title: Estimation of the EEG power spectrum using MRI T(2) relaxation time in traumatic brain injury.
abstract: OBJECTIVE
  To study the relationship between magnetic resonance imaging (MRI) T(2) relaxation time and the power spectrum of the electroencephalogram (EEG) in long-term follow up of traumatic brain injury.
  
  
  METHODS
  Nineteen channel quantitative electroencephalograms or qEEG, tests of cognitive function and quantitative MRI T(2) relaxation times (qMRI) were measured in 18 mild to severe closed head injured outpatients 2 months to 4.6 years after injury and 11 normal controls. MRI T(2) and the Laplacian of T(2) were then correlated with the power spectrum of the scalp electrical potentials and current source densities of the qEEG.
  
  
  RESULTS
  qEEG and qMRI T(2) were related by a frequency tuning with maxima in the alpha (8-12Hz) and the lower EEG frequencies (0.5-5Hz), which varied as a function of spatial location. The Laplacian of T(2) acted like a spatial-temporal "lens" by increasing the spatial-temporal resolution of correlation between 3-dimensional T(2) and the ear referenced alert but resting spontaneous qEEG.
  
  
  CONCLUSIONS
  The severity of traumatic brain injury can be modeled by a linear transfer function that relates the molecular qMRI to qEEG resonant frequencies.
authors.affiliation: Bay Pines Veterans Administration Medical Center, Research and Development Service-151, Bldg 23, Room 117, Bay Pines, FL 33744, USA. bobt2@gte.net
authors.forename: R W
authors.initials: RW
authors.lastname: Thatcher
authors.forename: C
authors.initials: C
authors.lastname: Biver
authors.forename: J F
authors.initials: JF
authors.lastname: Gomez
authors.forename: D
authors.initials: D
authors.lastname: North
authors.forename: R
authors.initials: R
authors.lastname: Curtin
authors.forename: R A
authors.initials: RA
authors.lastname: Walker
authors.forename: A
authors.initials: A
authors.lastname: Salazar
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001930:Brain Injuries / Q000175:diagnosis* / Q000503:physiopathology* / Q000523:psychology; D006259:Craniocerebral Trauma / Q000175:diagnosis / Q000503:physiopathology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012016:Reference Values; D012535:Scalp / Q000503:physiopathology