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Papadopoulou AK, Samsouris C, Vlachos F, Badcock NA, Phylactou P, Papadatou-Pastou M. Exploring cerebral laterality of writing and the relationship to handedness: a functional transcranial Doppler ultrasound investigation. Laterality 2024; 29:117-150. [PMID: 38112692 DOI: 10.1080/1357650x.2023.2284407] [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: 02/02/2022] [Accepted: 11/10/2023] [Indexed: 12/21/2023]
Abstract
Cerebral lateralization of oral language has been investigated in a plethora of studies and it is well established that the left hemisphere is dominant for production tasks in the majority of individuals. However, few studies have focused on written language and even fewer have sampled left-handers. Writing comprises language and motor components, both of which contribute to cerebral activation, yet previous research has not disentangled. The aim of this study was to disentangle the language and motor components of writing lateralization. This was achieved through the comparison of cerebral activation during (i) written word generation and (ii) letter copying, as assessed by functional Transcranial Doppler (fTCD) ultrasound. We further assessed cerebral laterality of oral language. The sample was balanced for handedness. We preregistered the hypotheses that (i) cerebral lateralization of the linguistic component of writing would be weaker in left-handers compared to right-handers and (ii) oral language and the linguistic component of written language would not be correlated in terms of cerebral lateralization. No compelling evidence for either of our hypotheses was found. Findings highlight the complexity of the processes subserving written and oral language as well as the methodological challenges to isolate the linguistic component of writing.
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Affiliation(s)
- Anastasia-Konstantina Papadopoulou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
- Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Christos Samsouris
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
- Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Filippos Vlachos
- Department of Special Education, University of Thessaly, Volos, Greece
| | - Nicholas A Badcock
- School of Psychological Science, The University of Western Australia, Perth, Australia
| | - Phivos Phylactou
- School of Physical Therapy, University of Western Ontario, London, Canada
| | - Marietta Papadatou-Pastou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
- Biomedical Research Foundation, Academy of Athens, Athens, Greece
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2
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Barnes SC, Panerai RB, Beishon L, Hanby M, Robinson TG, Haunton VJ. Cerebrovascular responses to somatomotor stimulation in Parkinson's disease: A multivariate analysis. J Cereb Blood Flow Metab 2022; 42:1547-1558. [PMID: 35287495 PMCID: PMC9274867 DOI: 10.1177/0271678x211065204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder, yet little is known about cerebral haemodynamics in this patient population. Previous studies assessing dynamic cerebral autoregulation (dCA), neurovascular coupling (NVC) and vasomotor reactivity (VMR) have yielded conflicting findings. By using multi-variate modelling, we aimed to determine whether cerebral blood flow (CBF) regulation is impaired in PD patients.55 healthy controls (HC) and 49 PD patients were recruited. PD subjects underwent a second recording following a period of abstinence from their anti-Parkinsonian medication. Continuous bilateral transcranial Doppler in the middle cerebral arteries, beat-to-beat mean arterial blood pressure (MAP; Finapres), heart rate (HR; electrocardiogram), and end-tidal CO2 (EtCO2; capnography) were measured. After a 5-min baseline period, a passive motor paradigm comprising 60 s of elbow flexion was performed. Multi-variate modelling quantified the contributions of MAP, ETCO2 and neural stimulation to changes in CBF velocity (CBFV). dCA, VMR and NVC were quantified to assess the integrity of CBF regulation.Neural stimulation was the dominant input. dCA, NVC and VMR were all found to be impaired in the PD population relative to HC (p < 0.01, p = 0.04, p < 0.01, respectively). Our data suggest PD may be associated with depressed CBF regulation. This warrants further assessment using different neural stimuli.
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Affiliation(s)
- Sam C Barnes
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Lucy Beishon
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Martha Hanby
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Victoria J Haunton
- Department of Cardiovascular Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester, UK.,NIHR Leicester Biomedical Research Centre, BHF Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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3
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Mrachacz-Kersting N, Ibáñez J, Farina D. Towards a mechanistic approach for the development of non-invasive brain-computer interfaces for motor rehabilitation. J Physiol 2021; 599:2361-2374. [PMID: 33728656 DOI: 10.1113/jp281314] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 03/05/2021] [Indexed: 12/11/2022] Open
Abstract
Brain-computer interfaces (BCIs) designed for motor rehabilitation use brain signals associated with motor-processing states to guide neuroplastic changes in a state-dependent manner. These technologies are uniquely positioned to induce targeted and functionally relevant plastic changes in the human motor nervous system. However, while several studies have shown that BCI-based neuromodulation interventions may improve motor function in patients with lesions in the central nervous system, the neurophysiological structures and processes targeted with the BCI interventions have not been identified. In this review, we first summarize current knowledge of the changes in the central nervous system associated with learning new motor skills. Then, we propose a classification of current BCI paradigms for plasticity induction and motor rehabilitation based on the expected neural plastic changes promoted. This classification proposes four paradigms based on two criteria: the plasticity induction methods and the brain states targeted. The existing evidence regarding the brain circuits and processes targeted with these different BCIs is discussed in detail. The proposed classification aims to serve as a starting point for future studies trying to elucidate the underlying plastic changes following BCI interventions.
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Affiliation(s)
| | - Jaime Ibáñez
- Department of Bioengineering, Centre for Neurotechnologies, Imperial College London, London, UK
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, London, UK
| | - Dario Farina
- Department of Bioengineering, Centre for Neurotechnologies, Imperial College London, London, UK
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4
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Salinet AS, Silva NC, Caldas J, de Azevedo DS, de-Lima-Oliveira M, Nogueira RC, Conforto AB, Texeira MJ, Robinson TG, Panerai RB, Bor-Seng-Shu E. Impaired cerebral autoregulation and neurovascular coupling in middle cerebral artery stroke: Influence of severity? J Cereb Blood Flow Metab 2019; 39:2277-2285. [PMID: 30117360 PMCID: PMC6827118 DOI: 10.1177/0271678x18794835] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We aimed to assess cerebral autoregulation (CA) and neurovascular coupling (NVC) in stroke patients of differing severity comparing responses to healthy controls and explore the association between CA and NVC with functional outcome. Patients admitted with middle cerebral artery (MCA) stroke and healthy controls were recruited. Stroke severity was defined by the National Institutes of Health Stroke Scale (NIHSS) scores: ≤4 mild, 5-15 moderate and ≥16 severe. Transcranial Doppler ultrasound and Finometer recorded MCA cerebral blood flow velocity (CBFv) and blood pressure, respectively, over 5 min baseline and 1 min passive movement of the elbow to calculate the autoregulation index (ARI) and CBFv amplitude responses to movement. All participants were followed up for three months. A total of 87 participants enrolled in the study, including 15 mild, 27 moderate and 13 severe stroke patients, and 32 control subjects. ARI was lower in the affected hemisphere (AH) of moderate and severe stroke groups. Decreased NVC was seen bilaterally in all stroke groups. CA and NVC correlated with stroke severity and functional outcome. CBFv regulation is significantly impaired in acute stroke, and further compromised with increasing stroke severity. Preserved CA and NVC in the acute period were associated with improved three-month functional outcome.
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Affiliation(s)
- Angela Sm Salinet
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil.,Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Sao Bernardo do Campo, Sao Paulo, Brazil
| | - Nathália Cc Silva
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Juliana Caldas
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Daniel S de Azevedo
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Marcelo de-Lima-Oliveira
- Neurosurgical Division, Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Adriana B Conforto
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil.,Brain Institute, Albert Einstein Israelite Hospital, São Paulo, Brazil
| | - Manoel J Texeira
- Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Sao Bernardo do Campo, Sao Paulo, Brazil
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Edson Bor-Seng-Shu
- Neurosurgical Division, Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
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5
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Caruso P, Ridolfi M, Furlanis G, Ajčević M, Semenic M, Moretti R, Naccarato M, Manganotti P. Cerebral hemodynamic changes during motor imagery and passive robot-assisted movement of the lower limbs. J Neurol Sci 2019; 405:116427. [PMID: 31450060 DOI: 10.1016/j.jns.2019.116427] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 07/18/2019] [Accepted: 08/13/2019] [Indexed: 11/25/2022]
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6
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Beishon L, Williams CAL, Robinson TG, Haunton VJ, Panerai RB. Neurovascular coupling response to cognitive examination in healthy controls: a multivariate analysis. Physiol Rep 2018; 6:e13803. [PMID: 30033685 PMCID: PMC6055030 DOI: 10.14814/phy2.13803] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/24/2018] [Indexed: 12/21/2022] Open
Abstract
Cognitive testing with transcranial Doppler ultrasonography (TCD) has been used to assess neurovascular coupling (NVC), but few studies address its multiple contributions. Subcomponent analysis considers the relative myogenic (resistance area product, RAP) and metabolic (critical closing pressure (CrCP)) contributors. The aim of this study was to investigate the changes in subcomponents that occur with cognitive stimulation with the Addenbrooke's Cognitive Examination (ACE-III) in healthy controls. Healthy volunteers underwent continuous recording of bilateral TCD, heart rate (HR, three-lead ECG), end-tidal CO2 (ETCO2 , capnography), and mean arterial pressure (MAP, Finometer). The study comprised a 5-min baseline recording, followed by all 20 paradigms from the ACE-III. The cerebral blood flow velocity (CBFv) response was decomposed into the relative contributions (subcomponents); VBP (MAP), VCrCP (CrCP), and VRAP (RAP). Data are presented as peak population normalized mean changes from baseline, and median area under the curve (AUC). Forty bilateral datasets were obtained (27 female, 37 right hand dominant). VBP increased at task initiation in all paradigms but differed between tasks (range (SD): 4.06 (8.92)-16.04 (12.23) %, P < 0.05). HR, but not ETCO2 , also differed significantly (P < 0.05). Changes in VRAP reflected changes in MAP, but in some paradigms atypical responses were seen. VCrCP AUC varied significantly within paradigm sections (range [SD]: 18.4 [24.17] to 244.21 [243.21] %*s, P < 0.05). All paradigms demonstrated changes in subcomponents with cognitive stimulation, and can be ranked based on their relative presumed metabolic demand. The integrity of NVC requires further investigation in patient populations.
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Affiliation(s)
- Lucy Beishon
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
| | | | - Thompson G. Robinson
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
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7
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Caldas JR, Panerai RB, Salinet AM, Seng-Shu E, Ferreira GSR, Camara L, Passos RH, Galas FRBG, Almeida JP, Nogueira RC, de Lima Oliveira M, Robinson TG, Hajjar LA. Dynamic cerebral autoregulation is impaired during submaximal isometric handgrip in patients with heart failure. Am J Physiol Heart Circ Physiol 2018; 315:H254-H261. [PMID: 29652541 DOI: 10.1152/ajpheart.00727.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The incidence of neurological complications, including stroke and cognitive dysfunction, is elevated in patients with heart failure (HF) with reduced ejection fraction. We hypothesized that the cerebrovascular response to isometric handgrip (iHG) is altered in patients with HF. Adults with HF and healthy volunteers were included. Cerebral blood velocity (CBV; transcranial Doppler, middle cerebral artery) and arterial blood pressure (BP; Finometer) were continuously recorded supine for 6 min, corresponding to 1 min of baseline and 3 min of iHG exercise, at 30% maximum voluntary contraction, followed by 2 min of recovery. The resistance-area product was calculated from the instantaneous BP-CBV relationship. Dynamic cerebral autoregulation (dCA) was assessed with the time-varying autoregulation index estimated from the CBV step response derived by an autoregressive moving-average time-domain model. Forty patients with HF and 23 BP-matched healthy volunteers were studied. Median left ventricular ejection fraction was 38.5% (interquartile range: 0.075%) in the HF group. Compared with control subjects, patients with HF exhibited lower time-varying autoregulation index during iHG, indicating impaired dCA ( P < 0.025). During iHG, there were steep rises in CBV, BP, and heart rate in control subjects but with different temporal patterns in HF, which, together with the temporal evolution of resistance-area product, confirmed the disturbance in dCA in HF. Patients with HF were more likely to have impaired dCA during iHG compared with age-matched control subjects. Our results also suggest an impairment of myogenic, neurogenic, and metabolic control mechanisms in HF. The relationship between impaired dCA and neurological complications in patients with HF during exercise deserves further investigation. NEW & NOTEWORTHY Our findings provide the first direct evidence that cerebral blood flow regulatory mechanisms can be affected in patients with heart failure during isometric handgrip exercise. As a consequence, eventual blood pressure modulations are buffered less efficiently and metabolic demands may not be met during common daily activities. These deficits in cerebral autoregulation are compounded by limitations of the systemic response to isometric exercise, suggesting that patients with heart failure may be at greater risk for cerebral events during exercise.
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Affiliation(s)
- J R Caldas
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil.,Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil.,Critical Care Unit, Hospital São Rafael , Salvador , Brazil
| | - R B Panerai
- Department of Cardiovascular Sciences, University of Leicester , Leicester , United Kingdom.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital , Leicester , United Kingdom
| | | | - E Seng-Shu
- Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil
| | - G S R Ferreira
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil
| | - L Camara
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil
| | - R H Passos
- Critical Care Unit, Hospital São Rafael , Salvador , Brazil
| | - F R B G Galas
- Department of Anesthesia, Heart Institute, University of Sao Paulo , Sao Paulo , Brazil
| | | | - R C Nogueira
- Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil
| | - M de Lima Oliveira
- Department of Neurosurgery, Hospital das Clinicas, University of São Paulo , São Paulo , Brazil
| | - T G Robinson
- Department of Cardiovascular Sciences, University of Leicester , Leicester , United Kingdom.,NIHR Leicester Biomedical Research Centre, Glenfield Hospital , Leicester , United Kingdom
| | - L A Hajjar
- Department of Cardiopneumology, Heart Institute, University of Sao Paulo , São Paulo , Brazil
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8
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Beishon LC, Williams CAL, Panerai RB, Robinson TG, Haunton VJ. The assessment of neurovascular coupling with the Addenbrooke’s Cognitive Examination: a functional transcranial Doppler ultrasonographic study. J Neurophysiol 2018; 119:1084-1094. [DOI: 10.1152/jn.00698.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Cerebrovascular dysfunction occurs early in dementia and can be identified by transcranial Doppler ultrasonography (TCD). Few studies have examined cerebral blood flow velocity (CBFv) responses to a detailed cognitive battery. This study aimed to characterize all CBFv responses, and the effect of hemispheric dominance, to the Addenbrooke’s Cognitive Examination (ACE-III) in healthy volunteers. Forty volunteers underwent continuous bilateral TCD, beat-to-beat blood pressure (MAP; Finapres), heart rate (HR; electrocardiogram), and end-tidal CO2 (ETCO2; capnography) monitoring. After a 5-min baseline period, all tasks from the ACE-III were performed in 3 sections (A: attention, fluency, memory; B: language; C: visuospatial, memory). Data are population mean normalized percentage (PM%) change from a 20-s baseline period before task initiation. Forty bilateral data sets were obtained (27 women, 37 right-hand dominant). All paradigms produced a sharp increase in CBFv in both dominant (PM% range: 3.29 to 9.70%) and nondominant (PM% range: 4.34 to 11.63%) hemispheres at task initiation, with associated increases in MAP (PM% range: 3.06 to 16.04%). ETCO2 did not differ significantly at task initiation (PM% range: −1.1 to 2.4%, P > 0.05). HR differed significantly across A and C tasks at initiation (PM% range: −1.1 to 2.4%, P < 0.05), but not B tasks. In conclusion, all tasks resulted in increases in CBFv, differing significantly between paradigms. These results require further investigation in a cognitively impaired population. NEW & NOTEWORTHY This study is the first to provide a normative data set of cerebral blood flow velocity (CBFv) responses to a complete cognitive assessment (Addenbrooke’s Cognitive Examination, ACE-III) in a large sample ( n = 40) of healthy volunteers. All tasks produced peak and sustained increases in CBFv to different extents. The ACE-III is a feasible tool to assess neurovascular coupling with transcranial Doppler ultrasonography. These data can be used to inform the most appropriate cognitive task to elicit CBFv responses for future studies.
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Affiliation(s)
- Lucy C. Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Claire A. L. Williams
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Thompson G. Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
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9
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Reproducibility of task activation using the Addenbrooke’s cognitive examination in healthy controls: A functional Transcranial Doppler ultrasonography study. J Neurosci Methods 2017; 291:131-140. [DOI: 10.1016/j.jneumeth.2017.08.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/04/2017] [Accepted: 08/14/2017] [Indexed: 11/22/2022]
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10
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Llwyd O, Panerai RB, Robinson TG. Effects of dominant and non-dominant passive arm manoeuvres on the neurovascular coupling response. Eur J Appl Physiol 2017; 117:2191-2199. [PMID: 28875348 DOI: 10.1007/s00421-017-3707-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/24/2017] [Indexed: 01/10/2023]
Abstract
PURPOSE Models designed to study neurovascular coupling (NVC) describe a possible cerebral hemisphere dominance dependent on task completed and preference in handedness. We investigated whether passive arm manoeuvre performed with dominant (Dom-Arm) or non-dominant arm (ND-Arm) stimulated haemodynamic differences in either contralateral (Cont-H) or ipsilateral (Ipsil-H) cerebral hemisphere. METHODS Healthy individuals lying in supine position, had measurements of beat-to-beat blood pressure (BP, mmHg), electrocardiogram (HR, bpm), end-tidal CO2 (etCO2, mmHg), and bilateral insonation of the middle cerebral arteries (MCA, cm s-1). Arm movement was performed for 60 s with passive flexion and extension of the elbow (1 Hz), before manoeuvre was repeated on other arm. Data were normalised and effect of treatment was analysed for differences between manoeuvres and within each time period. RESULTS Seventeen (eight males) healthy volunteers, aged 56 ± 7 years, were studied. Dom-Arm and ND-Arm manoeuvres stimulated a comparable temporal response in peripheral and cerebral haemodynamic parameters between Cont-H and Ipsil-H. CONCLUSIONS Both manoeuvres can be used to evoke similar bilateral MCA responses in assessing NVC. This finding should lead to more efficient protocols when using passive arm movement for NVC studies in healthy subjects.
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Affiliation(s)
- Osian Llwyd
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK. .,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK.
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, LE2 7LX, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
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11
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Caldas JR, Panerai RB, Bor-Seng-Shu E, Almeida JP, Ferreira GSR, Camara L, Nogueira RC, Oliveira ML, Jatene FB, Robinson TG, Hajjar LA. Cerebral hemodynamics with intra-aortic balloon pump: business as usual? Physiol Meas 2017; 38:1349-1361. [PMID: 28333037 DOI: 10.1088/1361-6579/aa68c4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Intra-aortic balloon pump (IABP) is commonly used as mechanical support after cardiac surgery or cardiac shock. Although its benefits for cardiac function have been well documented, its effects on cerebral circulation are still controversial. We hypothesized that transfer function analysis (TFA) and continuous estimates of dynamic cerebral autoregulation (CA) provide consistent results in the assessment of cerebral autoregulation in patients with IABP. APPROACH Continuous recordings of blood pressure (BP, intra-arterial line), end-tidal CO2, heart rate and cerebral blood flow velocity (CBFV, transcranial Doppler) were obtained (i) 5 min with IABP ratio 1:3, (ii) 5 min, starting 1 min with the IABP-ON, and continuing for another 4 min without pump assistance (IABP-OFF). Autoregulation index (ARI) was estimated from the CBFV response to a step change in BP derived by TFA and as a function of time using an autoregressive moving-average model during removal of the device (ARI t ). Critical closing pressure and resistance area-product were also obtained. MAIN RESULTS ARI with IABP-ON (4.3 ± 1.2) were not different from corresponding values at IABP-OFF (4.7 ± 1.4, p = 0.42). Removal of the balloon had no effect on ARI t , CBFV, BP, cerebral critical closing pressure or resistance area-product. SIGNIFICANCE IABP does not disturb cerebral hemodynamics. TFA and continuous estimates of dynamic CA can be used to assess cerebral hemodynamics in patients with IABP. These findings have important implications for the design of studies of critically ill patients requiring the use of different invasive support devices.
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Affiliation(s)
- J R Caldas
- Department of Anesthesia, University of São Paulo, São Paulo, Brazil. Department of Neurosurgery, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil
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12
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Stewart JM, Balakrishnan K, Visintainer P, Del Pozzi AT, Messer ZR, Terilli C, Medow MS. Oscillatory lower body negative pressure impairs task related functional hyperemia in healthy volunteers. Am J Physiol Heart Circ Physiol 2016; 310:H775-84. [PMID: 26801310 DOI: 10.1152/ajpheart.00747.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 12/29/2015] [Indexed: 11/22/2022]
Abstract
Neurovascular coupling refers to the link between an increase in neural activity in response to a task and an increase in cerebral blood flow denoted "functional hyperemia." Recent work on postural tachycardia syndrome indicated that increased oscillatory cerebral blood flow velocity (CBFv) was associated with reduced functional hyperemia. We hypothesized that a reduction in functional hyperemia could be causally produced in healthy volunteers by using oscillations in lower body negative pressure (OLBNP) to force oscillations in CBFv. CBFv was measured by transcranial Doppler ultrasound of the left middle cerebral artery. We used passive arm flexion applied during eight periodic 60-s flexion/60-s relaxation epochs to produce 120-s periodic changes in functional hyperemia (at 0.0083 Hz). We used -30 mmHg of OLBNP at 0.03, 0.05, and 0.10 Hz, the range for cerebral autoregulation, and measured spectral power of CBFv at all frequencies. Arm flexion power performed without OLBNP was compared with arm flexion power during OLBNP. OLBNP power performed in isolation was compared with power during OLBNP plus arm flexion. Cerebral flow velocity oscillations at 0.05 Hz reduced and at 0.10 Hz eliminated functional hyperemia, while 0.03 Hz did not reach significance. In contrast, arm flexion reduced OLBNP-induced oscillatory power at all frequencies. The interactions between OLBNP-driven CBFv oscillations and arm flexion-driven CBFv oscillations are reciprocal. Thus induced cerebral blood flow oscillations suppress functional hyperemia, and functional hyperemia suppresses cerebral blood flow oscillations. We conclude that oscillatory cerebral blood flow produces a causal reduction of functional hyperemia.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York; and Department of Physiology, New York Medical College, Valhalla, New York;
| | | | - Paul Visintainer
- Department of Epidemiology and Biostatistics, Baystate Medical Center, Tufts University School of Medicine, Springfield, Massachusetts; and
| | - Andrew T Del Pozzi
- School of Physical Education Sport & Exercise Science, Ball State University, Muncie, Indiana
| | - Zachary R Messer
- Department of Pediatrics, New York Medical College, Valhalla, New York; and
| | - Courtney Terilli
- Department of Pediatrics, New York Medical College, Valhalla, New York; and
| | - Marvin S Medow
- Department of Pediatrics, New York Medical College, Valhalla, New York; and Department of Physiology, New York Medical College, Valhalla, New York
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Mrachacz-Kersting N, Jiang N, Stevenson AJT, Niazi IK, Kostic V, Pavlovic A, Radovanovic S, Djuric-Jovicic M, Agosta F, Dremstrup K, Farina D. Efficient neuroplasticity induction in chronic stroke patients by an associative brain-computer interface. J Neurophysiol 2015; 115:1410-21. [PMID: 26719088 DOI: 10.1152/jn.00918.2015] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/18/2015] [Indexed: 01/12/2023] Open
Abstract
Brain-computer interfaces (BCIs) have the potential to improve functionality in chronic stoke patients when applied over a large number of sessions. Here we evaluated the effect and the underlying mechanisms of three BCI training sessions in a double-blind sham-controlled design. The applied BCI is based on Hebbian principles of associativity that hypothesize that neural assemblies activated in a correlated manner will strengthen synaptic connections. Twenty-two chronic stroke patients were divided into two training groups. Movement-related cortical potentials (MRCPs) were detected by electroencephalography during repetitions of foot dorsiflexion. Detection triggered a single electrical stimulation of the common peroneal nerve timed so that the resulting afferent volley arrived at the peak negative phase of the MRCP (BCIassociative group) or randomly (BCInonassociative group). Fugl-Meyer motor assessment (FM), 10-m walking speed, foot and hand tapping frequency, diffusion tensor imaging (DTI) data, and the excitability of the corticospinal tract to the target muscle [tibialis anterior (TA)] were quantified. The TA motor evoked potential (MEP) increased significantly after the BCIassociative intervention, but not for the BCInonassociative group. FM scores (0.8 ± 0.46 point difference, P = 0.01), foot (but not finger) tapping frequency, and 10-m walking speed improved significantly for the BCIassociative group, indicating clinically relevant improvements. Corticospinal tract integrity on DTI did not correlate with clinical or physiological changes. For the BCI as applied here, the precise coupling between the brain command and the afferent signal was imperative for the behavioral, clinical, and neurophysiological changes reported. This association may become the driving principle for the design of BCI rehabilitation in the future. Indeed, no available BCIs can match this degree of functional improvement with such a short intervention.
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Affiliation(s)
- Natalie Mrachacz-Kersting
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark;
| | - Ning Jiang
- Department of Neurorehabilitation Engineering, Bernstein Focus Neurotechnology Göttingen, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
| | - Andrew James Thomas Stevenson
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Imran Khan Niazi
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Vladimir Kostic
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksandra Pavlovic
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Sasa Radovanovic
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Federica Agosta
- Neuroimaging Research Unit, Division of Neuroscience, Institute of Experimental Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Kim Dremstrup
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Dario Farina
- Department of Neurorehabilitation Engineering, Bernstein Focus Neurotechnology Göttingen, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
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14
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Salinet ASM, Robinson TG, Panerai RB. Effects of cerebral ischemia on human neurovascular coupling, CO2 reactivity, and dynamic cerebral autoregulation. J Appl Physiol (1985) 2014; 118:170-7. [PMID: 25593216 DOI: 10.1152/japplphysiol.00620.2014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cerebral blood flow (CBF) regulation can be impaired in acute ischemic stroke but the combined effects of dynamic cerebral autoregulation (CA), CO2 cerebrovascular reactivity (CVR), and neurovascular coupling (NVC), obtained from simultaneous measurements, have not been described. CBF velocity in the middle cerebral artery (MCA) (CBFv, transcranial Doppler), blood pressure (BP, Finometer), and end-tidal Pco2 (PetCO2 , infrared capnography) were recorded during a 1-min passive movement of the arm in 27 healthy controls [mean age (SD) 61.4 (6.0) yr] and 27 acute stroke patients [age 63 (11.7) yr]. A multivariate autoregressive-moving average model was used to separate the contributions of BP, arterial Pco2 (PaCO2 ), and the neural activation to the CBFv responses. CBFv step responses for the BP, CO2, and stimulus inputs were also obtained. The contribution of the stimulus to the CBFv response was highly significant for the difference between the affected side [area under the curve (AUC) 104.5 (4.5)%] and controls [AUC 106.9 (4.3)%; P = 0.008]. CBFv step responses to CO2 [affected hemisphere 0.39 (0.7), unaffected 0.55 (0.8), controls 1.39 (0.9)%/mmHg; P = 0.01, affected vs. controls; P = 0.025, unaffected vs. controls] and motor stimulus inputs [affected hemisphere 0.20 (0.1), unaffected 0.22 (0.2), controls 0.37 (0.2) arbitrary units; P = 0.009, affected vs. controls; P = 0.02, unaffected vs. controls] were reduced in the stroke group compared with controls. The CBFv step responses to the BP input at baseline and during the paradigm were not different between groups (P = 0.07), but PetCO2 was lower in the stroke group (P < 0.05). These results provide new insights into the interaction of CA, CVR, and NVC in both health and disease states.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and National Institutes for Health Research (NIHR), Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom; and National Institutes for Health Research (NIHR), Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
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15
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Salinet ASM, Panerai RB, Robinson TG. The longitudinal evolution of cerebral blood flow regulation after acute ischaemic stroke. Cerebrovasc Dis Extra 2014; 4:186-97. [PMID: 25298773 PMCID: PMC4176407 DOI: 10.1159/000366017] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/20/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Acute stroke is known to impair cerebral blood flow (CBF) regulation, but the longitudinal changes of these effects have been poorly reported. The main CBF regulatory mechanisms [cerebral autoregulation (CA) and neurovascular coupling (NVC)] were assessed over 3 months after acute ischaemic stroke. METHODS Recordings of CBF velocity (CBFv), blood pressure (BP), and end-tidal CO2 were performed during 5 min baseline and 1 min passive movement of the elbow. Stroke patients were assessed <72 h of stroke onset, and at 2 weeks, 1 and 3 months after stroke. RESULTS Fifteen acute stroke subjects underwent all 4 sessions and were compared to 22 control subjects. Baseline recordings revealed a significantly lower CBFv in the affected hemisphere within 72 h after stroke compared to controls (p = 0.02) and a reduction in CA index most marked at 2 weeks (p = 0.009). CBFv rise in response to passive arm movement was decreased bilaterally after stroke, particularly in the affected hemisphere (p < 0.01). Both alterations in CA and NVC returned to control levels during recovery. CONCLUSION The major novel finding of this study was that both CA and NVC regulatory mechanisms deteriorated initially following stroke onset, but returned to control levels during the recovery period. These findings are relevant to guide the timing of interventions to manipulate BP and potentially for the impact of intensive rehabilitation strategies that may precipitate acute physiological perturbations but require further exploration in a larger population that better reflects the heterogeneity of stroke. Further, they will also enable the potential influence of stroke subtype to be investigated.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK ; National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Clinical Sciences Wing, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK ; National Institutes for Health Research, Biomedical Research Unit in Cardiovascular Sciences, Clinical Sciences Wing, Glenfield Hospital, Leicester, UK
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Meyer GF, Spray A, Fairlie JE, Uomini NT. Inferring common cognitive mechanisms from brain blood-flow lateralization data: a new methodology for fTCD analysis. Front Psychol 2014; 5:552. [PMID: 24982641 PMCID: PMC4059176 DOI: 10.3389/fpsyg.2014.00552] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 05/19/2014] [Indexed: 11/30/2022] Open
Abstract
Current neuroimaging techniques with high spatial resolution constrain participant motion so that many natural tasks cannot be carried out. The aim of this paper is to show how a time-locked correlation-analysis of cerebral blood flow velocity (CBFV) lateralization data, obtained with functional TransCranial Doppler (fTCD) ultrasound, can be used to infer cerebral activation patterns across tasks. In a first experiment we demonstrate that the proposed analysis method results in data that are comparable with the standard Lateralization Index (LI) for within-task comparisons of CBFV patterns, recorded during cued word generation (CWG) at two difficulty levels. In the main experiment we demonstrate that the proposed analysis method shows correlated blood-flow patterns for two different cognitive tasks that are known to draw on common brain areas, CWG, and Music Synthesis. We show that CBFV patterns for Music and CWG are correlated only for participants with prior musical training. CBFV patterns for tasks that draw on distinct brain areas, the Tower of London and CWG, are not correlated. The proposed methodology extends conventional fTCD analysis by including temporal information in the analysis of cerebral blood-flow patterns to provide a robust, non-invasive method to infer whether common brain areas are used in different cognitive tasks. It complements conventional high resolution imaging techniques.
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Affiliation(s)
- Georg F Meyer
- Department of Psychological Sciences, University of Liverpool Liverpool, UK
| | - Amy Spray
- School of Psychology, University of Liverpool Liverpool, UK
| | - Jo E Fairlie
- Department of Archaeology, Classics and Egyptology, University of Liverpool Liverpool, UK
| | - Natalie T Uomini
- Department of Archaeology, Classics and Egyptology, University of Liverpool Liverpool, UK
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Maggio P, Salinet ASM, Robinson TG, Panerai RB. Influence of CO2 on neurovascular coupling: interaction with dynamic cerebral autoregulation and cerebrovascular reactivity. Physiol Rep 2014; 2:e00280. [PMID: 24760531 PMCID: PMC4002257 DOI: 10.1002/phy2.280] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PaCO2 affects cerebral blood flow (CBF) and its regulatory mechanisms, but the interaction between neurovascular coupling (NVC), cerebral autoregulation (CA), and cerebrovascular reactivity to CO2 (CVR), in response to hypercapnia, is not known. Recordings of cerebral blood flow velocity (CBFv), blood pressure (BP), heart rate, and end‐tidal CO2 (EtCO2) were performed in 18 subjects during normocapnia and 5% CO2 inhalation while performing a passive motor paradigm. Together with BP and EtCO2, a gate signal to represent the effect of stimulation was used as input to a multivariate autoregressive‐moving average model to calculate their separate effects on CBFv. Hypercapnia led to a depression of dynamic CA at rest and during stimulation in both hemispheres (P <0.02) as well as impairment of the NVC response, particularly in the ipsilateral hemisphere (P <0.01). Neither hypercapnia nor the passive motor stimulation influenced CVR. Dynamic CA was not influenced by the motor paradigm during normocapnia. The CBFv step responses to each individual input (BP, EtCO2, stimulation) allowed identification of the influences of hypercapnia and neuromotor stimulation on CA, CVR, and NVC, which have not been previously described, and also confirmed the depressing effects of hypercapnia on CA and NVC. The stability of CVR during these maneuvers and the lack of influence of stimulation on dynamic CA are novel findings which deserve further investigation. Dynamic multivariate modeling can identify the complex interplay between different CBF regulatory mechanisms and should be recommended for studies involving similar interactions, such as the effects of exercise or posture on cerebral hemodynamics. The influence of hypercapnia on dynamic cerebral autoregulation (CA), CO2 vasoreactivity (CVR), and neurovascular coupling (NVC) was described based on a single recording during motor stimulation coupled to a new multivariate modeling approach. Hypercapnia led to a depression of CA at rest and during stimulation in both hemispheres as well as impairment of the NVC response. Neither hypercapnia nor the passive motor stimulation influenced CVR. Dynamic CA was not influenced by the motor paradigm during normocapnia. The stability of CVR during these maneuvers and the lack of influence of stimulation on dynamic CA are novel findings which deserve further investigation.
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Affiliation(s)
- Paola Maggio
- Neurologia Clinica, Università Campus Bio-Medico, Rome, Italy
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18
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Visually evoked blood flow responses and interaction with dynamic cerebral autoregulation: correction for blood pressure variation. Med Eng Phys 2014; 36:613-9. [PMID: 24507691 DOI: 10.1016/j.medengphy.2014.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 01/06/2014] [Accepted: 01/15/2014] [Indexed: 11/20/2022]
Abstract
Visually evoked flow responses recorded using transcranial Doppler ultrasonography are often quantified using a dynamic model of neurovascular coupling. The evoked flow response is seen as the model's response to a visual step input stimulus. However, the continuously active process of dynamic cerebral autoregulation (dCA) compensating cerebral blood flow for blood pressure fluctuations may induce changes of cerebral blood flow velocity (CBFV) as well. The effect of blood pressure variability on the flow response is evaluated by separately modeling the dCA-induced effects of beat-to-beat measured blood pressure related CBFV changes. Parameters of 71 subjects are estimated using an existing, well-known second order dynamic neurovascular coupling model proposed by Rosengarten et al., and a new model extending the existing model with a CBFV contributing component as the output of a dCA model driven by blood pressure as input. Both models were evaluated for mean and systolic CBFV responses. The model-to-data fit errors of mean and systolic blood pressure for the new model were significantly lower compared to the existing model: mean: 0.8%±0.6 vs. 2.4%±2.8, p<0.001; systolic: 1.5%±1.2 vs. 2.2%±2.6, p<0.001. The confidence bounds of all estimated neurovascular coupling model parameters were significantly (p<0.005) narrowed for the new model. In conclusion, blood pressure correction of visual evoked flow responses by including cerebral autoregulation in model fitting of averaged responses results in significantly lower fit errors and by that in more reliable model parameter estimation. Blood pressure correction is more effective when mean instead of systolic CBFV responses are used. Measurement and quantification of neurovascular coupling should include beat-to-beat blood pressure measurement.
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Salinet ASM, Robinson TG, Panerai RB. Cerebral blood flow response to neural activation after acute ischemic stroke: a failure of myogenic regulation? J Neurol 2013; 260:2588-95. [PMID: 23824356 DOI: 10.1007/s00415-013-7022-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/17/2013] [Accepted: 06/23/2013] [Indexed: 12/19/2022]
Abstract
We tested two hypotheses: (1) neurovascular coupling is impaired after acute ischemic stroke, (2) subcomponent analysis of cerebral blood flow velocity can reveal significant differences between acute ischemic stroke and healthy controls. This was explored through the comparison of nineteen acute ischemic stroke patients with healthy controls. Recordings of cerebral blood flow velocity, blood pressure and end-tidal CO2 were obtained during 60s of passive elbow flexion. Cerebral blood flow velocity changes were decomposed into standardized subcomponents describing the contributions of blood pressure (V BP), resistance area product (V RAP) and critical closing pressure (V CrCP). The passive paradigm led to a bilateral cerebral blood flow velocity increase in both groups, but in acute ischemic stroke the magnitude of change was significantly lower. Blood pressure increases were shown to be an important contributor to cerebral blood flow velocity response throughout the paradigm in both groups, with no significant difference between groups. The V CrCP contribution was not different between groups or hemispheres; its continuous rise during activation indicating a vasodilatory effect. On the other hand, the V RAP contribution showed significant differences (p = 0.03), thus suggesting myogenic impairment in acute ischemic stroke. Cerebral blood flow velocity responses to passive elbow flexion suggest an impairment of neurovascular coupling in acute ischemic stroke. Subcomponent analysis suggests an impairment of the myogenic pathways, giving a greater insight into the different mechanisms contributing to neurovascular coupling. Further research is needed to assess the clinical value of subcomponent analysis of neurovascular coupling and the natural history of such changes following acute ischemic stroke.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Trent Stroke Research Network Office, Victoria Building, Leicester Royal Infirmary, LE1 5WW, Leicester, UK,
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20
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Maggio P, Salinet ASM, Panerai RB, Robinson TG. Does hypercapnia-induced impairment of cerebral autoregulation affect neurovascular coupling? A functional TCD study. J Appl Physiol (1985) 2013; 115:491-7. [PMID: 23743398 DOI: 10.1152/japplphysiol.00327.2013] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Neurovascular coupling (NVC) and dynamic cerebral autoregulation (dCA) are both impaired in the acute phase of ischemic stroke, but their reciprocal interactions are difficult to predict. To clarify these aspects, the present study explored NVC in a healthy volunteer population during a surrogate state of impaired dCA induced by hypercapnia. This study aimed to test whether hypercapnia leads to a depression of NVC through an impairment of dCA. Continuous recordings of middle cerebral arteries cerebral blood flow velocity (CBFv), blood pressure (BP), heart rate, and end-tidal CO2 were performed in 19 right-handed subjects (aged >45 yr) before, during, and after 60 s of a passive paradigm during normocapnia and hypercapnia. The CBFv response was broken down into subcomponents describing the relative contributions of BP (VBP), critical closing pressure (VCrCP), and resistance area product (VRAP). VRAP reflects myogenic activity in response to BP changes, whereas VCrCP is more indicative of metabolic control. The results revealed that hypercapnia significantly affected NVC, with significant reductions in the relative contribution of VCrCP to the paradigm-induced increase in CBFv. The present study suggests that hypercapnia impairs both dCA and NVC, probably acting through an impairment of the metabolic component of CBF control.
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Affiliation(s)
- Paola Maggio
- Neurologia Clinica, Università Campus Bio-Medico, Rome, Italy
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21
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Salinet ASM, Robinson TG, Panerai RB. Active, passive, and motor imagery paradigms: component analysis to assess neurovascular coupling. J Appl Physiol (1985) 2013; 114:1406-12. [PMID: 23449939 DOI: 10.1152/japplphysiol.01448.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The association between neural activity and cerebral blood flow (CBF) has been used to assess neurovascular coupling (NVC) in health and diseases states, but little attention has been given to the contribution of simultaneous changes in peripheral covariates. We used an innovative approach to assess the contributions of arterial blood pressure (BP), PaCO2, and the stimulus itself to changes in CBF velocities (CBFv) during active (MA), passive (MP), and motor imagery (MI) paradigms. Continuous recordings of CBFv, beat-to-beat BP, heart rate, and breath-by-breath end-tidal CO2 (EtCO2) were performed in 17 right-handed subjects before, during, and after motor-cognitive paradigms performed with the right arm. A multivariate autoregressive-moving average model was used to calculate the separate contributions of BP, EtCO2, and the neural activation stimulus (represented by a metronome on-off signal) to the CBFv response during paradigms. Differences were found in the bilateral CBFv responses to MI compared with MA and MP, due to the contributions of stimulation (P < 0.05). BP was the dominant contributor to the initial peaked CBFv response in all paradigms with no significant differences between paradigms, while the contribution of the stimulus explained the plateau phase and extended duration of the CBFv responses. Separating the neural activation contribution from the influences of other covariates, it was possible to detect differences between three paradigms often used to assess disease-related NVC. Apparently similar CBFv responses to different motor-cognitive paradigms can be misleading due to the contributions from peripheral covariates and could lead to inaccurate assessment of NVC, particularly during MI.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.
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Salinet ASM, Haunton VJ, Panerai RB, Robinson TG. A systematic review of cerebral hemodynamic responses to neural activation following stroke. J Neurol 2013; 260:2715-21. [DOI: 10.1007/s00415-013-6836-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
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