Transcranial Doppler ultrasound blood flow velocity and pulsatility index as systemic indicators for Alzheimer's disease

Alex E. Roher, Zsolt Garami, Suzanne L. Tyas, Chera L. Maarouf, Tyler A. Kokjohn, Marek Belohlavek, Linda J. Vedders, Donald Connor, Marwan N. Sabbagh, Thomas G. Beach, Mark R. Emmerling

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


Background: Multiple lines of evidence suggest that cardiovascular co-morbidities hasten the onset of Alzheimer's disease (AD) or accelerate its course. Methods: To evaluate the utility of cerebral vascular physical function and/or condition parameters as potential systemic indicators of AD, transcranial Doppler (TCD) ultrasound was used to assess cerebral blood flow and vascular resistance of the 16 arterial segments comprising the circle of Willis and its major tributaries. Results: Our study showed that decreased arterial mean flow velocity and increased pulsatility index are associated with a clinical diagnosis of presumptive AD. Cerebral blood flow impairment shown by these parameters reflects the global hemodynamic and structural consequences of a multifaceted disease process yielding diffuse congestive microvascular pathology, increased arterial rigidity, and decreased arterial compliance, combined with putative age-associated cardiovascular output declines. Conclusions: TCD evaluation offers direct physical confirmation of brain perfusion impairment and might ultimately provide a convenient and a noninvasive means to assess the efficacy of medical interventions on cerebral blood flow or reveal incipient AD. In the near term, TCD-based direct assessments of brain perfusion might offer the prospect of preventing or mitigating AD simply by revealing patients who would benefit from interventions to improve circulatory system function.

Original languageEnglish (US)
Pages (from-to)445-455
Number of pages11
JournalAlzheimer's and Dementia
Issue number4
StatePublished - Jul 2011


  • Alzheimer's disease
  • Brain hypoperfusion
  • Cerebral blood flow
  • Mean flow velocity
  • Pulsatility index
  • Transcranial Doppler ultrasonography

ASJC Scopus subject areas

  • Epidemiology
  • Health Policy
  • Developmental Neuroscience
  • Clinical Neurology
  • Geriatrics and Gerontology
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience


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