title: Increased determinism in brain electrical activity occurs in association with multiple sclerosis.
abstract: OBJECTIVE
  Increased determinism (decreased complexity) of brain electrical activity has been associated with some brain diseases. Our objective was to determine whether a similar association occurred for multiple sclerosis (MS).
  
  
  METHODS
  Ten subjects  with a relapsing-remitting course of MS who were in remission were studied; the controls were age- and gender-matched clinically normal subjects. Recurrence plots were calculated using representative electroencephalogram (EEG) epochs (1-7 seconds) from six derivations; the plots  were quantified using the nonlinear variables percent recurrence (%R) and percent determinism (%D). The results were averaged over all derivations for each participant, and the means were compared between the groups. As a linear control procedure the groups were also compared using spectral  analysis.
  
  
  RESULTS
  The mean±SD of %R for the MS subjects was 6·6±1·3%, compared with 5·1±1·3% in the normal group (P = 0·017), indicating that brain activity in the subjects with MS was less complex, as hypothesized.  The groups were not distinguishable using %D or spectral analysis.
  
  
  CONCLUSIONS
  Taken together with our earlier report that %R could be used to discriminate between MS and normal subjects based on the ability to exhibit evoked potentials, the evidence suggests that complexity analysis  of the EEG has potential for development as a diagnostic test for MS.
authors.affiliation: Natural Sciences Department, Daemen College, Amherst, New York, USA.
authors.forename: Simona
authors.initials: S
authors.lastname: Carrubba
authors.forename: Alireza
authors.initials: A
authors.lastname: Minagar
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Chesson
authors.forename: Clifton
authors.initials: C
authors.lastname: Frilot
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Marino
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis* / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult