title: Quantitative EEG analysis using error reduction ratio-causality test; validation on simulated and real EEG data.
abstract: OBJECTIVE
  To introduce a new method of quantitative EEG analysis in the time domain, the error reduction ratio (ERR)-causality test. To compare performance against cross-correlation and coherence with phase measures.
  
  
  METHODS
  A simulation example was used as a gold standard to assess the performance of ERR-causality, against cross-correlation and coherence. The methods were then applied to real EEG data.
  
  
  RESULTS
  Analysis of both simulated and real EEG data demonstrates that ERR-causality successfully detects dynamically evolving changes between two signals, with very high time resolution, dependent on the sampling rate of the data. Our method can properly detect both linear and non-linear effects, encountered during analysis of focal and generalised seizures.
  
  
  CONCLUSIONS
  We introduce a new quantitative EEG method of analysis. It detects real time levels of synchronisation in the linear and non-linear domains. It computes directionality of information flow with corresponding time lags.
  
  
  CONCLUSIONS
  This novel dynamic real time EEG signal analysis unveils hidden neural network interactions with a very high time resolution. These interactions cannot be adequately resolved by the traditional methods of coherence and cross-correlation, which provide limited results in the presence of non-linear effects and lack fidelity for changes appearing over small periods of time.
authors.affiliation: Department of Clinical Neurophysiology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, United Kingdom. Electronic address: ptolemaios.sarrigiannis@sth.nhs.uk.
authors.forename: Ptolemaios G
authors.initials: PG
authors.lastname: Sarrigiannis
authors.affiliation: Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, United Kingdom.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, United Kingdom.
authors.forename: Hua-Liang
authors.initials: HL
authors.lastname: Wei
authors.affiliation: Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, United Kingdom.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Billings
authors.affiliation: Department of Clinical Neurophysiology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, United Kingdom.
authors.forename: Jayne
authors.initials: J
authors.lastname: Fotheringham
authors.affiliation: Department of Neurology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, United Kingdom.
authors.forename: Marios
authors.initials: M
authors.lastname: Hadjivassiliou
mesh_terms: D015984:Causality; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004569:Electroencephalography / Q000592:standards* / Q000706:statistics & numerical data*; D004828:Epilepsies, Partial / Q000503:physiopathology; D004829:Epilepsy, Generalized / Q000503:physiopathology; D006801:Humans; D008959:Models, Neurological; D012640:Seizures / Q000503:physiopathology; D013997:Time Factors
keywords: 0-Lag; EEG; Linear; Non-linear; Phase-lag; Synchronisation