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Identification of fetal auditory evoked cortical responses using a denoising method based on periodic component analysis

  • Liviu Moraru
  • R. Sameni
  • U. Schneider
  • C. Jutten
  • J. Haueisen
  • D. Hoyer
Part of the IFMBE Proceedings book series (IFMBE, volume 22)

Abstract

The analysis of auditory evoked cortical responses in the MEG of preterm neonates may result in early markers of functional cerebral development. A major constraint to this approach is the very low signal-to-noise ratio due to the fact that fMEG recordings are contaminated by other biological sources (mainly maternal and fetal cardiac activities). This paper presents a study of the fetal auditory response to external stimuli using a novel algorithm to remove the maternal and fetal cardiac activities based on Periodic Component Analysis, an improved extension of the conventional source separation techniques being customized for MCG signal decomposition and filtering. Acoustic stimuli were delivered to 10 normal healthy fetuses at different stages of gestation (between 29th and 34th completed gestational weeks). The MEG sensors were placed in a location over the women’s abdomen nearest to the fetal head, as determined by ultrasound images. In 7 out of the 10 cases clear responses of the fetal auditory evoked potentials could be detected by visual examination of the averaged time courses, characterized by a clear prominent component having latencies in the range 150–300 ms. A significance measure based on a bootstrap confidence interval has been employed in order to validate the identified responses. The accurate identification and removal of the MCG components enabled the detection of the evoked cortical responses in low signal-to-noise ratio conditions.

Keywords

Auditory evoked cortical responses fMEG magnetoencephalography periodic component analysis 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Liviu Moraru
    • 1
  • R. Sameni
    • 2
  • U. Schneider
    • 3
  • C. Jutten
    • 2
  • J. Haueisen
    • 1
  • D. Hoyer
    • 1
  1. 1.Biomagnetic Center, Department of NeurologyFSUJenaGermany
  2. 2.Department of Images and Signals, INPGGIPSA-LabGrenoble CedexFrance
  3. 3.Department of Obstetrics, University HospitalFriedrich Schiller University JenaGermany

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