The effect of sodium valproate on the photosensitive VEP

Herrick, C. E.; Harding, G. F. A.

doi:10.1007/978-94-011-6645-4_64

Cited by 4 publications

(2 citation statements)

References 27 publications

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“…Using an on-off SSVEP paradigm, Geller et al (2005) found no effect of VPA on the second harmonic amplitude in generalized epilepsy compared to healthy controls. In contrast to the above, amplitude of the flash VEP in photosensitive epilepsy patients decreased following treatment with VPA (Herrick and Harding, 1980). Similar results were reported for other AEDs.…”

Section: Discussionmentioning

confidence: 96%

Altered visual contrast gain control is sensitive for idiopathic generalized epilepsies

Won

Kim

Chaovalitwongse

et al. 2017

Clinical Neurophysiology

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Objective Visual hyperexcitability in the form of abnormal contrast gain control has been shown in photosensitive epilepsy and idiopathic generalized epilepsies. We assessed the accuracy and reliability of measures of visual contrast gain control in discerning individuals with idiopathic generalized epilepsies from healthy controls. Methods Twenty-four adult patients with idiopathic generalized epilepsy and 32 neurotypical control subjects from two study sites participated in a prospective, cross-sectional study. We recorded steady-state visual evoked potentials to a wide range of contrasts of a flickering grating stimulus. The resultant response magnitude vs. contrast curves were fitted to a standard model of contrast response function, and the model parameters were used as input features to a linear classifier to separate patients from controls. Additionally we compared the relative contribution of model parameters towards the classification using a sparse feature-selection approach. Results Classification accuracy was 80% or better. Sensitivity and specificity both were 80–85%. Cross validation confirmed robust classifier performance generalizable across the data from the two samples. Patients’ relative lack of gain control at high contrasts was the most important information distinguishing patients from controls. Conclusions Individuals with idiopathic generalized epilepsy were distinguishable from the neurotypical with a high degree of accuracy and reliability by a reduction in gain control at high contrasts. Significance Gain control is an essential neural operation that regulates neuronal sensitivity to stimuli and may represent a novel biomarker of hyperexcitability.

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Section: Discussionmentioning

confidence: 96%

Altered visual contrast gain control is sensitive for idiopathic generalized epilepsies

Won

Kim

Chaovalitwongse

et al. 2017

Clinical Neurophysiology

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“…Hence, this response is not as specific as the generalized spike and wave discharge. In treating PSE with sodium valproate (VPA), it is noted [9,10] that although the generalized seizure disappeared, the amplitude of N2-P2-N3 due to VPA in relation to predrug levels remained larger in comparison to controls.…”

Section: Introductionmentioning

confidence: 99%

Efficacy of Sodium Valproate in the Treatment of Photosensitive Epilepsy (PSE) and the Probable Reasons for the Persistence of Occipital Spikes

Anyanwu¹,

Ehiri

2004

The Scientific World JOURNAL

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Intermittent photic stimulation (IPS) in patients with photosensitive epilepsy (PSE) leads to EEG abnormalities, which include generalized discharges with spike and wave activity. This paper investigates 33 PSE patients, 14 (42%) males and 19 (58%) females. The age range was between 8 and 45 years. After the treatment of the patients with sodium valproate (VPA), the EEG examinations showed that the generalized discharges disappeared, while the occipital spikes persisted. The mechanism of action of VPA was re-evaluated in order to ascertain whether or not the persistent occipital was due to a failure in inhibitory postsynaptic potential (IPSP). It was concluded that the possible causes of VPA's inefficacy in abolishing occipital spikes in PSE was not necessarily due to a failure in IPSP, but rather it could be due to a time-dependent failure of certain cells of the visual system to respond positively to the VPA's modulatory activity, probably involving the ionic channels, neurotransmitters, and the second messenger systems. The relationship between occipital spikes and visual evoked response is discussed. The extent to which metabolic processes and neurotransmitters are involved is also evaluated.

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The Effect of Sodium Valproate on Sleep, Reaction Times, and Visual Evoked Potential in Normal Subjects

1985

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The effect of enteric-coated sodium valproate on 10 normal volunteer subjects was evaluated using simple reaction times, the visual evoked potential (VEP), and EEG sleep recording. Placebo, low-drug (500 mg), high-drug (1,000 mg), and withdrawal conditions were investigated. No significant treatment effect was found for simple reaction time nor was there any significant effect on either the latency or the amplitude of the VEP. Sleep recordings were analysed visually and also using an automated technique consisting of simple period analysis. The automated sleep results suggested that there was a decrease in rapid eye movement activity and an increase in delta activity under the high-drug condition. The visually analysed data did not reach significance, although they followed the same trends as those analysed automatically. It is possible that the automated results reflect an EEG frequency change rather than a change in the sleep cycle itself caused by treatment with sodium valproate.

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The effect of sodium valproate on the photosensitive VEP

Cited by 4 publications

References 27 publications

Altered visual contrast gain control is sensitive for idiopathic generalized epilepsies

Altered visual contrast gain control is sensitive for idiopathic generalized epilepsies

Efficacy of Sodium Valproate in the Treatment of Photosensitive Epilepsy (PSE) and the Probable Reasons for the Persistence of Occipital Spikes

The Effect of Sodium Valproate on Sleep, Reaction Times, and Visual Evoked Potential in Normal Subjects

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