Cardiovascular, Cerebrovascular, and Cognitive Function in Spinal Cord Injury
Condition: Spinal Cord Injury
MeSH terms: Spinal Cord Injuries; Wounds and Injuries
Study type: Observational

Summary: 
      Increased life expectancy in individuals with spinal cord injury (SCI) present clinicians
      with the challenge of managing the secondary complications of SCI with the chronic diseases
      common in an aging population. Cardiovascular disease, cerebral vascular disease, and
      cognitive dysfunction are among the primary challenges facing clinicians in the treatment of
      an aging population. Cognitive dysfunction has been reported in upwards of 60% of the SCI
      population, which have been primarily attributed to concomitant traumatic brain injury or
      pre-morbid conditions. Identifying possible modifiable risk factors which contribute to the
      increased prevalence of cognitive dysfunction in the SCI population is of significant
      clinical relevance and cardiovascular and cerebrovascular disorders have emerged as possible
      contributors to the cognitive disorders in the general population. These risk factors
      include: physical inactivity, chronically low or high blood pressure (BP), reduced blood flow
      to the brain, arterial stiffening, and impaired nervous system regulation of the
      cardiovascular system. These risk factors are particularly prominent in the SCI population as
      they represent a model of profound inactivity, have trouble regulating blood pressure, and
      suffer impaired cardiovascular regulation from their injury. In addition, we've recently
      reported deficits in blood flow to the brain at rest and during cognitive tests; with results
      being further impaired in SCI with chronically low blood pressure. Therefore the goals of
      this project are to determine the influence of cardiovascular and cerebral vascular responses
      at rest and during cognitive testing on test performance in 80 individuals with SCI compared
      to 50 age-matched non-SCI controls. All potential subjects will undergo a rigorous two-part
      screening process which consists of an initial screening via telephone and a detailed,
      in-person screening. Eligible subjects will be invited to participate in a 3 hour laboratory
      visit during which their arterial stiffness, blood pressure, heart rate, respiration rate
      and, blood flow to the brain will be monitored at rest and during a comprehensive series of
      cognitive tests.

      We hypothesize that blood pressure and cerebrovascular response to testing will account
      significantly for performance in cognitive testing that otherwise would have been
      attributable to SCI status.
    

Detailed description: 
      The cognitive test battery will consists of the tests listed below, administered in the order
      given. Each test will be scored according to the

        1. California Verbal Learning Test (Total & SD?)

        2. Controlled oral word association test

        3. Symbol Digit Modalities Test (Oral version)

        4. Trail Making Test (Oral version)

        5. Stroop Test (W?, C?, CW?)

        6. Digit Span (Forwards, Backwards, and Sequencing)

        7. California Verbal Learning Test (LD? & Recognition?)

        8. Letter-Number Sequencing

        9. California Verbal Learning Test (LD Forced recognition?)

       10. WASI-II Sub-tests (Vocabulary, Similarities, and Matrix Reasoning)
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        80 subjects with chronic SCI and 50 age-matched non-SCI controls will be recruited from
        out-patient clinics at the JJP VAMC and the Center of Excellence. This includes subjects
        who have completed various protocols in the Cardiovascular autonomic testing laboratory or
        patients referred by their physicians following routine physical examinations. Physicians
        will be informed of the inclusion and exclusion criteria for this study and will be able to
        provide us with the assurance that the patient is an appropriate candidate for the study
        and that he/she was willing to speak with the study coordinators.
      
Keywords: spinal cord injury; autonomic dysreflexia; baroreceptor integrity; sympathetic integrity; vagal integrity; autonomic integrity; arterial stiffness; cognitive function; traumatic brain injury; cerebral blood flow