scholarly journals The Decreased Complexity of Blood Pressure Dynamics Is Associated With Higher White Matter Lesions in Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 213-213
Author(s):  
Xin Jiang ◽  
Xia Gao ◽  
Hui Zhang ◽  
Wuhong Deng ◽  
Wen Fu ◽  
...  
Keyword(s):  
Older Adults ◽  
White Matter ◽  
White Matter Lesions ◽  
Microvascular Disease ◽  
Underlying Mechanism ◽  
Multiscale Entropy ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Lower Complexity ◽  
Fazekas Scale

Abstract White matter lesions (WML) are highly prevalent in older adults and thought to represent cerebral microvascular disease, contributing to slow gait and dementia. Hypertension is associated with WML. However, the underlying mechanism of this association is unclear. The complex beat-to-beat BP fluctuations represent the influence of BP regulatory mechanisms over multiple time scales. The association between WML and abnormalities in BP regulation may be manifest as a loss of complexity in BP dynamics. The aim of this study is thus to explore the relationships between hypertension, BP complexity, and WML in older adults. Twenty-two older adults with hypertension (SBP>140 mmHg) and 19 age-matched older adults without hypertension (i.e., control) completed this study. Their whole-brain WML were assessed by two neurologists using the Fazekas Scale. Greater score reflects higher WML grade. Each participant completed a 10-minute BP assessment when sitting quietly following the MRI. The continuous SBP and DBP series were recorded, and the complexity of them was quantified using multiscale entropy (MSE). Lower MSE reflects lower complexity. Compared to the controls, hypertensives had significantly greater Fazekas scores (i.e., higher WML grade) (F=4.8, p=0.02) and lower complexity of SBP and DBP (F>3.7, p<0.01), after adjusting for age. Across two cohorts, those with lower SBP and DBP complexity had higher Fazekas score (r<-0.51, p<0.01), and this association was independent of age and group. These results suggest that WML are associated with a loss of complexity in BP dynamics. Future longitudinal studies are needed to examine the causal relationship between WML and BP.

scholarly journals Multiscale Dynamics of Blood Pressure Fluctuation Is Associated With White Matter Lesion Burden in Older Adults With and Without Hypertension: Observations From a Pilot Study

2021 ◽  
Vol 8 ◽  
Author(s):  
Xin Jiang ◽  
Yi Guo ◽  
Yue Zhao ◽  
Xia Gao ◽  
Dan Peng ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Older Adults ◽  
White Matter ◽  
Pilot Study ◽  
White Matter Lesions ◽  
Structural Mri ◽  
Multiscale Entropy ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Fazekas Scale

Background: White matter lesions (WMLs) are highly prevalent in older adults, and hypertension is one of the main contributors to WMLs. The blood pressure (BP) is regulated by complex underlying mechanisms over multiple time scales, thus the continuous beat-to-beat BP fluctuation is complex. The association between WMLs and hypertension may be manifested as diminished complexity of BP fluctuations. The aim of this pilot study is to explore the relationships between hypertension, BP complexity, and WMLs in older adults.Method: Fifty-three older adults with clinically diagnosed hypertension and 47 age-matched older adults without hypertension completed one MRI scan and one BP recording of 10–15 min when sitting quietly. Their cerebral WMLs were assessed by two neurologists using the Fazekas scale based on brain structural MRI of each of their own. Greater score reflected higher WML grade. The complexity of continuous systolic (SBP) and diastolic (DBP) BP series was quantified using multiscale entropy (MSE). Lower MSE reflected lower complexity.Results: Compared to the non-hypertensive group, hypertensives had significantly greater Fazekas scores (F > 5.3, p < 0.02) and lower SBP and DBP complexity (F > 8.6, p < 0.004). Both within each group (β < −0.42, p < 0.01) and across groups (β < −0.47, p < 0.003), those with lower BP complexity had higher Fazekas score. Moreover, complexity of both SBP and DBP mediated the influence of hypertension on WMLs (indirect effects > 0.25, 95% confidence intervals = 0.06 – 0.50).Conclusion: These results suggest that diminished BP complexity is associated with WMLs and may mediate the influence of hypertension on WMLs. Future longitudinal studies are needed to examine the causal relationship between BP complexity and WMLs.

scholarly journals Painting by Lesions: Functional Networks Affected by White Matter Lesions Are Associated with Poorer Cognition

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 490-491
Author(s):  
Rachel Crockett ◽  
Chun Liang Hsu ◽  
Roger Tam ◽  
Todd Handy ◽  
Teresa Liu-Ambrose
Keyword(s):  
Older Adults ◽  
White Matter ◽  
Clinical Sample ◽  
White Matter Lesions ◽  
Functional Networks ◽  
Digit Symbol Substitution Test ◽  
Symbol Substitution ◽  
Trail Making ◽  
Global Cognition ◽  
Visual Network

Abstract Cerebrovascular disease (CvD) is the second most common cause of dementia. Its associated pathology, such as white matter lesions (WML), is associated with reduced cognition. Due to the high variability, the relevance of WML location remains unknown. We hypothesised that although the location of WMLs may appear sporadic, they may actually lie within common functional networks. We used novel imaging methods to map the location of WMLs in a clinical sample with the functional connectivity associated with the same location in the human connectome. This identified the functional networks containing the largest WML load (>50%) in older adults with CvD. We then analyzed the association between level of disruption to these networks and measures of global cognition and executive functions. Included in this study were 164 older adults (>55 years old) with CvD. Cognition was assessed using the: 1) Montreal Cognitive Assessment (MoCA); 2) Stroop Colour Word Test; 3) Trail Making Tests; and 4) Digit Symbol Substitution Test. Our results found that the visual network and ventral attention network (VAN) surpassed the 50% overlap threshold with 85% and 66% overlap respectively. Additionally, after controlling for multiple comparisons and age, the level of disruption to the VAN was significantly associated with poorer global cognition, as measured by the MoCA (p=.001). These novel findings identify the functional networks most affected by the presence of WMLs in older adults with CvD and suggest that the disruption to the VAN caused by WML load may underlie the deficits seen in cognition in this population.

scholarly journals White matter lesions defined by diffusion tensor imaging in older adults

2011 ◽  
Vol 70 (3) ◽  
pp. 465-476 ◽  
Author(s):  
Stephen A. Back ◽  
Christopher D. Kroenke ◽  
Larry S. Sherman ◽  
Gus Lawrence ◽  
Xi Gong ◽  
...  
Keyword(s):  
Older Adults ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
White Matter Lesions

Abstract MP13: Evaluation Of The Effect Of Low Grade Inflammation And Hypertension On The Development Of White Matter Lesions

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Chris Woldstad ◽  
Henry Rusinek ◽  
Elizabeth Sweeney ◽  
Tracy Butler ◽  
Yi Li ◽  
...  
Keyword(s):  
White Matter ◽  
White Matter Lesions ◽  
Low Grade ◽  
Entire Cohort ◽  
Flair Sequence ◽  
Inflammatory Score ◽  
The Central Nervous System ◽  
Fazekas Scale ◽  
Low Grade Inflammation ◽  
The Relationship

Introduction: The risk of degenerative disease development is closely linked to persistent and continuous systemic inflammation. Although relationships between chronic low-grade inflammation (LGI) measurements and the progression of cardiovascular diseases are becoming established, the burden of the cardio-pathology and LGI on the central nervous system has not been fully investigated. Specifically, there is limited data on how hypertension (HTN) and related LGI impact white matter lesion (WML) pathogenesis. Methods: We examined 448 subjects with a mean age of 69.3 ± 7.4 years, with 62% of the cohort being women (n=276), and 45% having hypertension (n=200). Components of the LGI score included white blood cell count, albumin levels, platelet counts, and granulocyte/lymphocyte ratio, modified after. Larger LGI scores represented an increase in measured LGI intensity at that time point. MR images were obtained on a 3T system using fluid attenuation inversion recovery (FLAIR) sequence. WML burden was ascertained using Fazekas scale, done separately for both deep WML and periventricular WML. Summated score of greater than or equal to 4 was considered high overall WML burden. Results: It was found that subjects with hypertension had significantly higher LGI score when compared to subjects without hypertension after accounting for sex and BMI (F=4.8, p=0.03). Using logistic regression. we found that LGI score was related to higher WML burden (p=0.047) within the entire cohort. However, further analyses have shown that this finding was driven by the normotensive group, in which the relationship between higher WML burden and respective LGI score was significant (p=0.007). This was not the case among hypertensive subjects. Conclusion: It is clear from the data presented that a relationship between LGI and hypertension exists, confirming that inflammation is an underlying process in cardiovascular pathogenesis. However, LGI scores were related to WML in only normotensive cohorts. We offer that the effects of chronic HTN (related to higher inflammatory score itself ) overshadow the effect of LGI among hypertensive subjects. It is worth emphasizing that even in subjects without HTN white matter damage is related to LGI

Complexity and Frailty: Multiscale Entropy of Balance Dynamics During Quiet Standing and Dual-Task: The Mobilize Boston Study

2008 ◽  
Author(s):  
Hyun Gu Kang ◽  
Madalena Costa ◽  
Attila A. Priplata ◽  
Olga V. Starobinets ◽  
Ary L. Goldberger ◽  
...  
Keyword(s):  
Postural Control ◽  
Dual Task ◽  
Center Of Pressure ◽  
Balance Control ◽  
Community Dwelling ◽  
Multiscale Entropy ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Boston Study ◽  
Balance Dynamics

Balance control during standing is attributable to the complex, nonlinear interactions of multiple postural control systems, manifested as the highly irregular displacements in center of pressure (COP) during standing. Aging and associated frailty may result in the degradation of these complex interactions and manifest as a loss of complexity in COP dynamics. Furthermore, frail individuals may not be able to adapt to a superimposed stress that challenges balance, leading to falls. To test these hypotheses, data were analyzed from the MOBILIZE Boston Study, an ongoing population-based study of community-dwelling older adults. Each participant’s frailty phenotype (not frail, pre-frail, frail) was determined using the Fried et al. 2001 definition. 551 participants (age 77.9±5.5) stood on a balance platform, with or without concurrently performing serial subtractions. Complexity of balance dynamics over multiple time scales was quantified using multiscale entropy (MSE), a more sensitive measure of physiologic health than variance. Of the participants, 39% were pre-frail and 6% were frail. Baseline MSE was lower with each successive frailty condition (p<0.002). When performing the cognitive task, MSE was lowered similarly in all groups (p<0.001). Frailty was associated with a loss of complexity in the dynamics of postural sway, which may be due to the degradation of integrated postural control networks that enable upright stance. Performance of a dual-task further reduced this complexity. Cognitive distractions during standing may further compromise balance control in frail individuals, which may explain their increased fall risk.

Quantifying the dynamics of electroencephalographic (EEG) signals to distinguish alcoholic and non-alcoholic subjects using an MSE based K-d tree algorithm

2018 ◽  
Vol 63 (4) ◽  
pp. 481-490 ◽  
Author(s):  
Lal Hussain ◽  
Wajid Aziz ◽  
Sharjil Saeed ◽  
Saeed Arif Shah ◽  
Malik Sajjad A. Nadeem ◽  
...  
Keyword(s):  
Time Scales ◽  
Coarse Grained ◽  
Multiscale Entropy ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Operating Characteristics ◽  
Eeg Signals ◽  
Temporal Scales ◽  
Online Application ◽  
Time And Space Complexity

Abstract In this paper, we have employed K-d tree algorithmic based multiscale entropy analysis (MSE) to distinguish alcoholic subjects from non-alcoholic ones. Traditional MSE techniques have been used in many applications to quantify the dynamics of physiological time series at multiple temporal scales. However, this algorithm requires O(N2), i.e. exponential time and space complexity which is inefficient for long-term correlations and online application purposes. In the current study, we have employed a recently developed K-d tree approach to compute the entropy at multiple temporal scales. The probability function in the entropy term was converted into an orthogonal range. This study aims to quantify the dynamics of the electroencephalogram (EEG) signals to distinguish the alcoholic subjects from control subjects, by inspecting various coarse grained sequences formed at different time scales, using traditional MSE and comparing the results with fast MSE (fMSE). The performance was also measured in terms of specificity, sensitivity, total accuracy and receiver operating characteristics (ROC). Our findings show that fMSE, with a K-d tree algorithmic approach, improves the reliability of the entropy estimation in comparison with the traditional MSE. Moreover, this new technique is more promising to characterize the physiological changes having an affect at multiple time scales.

scholarly journals INTEREST GROUP SESSION—MEASUREMENT, STATISTICS, AND RESEARCH DESIGN: ANALYSIS OF DEVELOPMENTAL AND COMPLEX SYSTEMS: UNDERSTANDING THE DYNAMICS OF AGING

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S376-S376
Author(s):  
Xiao Yang ◽  
Nilam Ram ◽  
Nilam Ram
Keyword(s):  
Complex Systems ◽  
Dynamic Models ◽  
Initial Conditions ◽  
Developmental Trajectories ◽  
Dynamic Change ◽  
System Thinking ◽  
Multiscale Entropy ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Regulation Model

Abstract Aging is the product of numerous dynamic processes that span multiple domains of functioning (e.g., biological, psychological, social), multiple levels of analysis, and multiple time-scales. Scientific inquiry in many fields has benefited from articulation and analysis of complex systems. This symposium brings together a collection of papers that illustrate how dynamical systems modeling is contributing to both theory and understanding of aging. Yang and colleagues apply Boolean network approach to intensive longitudinal data to identify sequences of emotion and behavior that lead to a stable equilibrium, and suggest how that information can be used to design interventions that push individuals toward a healthier equilibrium. Rector and colleagues illustrate use of dynamic indicators and multiscale entropy measures as indicators of resilience and explain how those measures may be used in prediction of physical recovery. Brick highlights how sequence mining methods can be used to identify commonalities and differences in dynamic change, and how those patterns characterize and distinguish groups with respect to aging trajectories. Moulder and colleagues demonstrate how latent maximum Lyapunov exponents can be used to study sensitivity of individuals’ developmental trajectories to initial conditions. Boker and colleagues provide a general overview of how dynamic models, including an adaptive equilibrium regulation model, distinguish resilience to acute versus chronic stressors and patterns of regulation. Together these papers highlight the value complex system thinking can add to our understanding and optimization of aging.

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