Authors:
Antje Bock
1
;
Andrea A. Kühn
1
;
Lutz Trahms
2
and
Tilmann H. Sander
2
Affiliations:
1
Charité Berlin, Germany
;
2
Physikalisch-Technische Bundesanstalt, Germany
Keyword(s):
Magnetoencephalography, Deep brain stimulation, Local field potentials, Cardiac cycle artefact, Principal component analysis, Signal space projection, Coherence.
Related
Ontology
Subjects/Areas/Topics:
Applications and Services
;
Biomedical Engineering
;
Biomedical Signal Processing
;
Computer Vision, Visualization and Computer Graphics
;
Electromagnetic Fields in Biology and Medicine
;
Informatics in Control, Automation and Robotics
;
Medical Image Detection, Acquisition, Analysis and Processing
;
Signal Processing, Sensors, Systems Modeling and Control
;
Time and Frequency Response
;
Time-Frequency Analysis
Abstract:
Simultaneous magnetoencephalography (MEG) and local field potential (LFP) recordings in patients undergoing deep brain stimulation (DBS) for severe movement disorders is a promising technique both for clinical applications and basic research. Recordings can be accomplished during the time interval between electrode insertion and implantation of the stimulator while electrodes are externalised. At present, strong cardiac cycle artefacts (CCA) are observed in theMEG signals around the area, where the disposable stainless steel electrode wires leave the skull. The CCA refers to the remanent magnetic field of those wires underneath the sensors, which are moved by local pulsations of the blood vessels. Here, we demonstrate a new approach to partially remove the CCA by applying principal component analysis (PCA) to an averaged CCA and subsequent signal space projection (SSP) method. Further steps of analysis such as coherence calculations are less distorted after SSP.