title: Comparison of Model-Based Indices of Cerebral Autoregulation and Vasomotor Reactivity Using Transcranial Doppler versus Near-Infrared Spectroscopy in Patients with Amnestic Mild Cognitive Impairment.
abstract: We recently introduced model-based "physiomarkers" of dynamic cerebral autoregulation and CO2 vasomotor reactivity as an aid for diagnosis of early-stage Alzheimer's disease (AD) [1], where significant impairment of dynamic vasomotor reactivity (DVR) was observed in early-stage AD patients relative to age-matched controls. Milder impairment of DVR was shown in patients with amnestic mild cognitive impairment (MCI) using the same approach in a subsequent study [2]. The advocated approach utilizes subject-specific data-based models of cerebral hemodynamics to quantify the dynamic effects of resting-state changes in arterial blood pressure and end-tidal CO2 (the putative inputs) upon cerebral blood flow velocity (the putative output) measured at the middle cerebral artery via transcranial Doppler (TCD). The obtained input-output models are then used to compute model-based indices of DCA and DVR from model-predicted responses to an input pressure pulse or an input CO2 pulse, respectively. In this paper, we compare these model-based indices of DVR and DCA in 46 amnestic MCI patients, relative to 20 age-matched controls, using TCD measurements with their counterparts using Near-Infrared Spectroscopy (NIRS) measurements of blood oxygenation at the lateral prefrontal cortex in 43 patients and 22 age-matched controls. The goal of the study is to assess whether NIRS measurements can be used instead of TCD measurements to obtain model-based physiomarkers with comparable diagnostic utility. The results corroborate this view in terms of the ability of either output to yield model-based physiomarkers that can differentiate the group of aMCI patients from age-matched healthy controls.
authors.affiliation: Biomedical Simulations Resource Center, University of Southern California, Los Angeles, CA, USA.
authors.forename: Vasilis Z
authors.initials: VZ
authors.lastname: Marmarelis
authors.affiliation: Biomedical Simulations Resource Center, University of Southern California, Los Angeles, CA, USA.
authors.forename: Dae C
authors.initials: DC
authors.lastname: Shin
authors.affiliation: Exercise Physiology & Rehabilitation Center, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tarumi
authors.affiliation: Exercise Physiology & Rehabilitation Center, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000647:Amnesia / Q000150:complications; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology; D008609:Mental Status Schedule; D008875:Middle Aged; D008954:Models, Biological; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D017585:Ultrasonography, Doppler, Transcranial
keywords: Alzheimer’s disease; cerebral blood flow; cerebral circulation; mild cognitive impairment