scholarly journals Effects of age and knee osteoarthritis on the modular control of walking: A pilot study

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261862
Author(s):  
Sarah A. Roelker ◽  
Rebekah R. Koehn ◽  
Elena J. Caruthers ◽  
Laura C. Schmitt ◽  
Ajit M. W. Chaudhari ◽  
...  
Keyword(s):  
Older Adults ◽  
Pilot Study ◽  
Knee Osteoarthritis ◽  
Walking Speed ◽  
Younger Adults ◽  
Activation Patterns ◽  
Modular Control ◽  
Walking Performance ◽  
End Stage ◽  
Insight Into

Background Older adults and individuals with knee osteoarthritis (KOA) often exhibit reduced locomotor function and altered muscle activity. Identifying age- and KOA-related changes to the modular control of gait may provide insight into the neurological mechanisms underlying reduced walking performance in these populations. The purpose of this pilot study was to determine if the modular control of walking differs between younger and older adults without KOA and adults with end-stage KOA. Methods Kinematic, kinetic, and electromyography data were collected from ten younger (23.5 ± 3.1 years) and ten older (63.5 ± 3.4 years) adults without KOA and ten adults with KOA (64.0 ± 4.0 years) walking at their self-selected speed. Separate non-negative matrix factorizations of 500 bootstrapped samples determined the number of modules required to reconstruct each participant’s electromyography. One-way Analysis of Variance tests assessed the effect of group on walking speed and the number of modules. Kendall rank correlations (τb) assessed the association between the number of modules and self-selected walking speed. Results The number of modules required in the younger adults (3.2 ± 0.4) was greater than in the individuals with KOA (2.3 ± 0.7; p = 0.002), though neither cohorts’ required number of modules differed significantly from the unimpaired older adults (2.7 ± 0.5; p ≥ 0.113). A significant association between module number and walking speed was observed (τb = 0.350, p = 0.021) and individuals with KOA walked significantly slower (0.095 ± 0.21 m/s) than younger adults (1.24 ± 0.15 m/s; p = 0.005). Individuals with KOA also exhibited altered module activation patterns and composition (which muscles are associated with each module) compared to unimpaired adults. Conclusion These findings suggest aging alone may not significantly alter modular control; however, the combined effects of knee osteoarthritis and aging may together impair the modular control of gait.

scholarly journals Effects of Age and Knee Osteoarthritis on the Modular Control of Walking: A Pilot Study

2020 ◽  
Author(s):  
Sarah A. Roelker ◽  
Rebekah R. Koehn ◽  
Elena J. Caruthers ◽  
Laura C. Schmitt ◽  
Ajit M.W. Chaudhari ◽  
...  
Keyword(s):  
Older Adults ◽  
Pilot Study ◽  
Knee Osteoarthritis ◽  
Control Strategy ◽  
Neuromuscular Control ◽  
Younger Adults ◽  
Modular Control ◽  
Significant Difference ◽  
Walking Performance ◽  
Insight Into

ABSTRACTOlder adults and individuals with knee osteoarthritis (KOA) often exhibit reduced locomotor function and altered muscle activity. Identifying age- and KOA-related changes to the modular control of gait may provide insight into the neurological mechanisms underlying reduced walking performance in these populations. The purpose of this pilot study was to determine if the modular control of walking differs between younger and older adults without KOA and adults with end-stage KOA. Kinematic, kinetic, and electromyography (EMG) data were collected from ten younger (23.9 ± 2.8 years) and ten older (62.4 ± 2.6 years) adults without KOA and ten KOA patients (63.5 ± 3.4 years) walking at their self-selected speed. Separate non-negative matrix factorizations determined the number of modules required to reconstruct each participant’s EMG. There was no significant difference (p = 0.056) in the number of required modules between younger adults (4.1 ± 1.0), older adults without KOA (3.4 ± 0.8), and KOA patients (3.1 ± 0.6). However, a significant association between module number and walking speed was observed (r = 0.401; p = 0.028) and the KOA patients walked significantly slower (1.01 ± 0.16 m/s) than the younger adults (1.24 ± 0.18 m/s; p = 0.026). In addition, KOA patients exhibited altered module activation timing profiles and composition (which muscles are associated with each module) characterized by increased muscle co-activity compared to unimpaired younger and older adults who required the same number of modules. Thus, disease-related changes in neuromuscular control strategy may be associated with functional deficits in KOA patients.NEW AND NOTEWORTHYDifferentiating between age- and disease-related changes in motor control may provide insight into mechanisms underlying impaired walking performance in individuals with knee osteoarthritis. There was no significant difference in the number of modules required by individuals with knee osteoarthritis and unimpaired younger and older adults. However, knee osteoarthritis patients exhibited altered module composition and timing characterized by increased muscle co-activity, which suggests a change in underlying neural control strategy may be associated with knee osteoarthritis.

The Functional Utilization of Propulsive Capacity During Human Walking

2018 ◽  
Vol 34 (6) ◽  
pp. 474-482 ◽  
Author(s):  
Katie A. Conway ◽  
Randall G. Bissette ◽  
Jason R. Franz
Keyword(s):  
Power Generation ◽  
Older Adults ◽  
Human Walking ◽  
Reserve Capacity ◽  
Maximum Speed ◽  
Ankle Moment ◽  
Mechanistic Insight ◽  
Walking Performance ◽  
Young Subjects ◽  
Insight Into

Aging and many gait pathologies are characterized by reduced propulsive forces and ankle moment and power generation during trailing leg push-off in walking. Despite those changes, we posit that many individuals retain an underutilized reserve for enhancing push-off intensity during walking that may be missed using conventional dynamometry. By using a maximum ramped impeding force protocol and maximum speed walking, we gained mechanistic insight into the factors that govern push-off intensity and the available capacity thereof during walking in young subjects. We discovered in part that young subjects walking at their preferred speed retain a reserve capacity for exerting larger propulsive forces of 49%, peak ankle power of 43%, and peak ankle moment of 22% during push-off—the latter overlooked by maximum isometric dynamometry. We also provide evidence that these reserve capacities are governed at least in part by the neuromechanical behavior of the plantarflexor muscles, at least with regard to ankle moment generation. We envision that a similar paradigm used to quantify propulsive reserves in older adults or people with gait pathology would empower the more discriminate and personalized prescription of gait interventions seeking to improve push-off intensity and thus walking performance.

scholarly journals Self-Selected Walking Speed Is Predictive of Daily Ambulatory Activity in Older Adults

2016 ◽  
Vol 24 (2) ◽  
pp. 214-222 ◽  
Author(s):  
Addie Middleton ◽  
George D. Fulk ◽  
Michael W. Beets ◽  
Troy M. Herter ◽  
Stacy L. Fritz
Keyword(s):  
Older Adults ◽  
Linear Regression ◽  
Functional Status ◽  
Walking Speed ◽  
Activity Monitoring ◽  
Community Dwelling ◽  
Ambulatory Activity ◽  
Steps Per Day ◽  
Community Dwelling Older Adults ◽  
Insight Into

Daily ambulatory activity is associated with health and functional status in older adults; however, assessment requires multiple days of activity monitoring. The objective of this study was to determine the relative capabilities of self-selected walking speed (SSWS), maximal walking speed (MWS), and walking speed reserve (WSR) to provide insight into daily ambulatory activity (steps per day) in community-dwelling older adults. Sixty-seven older adults completed testing and activity monitoring (age 80.39 [6.73] years). SSWS (R2 = .51), MWS (R2 = .35), and WSR calculated as a ratio (R2 = .06) were significant predictors of daily ambulatory activity in unadjusted linear regression. Cutpoints for participants achieving < 8,000 steps/day were identified for SSWS (≤ 0.97 m/s, 44.2% sensitivity, 95.7% specificity, 10.28 +LR, 0.58 −LR) and MWS (≤ 1.39 m/s, 60.5% sensitivity, 78.3% specificity, 2.79 +LR, 0.50 −LR). SSWS may be a feasible proxy for assessing and monitoring daily ambulatory activity in older adults.

In Vivo Brain Glutathione is Higher in Older Age and Correlates with Mobility

2020 ◽  
Author(s):  
K. E. Hupfeld ◽  
H. W. Hyatt ◽  
P. Alvarez Jerez ◽  
M. Mikkelsen ◽  
C. J. Hass ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Older Adults ◽  
Motor Performance ◽  
Resonance Spectroscopy ◽  
Younger Adults ◽  
Age Related ◽  
Brain Oxidative Stress ◽  
Brain Antioxidants ◽  
Insight Into

AbstractBrain markers of oxidative damage increase with advancing age. In response, brain antioxidant levels may also increase with age, although this has not been well investigated. Here we used edited magnetic resonance spectroscopy to quantify endogenous levels of glutathione (GSH, one of the most abundant brain antioxidants) in 37 young (mean: 21.8 (2.5) years; 19 F) and 23 older adults (mean: 72.8 (8.9) years; 19 F). Accounting for age-related atrophy, we identified higher frontal and sensorimotor GSH levels for the older compared to the younger adults. For the older adults only, higher sensorimotor (but not frontal) GSH was correlated with poorer balance, gait, and manual dexterity. This suggests a regionally-specific relationship between higher brain oxidative stress levels and motor performance declines with age. We suggest these findings reflect a compensatory upregulation of GSH in response to increasing brain oxidative stress with normal aging. Together, these results provide insight into age differences in brain antioxidant levels and implications for motor function.

scholarly journals Using sweat to measure cytokines in older adults compared to younger adults: A pilot study

2018 ◽  
Vol 454 ◽  
pp. 1-5 ◽  
Author(s):  
Melissa D. Hladek ◽  
Sarah L. Szanton ◽  
Young-Eun Cho ◽  
Chen Lai ◽  
Caroline Sacko ◽  
...  
Keyword(s):  
Older Adults ◽  
Pilot Study ◽  
Younger Adults

scholarly journals Neural distinctiveness declines with age in auditory cortex and is associated with auditory GABA levels

2018 ◽  
Author(s):  
Poortata Lalwani ◽  
Holly Gagnon ◽  
Kaitlin Cassady ◽  
Molly Simmonite ◽  
Scott Peltier ◽  
...  
Keyword(s):  
Older Adults ◽  
Visual Cortex ◽  
Individual Differences ◽  
Magnetic Resonance ◽  
Auditory Cortex ◽  
Aging Brain ◽  
Resonance Spectroscopy ◽  
Younger Adults ◽  
Activation Patterns ◽  
Age Related

AbstractNeural activation patterns in the ventral visual cortex in response to different categories of visual stimuli (e.g., faces vs. houses) are less selective, or distinctive, in older adults than in younger adults, a phenomenon known as age-related neural dedifferentiation. Previous work in animals suggests that age-related reductions of the inhibitory neurotransmitter, gamma aminobutyric acid (GABA), may play a role in this age-related decline in neural distinctiveness. In this study, we investigated whether neural dedifferentiation extends to auditory cortex and whether individual differences in GABA are associated with individual differences in neural distinctiveness in humans. 20 healthy young adults (ages 18-29) and 23 healthy older adults (over 65) completed a functional magnetic resonance imaging (fMRI) scan, during which neural activity was estimated while they listened to foreign speech and music. GABA levels in the auditory, ventrovisual and sensorimotor cortex were estimated in the same individuals in a separate magnetic resonance spectroscopy (MRS) scan. Relative to the younger adults, the older adults exhibited both (1) less distinct activation patterns for music vs. speech stimuli and (2) lower GABA levels in the auditory cortex. Also, individual differences in auditory GABA levels (but not ventrovisual or sensorimotor GABA levels) predicted individual differences in neural distinctiveness in the auditory cortex in the older adults. These results demonstrate that age-related neural dedifferentiation extends to the auditory cortex and suggest that declining GABA levels may play a role in neural dedifferentiation in older adults.Significance StatementPrior work has revealed age-related neural dedifferentiation in the visual cortex. GABA levels also decline with age in several parts of the human cortex. Here, we report that these two age-related changes are linked; neural dedifferentiation is associated with lower GABA levels in older adults. We also show that age-related neural dedifferentiation extends to auditory cortex, suggesting that it may be a general feature of the aging brain. These findings provide novel insights into the neurochemical basis of age-related neural dedifferentiation in humans and also offer a potential new avenue for investigating age-related declines in central auditory processing.

scholarly journals The Complexity of Blood Pressure Fluctuation Mediated the Effects of Hypertension on Walking Speed in Older Adults

2021 ◽  
Vol 13 ◽  
Author(s):  
Xin Jiang ◽  
Yurun Cai ◽  
Yue Zhao ◽  
Xia Gao ◽  
Dan Peng ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Older Adults ◽  
Cognitive Function ◽  
Dual Task ◽  
Pressure Fluctuation ◽  
Walking Speed ◽  
Equation Modeling ◽  
Walking Performance ◽  
Blood Pressure Fluctuation ◽  
Task Conditions

Background: Older adults with hypertension often had diminished walking performance. The underlying mechanism through which hypertension affects walking performance, however, has not been fully understood. We here measured the complexity of the continuous systolic (SBP) and diastolic (DBP) blood pressure fluctuation, grade of white matter lesions (WMLs), and cognitive function and used structural equation modeling (SEM) to examine the interrelationships between hypertension, BP complexity, WMLs, cognitive function, and walking speed in single- and dual-task conditions.Methods: A total of 152 older adults with age &gt; 60 years (90 hypertensive and 62 normotensive participants) completed one MRI scan of brain structure, a finger BP assessment of at least 10 min, Mini-Mental State Examination (MMSE) to assess cognitive function, and 10-meter walking tests in single (i.e., normal walking) and dual tasks (i.e., walking while performing a serial subtraction of three from a random three-digit number). The grade of WMLs was assessed using the total score of Fazekas scale; the complexity of SBP and DBP was measured using multiscale entropy (MSE), and the walking performance was assessed by walking speed in single- and dual-task conditions.Results: As compared to normotensives, hypertensive older adults had significantly slower walking speed, lower complexity of SBP and DBP, greater grade of WMLs, and poorer cognitive function (p &lt; 0.03). Those with lower BP complexity (β &gt; 0.31, p &lt; 0.003), greater WML grade (β &lt; −0.39, p &lt; 0.0002), and/or poorer cognitive function (β &lt; −0.39, p &lt; 0.0001) had slower walking speed in single- and/or dual-task conditions. The SEM model demonstrated significant total effects of hypertension on walking speed, and such effects were mediated by BP complexity only, or BP complexity, WML grade, and cognitive function together.Conclusion: This study demonstrates the cross-sectional association between the complexity of continuous beat-to-beat BP fluctuation, WML grade, cognitive function, and walking speed in hypertensive and normotensive older adults, revealing a potential mechanism that hypertension may affect walking performance in older adults through diminished BP complexity, increased WML grade, and decreased cognitive function, and BP complexity is an important factor for such effects. Future longitudinal studies are warranted to confirm the findings in this study.

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