The Dynamic Relationship Between Cortical Oxygenation and End-Tidal CO2 Transient Changes Is Impaired in Mild Cognitive Impairment Patients

Background: Recent studies have utilized data-based dynamic modeling to establish strong association between dysregulation of cerebral perfusion and Mild Cognitive Impairment (MCI), expressed in terms of impaired CO2 dynamic vasomotor reactivity in the cerebral vasculature. This raises the question of whether this is due to dysregulation of central mechanisms (baroreflex and chemoreflex) or mechanisms of cortical tissue oxygenation (CTO) in MCI patients. We seek to answer this question using data-based input-output predictive dynamic models.Objective: To use subject-specific data-based multivariate input-output dynamic models to quantify the effects of systemic hemodynamic and blood CO2 changes upon CTO and to examine possible differences in CTO regulation in MCI patients versus age-matched controls, after the dynamic effects of central regulatory mechanisms have been accounted for by using cerebral flow measurements as another input.Methods: The employed model-based approach utilized the general dynamic modeling methodology of Laguerre expansions of kernels to analyze spontaneous time-series data in order to quantify the dynamic effects upon CTO (an index of relative capillary hemoglobin saturation distribution measured via near-infrared spectroscopy) of contemporaneous changes in end-tidal CO2 (proxy for arterial CO2), arterial blood pressure and cerebral blood flow velocity in the middle cerebral arteries (measured via transcranial Doppler). Model-based indices (physio-markers) were computed for these distinct dynamic relationships.Results: The obtained model-based indices revealed significant statistical differences of CO2 dynamic vasomotor reactivity in cortical tissue, combined with “perfusivity” that quantifies the dynamic relationship between flow velocity in cerebral arteries and CTO in MCI patients versus age-matched controls (p = 0.006). Significant difference between MCI patients and age-matched controls was also found in the respective model-prediction accuracy (p = 0.0001). Combination of these model-based indices via the Fisher Discriminant achieved even smaller p-value (p = 5 × 10–5) when comparing MCI patients with controls. The differences in dynamics of CTO in MCI patients are in lower frequencies (<0.05 Hz), suggesting impairment in endocrine/metabolic (rather than neural) mechanisms.Conclusion: The presented model-based approach elucidates the multivariate dynamic connectivity in the regulation of cerebral perfusion and yields model-based indices that may serve as physio-markers of possible dysregulation of CTO during transient CO2 changes in MCI patients.

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Modeling Cerebral Hemodynamics Using BOLD Magnetic Resonance Imaging and its Application in Mild Cognitive Impairment

10.1101/2020.02.23.20018846 ◽

2020 ◽

Author(s):

B.C. Henley ◽

M.O. Okafor ◽

I. Hajjar

Keyword(s):

Magnetic Resonance Imaging ◽

Blood Pressure ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Pulse Rate ◽

Cerebral Perfusion ◽

Cerebral Hemodynamics ◽

Resonance Imaging ◽

Temporal Lobes ◽

End Tidal

AbstractObjectiveThis study develops a procedure and related analytical methods for deriving indices of cerebral hemodynamics in the magnetic resonance imaging (MRI) setting using resting state recordings of systemic blood pressure, pulse rate, and end-tidal CO2 synchronized with the MRI image acquisitions of blood oxygenation level dependent (BOLD) data as a measure of cerebral perfusion.MethodsWe employed the concept of Principal Dynamic Modes (PDM) to model the effect of three determinants of cerebral perfusion: mean arterial blood pressure (MABP), end-tidal CO2 (PETCO2), and pulse rate (PR). The relation between these signals and the BOLD signal were used respectively to quantify cerebral autoregulation (CA), CO2 vasoreactivity (CVR), and pulse rate reactivity (PRR).ResultsHemodynamic indices were obtained from 129 participants with normal cognition (NC) and mild cognitive impairment (MCI). CA was reduced in MCI compared to NC in the parietal lobe, CVR was reduced in MCI in the occipital and temporal lobes, and PRR was reduced in the frontal, parietal, occipital and temporal lobes. Reduced CVR and PRR were associated with worse cognitive scores including memory and executive function.ConclusionEmployed acquisition and analysis of MRI hemodynamic identified cerebral hemodynamic alterations in MCI, related to PR and ETCO2 changes.SignificanceThis modeling approach may offer a novel way to clinically assess cerebral hemodynamics during MRI.

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AN INPUT-OUTPUT MODEL BASED ON ORIGIN-DESTINATION DATA OF FOREIGN VISITORS IN JAPAN - FOR IMPACT ANALYSIS OF INCREASING FOREIGN VISITORS BY INTERNATIONAL AIRPORT SALES

Journal of Japan Society of Civil Engineers Ser D3 (Infrastructure Planning and Management) ◽

10.2208/jscejipm.73.178 ◽

2017 ◽

Vol 73 (3) ◽

pp. 178-185

Author(s):

Takaaki OKUDA

Keyword(s):

Impact Analysis ◽

Input Output ◽

International Airport ◽

Model Based

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Intradialytic Cerebral Hypoperfusion as Mechanism for Cognitive Impairment in Patients on Hemodialysis

Journal of the American Society of Nephrology ◽

10.1681/asn.2019050461 ◽

2019 ◽

Vol 30 (11) ◽

pp. 2052-2058 ◽

Cited By ~ 7

Author(s):

Dawn F. Wolfgram

Keyword(s):

Cognitive Impairment ◽

Cerebral Perfusion ◽

Ischemic Injury ◽

Hemodialysis Patients ◽

Cognitive Outcomes ◽

Cerebral Injury ◽

Cerebral Hypoperfusion ◽

Increased Risk ◽

Cerebral Ischemic Injury ◽

Cerebral Ischemic

The high frequency of cognitive impairment in individuals on hemodialysis is well characterized. In-center hemodialysis patients are disproportionately affected by cognitive impairment compared with other dialysis populations, identifying hemodialysis itself as a possible factor. The pathophysiology of cognitive impairment has multiple components, but vascular-mediated cerebral injury appears to contribute based on studies demonstrating increased cerebral ischemic lesions and atrophy in brain imaging of patients on hemodialysis. Patients on hemodialysis may be at increased risk for cerebral ischemic injury disease due to vasculopathy associated with ESKD and from their comorbid diseases, such as hypertension and diabetes. This review focuses on the intradialytic cerebral hypoperfusion that can occur during routine hemodialysis due to the circulatory stress of hemodialysis. This includes a review of current methods used to monitor intradialytic cerebral perfusion and the structural and functional cognitive outcomes that have been associated with changes in intradialytic cerebral perfusion. Monitoring of intradialytic cerebral perfusion may become clinically relevant as nephrologists try to avoid the cognitive complications seen with hemodialysis. Identifying the appropriate methods to assess risk for cerebral ischemic injury and the relationship of intradialytic cerebral hypoperfusion to cognitive outcomes will help inform the decision to use intradialytic cerebral perfusion monitoring in the clinical setting as part of a strategy to prevent cognitive decline.

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P3-229: MODEL-BASED QUANTIFICATION OF CHEMO-REFLEX DYSREGULATION ALLOWS DIFFERENTIATION OF MCI PATIENTS FROM CONTROLS AND ACCOUNTS LARGELY FOR THE IMPAIRMENT OF VASOMOTOR REACTIVITY AT CEREBRAL ARTERIES

Alzheimer s & Dementia ◽

10.1016/j.jalz.2019.06.3259 ◽

2019 ◽

Vol 15 ◽

pp. P1019-P1020

Author(s):

Vasilis Marmarelis ◽

Dae Shin ◽

Takashi Tarumi ◽

Rong Zhang

Keyword(s):

Cerebral Arteries ◽

Vasomotor Reactivity ◽

Model Based

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A brain stress test: Cerebral perfusion during memory encoding in mild cognitive impairment

NeuroImage Clinical ◽

10.1016/j.nicl.2016.03.002 ◽

2016 ◽

Vol 11 ◽

pp. 388-397 ◽

Cited By ~ 17

Author(s):

Long Xie ◽

Sudipto Dolui ◽

Sandhitsu R. Das ◽

Grace E. Stockbower ◽

Molly Daffner ◽

...

Keyword(s):

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Cerebral Perfusion ◽

Stress Test ◽

Memory Encoding

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Cerebrovascular time constant: dependence on cerebral perfusion pressure and end-tidal carbon dioxide concentration

Neurological Research ◽

10.1179/1743132811y.0000000040 ◽

2012 ◽

Vol 34 (1) ◽

pp. 17-24 ◽

Cited By ~ 24

Author(s):

Marek Czosnyka ◽

Hugh K Richards ◽

Matthias Reinhard2 ◽

Luzius A Steiner3 ◽

Karol Budohoski ◽

...

Keyword(s):

Carbon Dioxide ◽

Cerebral Perfusion Pressure ◽

Time Constant ◽

Cerebral Perfusion ◽

Perfusion Pressure ◽

Carbon Dioxide Concentration ◽

End Tidal Carbon Dioxide ◽

End Tidal

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Post-stroke cognitive impairment: screening with MMSE and MoCA and predictors of their persistence after treatment at the Stroke Center

Ukrainian Neurological Journal ◽

10.30978/unj2021-3-31 ◽

2021 ◽

Author(s):

Y. V. Flomin ◽

V. G. Gurianov ◽

L. I. Sokolova

Keyword(s):

Cognitive Impairment ◽

Mmse Score ◽

Cerebral Arteries ◽

High Rate ◽

Cerebral Stroke ◽

Time Interval ◽

Post Stroke ◽

Lower Baseline ◽

Stroke Center ◽

Moca Score

Objective — to analyze the results of screening for post‑stroke cognitive impairment (PCI) in patients with cerebral stroke (CS) admitted to the Stroke Center (SC) in different disease phases, and to determine independent predictors of the PCI persistence at discharge. Methods and subjects. 399 patients were enrolled, including 242 (60.7 %) men and 157 (39.3 %) women with the median age was 66.2 years (IQR 58.5 — 76.3). IS was diagnosed in 331 (82.9 %), and ICH in 68 (17.1 %) patients. Among patients with IS, 137 (41.4 %) had an atherothrombotic subtype, 152 (46.0 %) had a cardioembolic subtype, 21 (6.3 %) had a lacunar subtype, another 21 (6.3 %) had another or unknown cause of stroke. Patients were screened for PCI using the Mini‑Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) on admission and at discharge. Participants with MMSE score of 0 — 24 or a MoCA score of 0 — 25 were considered having PCI. Upon admission, all patients were assessed using the National Institutes of Health Stroke Scale (NIHSS), Bartel Index, and Modified Rankine Scale (mRS). The method of constructing and analyzing logistic regression models was used to determine independent predictors of the preservation of PCI at discharge. The analysis was carried out using the MedCalc v. 19.1. Results. The baseline NIHSS score ranged from 0 to 39 (median 11, IQR 6 — 18). The majority (64.2 %) of the subjects were hospitalized within the first 30 days from the CS onset. The MMSE score on admission ranged from 0 to 30 (median 20, IQR 2 — 27), and in 179 (44.9 %) of the patients the initial score was 0 to 17 (severe PCI), whereas in 61 (15 3 %) of the participants it was 18 to 24 (moderately severe PCI) and only 159 (39.8 %) persons scored 25 to 30 (no PCI). The baseline MoCA score ranged from 0 to 30 (median 15, IQR 1 — 24), and 356 (89.2 %) patients were shown to have PCI (score 0 to 25). According to screening with MMSE at discharge, 125 (31.4 %) patients had severe PCI, and 67 (16.8 %) had moderately severe PCI. The MoCA assessment before discharge indicated PCI in 324 (81.2 %) patients. According to both MMSE and MoCA, the rate of PCI on admission was significantly higher than at discharge (p < 0.001). Among the 240 patients who had PCI according to MMSE score, 239 (99.6 %) had PCI according to the MoCA score. However, among 159 patients who screened negative for PCI with MMSE at admission, 117 (73.6 %) screened positive with MoCA. Screening results using both MMSE and MoCA were not significantly associated with affected hemisphere. ICH was associated with lower (p < 0.0001) MMSE and MoCA scores compared with IS. Predictors of PCI according to MMSE score at discharge were a longer time interval from CS onset to SC admission, and a lower baseline MMSE score. However, with MoCA, the predictors were AT subtype IS, lesions in the distribution of the right or both middle cerebral arteries, older patient age, and a lower baseline MoCA score. Conclusions. In patients with MI, a high rate of PCI was documented on admission, but was significantly lower at discharge. In patients with established PCI, according to MMSE score, the use of MoCA for screening seems useless, however, screening with MoCA identified PCI in 3/4 in patients with a normal MMSE score. The independent predictors of scores on these two scales, indicating PCI, were significantly different, so they should not be considered interchangeable.

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