Documenta Ophthalmologica

, Volume 95, Issue 1, pp 1–14 | Cite as

Guidelines for calibration of stimulus and recording parameters used in clinical electrophysiology of vision

  • Mitchell Brigell
  • Michael Bach
  • Colin Barber
  • Kazuo Kawasaki
  • Aart Kooijman

Abstract

In order to perform a technically adequate clinical electrophysiological procedure it is necessary to calibrate the stimulating and recording equipment. Published standards for the electroretinogram (ERG)[1], electro-oculogram (EOG)[2], visual evoked potential (VEP)[3], and guidelines for the Pattern ERG (PERG)[4] specify stimulus and recording parameters. Yet, most commercial instruments do not provide the means for calibration of these parameters. The goal of this document is to provide guidelines for proper calibration of stimulus and recording equipment. The need for such guidelines is clear on both clinical and scientific grounds. Stimulus and amplifier characteristics have substantial effects on the peak latency and amplitude measurements that are commonly used in clinical electrophysiology. Many review articles on clinical electrophysiology emphasize the need for establishing norms for each laboratory as a function of age and gender rather than relying on published norms. However, if stimulus and recording parameters are not calibrated periodically, then these norms may actually be misleading due to changes in stimulus or recording conditions induced by aging of equipment or inadvertent change in settings.

This document is divided into two major sections. The first is concerned with calibration of the visual stimulus. It begins with background technical information on the physics of light and its measurement. This is followed by protocols for measurement of the luminous intensity of flash stimuli and the mean luminance, contrast, and visual angle of pattern stimuli. The second section is concerned with calibration of electrophysiologic recording systems. It begins with a description of the characteristics of bioelectrical signals and their measurement. This is followed by protocols for measurement of electrode impedance and amplifier calibration. Although this document was prepared as guidelines for clinical electrophysiological testing, it should be noted that the techniques described are more generally applicable to studies which are dependent upon accurate measurement of luminance or electrophysiological signals.

electroretinography luminance photometry visual evoked potentials 

References

  1. 1.
    Marmor MF, Zrenner E. Standard for clinical electroretinography (1994 update). Doc Ophthalmol 1995; 89:199–210.PubMedCrossRefGoogle Scholar
  2. 2.
    Marmor MF, Zrenner E. Standard for clinical electro-oculography. International Society For the Clinical Electrophysiology of Vision. Doc Ophthalmol 1993; 85:115–124.Google Scholar
  3. 3.
    Harding GFA, Odom JV, Spileers W, et al. Standard for visual evoked potentials 1995. Vis Res 1996; 36:3567–3572.PubMedCrossRefGoogle Scholar
  4. 4.
    Marmor MF, Holder GE, Porciatti V, et al. Guidelines for basic pattern electroretinography. Recommendations by The International Society For the Clinical Electrophysiology of Vision. Doc Ophthalmol 1996; 91:291–298.Google Scholar

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Mitchell Brigell
    • 1
  • Michael Bach
    • 1
  • Colin Barber
    • 1
  • Kazuo Kawasaki
    • 1
  • Aart Kooijman
    • 1
  1. 1.Calibration Standard Committee of the International Society for Clinical Electrophysiology of Vision (ISCEV)Germany

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