Photosensitive epilepsy: Spectral and coherence analyses of EEG using 14 Hz intermittent photic stimulation

E. Visani, G. Varotto, S. Binelli, L. Fratello, S. Franceschetti, G. Avanzini, F. Panzica

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Objective: To evaluate the EEG recorded in photosensitive idiopathic generalised epilepsy (IGE) patients at rest and during 14 Hz IPS, frequency capable of inducing photoparoxysmal responses (PPRs). Methods: Power spectrum density and coherence profiles were estimated using a block autoregressive parametric model (AR) in 28 patients and 22 controls. Results: At rest, the intra- and inter-hemispheric coherence spectra showed a significantly larger number of coherence peaks in the gamma band in patients with respect to controls. During intermittent photic stimulation (IPS), coherent gamma activity is mainly presented as IPS frequency harmonics; moreover, the patients' mean coherence values significantly increased. In six patients re-evaluated with IPS after putting on glasses with Z1 blue lens (which counteracts PPR) the spectral and coherence profiles tended to return to the resting ones. Conclusions: Patients are endowed with inherited EEG hyper-synchrony as shown by the large number of coherence peaks detectable under resting conditions, whereas IPS enhances intra- and inter-hemispheric mean coherence values in the gamma band. The persistence of alpha activity peaks during IPS in most controls but not in patients suggests that the alpha generating network plays a significant role in counteracting PPR. Significance: Both gamma and alpha EEG generators are involved in the PPR generation and in the widespread synchronisation characterising the IGE-associated photosensitivity.

Original languageEnglish
Pages (from-to)318-324
Number of pages7
JournalClinical Neurophysiology
Volume121
Issue number3
DOIs
Publication statusPublished - Mar 2010

Fingerprint

Reflex Epilepsy
Photic Stimulation
Electroencephalography
Lenses
Glass

Keywords

  • AR model
  • Coherence analysis
  • IGE
  • Photosensitivity
  • Spectral analysis

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Physiology (medical)
  • Sensory Systems

Cite this

Photosensitive epilepsy : Spectral and coherence analyses of EEG using 14 Hz intermittent photic stimulation. / Visani, E.; Varotto, G.; Binelli, S.; Fratello, L.; Franceschetti, S.; Avanzini, G.; Panzica, F.

In: Clinical Neurophysiology, Vol. 121, No. 3, 03.2010, p. 318-324.

Research output: Contribution to journalArticle

@article{d03aa040e783471487ea940b94e9e165,
title = "Photosensitive epilepsy: Spectral and coherence analyses of EEG using 14 Hz intermittent photic stimulation",
abstract = "Objective: To evaluate the EEG recorded in photosensitive idiopathic generalised epilepsy (IGE) patients at rest and during 14 Hz IPS, frequency capable of inducing photoparoxysmal responses (PPRs). Methods: Power spectrum density and coherence profiles were estimated using a block autoregressive parametric model (AR) in 28 patients and 22 controls. Results: At rest, the intra- and inter-hemispheric coherence spectra showed a significantly larger number of coherence peaks in the gamma band in patients with respect to controls. During intermittent photic stimulation (IPS), coherent gamma activity is mainly presented as IPS frequency harmonics; moreover, the patients' mean coherence values significantly increased. In six patients re-evaluated with IPS after putting on glasses with Z1 blue lens (which counteracts PPR) the spectral and coherence profiles tended to return to the resting ones. Conclusions: Patients are endowed with inherited EEG hyper-synchrony as shown by the large number of coherence peaks detectable under resting conditions, whereas IPS enhances intra- and inter-hemispheric mean coherence values in the gamma band. The persistence of alpha activity peaks during IPS in most controls but not in patients suggests that the alpha generating network plays a significant role in counteracting PPR. Significance: Both gamma and alpha EEG generators are involved in the PPR generation and in the widespread synchronisation characterising the IGE-associated photosensitivity.",
keywords = "AR model, Coherence analysis, IGE, Photosensitivity, Spectral analysis",
author = "E. Visani and G. Varotto and S. Binelli and L. Fratello and S. Franceschetti and G. Avanzini and F. Panzica",
year = "2010",
month = "3",
doi = "10.1016/j.clinph.2009.12.003",
language = "English",
volume = "121",
pages = "318--324",
journal = "Clinical Neurophysiology",
issn = "1388-2457",
publisher = "Elsevier Ireland Ltd",
number = "3",

}

TY - JOUR

T1 - Photosensitive epilepsy

T2 - Spectral and coherence analyses of EEG using 14 Hz intermittent photic stimulation

AU - Visani, E.

AU - Varotto, G.

AU - Binelli, S.

AU - Fratello, L.

AU - Franceschetti, S.

AU - Avanzini, G.

AU - Panzica, F.

PY - 2010/3

Y1 - 2010/3

N2 - Objective: To evaluate the EEG recorded in photosensitive idiopathic generalised epilepsy (IGE) patients at rest and during 14 Hz IPS, frequency capable of inducing photoparoxysmal responses (PPRs). Methods: Power spectrum density and coherence profiles were estimated using a block autoregressive parametric model (AR) in 28 patients and 22 controls. Results: At rest, the intra- and inter-hemispheric coherence spectra showed a significantly larger number of coherence peaks in the gamma band in patients with respect to controls. During intermittent photic stimulation (IPS), coherent gamma activity is mainly presented as IPS frequency harmonics; moreover, the patients' mean coherence values significantly increased. In six patients re-evaluated with IPS after putting on glasses with Z1 blue lens (which counteracts PPR) the spectral and coherence profiles tended to return to the resting ones. Conclusions: Patients are endowed with inherited EEG hyper-synchrony as shown by the large number of coherence peaks detectable under resting conditions, whereas IPS enhances intra- and inter-hemispheric mean coherence values in the gamma band. The persistence of alpha activity peaks during IPS in most controls but not in patients suggests that the alpha generating network plays a significant role in counteracting PPR. Significance: Both gamma and alpha EEG generators are involved in the PPR generation and in the widespread synchronisation characterising the IGE-associated photosensitivity.

AB - Objective: To evaluate the EEG recorded in photosensitive idiopathic generalised epilepsy (IGE) patients at rest and during 14 Hz IPS, frequency capable of inducing photoparoxysmal responses (PPRs). Methods: Power spectrum density and coherence profiles were estimated using a block autoregressive parametric model (AR) in 28 patients and 22 controls. Results: At rest, the intra- and inter-hemispheric coherence spectra showed a significantly larger number of coherence peaks in the gamma band in patients with respect to controls. During intermittent photic stimulation (IPS), coherent gamma activity is mainly presented as IPS frequency harmonics; moreover, the patients' mean coherence values significantly increased. In six patients re-evaluated with IPS after putting on glasses with Z1 blue lens (which counteracts PPR) the spectral and coherence profiles tended to return to the resting ones. Conclusions: Patients are endowed with inherited EEG hyper-synchrony as shown by the large number of coherence peaks detectable under resting conditions, whereas IPS enhances intra- and inter-hemispheric mean coherence values in the gamma band. The persistence of alpha activity peaks during IPS in most controls but not in patients suggests that the alpha generating network plays a significant role in counteracting PPR. Significance: Both gamma and alpha EEG generators are involved in the PPR generation and in the widespread synchronisation characterising the IGE-associated photosensitivity.

KW - AR model

KW - Coherence analysis

KW - IGE

KW - Photosensitivity

KW - Spectral analysis

UR - http://www.scopus.com/inward/record.url?scp=75449117269&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=75449117269&partnerID=8YFLogxK

U2 - 10.1016/j.clinph.2009.12.003

DO - 10.1016/j.clinph.2009.12.003

M3 - Article

C2 - 20071221

AN - SCOPUS:75449117269

VL - 121

SP - 318

EP - 324

JO - Clinical Neurophysiology

JF - Clinical Neurophysiology

SN - 1388-2457

IS - 3

ER -