China
Africa
Explore chapters and articles related to this topic
Tensor Methods for Clinical Informatics
Published in Kayvan Najarian, Delaram Kahrobaei, Enrique Domínguez, Reza Soroushmehr, Artificial Intelligence in Healthcare and Medicine, 2022
Cristian Minoccheri, Reza Soroushmehr, Jonathan Gryak, Kayvan Najarian
Naskovska et al. (2020) used both Magnetoencephalography (MEG) and EEG recordings to extract and differentiate physiologically meaningful signal sources during intermittent photic stimulation. The authors construct third-order tensors (with modes frequency, time, channels) from both MEG and EEG recordings, and – under the assumption that they have a common frequency mode – they use a coupled CP decomposition via simultaneous matrix diagonalization to extract features.
Factors That Can Exacerbate Seizures
Published in Stanley R. Resor, Henn Kutt, The Medical Treatment of Epilepsy, 2020
David E. Burdette, Robert G. Feldman
The induction of a photoconvulsive response via intermittent photic stimulation (IPS) often occurs without clinically evident seizure activity, although this may result from the practice of removing the IPS at the onset of paroxysmal activity on the EEG (36). In those patients who do have seizures, Jeavons and Harding (37) have found a preponderance of absence seizures, whereas Wadlington and Riley (38), who continued the photic stimulation in the face of paroxysmal electroencephalographic activity, have induced GTCSs in 80% of the 25 evaluated. The most sensitive frequencies for inducing photoconvulsive response have been found to be 15–20 hertz, and the binocular presentation of the photic stimulation enhances the epileptogenic effect (36,37). Investigation of other factors, such as the color of the stimulating light, has yielded inconsistent results, although some evidence suggests that red light may have a greater effect than other colors (36).
Electrodiagnosis
Published in Mark V. Boswell, B. Eliot Cole, Weiner's Pain Management, 2005
Ross E. Lipton, David M. Glick
In the experience of these authors and others, the migraineur demonstrates an occipital driving response at higher flash frequencies (at or above 20 flashes/s) during application of intermittent photic stimulation. This phenomenon is fairly specific for migraine (Golla & Winter, 1959; Slater, 1968; Smythe & Winter, 1964). This premise has been further established by spectral analysis (Simon et al., 1982).
Cortical excitability in epilepsy and the impact of antiepileptic drugs: transcranial magnetic stimulation applications
Published in Expert Review of Neurotherapeutics, 2020
Photosensitive epilepsy is a form of epilepsy in which generalized seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights; bold, regular patterns; or regular moving patterns. TMS findings include: (1) a high prevalence of phosphene [46], (2) a reduction in phosphene threshold, indicating a regional hyperexcitability in the primary visual cortex [46], (3) a normal SICI at ISI of 3 and 4 ms and ICF at ISIs of 12 and 14 ms [42], and (4) a lack of shortening of CSP duration to intermittent photic stimulation at 20 Hz in patients with photosensitive epilepsy and also have photoparoxysmal responses but not in those without photoparoxysmal response. It has to be remembered that photoparosysmal response and photosensitive generalized epilepsy are different entities but share a common feature which is the abnormal tendency to develop hypersynchronized neuronal activity throughout the brain. In normal individuals, there is a shortening of CSP duration to intermittent photic stimulation at 20 Hz which may have a possible protective nature [42]. The failure to shorten the CSP with intermittent photic stimulation in both conditions indicates an altered control of cortical excitability by visual input that may be linked to the abnormal tendency toward hypersynchronization and the weak influence of intermittent photic stimulation on the motor cortical output in such patients [47].
An update on EEG in migraine
Published in Expert Review of Neurotherapeutics, 2019
Several studies have reported that migraine patients exhibit an enhanced amplitude of EEG rhythms related to intermittent photic stimulation at approximately 20 Hz, the so-called ‘H response’ [17]. This EEG feature is relevant to the pathophysiology of migraine (see below), but has low diagnostic value. A randomized controlled study involving 171 patients with migraine without aura, 48 with chronic migraine, 61 with migraine with aura, and 24 controls, found an abnormal H response in one-half of the 171 migraine patients, with 82.24% sensitivity and 69.36% specificity. Quantitative EEG photic driving measurement confirmed its low diagnostic performance [18]. Although the study was affected by the bias of an imbalanced number of control conditions, its main conclusions are consistent with the general opinion regarding the scant utility of EEG for clinical diagnostic purposes [19]. Rare migraine forms, as migraine-associated vertigo, recently classified as vestibular migraine [20], presented with increased photic driving at frequencies between 3 and 24 Hz, when compared with Ménière’s disease.
Investigational small molecules in phase II clinical trials for the treatment of epilepsy
Published in Expert Opinion on Investigational Drugs, 2018
Marco Greco, Gaia Varriale, Giangennaro Coppola, Francesca Operto, Alberto Verrotti, Maria Laura Iezzi
Another phase II, multicenter, nonrandomized, single-blind, within-subject, placebo-controlled PoC study conducted at six specialized epilepsy centers in Germany, was made employing the PPR biomarker model (NCT00784212) [38]. In photosensitive patients, epileptiform electroencephalography (EEG) discharges can be evoked repeatedly in a very controlled manner in the laboratory by standardized intermittent photic stimulation (IPS). The SPR can be used as biomarkers of antiepileptic drug efficacy, because it can be acutely influenced by treatment with AEDs, compared with placebo [43,44]. This is the first time an AMPA receptor antagonist has been tested in this human model of reduction of SPR. The findings presented here showed a dose-dependent positive effect of BGG492 on the PPR and SPR in epilepsy patients with a generalized photoparoxysmal EEG response, meeting the PoC criteria of the study.