title: Removal of eye movement artefacts from single channel recordings of retinal evoked potentials using synchronous dynamical embedding and independent component analysis.
abstract: 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.
authors.affiliation: Department of Clinical Engineering, Royal Liverpool University Hospital, Medical School, Duncan Building, Prescot Street, Liverpool L78XP, UK. a.c.fisher@liv.ac.uk
authors.forename: A C
authors.initials: AC
authors.lastname: Fisher
authors.forename: W
authors.initials: W
authors.lastname: El-Deredy
authors.forename: R P
authors.initials: RP
authors.lastname: Hagan
authors.forename: M C
authors.initials: MC
authors.lastname: Brown
authors.forename: P J G
authors.initials: PJ
authors.lastname: Lisboa
mesh_terms: D016477:Artifacts; D003625:Data Collection; D003627:Data Interpretation, Statistical; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005133:Eye Movements; D012680:Sensitivity and Specificity