scholarly journals The Sit-to-Stand Technique for the Measurement of Dynamic Cerebral Autoregulation

2009 ◽  
Vol 35 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Farzaneh A. Sorond ◽  
Jorge M. Serrador ◽  
Richard N. Jones ◽  
Michele L. Shaffer ◽  
Lewis A. Lipsitz
Keyword(s):  
Cerebral Autoregulation ◽  
Sit To Stand ◽  
Dynamic Cerebral Autoregulation

scholarly journals Novel Application of a Force Sensor during Sit-to-Stands to Measure Dynamic Cerebral Autoregulation Onset

2022 ◽  
Author(s):  
Alicen A Whitaker ◽  
Eric D. Vidoni ◽  
Stacey E. Aaron ◽  
Adam G. Rouse ◽  
Sandra A Billinger
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cerebral Autoregulation ◽  
Force Sensor ◽  
Verbal Command ◽  
Post Stroke ◽  
Sit To Stand ◽  
Exact Moment ◽  
Small Change ◽  
Dynamic Cerebral Autoregulation

Purpose: Current sit-to-stand methods measuring dynamic cerebral autoregulation (dCA) do not capture the precise onset of the time delay (TD) response. Reduced sit-to-stand reactions in older adults and individuals post-stroke could inadvertently introduce variability, error, and imprecise timing. We applied a force sensor during a sit-to-stand task to more accurately determine how TD before dCA onset may be altered. Methods: Middle cerebral artery blood velocity (MCAv) and mean arterial pressure (MAP) were measured during two sit-to-stands separated by 15 minutes. Recordings started with participants sitting on a force-sensitive resistor for 60 seconds, then asked to stand for two minutes. Upon standing, the force sensor voltage immediately dropped and marked the exact moment of arise-and-off (AO). Time from AO until an increase in cerebrovascular conductance (CVC = MCAv/MAP) was calculated as TD. Results: We tested the sensor in 4 healthy young adults, 2 older adults, and 2 individuals post-stroke. Healthy young adults stood quickly and the force sensor detected a small change in TD compared to classically estimated AO, from verbal command to stand. When compared to the estimated AO, older adults had a delayed measured AO and TD decreased up to ~50% while individuals post-stroke had an early AO and TD increased up to ~14%. Conclusion: The transition reaction speed during the sit to stand has the potential to influence dCA metrics. As observed in the older adults and participants with stroke, this response may drastically vary and influence TD.

scholarly journals Multi-metrics assessment of dynamic cerebral autoregulation in middle and posterior cerebral arteries in young fit women

2020 ◽  
Author(s):  
Lawrence Labrecque ◽  
Audrey Drapeau ◽  
Kevan Rahimaly ◽  
Sarah Imhoff ◽  
François Billaut ◽  
...  
Keyword(s):  
Cerebral Artery ◽  
Cerebral Circulation ◽  
Cerebral Autoregulation ◽  
Regional Differences ◽  
Posterior Cerebral Artery ◽  
Blood Velocity ◽  
Percent Reduction ◽  
Sit To Stand ◽  
Posterior Cerebral Circulation ◽  
Dynamic Cerebral Autoregulation

AbstractIndividuals with low orthostatic tolerance show greater decrease in posterior cerebral artery mean blood velocity (PCAvmean). Since young fit women often experience presyncopal symptoms, their posterior cerebral circulation may be prone to greater decreases in PCAvmean, probably explained by an attenuated dynamic cerebral autoregulation (dCA). Regional differences in dCA have never been evaluated in young fit women. We compared dCA in the middle cerebral artery (MCA) and posterior cerebral artery (PCA) in 11 young fit women (25 ± 4y; ) in response to a sit-to-stand (5 min sitting followed by 5 min standing) and repeated squat-stand maneuvers performed at 0.05 Hz and 0.10 Hz. The cerebral pressure-flow relationship was characterized using four metrics: 1) percent reduction in blood velocity (BV) per percent reduction in MAP (% BV/% MAP) during initial orthostatic stress (0-15 s after sit-to-stand); 2) onset of the regulatory response (i.e. time delay before an increase in conductance (BV/MAP); 3) rate of regulation (RoR), following sit-to-stand and; 4) transfer function analysis (TFA) of forced MAP oscillations induced by repeated squat-stands. Upon standing, the relative decline in MCAvmean and PCAvmean was similar (−25 ± 9 vs. −30 ± 13%; p=0.29). The onset of the regulatory response (p=0.665), %ΔBV/%ΔMAP (p=0.129) and RoR (p=0.067) were not different between MCA and PCA. In regard to TFA, there was an ANOVA artery effect for gain (p<0.001) and a frequency effect for phase (p<0.001). These findings indicate the absence of regional differences in dCA in young fit women.New findingsWhat is the central question of this study?Are there regional differences in the dynamic cerebral autoregulation in young fit women?What is the main finding and its importance?The key finding of this study is that there are no differences in dynamic cerebral autoregulation between both arteries. These results indicate that dynamic cerebral autoregulation does not seem to be responsible for making the posterior cerebral circulation more vulnerable to transient reduction in blood pressure in young fit women.

scholarly journals Functional implications of impaired dynamic cerebral autoregulation in young healthy women; a comparative investigation

2018 ◽  
Author(s):  
Lawrence Labrecque ◽  
Kevan Rahimaly ◽  
Sarah Imhoff ◽  
Myriam Paquette ◽  
Olivier Le Blanc ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Orthostatic Hypotension ◽  
Cerebral Autoregulation ◽  
Cerebrovascular Reserve ◽  
Healthy Women ◽  
Sit To Stand ◽  
Transfer Function Analysis ◽  
Rapid Changes ◽  
The Face ◽  
Dynamic Cerebral Autoregulation

ABSTRACTWomen exhibit higher prevalence of orthostatic hypotension with presyncopal symptoms compared to men. These symptoms could be influenced by an attenuated ability of the cerebrovasculature to respond to rapid changes in blood pressure (BP) [dynamic cerebral autoregulation (dCA)]. However, the influence of sex on dCA remains equivocal. We compared dCA in 11 women (25 ± 2 y) and 11 age-matched men (24 ± 1 y) using a multimodal approach including a sit-to-stand maneuver and forced oscillations (5 min of squat-stand performed at 0.05 and 0.10 Hz). The prevalence of initial orthostatic hypotension (IOH; decrease in systolic ≥ 40 mmHg and/or diastolic BP ≥ 20 mmHg) during the first 15 sec of sit-to-stand was determined as a functional outcome. In women, the decrease in mean middle cerebral artery blood velocity (MCAvmean) following the sit-to-stand was greater (−20 ± 8 vs. -11 ± 7 cm sec-1; p=0.018) and the onset of the regulatory change (time lapse between the beginning of the sit-to-stand and the increase in the conductance index (MCAvmean/mean arterial pressure(MAP)) was delayed (p=0.007). Transfer function analysis gain during 0.05 Hz squat-stand was ∼48% higher in women (6.4 ± 1.3 vs. 3.8 ± 2.3 sec; p=0.017). The prevalence of IOH was comparable between groups (4/9 vs. 5/9, p=0.637). These results indicate the cerebrovasculature of healthy women has an attenuated ability to react to large and rapid changes in BP in the face of preserved orthostasis, which could be related to a higher cerebrovascular reserve to face a rapid transient hypotension.NEWS & NOTEWORTHYThe novel findings of this study are that healthy women have impaired dynamic cerebral autoregulation, although the prevalence of orthostatic intolerance was similar in women and men. These results indicate the cerebrovasculature of healthy women has an attenuated ability to react to large and rapid changes in blood pressure in the face of preserved orthostasis, which could be related to a higher cerebrovascular reserve to face a rapid transient hypotension.

scholarly journals Impaired Cerebrovascular Hemodynamics are Associated with Cerebral White Matter Damage

2013 ◽  
Vol 34 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Sushmita Purkayastha ◽  
Otite Fadar ◽  
Aujan Mehregan ◽  
David H Salat ◽  
Nicola Moscufo ◽  
...  
Keyword(s):  
White Matter ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Cerebral Autoregulation ◽  
Structural Integrity ◽  
Cerebral White Matter ◽  
Elderly Individuals ◽  
Transfer Function Analysis ◽  
Dynamic Cerebral Autoregulation ◽  
Cerebrovascular Hemodynamics

White matter hyperintensities (WMH) in elderly individuals with vascular diseases are presumed to be due to ischemic small vessel diseases; however, their etiology is unknown. We examined the cross-sectional relationship between cerebrovascular hemodynamics and white matter structural integrity in elderly individuals with vascular risk factors. White matter hyperintensity volumes, fractional anisotropy (FA), and mean diffusivity (MD) were obtained from MRI in 48 subjects (75±7years). Pulsatility index (PI) and dynamic cerebral autoregulation (dCA) was assessed using transcranial Doppler ultrasound of the middle cerebral artery. Dynamic cerebral autoregulation was calculated from transfer function analysis (phase and gain) of spontaneous blood pressure and flow velocity oscillations in the low (LF, 0.03 to 0.15 Hz) and high (HF, 0.16 to 0.5 Hz) frequency ranges. Higher PI was associated with greater WMH ( P<0.005). Higher phase across all frequency ranges was associated with greater FA and lower MD ( P<0.005). Lower gain was associated with higher FA in the LF range ( P=0.001). These relationships between phase and FA were significant in the territories limited to the middle cerebral artery as well as across the entire brain. Our results show a strong relationship between impaired cerebrovascular hemodynamics (PI and dCA) and loss of cerebral white matter structural integrity (WMH and DTI metrics) in elderly individuals.

scholarly journals Acute hypoxia impairs dynamic cerebral autoregulation: results from two independent techniques

2009 ◽  
Vol 107 (4) ◽  
pp. 1165-1171 ◽  
Author(s):  
Andrew W. Subudhi ◽  
Ronney B. Panerai ◽  
Robert C. Roach
Keyword(s):  
Cerebral Autoregulation ◽  
Acute Hypoxia ◽  
Latin Squares ◽  
Differential Sensitivity ◽  
Experimental Session ◽  
Assessment Techniques ◽  
Frequency Components ◽  
Autoregulation Index ◽  
Single Experimental Session ◽  
Dynamic Cerebral Autoregulation

We investigated the effect of acute hypoxia (AH) on dynamic cerebral autoregulation (CA) using two independent assessment techniques to clarify previous, conflicting reports. Twelve healthy volunteers (6 men, 6 women) performed six classic leg cuff tests, three breathing normoxic (FiO2 = 0.21) and three breathing hypoxic (FiO2 = 0.12) gas, using a single blinded, Latin squares design with 5-min washout between trials. Continuous measurements of middle cerebral artery blood flow velocity (CBFv; DWL MultiDop X2) and radial artery blood pressure (ABP; Colin 7000) were recorded in the supine position during a single experimental session. Autoregulation index (ARI) scores were calculated using the model of Tiecks et al. (Tiecks FP, Lam AM, Aaslid R, Newell DW. Stroke 26: 1014–1019, 1995) from ABP and CBFv changes following rapid cuff deflation (cuff ARI) and from ABP to CBFv transfer function, impulse, and step responses (TFA ARI) obtained during a 4-min period prior to cuff inflation. A new measure of %CBFv recovery 4 s after peak impulse was also derived from TFA. AH reduced cuff ARI (5.65 ± 0.70 to 5.01 ± 0.96, P = 0.04), TFA ARI (4.37 ± 0.76 to 3.73 ± 0.71, P = 0.04), and %Recovery (62.2 ± 10.9% to 50.8 ± 9.9%, P = 0.03). Slight differences between TFA and cuff ARI values may be attributed to heightened sympathetic activity during cuff tests as well as differential sensitivity to low- and high-frequency components of CA. Together, results provide consistent evidence that CA is impaired with AH. In addition, these findings demonstrate the potential utility of TFA ARI and %Recovery scores for future CA investigations.

Dynamic Cerebral Autoregulation After Mild Dehydration to Simulate Microgravity Effects

2009 ◽  
Vol 80 (5) ◽  
pp. 443-447 ◽  
Author(s):  
Yojiro Ogawa ◽  
Ken-ichi Iwasaki ◽  
Ken Aoki ◽  
Takashi Saitoh ◽  
Jitsu Kato ◽  
...  
Keyword(s):  
Cerebral Autoregulation ◽  
Dynamic Cerebral Autoregulation

Midlife Aerobic Exercise and Dynamic Cerebral Autoregulation: Associations with Baroreflex Sensitivity and Central Arterial Stiffness

2021 ◽  
Author(s):  
Tsubasa Tomoto ◽  
Justin Repshas ◽  
Rong Zhang ◽  
Takashi Tarumi
Keyword(s):  
Arterial Stiffness ◽  
Aerobic Exercise ◽  
Cerebral Autoregulation ◽  
Baroreflex Sensitivity ◽  
Function Analysis ◽  
Middle Aged ◽  
Age Related ◽  
Transfer Function Analysis ◽  
Carotid Distensibility ◽  
Dynamic Cerebral Autoregulation

Midlife aerobic exercise may significantly impact age-related changes in the cerebro- and cardiovascular regulations. This study investigated the associations of midlife aerobic exercise with dynamic cerebral autoregulation (dCA), cardiovagal baroreflex sensitivity (BRS), and central arterial stiffness. Twenty middle-aged athletes (MA) who had aerobic training for >10 years were compared with 20 young (YS) and 20 middle-aged sedentary (MS) adults. Beat-to-beat cerebral blood flow velocity, blood pressure (BP), and heart rate were measured at rest and during forced BP oscillations induced by repeated sit-stand maneuvers at 0.05 Hz. Transfer function analysis was used to calculate dCA and BRS parameters. Carotid distensibility was measured by ultrasonography. MA had the highest peak oxygen uptake (VO2peak) among all groups. During forced BP oscillations, MS showed lower BRS gain than YS, but this age-related reduction was absent in MA. Conversely, dCA was similar among all groups. At rest, BRS and dCA gains at low frequency (~0.1 Hz) were higher in the MA compared with MS and YS groups. Carotid distensibility was similar between MA and YS groups, but it was lower in the MS. Across all subjects, VO2peak was positively associated with BRS gains at rest and during forced BP oscillations (r=0.257~0.382, p=0.003~0.050) and carotid distensibility (r=0.428~0.490, p=0.001). Furthermore, dCA gain at rest and carotid distensibility were positively correlated with BRS gain at rest in YS and MA groups (all p<0.05). These findings suggest that midlife aerobic exercise improves central arterial elasticity and BRS which may contribute to CBF regulation through dCA.

Sign in / Sign up

Export Citation Format

Share Document