Removal of eye movement artefacts from single channel recordings of retinal evoked potentials using synchronous dynamical embedding and independent component analysis

• Published in: Medical & biological engineering & computing 2007-01, Vol.45 (1), p.69-77
• Main Authors: Fisher, A C, El-Deredy, W, Hagan, R P, Brown, M C, Lisboa, P J G
• Format: Article
• Language: English
• Subjects: Data Collection; Data Interpretation, Statistical; Electroretinography; Evoked Potentials, Visual - physiology; Eye Movements; Noise; Sensitivity and Specificity; Studies
• ISSN: 0140-0118; 1741-0444
• DOI: 10.1007/s11517-006-0123-4

A system is described for the removal of eye movement and blink artefacts from single channel pattern reversal electroretinogram recordings of very poor signal-to-noise ratios. Artefacts are detected and removed by using a blind source separation technique based on the jadeR independent component analysis algorithm. The single channel data are arranged as a series of overlapping time-delayed vectors forming a dynamical embedding matrix. The structure of this matrix is constrained to the phase of the stimulation epoch: the term synchronous dynamical embedding is coined. A novel method using a marker channel with a non-independent synchronous feature is employed to identify the single most relevant source estimation for reconstruction and signal recovery. This method is non-lossy, all underlying signal being recovered. In synthetic datasets of defined noise content and in standardised real data recordings, the performance of this technique is compared to conventional fixed-threshold hard-limit rejection. The most significant relative improvements are achieved when movement and blink artefacts are greatest: no improvement is demonstrable for the random noise only situation.