title: Test-retest reliability of resting EEG spectra validates a statistical signature of persons.
abstract: OBJECTIVE
  When EEG is recorded in humans, the question arises whether the resting EEG remains stable. We compared the inter-individual variation in spectral observables to the intra-individual stability over more than a year.
  
  
  METHODS
  We recorded resting EEG in 55 healthy adults with eyes closed. In 20 persons EEG was recorded in a second session with retest intervals 12-40 months. For electrodes AFz, Cz and Pz alpha peak frequency and alpha peak height were transformed into Z-scores. We compared the curve shape of power spectra by first aligning alpha peaks to 10Hz and then regressing spectra pairwise onto each other to calculate a t-value. The t-value and differences of Z-scores for all pairs of sessions were entered into a generalized linear model (GLM) where binary output represents the recognition probability. The results were cross-validated by out-of-sample testing.
  
  
  RESULTS
  Of the 40 sessions, 35 were correctly matched. The shape of power spectra contributed most to recognition. Out of all 2960 pairwise comparisons 99.5% were correct, with sensitivity 88% and specificity 99.5%.
  
  
  CONCLUSIONS
  Our statistical apparatus allows to identify those spectral EEG observables which qualify as statistical signature of a person.
  
  
  CONCLUSIONS
  The effect of external factors on EEG observables can be contrasted against their normal variability over time.
authors: Neurochirurgie, Universitätsspital Zürich, CH-8091 Zürich, Switzerland.
authors: Markus
authors: M
authors: Näpflin
authors: Marc
authors: M
authors: Wildi
authors: Johannes
authors: J
authors: Sarnthein
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013997:Time Factors