1
|
Olsen MH, Riberholt C, Capion T, Plovsing RR, Møller K, Berg RMG. Test-retest reliability of transfer function analysis metrics for assessing dynamic cerebral autoregulation to spontaneous blood pressure oscillations. Exp Physiol 2024; 109:1024-1039. [PMID: 38590228 PMCID: PMC11215465 DOI: 10.1113/ep091500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/18/2024] [Indexed: 04/10/2024]
Abstract
Transfer function analysis (TFA) is a widely used method for assessing dynamic cerebral autoregulation in humans. In the present study, we assessed the test-retest reliability of established TFA metrics derived from spontaneous blood pressure oscillations and based on 5 min recordings. The TFA-based gain, phase and coherence in the low-frequency range (0.07-0.20 Hz) from 19 healthy volunteers, 37 patients with subarachnoid haemorrhage and 19 patients with sepsis were included. Reliability assessments included the smallest real difference (SRD) and the coefficient of variance for comparing consecutive 5 min recordings, temporally separated 5 min recordings and consecutive recordings with a minimal length of 10 min. In healthy volunteers, temporally separating the 5 min recordings led to a 0.38 (0.01-0.79) cm s-1 mmHg-1 higher SRD for gain (P = 0.032), and extending the duration of recordings did not affect the reliability. In subarachnoid haemorrhage, temporal separation led to a 0.85 (-0.13 to 1.93) cm s-1 mmHg-1 higher SRD (P = 0.047) and a 20 (-2 to 41)% higher coefficient of variance (P = 0.038) for gain, but neither metric was affected by extending the recording duration. In sepsis, temporal separation increased the SRD for phase by 94 (23-160)° (P = 0.006) but was unaffected by extending the recording. A recording duration of 8 min was required to achieve stable gain and normalized gain measures in healthy individuals, and even longer recordings were required in patients. In conclusion, a recording duration of 5 min appears insufficient for obtaining stable and reliable TFA metrics when based on spontaneous blood pressure oscillations, particularly in critically ill patients with subarachnoid haemorrhage and sepsis.
Collapse
Affiliation(s)
- Markus Harboe Olsen
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
| | - Christian Riberholt
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
- Department of Neurorehabilitation/Traumatic Brain Injury Unit, The Neuroscience CentreCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
| | - Tenna Capion
- Department of Neurosurgery, The Neuroscience CentreCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
| | - Ronni R. Plovsing
- Department of Anaesthesia and Intensive CareCopenhagen University Hospital – HvidovreCopenhagenDenmark
- Department of Clinical Medicine, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Kirsten Møller
- Department of Neuroanaesthesiology, The Neuroscience CentreCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
- Department of Clinical Medicine, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Ronan M. G. Berg
- Department of Clinical Physiology and Nuclear Medicine, The Diagnostic CentreCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
- Centre for Physical Activity ResearchCopenhagen University Hospital – RigshospitaletCopenhagenDenmark
- Department of Biomedical Sciences, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesPontypriddUK
| |
Collapse
|
2
|
Panerai RB, Alshehri A, Beishon LC, Davies A, Haunton VJ, Katsogridakis E, Lam MY, Llwyd O, Robinson TG, Minhas JS. Determinants of the dynamic cerebral critical closing pressure response to changes in mean arterial pressure. Physiol Meas 2024; 45:065006. [PMID: 38838702 DOI: 10.1088/1361-6579/ad548d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 06/05/2024] [Indexed: 06/07/2024]
Abstract
Objective. Cerebral critical closing pressure (CrCP) represents the value of arterial blood pressure (BP) where cerebral blood flow (CBF) becomes zero. Its dynamic response to a step change in mean BP (MAP) has been shown to reflect CBF autoregulation, but robust methods for its estimation are lacking. We aim to improve the quality of estimates of the CrCP dynamic response.Approach. Retrospective analysis of 437 healthy subjects (aged 18-87 years, 218 males) baseline recordings with measurements of cerebral blood velocity in the middle cerebral artery (MCAv, transcranial Doppler), non-invasive arterial BP (Finometer) and end-tidal CO2(EtCO2, capnography). For each cardiac cycle CrCP was estimated from the instantaneous MCAv-BP relationship. Transfer function analysis of the MAP and MCAv (MAP-MCAv) and CrCP (MAP-CrCP) allowed estimation of the corresponding step responses (SR) to changes in MAP, with the output in MCAv (SRVMCAv) representing the autoregulation index (ARI), ranging from 0 to 9. Four main parameters were considered as potential determinants of the SRVCrCPtemporal pattern, including the coherence function, MAP spectral power and the reconstruction error for SRVMAP, from the other three separate SRs.Main results. The reconstruction error for SRVMAPwas the main determinant of SRVCrCPsignal quality, by removing the largest number of outliers (Grubbs test) compared to the other three parameters. SRVCrCPshowed highly significant (p< 0.001) changes with time, but its amplitude or temporal pattern was not influenced by sex or age. The main physiological determinants of SRVCrCPwere the ARI and the mean CrCP for the entire 5 min baseline period. The early phase (2-3 s) of SRVCrCPresponse was influenced by heart rate whereas the late phase (10-14 s) was influenced by diastolic BP.Significance. These results should allow better planning and quality of future research and clinical trials of novel metrics of CBF regulation.
Collapse
Affiliation(s)
- Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Abdulaziz Alshehri
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- College of Applied Medical Sciences, University of Najran, Najran, Saudi Arabia
| | - Lucy C Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Aaron Davies
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Victoria J Haunton
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Emmanuel Katsogridakis
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Man Y Lam
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Osian Llwyd
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- Wolfson Centre for Prevention of Stroke and Dementia, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Thompson G Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Jatinder S Minhas
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| |
Collapse
|
3
|
Smielewski P, Beqiri E, Mataczynski C, Placek M, Kazimierska A, Hutchinson P, Czosnyka M, Kasprowicz M. Advanced neuromonitoring powered by ICM+ and its place in the Brand New AI World, reflections at the 20th anniversary boundary. BRAIN & SPINE 2024; 4:102835. [PMID: 39071453 PMCID: PMC11278591 DOI: 10.1016/j.bas.2024.102835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 05/06/2024] [Accepted: 05/17/2024] [Indexed: 07/30/2024]
Abstract
Introduction Adoption of the ICM+® brain monitoring software by clinical research centres worldwide has been continuously growing over the past 20 years. This has necessitated ongoing updates to accommodate evolving neuromonitoring research needs, including recent explosion of artificial intelligence (AI). Research question We sought to provide an update on the current features of the software. In particular, we aimed to highlight the new options of integrating AI models. Material and methods We reviewed all currently available ICM+ analytical areas and discussed potential AI based extensions in each. We tested a proof-of-concept integration of an AI model and evaluated its performance for real-time data processing. Results ICM+ current analytical tools serve both real-time (bed-side) and offline (file based) analysis, including the calculation engine, Signal Calculator, Custom Statistics, Batch tools, ScriptLab and charting. The ICM+ Python plugin engine allows to execute custom Python scripts and take advantage of complex AI frameworks. For the proof-of-concept, we used a neural network convolutional model with 207,000 trainable parameters that classifies morphology of intracranial pressure (ICP) pulse waveform into 5 pulse categories (normal to pathological plus artefactual). When evaluated within ICM+ plugin script on a Windows 10 laptop the classification of a 5 min ICP waveform segment took only 0.19s with a 2.3s of initial, one-off, model loading time required. Conclusions Modernised ICM+ analytical tools, reviewed in this manuscript, include integration of custom AI models allowing them to be shared and run in real-time, facilitating rapid prototyping and validating of new AI ideas at the bed-side.
Collapse
Affiliation(s)
- P. Smielewski
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - E. Beqiri
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - C. Mataczynski
- Department of Computer Engineering, Faculty of Information and Communication Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - M. Placek
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - A. Kazimierska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - P.J. Hutchinson
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Department of Computer Engineering, Faculty of Information and Communication Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
- Neurosurgery Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - M. Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - M. Kasprowicz
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, Poland
| |
Collapse
|
4
|
Liu J, Simpson DM, Panerai RB. Point-Counterpoint: Transfer function analysis of dynamic cerebral autoregulation: To band or not to band? J Cereb Blood Flow Metab 2023; 43:1628-1630. [PMID: 35510667 PMCID: PMC10414009 DOI: 10.1177/0271678x221098448] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 03/07/2022] [Accepted: 03/18/2022] [Indexed: 11/16/2022]
Abstract
Transfer function analysis (TFA) is the most frequently adopted method for assessing dynamic cerebral autoregulation (CA) with continuously recorded arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). Conventionally, values of autoregulatory metrics (e.g., gain and phase) derived from TFA are averaged within three frequency bands separated by cut-off frequencies at 0.07 Hz and 0.20 Hz, respectively, to represent the efficiency of dynamic CA. However, this is of increasing concerns, as there remains no solid evidence for choosing these specific cut-off frequencies, and the rigid adoption of these bands can stifle further developments in TFA of dynamic CA. In this 'Point-Counterpoint' mini-review, we provide evidence against the fixed banding, indicate possible alternatives, and call for awareness of the risk of the 'one-size-fits-all' banding becoming dogmatic. We conclude that we need to remain open to the multiple possibilities offered by TFA to realize its full potential in studies of human dynamic CA.
Collapse
Affiliation(s)
- Jia Liu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - David M Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| |
Collapse
|
5
|
Panerai RB, Brassard P, Burma JS, Castro P, Claassen JA, van Lieshout JJ, Liu J, Lucas SJ, Minhas JS, Mitsis GD, Nogueira RC, Ogoh S, Payne SJ, Rickards CA, Robertson AD, Rodrigues GD, Smirl JD, Simpson DM. Transfer function analysis of dynamic cerebral autoregulation: A CARNet white paper 2022 update. J Cereb Blood Flow Metab 2023; 43:3-25. [PMID: 35962478 PMCID: PMC9875346 DOI: 10.1177/0271678x221119760] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cerebral autoregulation (CA) refers to the control of cerebral tissue blood flow (CBF) in response to changes in perfusion pressure. Due to the challenges of measuring intracranial pressure, CA is often described as the relationship between mean arterial pressure (MAP) and CBF. Dynamic CA (dCA) can be assessed using multiple techniques, with transfer function analysis (TFA) being the most common. A 2016 white paper by members of an international Cerebrovascular Research Network (CARNet) that is focused on CA strove to improve TFA standardization by way of introducing data acquisition, analysis, and reporting guidelines. Since then, additional evidence has allowed for the improvement and refinement of the original recommendations, as well as for the inclusion of new guidelines to reflect recent advances in the field. This second edition of the white paper contains more robust, evidence-based recommendations, which have been expanded to address current streams of inquiry, including optimizing MAP variability, acquiring CBF estimates from alternative methods, estimating alternative dCA metrics, and incorporating dCA quantification into clinical trials. Implementation of these new and revised recommendations is important to improve the reliability and reproducibility of dCA studies, and to facilitate inter-institutional collaboration and the comparison of results between studies.
Collapse
Affiliation(s)
- Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, and Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Joel S Burma
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Pedro Castro
- Department of Neurology, Centro Hospitalar Universitário de São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Jurgen Ahr Claassen
- Department of Geriatric Medicine and Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Johannes J van Lieshout
- Department of Internal Medicine, Amsterdam, UMC, The Netherlands and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, UK
| | - Jia Liu
- Institute of Advanced Computing and Digital Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen University Town, Shenzhen, China
| | - Samuel Je Lucas
- School of Sport, Exercise and Rehabilitation Sciences and Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Jatinder S Minhas
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Québec, QC, Canada
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Stephen J Payne
- Institute of Applied Mechanics, National Taiwan University, Taipei
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Andrew D Robertson
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel D Rodrigues
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Jonathan D Smirl
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - David M Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
| | | |
Collapse
|
6
|
Xin Q, Hu S, Liu S, Zhao L, Zhang YD. An Attention-based Wavelet Convolution Neural Network for Epilepsy EEG Classification. IEEE Trans Neural Syst Rehabil Eng 2022; 30:957-966. [PMID: 35404819 DOI: 10.1109/tnsre.2022.3166181] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
As a kind of non-invasive, low-cost, and readily available brain examination, EEG has attached significance to the means of clinical diagnosis of epilepsy. However, the reading of long-term EEG records has brought a heavy burden to neurologists and experts. Therefore, automatic EEG classification for epileptic patients plays an essential role in epilepsy diagnosis and treatment. This paper proposes an Attention Mechanism-based Wavelet Convolution Neural Network for epilepsy EEG classification. Attention Mechanism-based Wavelet Convolution Neural Network firstly uses multi-scale wavelet analysis to decompose the input EEGs to obtain their components in different frequency bands. Then, these decomposed multi-scale EEGs are input into the Convolution Neural Network with an attention mechanism for further feature extraction and classification. The proposed algorithm achieves 98.89% triple classification accuracy on the Bonn EEG database and 99.70% binary classification accuracy on the Bern-Barcelona EEG database. Our experiments prove that the proposed algorithm achieves a state-of-the-art classification effect on epilepsy EEG.
Collapse
|
7
|
Chen J, Dong P, Dong K, Mo D, Wang Y, Zhao X, Wang Y, Gong X. Improvement of exhausted cerebral autoregulation in patients with idiopathic intracranial hypertension benefit of venous sinus stenting. Physiol Meas 2021; 42. [PMID: 34293729 DOI: 10.1088/1361-6579/ac172c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 07/22/2021] [Indexed: 02/06/2023]
Abstract
Objective.To evaluate the cerebral autoregulation (CA) in idiopathic intracranial hypertension (IIH) patients with transfer function analysis, and to explore its improvement after venous sinus stenting.Approach. In total, 15 consecutive IIH patients with venous sinus stenosis and 15 controls were recruited. All the patients underwent digital subtraction angiography and venous manometry. Venous sinus stenting was performed for IIH patients with a trans-stenosis pressure gradient ≥8 mmHg. CA was assessed before and after the operation with transfer function analysis, by using the spontaneous oscillations of the cerebral blood flow velocity in the bilateral middle cerebral artery and blood pressure.Main results. Compared with controls, the autoregulatory parameters, phase shift and rate of recovery, were both significantly lower in IIH patients [(57.94° ± 23.22° versus 34.59° ± 24.15°,p < 0.001; (39.87 ± 21.95) %/s versus (20.56 ± 46.66) %/s,p= 0.045, respectively). In total, six patients with bilateral transverse or sigmoid sinus stenosis received venous sinus stenting, in whom, the phase shift significantly improved after venous sinus stenting (39.62° ± 20.26° versus 22.79° ± 19.96°,p = 0.04).Significance. The study revealed that dynamic CA was impaired in IIH patients and was improved after venous sinus stenting. CA assessment has the potential to be used for investigating the hemodynamics in IIH patients.
Collapse
Affiliation(s)
- Jie Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Pei Dong
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Kehui Dong
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Dapeng Mo
- Neurointervention Center, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Yilong Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xingquan Zhao
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Yongjun Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Xiping Gong
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| |
Collapse
|
8
|
Wu M, Zhang W, Guo Z, Song J, Zeng Y, Huang Y, Yang Y, Zhang P, Liu J. Separation of normal and impaired dynamic cerebral autoregulation using deep embedded clustering: a proof-of-concept study. Physiol Meas 2021; 42. [PMID: 34167102 DOI: 10.1088/1361-6579/ac0e81] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/24/2021] [Indexed: 11/11/2022]
Abstract
Objective. A previous study has shown that a data-driven approach can significantly improve the discriminative power of transfer function analysis (TFA) used to differentiate between normal and impaired cerebral autoregulation (CA) in two groups of data. The data was collected from both healthy subjects (assumed to have normal CA) and symptomatic patients with severe stenosis (assumed to have impaired CA). However, the sample size of the labeled data was relatively small, owing to the difficulty in data collection. Therefore, in this proof-of-concept study, we investigate the feasibility of using an unsupervised learning model to differentiate between normal and impaired CA on TFA variables without requiring labeled data for learning.Approach. Continuous arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV), which were recorded simultaneously for approximately 10 min, were included from 148 subjects (41 healthy subjects, 31 with mild stenosis, 13 with moderate stenosis, 22 asymptomatic patients with severe stenosis, and 41 symptomatic patients with severe stenosis). Tiecks' model was used to generate surrogate data with normal and impaired CA. A recently proposed unsupervised learning model was optimized and applied to separate the normal and impaired CA for both the surrogate data and real data.Main results. It achieved 98.9% and 74.1% accuracy for the surrogate and real data, respectively.Significance. To our knowledge, this is the first attempt to employ an unsupervised data-driven approach to assess CA using TFA. This method enables the development of a classifier to determine the status of CA, which is currently lacking.
Collapse
Affiliation(s)
- Menglu Wu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China.,Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, People's Republic of China
| | - Wei Zhang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China.,Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, People's Republic of China
| | - Zhenni Guo
- Stroke Center, Department of Neurology, the First Hospital of Jilin University, Changchun, People's Republic of China
| | - Jianing Song
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China.,Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, People's Republic of China
| | - Yuhong Zeng
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China.,Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, People's Republic of China
| | - Yuyu Huang
- Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, People's Republic of China
| | - Yi Yang
- Stroke Center, Department of Neurology, the First Hospital of Jilin University, Changchun, People's Republic of China
| | - Pandeng Zhang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China.,Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, People's Republic of China
| | - Jia Liu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China.,Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, People's Republic of China
| |
Collapse
|
9
|
Robles FAB, Panerai RB, Katsogridakis E, Chacon M. Superior fitting of arterial resistance and compliance parameters with genetic algorithms in models of dynamic cerebral autoregulation. IEEE Trans Biomed Eng 2021; 69:503-512. [PMID: 34314353 DOI: 10.1109/tbme.2021.3100288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE The capacity of discriminating between normal and impaired dynamic cerebral autoregulation (dCA), based on spontaneous fluctuations in arterial blood pressure (ABP) and cerebral blood flow (CBF), has considerable clinical relevance. This study aimed to quantify the separate contributions of vascular resistance and compliance as parameters that could reflect myogenic and metabolic mechanisms to dCA. METHODS Forty-five subjects were studied under normo and hypercapnic conditions induced by breathing a mixture of 5% carbon dioxide in air. Dynamic cerebrovascular resistance and compliance models with ABP as input and CBFV as output were fitted using Genetic Algorithms to identify parameter values for each subject, and respiratory condition. RESULTS The efficiency of dCA was assessed from the models generated CBFV response to an ABP step change, corresponding to an autoregulation index of 5.561.57 in normocapnia and 2.381.73 in hypercapnia, with an area under the ROC curve (AUC) of 0.9 between both conditions. Vascular compliance increased from 0.750.7 ml/mmHg in normocapnia to 5.8212.0 ml/mmHg during hypercapnia, with an AUC of 0.88. CONCLUSION we demonstrated that Genetic Algorithms are a powerful tool to provide accurate identification of model parameters expressing the performance of human CA Significance: Further work is needed to validate this approach in clinical applications where individualised model parameters could provide relevant diagnostic and prognostic information about dCA impairment Index Terms arterial compliance, autoregulation impairment, cerebral blood flow, Genetic Algorithms, hypercapnia.
Collapse
|