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Zhang X, Wang Z, Zou J, Zhang L, Ning JH, Jiang B, Liang Y, Zhang YZ. Association between physical frailty and cortical structure in middle-aged and elderly people: a Mendelian randomization study. Front Aging Neurosci 2024; 16:1395553. [PMID: 38841102 PMCID: PMC11150765 DOI: 10.3389/fnagi.2024.1395553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 05/06/2024] [Indexed: 06/07/2024] Open
Abstract
Introduction Physical weakness is associated with cortical structures, but the exact causes remain to be investigated. Therefore, we utilized Mendelian randomization (MR) analysis to uncover the underlying connection between frailty and cortical structures. Methods The Genome-Wide Association Study (GWAS) on frailty pooled data from publicly available sources such as the UK Biobank and included five indicators of frailty: weakness, walking speed, weight loss, physical activity, and exhaustion. GWAS data on cerebral cortical structure were obtained from the ENIGMA consortium, and we assessed the causal relationship between hereditary frailty and cortical surface area (SA) or cortical thickness (TH). Inverse variance weighting (IVW) was used as the primary estimate, and heterogeneity and multidimensionality were monitored by MR-PRESSO to detect outliers. Additionally, MR-Egger, Cochran's Q test, and weighted median were employed. Results At the aggregate level, there was no causal relationship between frailty and cortical thickness or surface area. At the regional level, frailty was associated with the thickness of the middle temporal lobe, parahippocampus, rostral middle frontal lobe, lower parietal lobe, anterior cingulate gyrus, upper temporal lobe, lateral orbital frontal cortex, pericardial surface area, rostral middle frontal lobe, upper temporal lobe, rostral anterior cingulate gyrus, lower parietal lobe, and upper parietal lobe. These results were nominally significant, and sensitivity analyses did not detect any multidirectionality or heterogeneity, suggesting that the results of our analyses are reliable. Discussion The results of our analyses suggest a potential causal relationship between somatic weakness and multiple regions of cortical structure. However, the specific mechanisms of influence remain to be investigated. Preliminary results from our analysis suggest that the effects of physical frailty on cortical structures are influenced by various factors related to frailty exposure. This relationship has been documented, and it is therefore both feasible and meaningful to build on existing research to explore the clinical significance of the relationship.
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Affiliation(s)
- Xin Zhang
- College of Basic Medical Sciences, Dali University, Dali, Yunnan, China
| | - Zhen Wang
- College of Basic Medical Sciences, Dali University, Dali, Yunnan, China
| | - Jing Zou
- The First Affiliated Hospital of Dali University, Dali, Yunnan, China
| | - Le Zhang
- College of Basic Medical Sciences, Dali University, Dali, Yunnan, China
| | - Jing-Hua Ning
- College of Basic Medical Sciences, Dali University, Dali, Yunnan, China
| | - Bei Jiang
- Yunnan Key Laboratory of Screening and Research on Anti-pathogenic Plant Resources from West Yunnan (Cultivation), Dali, Yunnan, China
| | - Yi Liang
- Princess Margaret Cancer Centre, TMDT-MaRS Centre, University Health Network, Toronto, ON, Canada
| | - Yu-Zhe Zhang
- College of Basic Medical Sciences, Dali University, Dali, Yunnan, China
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Sato SD, Shah VA, Fettrow T, Hall KG, Tays GD, Cenko E, Roy A, Clark DJ, Ferris DP, Hass CJ, Manini TM, Seidler RD. Resting state brain network segregation is associated with walking speed and working memory in older adults. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592861. [PMID: 38766046 PMCID: PMC11100712 DOI: 10.1101/2024.05.07.592861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Older adults exhibit larger individual differences in walking ability and cognitive function than young adults. Characterizing intrinsic brain connectivity differences in older adults across a wide walking performance spectrum may provide insight into the mechanisms of functional decline in some older adults and resilience in others. Thus, the objectives of this study were to: (1) determine whether young adults and high- and low-functioning older adults show group differences in brain network segregation, and (2) determine whether network segregation is associated with working memory and walking function in these groups. The analysis included 21 young adults and 81 older adults. Older adults were further categorized according to their physical function using a standardized assessment; 54 older adults had low physical function while 27 were considered high functioning. Structural and functional resting state magnetic resonance images were collected using a Siemens Prisma 3T scanner. Working memory was assessed with the NIH Toolbox list sorting test. Walking speed was assessed with a 400 m-walk test at participants' self-selected speed. We found that network segregation in mobility-related networks (sensorimotor, vestibular, and visual networks) was higher in younger adults compared to older adults. There were no group differences in laterality effects on network segregation. We found multivariate associations between working memory and walking speed with network segregation scores. Higher right anterior cingulate cortex network segregation was associated with higher working memory function. Higher right sensorimotor, right vestibular, right anterior cingulate cortex, and lower left anterior cingulate cortex network segregation was associated with faster walking speed. These results are unique and significant because they demonstrate higher network segregation is largely related to higher physical function and not age alone.
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Affiliation(s)
- Sumire D Sato
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
| | - Valay A Shah
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
| | - Tyler Fettrow
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
- NASA Langley Research Center, Hampton, VA, USA
| | - Kristina G Hall
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
| | - Grant D Tays
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
| | - Erta Cenko
- Department of Epidemiology, College of Public Health and Health Professions, and College of Medicine, University of Florida, Gainesville, FL, USA
| | - Arkaprava Roy
- Department of Biostatistics, University of Florida, Gainesville, FL, USA
| | - David J Clark
- Department of Neurology, University of Florida, Gainesville, FL, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA
| | - Daniel P Ferris
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Chris J Hass
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
| | - Todd M Manini
- Department of Health Outcomes and Biomedical Informatics, University of Florida, Gainesville, FL, USA
| | - Rachael D Seidler
- Department of Applied Kinesiology and Physiology, University of Florida, Gainesville, FL, USA
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Richardson DP, Foxe JJ, Freedman EG. Reduced Proactive and Reactive Cognitive Flexibility in Older Adults Underlies Performance Costs During Dual-Task Walking: A Mobile Brain/Body Imaging (MoBI) Study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.27.577090. [PMID: 38328169 PMCID: PMC10849668 DOI: 10.1101/2024.01.27.577090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Age-related reductions in cognitive flexibility may limit modulation of control processes during systematic increases to cognitive-motor demands, exacerbating dual-task costs. In this study, behavioral and neurophysiologic changes to proactive and reactive control during progressive cognitive-motor demands were compared across older and younger adults to explore the basis for age-differences in cognitive-motor interference (CMI). 19 younger (19 - 29 years old, mean age = 22.84 +/- 2.75 years, 6 male, 13 female) and 18 older (60 - 77 years old, mean age = 67.89 +/- 4.60 years, 9 male, 9 female) healthy adults completed cued task-switching while alternating between sitting and walking on a treadmill. Gait kinematics, task performance measures, and brain activity were recorded using electroencephalography (EEG) based Mobile Brain/Body Imaging (MoBI). Response accuracy on easier trial types improved in younger, but not older adults when they walked while performing the cognitive task. As difficulty increased, walking provoked accuracy costs in older, but not younger adults. Both groups registered faster responses and reduced gait variability during dual-task walking. Older adults exhibited lower amplitude modulations of proactive and reactive neural activity as cognitive-motor demands systematically increased, which may reflect reduced flexibility for progressive preparatory and reactive adjustments over behavioral control.
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Affiliation(s)
- David P. Richardson
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry Rochester, New York, USA
| | - John J. Foxe
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry Rochester, New York, USA
| | - Edward G. Freedman
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry Rochester, New York, USA
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Suri A, VanSwearingen J, Rosano C, Brach JS, Redfern MS, Sejdić E, Rosso AL. Uneven surface and cognitive dual-task independently affect gait quality in older adults. Gait Posture 2023; 106:34-41. [PMID: 37647710 PMCID: PMC10591986 DOI: 10.1016/j.gaitpost.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/07/2023] [Accepted: 08/21/2023] [Indexed: 09/01/2023]
Abstract
BACKGROUND Real-world mobility involves walking in challenging conditions. Assessing gait during simultaneous physical and cognitive challenges provides insights on cognitive health. RESEARCH QUESTION How does uneven surface, cognitive task, and their combination affect gait quality and does this gait performance relate to cognitive functioning? METHODS Community-dwelling older adults (N = 104, age=75 ± 6 years, 60 % females) performed dual-task walking paradigms (even and uneven surface; with and without alphabeting cognitive task (ABC)) to mimic real-world demands. Gait quality measures [speed(m/s), rhythmicity(steps/minute), stride time variability (%), adaptability (m/s2), similarity, smoothness, power (Hz) and regularity] were calculated from an accelerometer worn on the lower back. Linear-mixed modelling and Tukey analysis were used to analyze independent effects of surface and cognitive task and their interaction on gait quality. Partial Spearman correlations compared gait quality with global cognition and executive function. RESULTS No interaction effects between surface and cognitive task were found. Uneven surface reduced gait speed(m/s) (β = -0.07). Adjusted for speed, uneven surface reduced gait smoothness (β = -0.27) and increased regularity (β = 0.09), Tukey p < .05, for even vs uneven and even-ABC vs uneven-ABC. Cognitive task reduced gait speed(m/s) (β = -0.12). Adjusted for speed, cognitive task increased variability (β = 7.60), reduced rhythmicity (β = -6.68) and increased regularity (β = 0.05), Tukey p < .05, for even vs even-ABC and uneven vs uneven-ABC. With demographics as covariates, gait speed was not associated with cognition. Gait quality [lower variability during even-ABC (ρp =-.31) and uneven-ABC (ρp =-.28); greater rhythmicity (ρp between.22 and.29) and greater signal-adaptability AP (ρp between.22 and.26) during all walking tasks] was associated with better global cognition. Gait adaptability during even (ρp =-0.21, p = 0.03) and uneven(ρp =-0.19, p = 0.04) walking was associated with executive function. SIGNIFICANCE Surface and cognitive walking tasks independently affected gait quality. Our study with high-functioning older adults suggests that task-related changes in gait quality are related to subtle changes in cognitive functioning.
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Affiliation(s)
- Anisha Suri
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, PA, USA
| | - Jessie VanSwearingen
- Department of Physical Therapy, School of Rehabilitation Sciences, University of Pittsburgh, PA, USA
| | - Caterina Rosano
- Department of Epidemiology, School of Public Health, University of Pittsburgh, PA, USA
| | - Jennifer S Brach
- Department of Physical Therapy, School of Rehabilitation Sciences, University of Pittsburgh, PA, USA
| | - Mark S Redfern
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA
| | - Ervin Sejdić
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, PA, USA; The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada; North York General Hospital, Toronto, ON, Canada
| | - Andrea L Rosso
- Department of Epidemiology, School of Public Health, University of Pittsburgh, PA, USA.
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Liu C, Downey RJ, Mu Y, Richer N, Hwang J, Shah VA, Sato SD, Clark DJ, Hass CJ, Manini TM, Seidler RD, Ferris DP. Comparison of EEG Source Localization Using Simplified and Anatomically Accurate Head Models in Younger and Older Adults. IEEE Trans Neural Syst Rehabil Eng 2023; 31:2591-2602. [PMID: 37252873 PMCID: PMC10336858 DOI: 10.1109/tnsre.2023.3281356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Accuracy of electroencephalography (EEG) source localization relies on the volume conduction head model. A previous analysis of young adults has shown that simplified head models have larger source localization errors when compared with head models based on magnetic resonance images (MRIs). As obtaining individual MRIs may not always be feasible, researchers often use generic head models based on template MRIs. It is unclear how much error would be introduced using template MRI head models in older adults that likely have differences in brain structure compared to young adults. The primary goal of this study was to determine the error caused by using simplified head models without individual-specific MRIs in both younger and older adults. We collected high-density EEG during uneven terrain walking and motor imagery for 15 younger (22±3 years) and 21 older adults (74±5 years) and obtained [Formula: see text]-weighted MRI for each individual. We performed equivalent dipole fitting after independent component analysis to obtain brain source locations using four forward modeling pipelines with increasing complexity. These pipelines included: 1) a generic head model with template electrode positions or 2) digitized electrode positions, 3) individual-specific head models with digitized electrode positions using simplified tissue segmentation, or 4) anatomically accurate segmentation. We found that when compared to the anatomically accurate individual-specific head models, performing dipole fitting with generic head models led to similar source localization discrepancies (up to 2 cm) for younger and older adults. Co-registering digitized electrode locations to the generic head models reduced source localization discrepancies by ∼ 6 mm. Additionally, we found that source depths generally increased with skull conductivity for the representative young adult but not as much for the older adult. Our results can help inform a more accurate interpretation of brain areas in EEG studies when individual MRIs are unavailable.
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Hupfeld KE, McGregor HR, Hass CJ, Pasternak O, Seidler RD. Sensory system-specific associations between brain structure and balance. Neurobiol Aging 2022; 119:102-116. [PMID: 36030560 PMCID: PMC9728121 DOI: 10.1016/j.neurobiolaging.2022.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/26/2022] [Accepted: 07/28/2022] [Indexed: 11/15/2022]
Abstract
Nearly 75% of older adults in the US report balance problems. Although it is known that aging results in widespread brain atrophy, less is known about how brain structure relates to balance in aging. We collected T1- and diffusion-weighted MRI scans and measured postural sway of 36 young (18-34 years) and 22 older (66-84 years) adults during eyes open, eyes closed, eyes open-foam, and eyes closed-foam conditions. We calculated summary measures indicating visual, proprioceptive, and vestibular contributions to balance. Across both age groups, thinner cortex in multisensory integration regions was associated with greater reliance on visual inputs for balance. Greater gyrification within sensorimotor and parietal cortices was associated with greater reliance on proprioceptive inputs. Poorer vestibular function was correlated with thinner vestibular cortex, greater gyrification within sensorimotor, parietal, and frontal cortices, and lower free water-corrected axial diffusivity across the corona radiata and corpus callosum. These results expand scientific understanding of how individual differences in brain structure relate to balance and have implications for developing brain stimulation interventions to improve balance.
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Affiliation(s)
- K E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - H R McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - C J Hass
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - O Pasternak
- Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - R D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; University of Florida Norman Fixel Institute for Neurological Diseases, Gainesville, FL, USA.
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Alzaid H, Ethofer T, Kardatzki B, Erb M, Scheffler K, Berg D, Maetzler W, Hobert MA. Gait decline while dual-tasking is an early sign of white matter deterioration in middle-aged and older adults. Front Aging Neurosci 2022; 14:934241. [PMID: 36247983 PMCID: PMC9558904 DOI: 10.3389/fnagi.2022.934241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Loss of white matter integrity (WMI) is associated with gait deficits in middle-aged and older adults. However, these deficits are often only apparent under cognitively demanding situations, such as walking and simultaneously performing a secondary cognitive task. Moreover, evidence suggests that declining executive functions (EF) are linked to gait decline, and their co-occurrence may point to a common underlying pathology, i.e., degeneration of shared brain regions. In this study, we applied diffusion tensor imaging (DTI) and a standardized gait assessment under single- and dual-tasking (DT) conditions (walking and subtracting) in 74 middle-aged and older adults without any significant gait or cognitive impairments to detect subtle WM alterations associated with gait decline under DT conditions. Additionally, the Trail Making Test (TMT) was used to assess EF, classify participants into three groups based on their performance, and examine a possible interaction between gait, EF, and WMI. Gait speed and subtracting speed while dual-tasking correlated significantly with the fractional anisotropy (FA) in the bilateral anterior corona radiata (highest r = 0.51/p < 0.0125 FWE-corrected). Dual-task costs (DTC) of gait speed correlated significantly with FA in widespread pathways, including the corpus callosum, bilateral anterior and superior corona radiata, as well as the left superior longitudinal fasciculus (highest r = −0.47/p < 0.0125 FWE-corrected). EF performance was associated with FA in the left anterior corona radiata (p < 0.05); however, EF did not significantly mediate the effects of WMI on DTC of gait speed. There were no significant correlations between TMT and DTC of gait and subtracting speed, respectively. Our findings indicate that gait decline under DT conditions is associated with widespread WM deterioration even in middle-aged and older adults without any significant gait or cognitive impairments. However, this relationship was not mediated by EF.
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Affiliation(s)
- Haidar Alzaid
- Department of Biomedical Magnetic Resonance, Tübingen University Hospital, Tübingen, Germany
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
- *Correspondence: Haidar Alzaid,
| | - Thomas Ethofer
- Department of Biomedical Magnetic Resonance, Tübingen University Hospital, Tübingen, Germany
- Department of Psychiatry and Psychotherapy, Tübingen University Hospital, Tübingen, Germany
| | - Bernd Kardatzki
- Department of Biomedical Magnetic Resonance, Tübingen University Hospital, Tübingen, Germany
| | - Michael Erb
- Department of Biomedical Magnetic Resonance, Tübingen University Hospital, Tübingen, Germany
| | - Klaus Scheffler
- Department of Biomedical Magnetic Resonance, Tübingen University Hospital, Tübingen, Germany
| | - Daniela Berg
- Department of Neurology, Kiel University Hospital, Kiel, Germany
| | - Walter Maetzler
- Department of Neurology, Kiel University Hospital, Kiel, Germany
| | - Markus A. Hobert
- Department of Neurology, Kiel University Hospital, Kiel, Germany
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