This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Gomez, S. M. Articles by Hall, I. S. Search for Related Content PubMed PubMed Citation Articles by Gomez, S. M. Articles by Hall, I. S.

Stroke, Vol 21, 1746-1748, Copyright © 1990 by American Heart Association

ARTICLES

Transcranial Doppler ultrasonographic assessment of intermittent light stimulation at different frequencies

SM Gomez, CR Gomez and IS Hall
Department of Neurology, St. Louis University Medical Center, MO 63110- 0250.

Seven normal adult volunteers underwent intermittent photic stimulation at frequencies of 5-60 Hz while their posterior cerebral arteries were monitored using transcranial Doppler ultrasound. Baseline measurements were obtained under conditions of total darkness, and sampling was also done during continuous illumination. Overall variation in mean flow velocity between complete darkness and continuous illumination was 9.8%, but the maximal change (expressed as percentage deviation from baseline) occurred consistently when stimulation was undertaken at frequencies of 10 (21%) and 20 (19%) Hz (p = 0.05). Frequencies higher than 20 Hz resulted in mean flow velocity variations that were not significantly different from that found during continuous illumination. The optimal frequency of intermittent visual stimulation required to induce measurable changes in posterior cerebral artery Doppler characteristics appears to be in the range 10-20 Hz.

This article has been cited by other articles:

				G. Panczel, M. Daffertshofer, S. Ries, D. Spiegel, and M. Hennerici Age and Stimulus Dependency of Visually Evoked Cerebral Blood Flow Responses Stroke, March 1, 1999; 30(3): 619 - 623. [Abstract] [Full Text] [PDF]

				S. Knecht, M. Deppe, E.-B. Ringelstein, M. Wirtz, H. Lohmann, B. Drager, T. Huber, and H. Henningsen Reproducibility of Functional Transcranial Doppler Sonography in Determining Hemispheric Language Lateralization Stroke, June 1, 1998; 29(6): 1155 - 1159. [Abstract] [Full Text] [PDF]

				S. Knecht, M. Deppe, A. Ebner, H. Henningsen, T. Huber, H. Jokeit, and E.-B. Ringelstein Noninvasive Determination of Language Lateralization by Functional Transcranial Doppler Sonography : A Comparison With the Wada Test Stroke, January 1, 1998; 29(1): 82 - 86. [Abstract] [Full Text] [PDF]

				M. Sturzenegger, D. W. Newell, and R. Aaslid Visually Evoked Blood Flow Response Assessed by Simultaneous Two-Channel Transcranial Doppler Using Flow Velocity Averaging Stroke, December 1, 1996; 27(12): 2256 - 2261. [Abstract] [Full Text]

				V. U. Becker, H. C. Hansen, U. Brewitt, and A. Thie Visually Evoked Cerebral Blood Flow Velocity Changes in Different States of Brain Dysfunction Stroke, March 1, 1996; 27(3): 446 - 449. [Abstract] [Full Text]

				P.P. Urban, A. Allardt, B. Tettenborn, H.C. Hopf, S. Pfennigsdorf, and W. Lieb Photoreactive Flow Changes in the Posterior Cerebral Artery in Control Subjects and Patients With Occipital Lobe Infarction Stroke, October 1, 1995; 26(10): 1817 - 1819. [Abstract] [Full Text]