epilepsies associated with generalized spike-and-wave discharges, myoclonic epilepsies or photosensitive epilepsies, and is of especial value in children and mentally retarded patients because it lacks sedating effects and often induces liveliness.