Advertisement

Documenta Ophthalmologica

, Volume 112, Issue 3, pp 169–175 | Cite as

Automated Post Hoc Removal of Power-Line and CRT Frame Pulse Contamination from Retinal and Cortical Evoked Potentials (EPs)

  • Anthony C. FisherEmail author
  • Azzam F. G. Taktak
  • Richard P. Hagan
  • Malcolm C. Brown
Original Paper

Abstract

Recordings of the ERG, PERG, VEP and their multi-focal variants are occasionally contaminated with harmonic noise arising from the mains supply and CRT monitors. These noise contributions can be modelled as distorted sinusoids and identified by means of non-linear multiple regression and removed: no a priori estimates of number or frequency of noise sources are required. This approach is termed noise cancellation and does not constitute any form of notch filter: the fidelity of the underlying waveform is preserved. Here the simple theory is illustrated in artificial datasets and then applied to clinical examples of PERG and VEP. The programming language used throughout is MatLab R13SP3 (Mathworks UK Ltd.).

Keywords

ERG Noise cancellation Notch filter PERG VEP 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Holder GE (2001) The pattern electroretinogram. In: Fishman GA, Birch DG, Holder GE, Brigell MG (eds) Electrophysiologic testing, 2nd edn. The Foundation of The American Academy of Ophthalmology, San Francisco, pp␣197–235Google Scholar
  2. 2.
    Bach M, Hawlina M, Holder GE, Marmor M, Meigen T, Vaegan, Miyake Y (2000) Standard for pattern electroretinography. Doc Ophthalmol 101:11–18PubMedCrossRefGoogle Scholar
  3. 3.
    Lagarias JC, Reeds JA, Wright MH, Wright PE (1998) Convergence properties of the Nelder–Mead simplex method in low dimensions. SIAM J Optim 9:12–147CrossRefGoogle Scholar
  4. 4.
  5. 5.
    Fisher AC, Brown MC, Hagan RP (2005) An adaptive heuristic artefact rejection scheme for visual electrodiagnostic recordings. Proceedings of ISCEV Conference, Glasgow, September 2005. Internet: http://www.briscev.org.uk
  6. 6.
    Brown MC, Hagan RP, Fisher, AC. Post capture processing of electro-diagnostic signals. Proceedings of ISCEV Conference, Glasgow, September 2005. Internet: http://www.briscev.org.uk

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Anthony C. Fisher
    • 1
    Email author
  • Azzam F. G. Taktak
    • 1
  • Richard P. Hagan
    • 1
  • Malcolm C. Brown
    • 1
  1. 1.Department of Clinical Engineering and Clinical Eye Research CentreRoyal Liverpool University HospitalLiverpoolUK

Personalised recommendations