Detection of foveation windows and analysis of foveation sequences in congenital nystagmus

Giulio Pasquariello*, Mario Cesarelli, Paolo Bifulco, Antonio Fratini, Antonio La Gatta, Domenico Boccuzzi

*Corresponding author for this work

Research output: Chapter in Book/Published conference outputConference publication

Abstract

Congenital nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated ocular oscillations, that can arise since the first months of life. Pathogenesis of congenital nystagmus is still under investigation. In general, CN patients show a considerable decrease of their visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations, mainly horizontal. However, image stabilisation is still achieved during the short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals). To quantify the extent of nystagmus, eye movement recording are routinely employed, allowing physicians to extract and analyse nystagmus main features such as shape, amplitude and frequency. Using eye movement recording, it is also possible to compute estimated visual acuity predictors: analytical functions which estimates expected visual acuity using signal features such as foveation time and foveation position variability. Use of those functions add information to typical visual acuity measurement (e.g. Landolt C test) and could be a support for therapy planning or monitoring. This study focus on robust detection of CN patients' foveations. Specifically, it proposes a method to recognize the exact signal tracts in which a subject foveates, This paper also analyses foveation sequences. About 50 eyemovement recordings, either infrared-oculographic or electrooculographic, from different CN subjects were acquired. Results suggest that an exponential interpolation for the slow phases of nystagmus could improve foveation time computing and reduce influence of breaking saccades and data noise. Moreover a concise description of foveation sequence variability can be achieved using non-fitting splines.

Original languageEnglish
Title of host publication4th European Conference of the International Federation for Medical and Biological Engineering
Subtitle of host publicationECIFMBE 2008 23–27 November 2008 Antwerp, Belgium
EditorsJos Vander Sloten, Pascal Verdonck, Marc Nyssen, Jens Haueisen
Place of PublicationBerlin (DE)
PublisherSpringer
Pages364-367
Number of pages4
ISBN (Electronic)978-3-540-89208-3
ISBN (Print)978-3-540-89207-6
DOIs
Publication statusPublished - 2008
Event4th European Conference of the International Federation for Medical and Biological Engineering - Antwerp, Belgium
Duration: 23 Nov 200827 Nov 2008

Publication series

NameIFMBE proceedings
PublisherSpringer
Volume22
ISSN (Print)1680-0737

Conference

Conference4th European Conference of the International Federation for Medical and Biological Engineering
Abbreviated titleECIFMBE 2008
Country/TerritoryBelgium
CityAntwerp
Period23/11/0827/11/08

Keywords

  • congenital nystagmus
  • eye movement signal processing
  • foveation
  • interpolation

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  • Correspondence between muscle motion and EMG activity during whole body vibration

    Fratini, A., Bifulco, P., Cesarelli, M., Pasquariello, G., Romano, M. & la Gatta, A., 2008, 4th European Conference of the International Federation for Medical and Biological Engineering: ECIFMBE 2008 23–27 November 2008 Antwerp, Belgium. Vander Sloten, J., Verdonck, P., Nyssen, M. & Haueisen, J. (eds.). Berlin (DE): Springer, p. 2069-2072 4 p. (IFMBE proceedings; vol. 22).

    Research output: Chapter in Book/Published conference outputConference publication

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