Balance marks cognitive changes in old age because it reflects global brain atrophy and cerebro-arterial blood-flow

The association between dynamic balance and executive function: Which dynamic balance test has the strongest association with executive function? A systematic review and meta-analysis

AIM

The aging global population poses increasing challenges related to falls and dementia. Early identification of cognitive decline, particularly before noticeable symptoms manifest, is crucial for effective intervention. This review aims to determine the dynamic balance test most closely associated with executive function, potentially serving as a biomarker for cognitive decline.

RECENT FINDINGS

Based on recent reviews, inhibitory control, a component of executive function, holds significance in influencing balance performance. Studies suggest that the strength of the correlation between cognition and balance tends to be domain-specific and task-specific. Despite these findings, inconclusive evidence remains regarding the connection between executive function and various dynamic balance assessments. Our review identifies a significant association between all dynamic balance tests and executive function, albeit with varying strengths. Notably, a medium effect size is observed for the Timed Up and Go and Functional Reach Test, a small effect size for balance scales, and a strong effect size for postural sway. This review underscores a clear relationship between dynamic balance task performance and executive function. Dynamic posturography holds potential as a clinical biomarker for early detection of cognitive decline, with a note of caution due to observed heterogeneity and limited studies.

The Association Between Cognitive Domains and Postural Balance among Healthy Older Adults: A Systematic Review of Literature and Meta-Analysis

PURPOSE OF REVIEW

This review aims to explore which cognitive domain is more closely associated with which type of balance (static or dynamic).

RESENT FINDING

Based on recent reviews, inhibitory control, a part of cognition, plays a crucial role in balance performance. Previous reviews report significant links between cognition, mobility, and physical function in older adults. However, evidence regarding the relationship between cognition and balance scores remains inconclusive. The strength of association between cognition and balance appears to be domain-specific and task-specific. Executive function exhibits the strongest correlation with balance, while episodic memory shows a small link with dynamic balance. Processing speed and global cognition demonstrate moderate correlations. Additionally, there is a slight association between cognitive domains and static balance. Further research is needed to elucidate the underlying mechanisms and develop targeted interventions for managing balance-related concerns that are domain-specific and task-specific.

Blood-Brain Barrier Leakage Is Increased in Parkinson's Disease

Background

Blood–brain barrier (BBB) disruption has been noted in animal models of Parkinson’s disease (PD) and forms the basis of the vascular hypothesis of neurodegeneration, yet clinical studies are lacking.

Objective

To determine alterations in BBB integrity in PD, with comparison to cerebrovascular disease.

Methods

Dynamic contrast enhanced magnetic resonance images were collected from 49 PD patients, 15 control subjects with cerebrovascular disease [control positive (CP)] and 31 healthy control subjects [control negative (CN)], with all groups matched for age. Quantitative maps of the contrast agent transfer coefficient across the BBB (K^trans) and plasma volume (v_p) were produced using Patlak analysis. Differences in K^trans and v_p were assessed with voxel-based analysis as well as in regions associated with PD pathophysiology. In addition, the volume of white matter lesions (WMLs) was obtained from T₂-weighted fluid attenuation inversion recovery (FLAIR) images.

Results

Higher K^trans, reflecting higher BBB leakage, was found in the PD group than in the CN group using voxel-based analysis; differences were most prominent in the posterior white matter regions. Region of interest analysis confirmed K^trans to be significantly higher in PD than in CN, predominantly driven by differences in the substantia nigra, normal-appearing white matter, WML and the posterior cortex. WML volume was significantly higher in PD compared to CN. K^trans values and WML volume were similar in PD and CP, suggesting a similar burden of cerebrovascular disease despite lower cardiovascular risk factors.

Conclusion

These results show BBB disruption in PD.

Deficits of psychomotor and mnesic functions across aging in mouse lemur primates

Owing to a similar cerebral neuro-anatomy, non-human primates are viewed as the most valid models for understanding cognitive deficits. This study evaluated psychomotor and mnesic functions of 41 young to old mouse lemurs (Microcebus murinus). Psychomotor capacities and anxiety-related behaviors decreased abruptly from middle to late adulthood. However, mnesic functions were not affected in the same way with increasing age. While results of the spontaneous alternation task point to a progressive and widespread age-related decline of spatial working memory, both spatial reference and novel object recognition (NOR) memory tasks did not reveal any tendency due to large inter-individual variability in the middle-aged and old animals. Indeed, some of the aged animals performed as well as younger ones, whereas some others had bad performances in the Barnes maze and in the object recognition test. Hierarchical cluster analysis revealed that declarative-like memory was strongly impaired only in 7 out of 25 middle-aged/old animals. These results suggest that this analysis allows to distinguish elder populations of good and bad performers in this non-human primate model and to closely compare this to human aging.

Intra-individual variability in gait and in cognitive performance are not related in the elderly

As humans age, the amount of intra-individual variability (IIV) present in both their gait and their cognitive performance tends to increase. Both gait and cognitive IIV are associated with attentional control and with cerebrovascular disease, suggesting that the IIV in gait and cognitive function should be strongly correlated in the elderly. In this study temporal gait variability was determined from a 60-second period of walking. Cognitive variability was determined from two decision-time tasks assessing inhibition. Despite the presence of substantial amounts of gait and cognitive IIV in 71 elderly individuals, there were no significant correlations between measures of cognitive and gait IIV, suggesting that different factors drive IIV in the motor and cognitive performance of older individuals. These results are not consistent with the common cause theory of aging, which predicts that cognitive and sensorimotor performance should show related declines due to age-related disruption of a common neurological substrate.

Global brain atrophy is associated with physical performance and the risk of falls in older adults with cognitive impairment

AIM

Falls are common in patients with cognitive disorder. The purpose of this study was to determine whether global brain atrophy is associated with cognitive function, physical performance and fall incidents in older adults with mild cognitive disorder.

METHODS

A total of 31 older adults with mild cognitive disorders (mean age 78.9 ± 7.3 years) were studied, and 10 of them had experienced falls and the others had not in the past 1 year. Cognitive function and physical performance were measured in these patients. Global brain atrophy was determined by the Voxel-Based Specific Regional Analysis System for Alzheimer's Disease software.

RESULTS

Fallers showed significantly worse scores than the non-fallers in the Global Brain Atrophy Index, Clock Drawing Test (CDT), Verbal Fluency Test (animal), maximum walking time and Timed Up & Go (TUG) Test. The Global Brain Atrophy Index was correlated with the Verbal Fluency Test (animal; r = -0.522), the Verbal Fluency Test with letter (ka; r = -0.337), CDT (r = -0.547), TUG (r = 0.276) and Five Chair Stands Test (r = 0.303) by age-adjusted correlation analyses. Stepwise regression analysis showed that the Global Brain Atrophy Index (β = 1.265, 95% CI 1.022-1.567) was a significant and independent determinant of falls (R(2) = 0.356, P = 0.003).

CONCLUSION

Global brain atrophy might be indicated as one of the risk factors for falls in older adults with mild cognitive disorders.

Clinical correlates of cerebral white matter hyperintensities in cognitively normal older adults

Many research studies have demonstrated asymptomatic white matter hyperintensities (WMHs) in older adults, which are postulated to be ischemic in origin. We hypothesized that certain clinical predictors, measured in a population of healthy older adults, would have a positive relationship with WMH scoring on magnetic resonance imaging (MRI). As part of a longitudinal study of cognitive aging we have performed MRI on healthy older adults. In a group of 46 volunteers (25 females; median age 73, range 63-84 years), we have calculated of the Hachinski score and Framingham Stroke Risk Profile (FSRP). Volunteers also provided self-reported health information using the Cornell Medical Index (CMI). These were compared against the total Age Related White Matter Changes (ARWMC) score. The mean total ARWMC score was 7.4 + or - 5.27 (+ or - S.D.) and only 3 (6.5%) individuals had no evidence of WMH. Regression analysis of individual variables identified self-report of cardiovascular disease from the CMI, section C as the only significant predictor of ARWMC. A multivariate linear regression model also identified FSRP at 1 year as a second independently significant predictor. The multivariate model accounted for 19% of the variance in total ARWMC score. The only 6.5% of individuals who had no WMH is in keeping with previous studies. The important finding was the positive relationship with self-reported cardiovascular disease, which is a possible biomarker of sub-clinical cerebrovascular disease (CVD).

Lifetime cognitive performance is associated with midlife physical performance in a prospective national birth cohort study

OBJECTIVES

To examine whether measures of cognitive performance across life are related to physical performance at age 53 years, allowing for potential confounders.

METHODS

In a large representative British birth cohort of men and women (N = 2135) the associations between cognitive performance across life (i.e., standardized cognition scores at ages 15, 43, and 53 years and changes in verbal memory and search speed scores between 43 and 53 years) and measures of physical performance at age 53 years (i.e., standing balance, chair rising, and grip strength) were examined. Adjustments were made for body size, physical activity levels, health status, and socioeconomic conditions at age 53 years.

RESULTS

Higher cognitive scores on all childhood and adult tests, and a slower decline in verbal memory and search speed, were associated with better standing balance. Higher verbal fluency scores and a slower decline in verbal memory and search speed were more strongly related than scores on tests of general cognitive ability to chair rising. The relationships between cognitive performance and grip strength were inconsistent and weak.

CONCLUSIONS

The differential patterns of association found are consistent with the degree to which each is dependent on central nervous system function. Our findings suggest that initial developmental differences as well as shared ageing processes may underlie associations found between cognitive and physical performance.

Increased risk of falling in older community-dwelling women with mild cognitive impairment

BACKGROUND

Falls are a major health care problem for older people and are associated with cognitive dysfunction. Mild cognitive impairment (MCI) is an increasingly recognized clinical problem. No study has comprehensively compared people with and without MCI for fall risk factors in both the physiological and cognitive domains.

OBJECTIVE

The purpose of this cross-sectional study was to comprehensively compare fall risk factors in community-dwelling older women with and without MCI.

DESIGN

A cross-sectional design was used in the study.

METHODS

Community-dwelling women (N=158) with Folstein Mini Mental State Examination scores of >or=24 participated in the study. The Montreal Cognitive Assessment (MoCA) was used to categorize participants as either having or not having MCI. Each participant's fall risk profile was assessed with the Physiological Profile Assessment (PPA). Three central executive functions were assessed: (1) set shifting was assessed with the Trail Making Test (part B), (2) updating (ie, working memory) was assessed with the Verbal Digits Backward Test, and (3) response inhibition was assessed with the Stroop Colour-Word Test.

RESULTS

Both the composite PPA score and its subcomponent, postural sway performance, were significantly different between the 2 groups; participants with MCI had higher composite PPA scores and greater postural sway compared with participants without MCI. Participants with MCI performed significantly worse on all 3 central executive function tests compared with participants without MCI.

LIMITATIONS

A screening tool was used to categorize participants as having MCI, and fall risk factors were compared rather than the actual incidence of falls.

CONCLUSIONS

Fall risk screening may be prudent in older adults with MCI.

Brain flexibility and balance and gait performances mark morphological and metabolic abnormalities in the elderly

Although previous studies have found that cerebral white matter hyperintensities are associated with balance-gait disorders, no proton magnetic resonance spectroscopy data at the plane of the basal ganglia have been published. We investigated a possible relationship between balance performance and brain metabolite ratios or structural MRI measurements. We also included neuropsychological tests to determine whether such tests are related to structural or metabolic findings. All 80 participants were taken from the cohort of the Three-City study (Dijon-Bordeaux-Montpellier, France). The ratios of N-acetyl-aspartate to creatine (NAA/Cr) and choline to creatine (Cho/Cr) were calculated in the basal ganglia, thalami and insular cortex. We used univariate regression to identify which variables predicted changes in NAA/Cr and Cho/Cr, and completed the analysis with a multiple linear or logistic regression. After the multivariate analysis including hypertension, age, balance-gait, sex, white matter lesions, brain atrophy and body mass index, only balance-gait performance remained statistically significant for NAA/Cr (p=0.01) and for deep white-matter lesions (p=0.02). The Trail-Making Test is independently associated with brain atrophy and periventricular white-matter hyperintensities. Neuronal and axonal integrity at the plane of the basal ganglia is associated with balance and gait in the elderly, whereas brain flexibility is associated with structural MRI brain abnormalities.