Beaming Signal Sources in Measurement of Focal Visual Evoked Cortical Potentials

Abstract

VECPs (Visual Evoked Cortical Potential) after focal stimulation used in perimetry have weak amplitudes in comparison to the spontaneous EEG, thus the SNR (Signal-to-Noise Ratio) falls off down to -20dB and less. The shape of the VECP waves depends on several parameters and is unknown in general. Then for SNR enhancement and signal detection shape-independent methods can be used only. The most common of them is the stimulus synchronized averaging, which causes cumulative prolongation of the measurement time corresponding to the averaging order. For online measurements of VECP other ways in signal improvement are needed. in this paper a new method for SNR enhancement based on beam forming is introduced. While the anatomical structures of sources generating the focal VECP are known roughly and the electrode positions have sufficient density over the visual cortex, signal sources can be focused by controlling the channel delay.

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Document Details

Document Type
Technical Report
Publication Date
Oct 25, 2001
Accession Number
ADA410002

Entities

People

  • G. Henning
  • K. Schellhorn
  • K. U. Plagwitz
  • P. Husar
  • S. Berkes

Tags

Communities of Interest

  • Biomedical
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Analogs
  • Biomedical Engineering
  • Data Analysis
  • Digital Signal Processing
  • Electrical Engineering
  • Electrodes
  • Engineering
  • Horizontal Orientation
  • Light Emitting Diodes
  • Military Research
  • Noise
  • Orientation (Direction)
  • Signal Processing
  • United Kingdom
  • Visual Cortex
  • White Noise

Readers

  • Pulsed Power and Plasma Physics.
  • Radio communications and signal processing.
  • Vision Science/Vision Psychology/Cognitive Neuroscience.