Eye closure abnormalities and occipital spikes: two types of photosensitive epilepsy

1997 ◽  
Vol 102 (5) ◽  
pp. P65
Author(s):  
G.F.A. Harding ◽  
F. Fylan
2004 ◽  
Vol 4 ◽  
pp. 521-530 ◽  
Author(s):  
Ebere C. Anyanwu ◽  
John E. Ehiri ◽  
Andrew W. Campbell

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.


2015 ◽  
Vol 23 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Athanasios Covanis

Summary Introduction. Eyelid myoclonia and absences (ELMA) was first described by Jeavons in 1977 as a separate type of photosensitive epilepsy. Aim and method. The aim is to consider the updated electro-clinical pathophysiology and to discuss terminology, classification and differential diagnosis. The review includes our own research and relevant papers on the subject of Jeavons syndrome (JS). Review and differential diagnosis. Definition: Jeavons syndrome is a generalized idiopathic (genetic) epilepsy syndrome (IGE) characterized by eyelid myoclonia, other seizures (absences, myoclonic and or generalized tonic-clonic) and EEG paroxysms induced by voluntary or on command eye closure, in the light and photosensitivity. Demographical data: The prevalence of JS has been reported to vary from 7.3% to 12.9% among idiopathic generalized epilepsies and 2.5% to 2.7% among all patients with epileptic disorders. Etiology: JS, as is the case for all idiopathic generalized epilepsies, is genetic and the familial preponderance and concordance is high. Pathophysiology: Three factors are important in order for JS to manifest clinically; the genetic predisposition, the voluntary or on command eye closure and the light input. Clinical forms of JS: we have identified four forms of JS; early onset (< 4 years), mild form, classical form and an ELMA-JME form. Diagnosis: the diagnosis of JS is based on the history, clinical observation and provocation and the confirmation with an EEG. Differential diagnosis: is easily made from tics, other idiopathic generalized or focal cryptogenic/symptomatic epilepsies. Conclusion. JS is characterized by unique electro-clinical features evoked by voluntary or on command eye closure in the light and photosensitivity.


CNS Drugs ◽  
2020 ◽  
Vol 34 (10) ◽  
pp. 1075-1086
Author(s):  
Ronald C. Reed ◽  
William E. Rosenfeld ◽  
Susan M. Lippmann ◽  
Rene M. J. C. Eijkemans ◽  
Dorothee G. A. Kasteleijn-Nolst Trenité

2019 ◽  
Vol 40 (4) ◽  
pp. 341-346
Author(s):  
Kulwinder Singh ◽  
Karan Goel ◽  
Kamaljit Singh Bhatia ◽  
Hardeep Singh Ryait

Abstract Different fiber amplifiers such as semiconductor optical amplifier, erbium-doped fiber amplifier and erbium ytterbium-co-doped fiber amplifier (EYCDFA) are investigated for 16×40 GB/s wavelength division multiplexing system. Various performance parameters including Q-factor, bit error rate, jitter, eye opening and eye closure are observed and analyzed. It is reported that EYCDFA is a better choice among the tested amplifiers. The proposed system is also investigated in terms of transmission distance.


Author(s):  
A. Tartaglione ◽  
F. Bandini ◽  
M. Maculotti ◽  
M. Marogna ◽  
L. Spadavecchia ◽  
...  
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