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

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.

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Impaired dynamic cerebral autoregulation in young adults with mild depression

Psychophysiology ◽

10.1111/psyp.13949 ◽

2021 ◽

Author(s):

Weijun Zhang ◽

Wen Fu ◽

Luda Yan ◽

Mengyu Wang ◽

Baile Ning ◽

...

Keyword(s):

Young Adults ◽

Cerebral Autoregulation ◽

Mild Depression ◽

Dynamic Cerebral Autoregulation

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The Interaction of Dynamic Cerebral Autoregulation and Neurovascular Coupling in Cognitive Impairment

Current Alzheimer Research ◽

10.2174/1567205019666211227102936 ◽

2021 ◽

Vol 18 (14) ◽

pp. 1067-1076

Author(s):

Lucy C. Beishon ◽

Kannakorn Intharakham ◽

Victoria J. Haunton ◽

Thompson G. Robinson ◽

Ronney B. Panerai

Keyword(s):

Older Adults ◽

Cognitive Impairment ◽

Cerebral Autoregulation ◽

Function Analysis ◽

Neurovascular Coupling ◽

Cognitively Impaired ◽

Healthy Older Adults ◽

Transfer Function Analysis ◽

Dynamic Cerebral Autoregulation ◽

Task Activation

Background: Dynamic cerebral autoregulation (dCA) remains intact in both ageing and dementia, but studies of neurovascular coupling (NVC) have produced mixed findings. Objective: We investigated the effects of task-activation on dCA in healthy older adults (HOA), and patients with mild cognitive impairment (MCI) and Alzheimer’s Disease (AD). Methods: Resting and task-activated data from thirty HOA, twenty-two MCI, and thirty-four AD were extracted from a database. The autoregulation index (ARI) was determined at rest and during five cognitive tasks from transfer function analysis. NVC responses were present where group-specific thresholds of cross-correlation peak function and variance ratio were exceeded. Cumulative response rate (CRR) was the total number of positive responses across five tasks and two hemispheres. Results: ARI differed between groups in dominant (p=0.012) and non-dominant (p=0.042) hemispheres at rest but not during task-activation (p=0.33). ARI decreased during language and memory tasks in HOA (p=0.002) but not in MCI or AD (p=0.40). There was a significant positive correlation between baseline ARI and CRR in all groups (r=0.26, p=0.018), but not within sub-groups. Conclusion: dCA efficiency was reduced in task-activation in healthy but not cognitively impaired participants. These results indicate differences in neurovascular processing in healthy older adults relative to cognitively impaired individuals.

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Lifelong Exercise Improves Cardiac Baroreflex Function But Not Dynamic Cerebral Autoregulation In Older Adults

The FASEB Journal ◽

10.1096/fasebj.26.1_supplement.1138.33 ◽

2012 ◽

Vol 26 (S1) ◽

Author(s):

Vincent Laurens Aengevaeren ◽

Kyle Armstrong ◽

Dean Palmer ◽

Benjamin Levine ◽

Rong Zhang

Keyword(s):

Older Adults ◽

Cerebral Autoregulation ◽

Baroreflex Function ◽

Dynamic Cerebral Autoregulation ◽

Lifelong Exercise

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Decreased Trunk Angular Displacement During Sitting Down: An Early Feature of Aging

Physical Therapy ◽

10.1093/ptj/85.5.404 ◽

2005 ◽

Vol 85 (5) ◽

pp. 404-412 ◽

Cited By ~ 42

Author(s):

Véronique Dubost ◽

Olivier Beauchet ◽

Patrick Manckoundia ◽

François Herrmann ◽

France Mourey

Keyword(s):

Older Adults ◽

Young Adults ◽

Angular Displacement ◽

Orientation Angle ◽

Community Dwelling ◽

Trunk Motion ◽

Sit To Stand ◽

Standing Up ◽

Angular Displacements ◽

Effects Of Aging

Abstract Background and Purpose. Trunk motion plays an important role in achieving both sit-to-stand and stand-to-sit transfers. However, these 2 body transfers depend on different postural and mechanical constraints. Although the effects of aging on sit-to-stand transfers have been widely studied, there is a lack of information concerning stand-to-sit transfers. The aim of this study was to determine how angular displacements of the trunk and shank are affected by aging during sit-to-stand and stand-to-sit transfers. Subjects. Ten community-dwelling older adults (mean age=75.9 years, SD=3.2) and 9 young adults (mean age=26.8 years, SD=4.7) volunteered to participate. Methods. Maximal angular displacements of the trunk and shank with respect to the vertical (ie, orientation angles) were measured, during standing up and sitting down, using an optoelectronic movement analyzer. Results. For standing up, there was no difference between the young and older adults with regard to both maximal orientation angles. During sitting down, the maximal shank orientation angle was not affected by age, whereas the older adults had a smaller trunk motion compared with the young adults (approximately 10° less). Discussion and Conclusion. The results showed that older adults tended to minimize the forward body displacement during sitting down. This strategy could be seen as an adaptive mechanism to decrease the risk of anterior disequilibrium. The authors suggest that this feature could be used as an early marker of aging on postural control.

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Muscle quality index and isometric strength in older adults with hip osteoarthritis

PeerJ ◽

10.7717/peerj.7471 ◽

2019 ◽

Vol 7 ◽

pp. e7471 ◽

Cited By ~ 4

Author(s):

Daniel Jerez-Mayorga ◽

Luis Javier Chirosa Ríos ◽

Alvaro Reyes ◽

Pedro Delgado-Floody ◽

Ramon Machado Payer ◽

...

Keyword(s):

Older Adults ◽

Young Adults ◽

Quality Index ◽

External Rotation ◽

Hip Osteoarthritis ◽

Peak Force ◽

Isometric Strength ◽

Muscle Quality ◽

Stand Test ◽

Sit To Stand

Background Older adults with hip osteoarthritis (OA) suffer a progressive loss of muscle quality and strength, affecting their daily activities and quality of life. The purpose of this study is to compare the levels of isometric strength among older adults with and without hip OA and healthy young adults, and to determine the relationship between muscle quality index (MQI) and isometric strength. Methods Fourteen subjects with hip OA (65.6 ± 3.0 years), 18 healthy older adults (66.6 ± 6.5 years) and 32 young adults (20.7 ± 2.0 years) participated in the study. MQI, isometric muscle strength of the hip, ten time sit-to-stand tests, and body composition were measured. Results The MQI was lower in subjects with hip OA, with no significant differences between groups (p > 0.054). Subjects with OA produced significantly less isometric strength in hip extension (p < 0.001), flexion (p < 0.001), abduction (p < 0.05), adduction (p < 0.001), external (p < 0.05) and internal rotation (p < 0.05). Subjects with OA demonstrated longer time in the execution of the sit-to-stand test (p < 0.001) in comparison with healthy older and young adults. High correlations between MQI, sit-to-stand (r = − 0.76, p < 0.01) and peak force during hip abduction (r = 0.78, p < 0.01) where found in subjects with OA. Moderate correlation between MQI and peak force during hip flexion (r = 0.55, p < 0.05) and external rotation (r = 0.61, p < 0.05) were found in the OA group. Conclusions Subjects with OA have lower MQI than old and young healthy controls. In subjects with OA, there was a significant relationship between isometric strength of hip muscles and performance on the sit-to-stand test and the MQI.

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Cardiac baroreflex function and dynamic cerebral autoregulation in elderly Masters athletes

Journal of Applied Physiology ◽

10.1152/japplphysiol.00402.2012 ◽

2013 ◽

Vol 114 (2) ◽

pp. 195-202 ◽

Cited By ~ 29

Author(s):

Vincent L. Aengevaeren ◽

Jurgen A. H. R. Claassen ◽

Benjamin D. Levine ◽

Rong Zhang

Keyword(s):

Older Adults ◽

Exercise Training ◽

Cerebral Autoregulation ◽

Function Analysis ◽

Baroreflex Function ◽

Transfer Function Analysis ◽

Masters Athletes ◽

The Impact ◽

Dynamic Cerebral Autoregulation ◽

Lifelong Exercise

Cerebral blood flow (CBF) is stably maintained through the combined effects of blood pressure (BP) regulation and cerebral autoregulation. Previous studies suggest that aerobic exercise training improves cardiac baroreflex function and beneficially affects BP regulation, but may negatively affect cerebral autoregulation. The purpose of this study was to reveal the impact of lifelong exercise on cardiac baroreflex function and dynamic cerebral autoregulation (CA) in older adults. Eleven Masters athletes (MA) (8 men, 3 women; mean age 73 ± 6 yr; aerobic training >15 yr) and 12 healthy sedentary elderly (SE) (7 men, 5 women; mean age 71 ± 6 yr) participated in this study. BP, CBF velocity (CBFV), and heart rate were measured during resting conditions and repeated sit-stand maneuvers to enhance BP variability. Baroreflex gain was assessed using transfer function analysis of spontaneous changes in systolic BP and R-R interval in the low frequency range (0.05–0.15 Hz). Dynamic CA was assessed during sit-stand–induced changes in mean BP and CBFV at 0.05 Hz (10 s sit, 10 s stand). Cardiac baroreflex gain was more than doubled in MA compared with SE (MA, 7.69 ± 7.95; SE, 3.18 ± 1.29 ms/mmHg; P = 0.018). However, dynamic CA was similar in the two groups (normalized gain: MA, 1.50 ± 0.56; SE, 1.56 ± 0.42% CBFV/mmHg; P = 0.792). These findings suggest that lifelong exercise improves cardiac baroreflex function, but does not alter dynamic CA. Thus, beneficial effects of exercise training on BP regulation can be achieved in older adults without compromising dynamic regulation of CBF.

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Discriminative Mobility Characteristics between Neurotypical Young, Middle-Aged, and Older Adults Using Wireless Inertial Sensors

Sensors ◽

10.3390/s21196644 ◽

2021 ◽

Vol 21 (19) ◽

pp. 6644

Author(s):

Clayton W. Swanson ◽

Brett W. Fling

Keyword(s):

Older Adults ◽

Young Adults ◽

Inertial Sensors ◽

Comprehensive Analysis ◽

Middle Aged ◽

Balance Test ◽

Mobility Test ◽

Sit To Stand ◽

Age Related ◽

Middle Aged Adults

Age-related mobility research often highlights significant mobility differences comparing neurotypical young and older adults, while neglecting to report mobility outcomes for middle-aged adults. Moreover, these analyses regularly do not determine which measures of mobility can discriminate groups into their age brackets. Thus, the current study aimed to provide a comprehensive analysis for commonly performed aspects of mobility (walking, turning, sit-to-stand, and balance) to determine which variables were significantly different and furthermore, able to discriminate between neurotypical young adults (YAs), middle-aged adults (MAAs), and older adults (OAs). This study recruited 20 YAs, 20 MAAs, and 20 OAs. Participants came into the laboratory and completed mobility testing while wearing wireless inertial sensors. Mobility tests assessed included three distinct two-minute walks, 360° turns, five times sit-to-stands, and a clinical balance test, capturing 99 distinct mobility metrics. Of the various mobility tests assessed, only 360° turning measures demonstrated significance between YAs and MAAs, although the capacity to discriminate between groups was achieved for gait and turning measures. A variety of mobility measures demonstrated significance between MAAs and OAs, and furthermore discrimination was achieved for each mobility test. These results indicate greater mobility differences between MAAs and OAs, although discrimination is achievable for both group comparisons.

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

10.1101/2020.05.25.114447 ◽

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.

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

10.1101/406827 ◽

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.

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