TITLE

Is colour modulation an independent factor in human visual photosensitivity?

AUTHOR(S)
Jaime Parra; Fernando H. Lopes da Silva; Hans Stroink; Stiliyan Kalitzin
PUB. DATE
June 2007
SOURCE
Brain: A Journal of Neurology;Jun2007, Vol. 130 Issue 6, p1679
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Considering that the role of colour in photosensitive epilepsy (PSE) remains unclear, we designed a study to determine the potential of different colours, colour combinations and white light to trigger photoparoxysmal responses (PPRs) under stringent controlled conditions. After assessing their photosensitivity to stroboscopic white light and black and white patterns, we studied 43 consecutive PSE patients (mean age 19 years, 34 women), using a specially designed colour stimulator. Stimuli included: pulse trains between 10 and 30 Hz of white light and of all primary colours, and also isoluminant alternating time-sequences of colours. Illuminance was kept constant at 100 lux. A progressive stepwise increase of the modulation-depth (MD) of the stimuli was used to determine PPRs threshold. Whereas all the 43 patients were found to be sensitive during the stroboscopic and pattern protocol, only 25 showed PPRs (Waltzs score >2) at least in one session when studied with the colour stimulator. Coloured stimuli elicited PPRs in all these patients, whereas white light did so only in 17 patients. Of the primary colours, red elicited more PPRs (54 in 22 patients) and at a lower MD (max Z-score 0.93 at 10 Hz). Of the alternating sequences, the red–blue was the most provocative stimulus, especially below 30 Hz (100% of patients, max Z-score: 1.65 at 15 Hz). Blue–green was the least provocative stimulus, since it elicited only seven PPRs in seven (28%) patients (max Z-score 0.44 at 10 Hz). Sensitivity to alternating colours was not correlated to sensitivity to individual colours. We conclude that colour sensitivity follows two different mechanisms: one, dependent on colour modulation, plays a role at lower frequencies (<30 Hz). Another, dependent on single-colour light intensity modulation correlates to white light sensitivity and is activated at higher frequencies. Our results suggest that the prescription of spectacles with coloured lenses, tailored to the patient, can be an effective preventative measure against visually induced seizures.
ACCESSION #
25208671

 

Related Articles

  • Visual-Sensitive Epilepsies: Classification and Review. Seshia, Shashi S.; Carmant, Lionel // Canadian Journal of Neurological Sciences;Aug2005, Vol. 32 Issue 3, p298 

    Studies the concepts of photosensitivity, photosensitive seizures and photosensitive epilepsy. Characteristics of visual-sensitive epilepsies; Ability of chromosomal and DNA testing to refine the classification of photosensitive seizures and epilepsies; Recommendation of a standardized approach...

  • Clinical and EEG Analysis of Patients With Idiopathic Generalized Epilepsy and Photosensitivity. Demırkaya, Nazlı; Yavuz, Ebru Nur Vanli; Altindağ, Ebru; Baykan, Betul // Journal of Neurological Sciences;2009, Vol. 26 Issue 1, p26 

    Introduction: Our aim is to define the electroclinical characteristics of patients with photosensitive idiopathic generalized epilepsy (IGE) and to investigate the differences in seizure types, therapy and outcome between subgroups, based on photoparoxysmal response (PPR)/EEG characteristics and...

  • Lack of cortical contrast gain control in human photosensitive epilepsy. Porciatti, Vittorio; Bonanni, Paolo; Fiorentini, Adriana; Guerrini, Renzo // Nature Neuroscience;Mar2000, Vol. 3 Issue 3, p259 

    Television and video games may be powerful triggers for visually induced epileptic seizures. To better understand the triggering elements of visual stimuli and cortical mechanisms of hyperexcitability, we examined eleven patients with idiopathic photosensitive epilepsy by recording visually...

  • Immediate versus remote judgements: Delay of response and rate of stimulus presentation in time... Vitulli, William F.; Crimmins, Kathleen A. // Perceptual & Motor Skills;Feb98, Vol. 86 Issue 1, p19 

    Focuses on the effect of a delay between stimulus presentations and estimations of time, while assessing the reliability of a 1996 study by Vitulli and Shepard pertaining to time estimation and delay. Detailed information on the subjects used in the study; Details on the main effects for rate...

  • Photosensitive epilepsy in children who set fires. Meinhard, Elizabeth A.; Oozeer, Rowena; Cameron, Duncan // British Medical Journal (Clinical Research Edition);6/25/1988, Vol. 296 Issue 6639, p1773 

    Investigates the influences of photosensitive epilepsy in children with repeated actuation of fire setting in Great Britain. Presentation of cases; Implications of sensitivity to television as a cause of epilepsy; Importance of submitting patients to electroencephalography.

  • PHOTOSENSITIVITY. Tatum IV, William O.; Kaplan, Peter W.; Jallon, Pierre // Epilepsy A to Z: A Concise Encyclopedia;2009, p255 

    An encyclopedia entry for "photosensitivity" is presented. It refers to the triggering of clinical seizures or the demonstration of bursts of spontaneous interictal epileptiform discharges (IED) on the electroencephalogram (EEG) by light. Photosensitivity may less frequently be associated with...

  • Headache, epilepsy and photosensitivity: how are they connected? Kasteleijn-Nolst Trenité, Dorothée G. A.; Verrotti, Alberto; Di Fonzo, Alessia; Cantonetti, Laura; Bruschi, Raffaella; Chiarelli, Francesco; Villa, Maria Pia; Parisi, Pasquale // Journal of Headache & Pain;Dec2010, Vol. 11 Issue 6, p469 

    lthough headache and epilepsy have often been associated, the precise electroclinical and pathophysiological interaction between these disorders and in particular its relations with photosensitivity is as yet to be fully understood in adults or children. The association between headache and...

  • Reconfiguration of task-set: Is it easier to switch to the weaker task? Monsell, Stephen; Yeung, Nick; Azuma, Rayna // Psychological Research;2000, Vol. 63 Issue 3/4, p250 

    Abstract Switching between two tasks afforded by the same stimuli results in slower reactions and more errors on the first stimulus after the task changes. This "switch cost" is reduced, but not usually eliminated, by the opportunity to prepare for a task switch. While there is agreement that...

  • Behavior Analytic Instruction for Learners with Autism: Advances in Stimulus Control Technology. Green, Gina // Focus on Autism & Other Developmental Disabilities;Summer 2001, Vol. 16 Issue 2, p72 

    Assesses some selected stimulus control techniques for learners with autism. Overview on the applied behavior analysis for autism; Discussion on teaching discriminations and stimulus equivalence classes; Suggestions on promoting independence and initiations.

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics