title: Systemic and cerebral hemodynamics during cognitive testing.
abstract: OBJECTIVE
  Cognitive deficits are reported in 10-60% of individuals with SCI, the primary etiology of these deficits is believed to be concomitant traumatic brain injury (TBI). We recently documented diminished memory and marginally deficient attention and processing speed in individuals with SCI discordant for hypotension but matched for TBI.
  
  
  METHODS
  Twenty-nine individuals participated: 16 non-SCI controls, 6 paraplegic (T2-T10) and 7 tetraplegic (C4-C8). The Stroop test was used to measure cognitive function and transcranial Doppler ultrasound was used to measure cerebral blood flow (CBF) while resting (5 min) and continuously during cognitive testing. Mean arterial pressure (MAP) was calculated from three brachial blood pressures and cerebral vascular resistance index was calculated as: CVRi = MAP/CBF.
  
  
  RESULTS
  The paraplegia group (54 ± 6) was marginally older than the non-SCI (42 ± 15; p = 0.06) and tetraplegic (42 ± 11; p = 0.09) groups. Compared to non-SCI group, normalized t-score on the Stroop Color (SC) task was significantly lower in the paraplegic group (p < 0.05). In the tetraplegic group, MAP was significantly lower (p < 0.05) than the non-SCI and paraplegic groups, and related to SC t-score (r                            (2) = 0.873; p < 0.01). In the paraplegic group, CBF was reduced (p < 0.05) and CVRi increased (p < 0.05) compared to the non-SCI group, and CVRi was increased compared to the tetraplegic group (p < 0.05). A significant inverse relationship was noted between change in CVRi and SC t-score in the non-SCI group.
  
  
  CONCLUSIONS
  Asymptomatic hypotension relates to cognitive performance in persons with tetraplegia; therefore, BP normalization should be considered. The inappropriate cerebral vascular response to cognitive testing and poor test performance should be investigated in persons with paraplegia.
authors.affiliation: Center of Excellence: Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY 10468, USA. jm.wecht@va.gov
authors.forename: Jill M
authors.initials: JM
authors.lastname: Wecht
authors.forename: Dwindally
authors.initials: D
authors.lastname: Rosado-Rivera
authors.forename: Adejoke
authors.initials: A
authors.lastname: Jegede
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Cirnigliaro
authors.forename: Marley A
authors.initials: MA
authors.lastname: Jensen
authors.forename: Steve
authors.initials: S
authors.lastname: Kirshblum
authors.forename: William A
authors.initials: WA
authors.lastname: Bauman
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010264:Paraplegia / Q000503:physiopathology / Q000523:psychology; D011782:Quadriplegia / Q000503:physiopathology / Q000523:psychology; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000523:psychology*; D013315:Stress, Psychological / Q000503:physiopathology; D057190:Stroop Test; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult