title: Functional network changes associated with sleep deprivation and fatigue during simulated driving: validation using blood biomarkers.
abstract: OBJECTIVE
  Network analysis of electroencephalograph (EEG) signals to study the effect of fatigue and sleep deprivation in human drivers and its validation using blood biochemical parameters.
  
  
  METHODS
  We present a new method of detection of human fatigue and sleepiness by studying the variation of functional interdependencies among EEG signals from various channels. An experiment has been designed to induce fatigue in 12 subjects through several stages over 36 h of sleep deprivation. The functional interdependency among the signals has been computed using synchronisation likelihood (SL), which measures the dynamical (both linear and non-linear) interdependency between two or more non-stationary time series. A network structure has been generated based on the likelihood values and is characterised by a number of standard network-characterising parameters at each stage. Finally, the trends in the network parameters have been validated using biochemical analysis of three blood parameters: glucose, blood urea and creatinine.
  
  
  RESULTS
  An increasing trend in the degree of connectivity and clustering coefficient and a decreasing trend in the characteristic path length have been observed in some bands of signals at successive stages of the experiment.
  
  
  CONCLUSIONS
  Synchronisation of specific bands of the EEG signals from different cortical areas has been observed along with variation in network parameters at increased levels of fatigue and sleep deprivation.
  
  
  CONCLUSIONS
  The results indicate that the network parameters may be used to detect and quantify the level of fatigue and sleepiness.
authors.affiliation: Department of Electrical Engineering, Indian Institute of Technology, Kharagpur, India. sibsambhukar@gmail.com
authors.forename: Sibsambhu
authors.initials: S
authors.lastname: Kar
authors.forename: Aurobinda
authors.initials: A
authors.lastname: Routray
authors.forename: Bibhukalyan Prasad
authors.initials: BP
authors.lastname: Nayak
mesh_terms: D000328:Adult; D001334:Automobile Driving; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose; D002540:Cerebral Cortex / Q000503:physiopathology*; D003198:Computer Simulation; D003404:Creatinine / Q000097:blood; D004569:Electroencephalography; D005221:Fatigue / Q000097:blood / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D012892:Sleep Deprivation / Q000097:blood / Q000503:physiopathology*; D014508:Urea / Q000097:blood
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D014508:Urea; D003404:Creatinine