title: Abnormality of low frequency cerebral hemodynamics oscillations in TBI population.
abstract: Functional Near Infrared Spectroscopy (fNIRS) can non-invasively capture dynamic cognitive activation and underlying physiological processes by measuring changes in oxy- and deoxy-hemoglobin levels, correlated to brain activation. It is a portable, inexpensive and user-friendly device which is easily adapted to the outpatient setting for the assessment of cognitive functions after Traumatic Brain Injury (TBI). Low frequency oscillations in hemodynamic signal, attributed in the literature to cerebral autoregulation, were assessed using recently introduced metrics, Oxygenation Variability (OV Index), obtained from oxy/deoxy-hemoglobin variations in response to mental tasks for a group of healthy control (HC, n=14) and TBI (n=29). Participants responded to an action complexity judgment task (evaluating the complexity of daily life activities by classifying the number of steps as "few" or "many") with a varying degree of cognitive load to produce brain activation. During the task, we measured blood variations with fNIRS and analyzed OV Index changes. Mean OV indices, corresponding to high complexity tasks, are higher than that of low complexity tasks in the HC group, revealing strong parametric effect (0.039±0.017 for low, 0.057±0.036 for high, p-value=0.069). However, no significant difference has been recorded for the OV indexes for two different loads in the TBI group (0.055±0.033 for low, 0.054±0.035 for high, p=0.9). OV index metrics proves to be sensitive to chronic TBI and can potentially be used to separate subpopulations TBI vs. HC. Noticeable differences in OV index spatial distributions between subpopulations have been observed.
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health Bethesda, MD 20892, United States.
authors.forename: Victor
authors.initials: V
authors.lastname: Chernomordik
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health Bethesda, MD 20892, United States.
authors.forename: Franck
authors.initials: F
authors.lastname: Amyot
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health Bethesda, MD 20892, United States.
authors.forename: Kimbra
authors.initials: K
authors.lastname: Kenney
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health Bethesda, MD 20892, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Wassermann
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health Bethesda, MD 20892, United States.
authors.forename: Ramon
authors.initials: R
authors.lastname: Diaz-Arrastia
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health Bethesda, MD 20892, United States. Electronic address: amir@helix.nih.gov.
authors.forename: Amir
authors.initials: A
authors.lastname: Gandjbakhche
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology / Q000503:physiopathology*; D000070642:Brain Injuries, Traumatic / Q000175:diagnosis / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011930:Reaction Time; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Cerebral autoregulation; Functional Near InfraRed Spectroscopy; Low frequency oscillations; Parametric effect of the judgment of complexity; Traumatic brain injury