EEG characteristics of epileptic pattern sensitivity and their relation to the nature of pattern stimulation and the effects of sodium valproate

Darby, C. E.; Park, D.M; Smith, Alice; Wilkins, Arnold J.

doi:10.1016/0013-4694(86)90139-2

Cited by 17 publications

(15 citation statements)

References 10 publications

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“…Particularly, developmental changes in the balance between the glutamatergic and γ‐aminobutyric acid (GABA)ergic neurotransmission may be responsible for changes of VPA effect over time (Pinto et al., 2010). Finally, the findings of our study are consistent with the observations of Darby et al. (1986), who demonstrated an effect of VPA on voltage, morphology, duration, and pattern of propagation of visually induced SWDs, but to a lesser degree on the prevalence of PPR.…”

Section: Discussionsupporting

confidence: 92%

“…(1986), who demonstrated an effect of VPA on voltage, morphology, duration, and pattern of propagation of visually induced SWDs, but to a lesser degree on the prevalence of PPR. These authors suggested that VPA reduces the spread of epileptic activity from the trigger site, but it may have relatively little influence on the trigger mechanism (Darby et al., 1986). Indeed, our studies on transcranial magnetic stimulation and visual evoked potentials in PPR revealed different changes of cortical excitability in the visual cortex in patients with occipital spikes only and patients with propagated PPR (Siniatchkin et al., 2007a) (Siniatchkin et al., 2007b).…”

Section: Discussionmentioning

confidence: 99%

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Valproate reduces spontaneous generalized spikes and waves but not photoparoxysmal reactions in patients with idiopathic generalized epilepsies

et al. 2011

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Summary Purpose: Patients with idiopathic generalized epilepsies (IGEs) often present with interictal spike‐wave discharges (SWDs) at rest (spontaneous SWDs), during hyperventilation, and in response to photic stimulation (photoparoxysmal response or PPR). Valproic acid (VPA) is a first‐line antiepileptic drug for therapy of patients with IGE. Herein we investigated the effect of VPA on all three types of SWDs in children and adolescents with IGE. Methods: Routine electroencephalography (EEG) during wakefulness, which was recorded before VPA monotherapy and up to four times during the first year of the VPA treatment, was analyzed retrospectively. For the analysis of the VPA effect on spontaneous SWDs and SWDs under hyperventilation, the number and duration of SWDs were counted. SWDs under intermittent photo stimulation (IPS) were classified according to the extent of propagation (grading). Response to VPA treatment (rest/hyperventilation) was defined as a disappearance of SWDs within the year after VPA introduction. Key Findings: Eighty‐four patients (37 male and 47 female, mean age 9.5 ± 4.1 years) exhibited spontaneous SWDs or SWDs under hyperventilation. From this sample, 34 patients exhibited the PPR (7 male and 27 female, mean age 10.1 ± 3.9 years). A significant reduction in the number and duration of spontaneous SWDs and SWDs under hyperventilation was observed in the first 6 weeks of treatment (p ≤ 0.001, corrected, 87.3% responders). This effect remained stable over the 1 year observation period. Concerning PPR, only 4 (12.9%) of 31 patients were classified as responders. The difference between groups of patients with spontaneous/induced SWDs and PPR according to the number of responders was significant (p < 0.001). Significance: This study provides evidence that the effect of VPA on SWDs differs dependent on the types of SWDs. In the majority of patients, spontaneous SWDs and SWDs induced by hyperventilation disappeared, whereas the PPR mostly remained under VPA treatment. These results point to different pathogenetic mechanisms underlying the spontaneous and the evoked generalized epileptic activity in the EEG.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Valproate reduces spontaneous generalized spikes and waves but not photoparoxysmal reactions in patients with idiopathic generalized epilepsies

et al. 2011

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“…However, when they viewed a pattern of moving black and white squares, the highest rate of cerebral blood flow was more lateral, in the temporoparietooccipital junction (52). Darby et al (47) noted that the topography of the EEG activity in response to patterns, when focal, is usually maximal over the posterior temporal and parietal scalp electrodes instead of the occipital electrodes; this is consistent with the positron emission tomographic results and our observations.…”

Section: Discussionsupporting

confidence: 93%

Pattern‐sensitive Epilepsy: Electroclinical Characteristics, Natural History, and Delineation of the Epileptic Syndrome

Radhakrishnan¹,

Louis²,

Johnson³

et al. 2005

Epilepsia

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Purpose: To elucidate the electroclinical features and long-term outcome of patients with pattern-sensitive epilepsy. Methods: We reviewed the clinical and electroencephalo-graphic (EEG) findings of 73 (43 female and 30 male) patients in whom pattern-sensitive epilepsy was diagnosed at Mayo Clinic (Rochester, Minnesota, U.S.A.) from 1950 through 1999. We contacted patients and their relatives by letter or telephone to obtain the latest seizure and quality-of-life outcomes. Results: The median age at onset of seizures was 12.8 years (range, 0.6-32.9 years). Most patients had absence, myoclonic, or generalized tonic-clonic seizures. Interictal epileptiform discharges in the EEG were detected in 61 (83.6%) patients and were generalized in 54 (74%). Paroxysmal epileptiform discharges in the EEG elicited with standard patterns were all generalized in two thirds of patients but were restricted to the posterior head region in one-third. Eight (11%) patients did not exhibit photosen-sitivity. Television was the most common precipitant [30 patients (41%)]. Twenty-nine patients gave a clear history of one or more seizures precipitated while viewing environmental patterns such as window screens, garments, tablecloths, and ceiling tiles; the rest of the patients admitted that they preferred to avoid looking at patterned objects because these objects made them uncomfortable. The electroclinical features suggested juvenile myoclonic epilepsy in 14 patients, progressive myoclonus epilepsy in three, progressive familial cerebellar ataxia with myoclonus in two, and severe myoclonic epilepsy of infancy in one. During a median follow-up period of 15.7 years, 25 (45.5%) of 55 patients who were followed up for ≥5 years achieved complete seizure remission. The median age at remission was 24.4 years. The absence of progressive neurologic disease was correlated significantly with remission; a family history of seizures showed a trend in favor of remission. More than two thirds of the patients did not consider the seizures an impediment to their family life or to educational and occupational achievements. Conclusions: Although pattern sensitivity as a trait occurs in various epileptic syndromes, pattern-sensitive epilepsy is a readily distinguishable subtype of the visually provoked reflex epilepsies. In our opinion, the location and extent of the excitable region or regions within the visual cortex concerned with different attributes of visual function dictate susceptibility to a specific trigger (intermittent light, pattern, or color) or closely related multiple triggers and the resultant electroclinical phenomenon.

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“…We thus concluded that blue sunglasses might be more beneficial than ND and brown sunglasses for photosensitive individuals. In fact, occasionally wearing blue sunglasses while watching television and when confronted by a flickering light stimulus, in conjunction with antiepileptic drug (e.g., valproate) therapy (Harding et al, 1978;Darby et al, 1986), has brought about good results in our experience (Tomioka et al, 1991). In a previous report (Takahashi and Tsukahara, 1976) we proposed that blue sunglasses were useful in the treatment of photosensitive patients.…”

Section: Discussionmentioning

confidence: 88%

Usefulness of Blue Sunglasses in Photosensitive Epilepsy

Takahashi

Tsukahara

1992

Epilepsia

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The suppressive effect of sunglasses upon photoparoxysmal responses (PPRs) elicited by 15-Hz flicker stimuli with a low luminance of nearly 10 nits was studied in eight patients with photosensitive epilepsy. Using three commercially available sunglasses of neutral density (ND), blue, and brown, the influence upon generalized PPRs elicited by a flickering dot pattern (FDP) and red flicker (RF) stimuli was separately examined in six patients; the luminance of the visual stimuli decreased from roughly one-fifth (ND and brown sunglasses) to one-tenth (blue sunglasses). With FDP stimulation, four of the six patients wearing each of the three sunglasses had no provocation of PPRs, whereas two of the six patients had provocation of generalized PPRs with all of the sunglasses. With RF stimulation, two of the six patients wearing ND sunglasses had provocation of generalized PPRs; three of the six patients wearing brown sunglasses had similar provocation; in contrast, none of the six patients showed provocation of PPRs while wearing blue sunglasses. These results suggest that the suppressive effect of the three sunglasses on FDP stimulation is mainly due to a luminance diminution, whereas that of blue sunglasses on RF stimulation is produced by an inhibitory effect of short wavelengths and possibly by a luminance diminution. Thus, blue sunglasses are thought to be useful in the treatment of patients with photosensitive epilepsy.

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EEG characteristics of epileptic pattern sensitivity and their relation to the nature of pattern stimulation and the effects of sodium valproate

Cited by 17 publications

References 10 publications

Valproate reduces spontaneous generalized spikes and waves but not photoparoxysmal reactions in patients with idiopathic generalized epilepsies

Valproate reduces spontaneous generalized spikes and waves but not photoparoxysmal reactions in patients with idiopathic generalized epilepsies

Pattern‐sensitive Epilepsy: Electroclinical Characteristics, Natural History, and Delineation of the Epileptic Syndrome

Usefulness of Blue Sunglasses in Photosensitive Epilepsy

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