Non-invasive Measurement of Cerebral Dynamic Autoregulation

The overall objective of this study is to evaluate the use of diffuse correlation spectroscopy to non-invasively measure dynamic cerebral autoregulation in subjects with vascular risk factors. Optical cerebral blood flow measurements will be correlated with changes in arterial blood pressure to assess how CBF is maintained in response to changes in ABP, and will be compared to transcranial doppler reference measurements.

Inclusion Criteria:

• Age greater than or equal to 50 years
• Positive history of at least one of the following vascular disk factors: hypertension, diabetes, hyperlipidemia, coronary artery disease, atrial fibrillation, prior myocardial infarct, transient ischemic attack, or history of smoking

Exclusion Criteria:

• Vascular risk factor subjects:

  1. Pregnant women
  2. Prisoners
  3. Prior neurosurgical procedure or traumatic brain injury, including hemicraniectomy or other skull defect
  4. Prior history of ischemic or hemorrhagic stroke
  5. Prior lower extremity amputation
  6. Peripheral vascular disease