scholarly journals Age-Related Differences in Muscle Synergy Organization during Step Ascent at Different Heights and Directions

2020 ◽  
Vol 10 (6) ◽  
pp. 1987 ◽  
Author(s):  
Remco J. Baggen ◽  
Jaap H. van Dieën ◽  
Evelien Van Roie ◽  
Sabine M. Verschueren ◽  
Georgios Giarmatzis ◽  
...  
Keyword(s):  
Motor Control ◽  
Older Women ◽  
Young Women ◽  
Age Groups ◽  
Neuromuscular Control ◽  
Significant Negative Correlation ◽  
Community Dwelling ◽  
Step Height ◽  
Muscle Synergy ◽  
Age Related

The aim of this study was to explore the underlying age-related differences in dynamic motor control during different step ascent conditions using muscle synergy analysis. Eleven older women (67.0 y ± 2.5) and ten young women (22.5 y ± 1.6) performed stepping in forward and lateral directions at step heights of 10, 20 and 30 cm. Surface electromyography was obtained from 10 lower limb and torso muscles. Non-negative matrix factorization was used to identify sets of (n) synergies across age groups and stepping conditions. In addition, variance accounted for (VAF) by the detected number of synergies was compared to assess complexity of motor control. Finally, correlation coefficients of muscle weightings and between-subject variability of the temporal activation patterns were calculated and compared between age groups and stepping conditions. Four synergies accounted for >85% VAF across age groups and stepping conditions. Age and step height showed a significant negative correlation with VAF during forward stepping but not lateral stepping, with lower VAF indicating higher synergy complexity. Muscle weightings showed higher similarity across step heights in older compared to young women. Neuromuscular control of young and community-dwelling older women could not be differentiated based on the number of synergies extracted. Additional analyses of synergy structure and complexity revealed subtle age- and step-height-related differences, indicating that older women rely on more complex neuromuscular control strategies.

scholarly journals The Dynamic Motor Control Index as a Marker of Age-Related Neuromuscular Impairment

2021 ◽  
Vol 13 ◽  
Author(s):  
Ashley N. Collimore ◽  
Ashlyn J. Aiello ◽  
Ryan T. Pohlig ◽  
Louis N. Awad
Keyword(s):  
Motor Control ◽  
Age Groups ◽  
Neuromuscular Control ◽  
Muscle Synergies ◽  
Age Related ◽  
Index Study ◽  
Two Measures ◽  
Study Participants ◽  
Young Old ◽  
Neuromuscular Impairment

Biomarkers that can identify age-related decline in walking function have potential to promote healthier aging by triggering timely interventions that can mitigate or reverse impairments. Recent evidence suggests that changes in neuromuscular control precede changes in walking function; however, it is unclear which measures are best suited for identifying age-related changes. In this study, non-negative matrix factorization of electromyography data collected during treadmill walking was used to calculate two measures of the complexity of muscle co-activations during walking for 36 adults: (1) the number of muscle synergies and (2) the dynamic motor control index. Study participants were grouped into young (18–35 years old), young-old (65–74 years old), and old–old (75+ years old) subsets. We found that the dynamic motor control index [χ2(2) = 9.41, p = 0.009], and not the number of muscle synergies [χ2(2) = 5.42, p = 0.067], differentiates between age groups [χ2(4) = 10.62, p = 0.031, Nagelkerke R2 = 0.297]. Moreover, an impairment threshold set at a dynamic motor control index of 90 (i.e., one standard deviation below the young adults) was able to differentiate between age groups [χ2(2) = 9.351, p = 0.009]. The dynamic motor control index identifies age-related differences in neuromuscular complexity not measured by the number of muscle synergies and may have clinical utility as a marker of neuromotor impairment.

Reference intervals for plasma lipoperoxides: age-, sex-, and specimen-related variations.

1987 ◽  
Vol 33 (12) ◽  
pp. 2289-2291 ◽  
Author(s):  
J A Knight ◽  
S E Smith ◽  
V E Kinder ◽  
H B Anstall
Keyword(s):  
Older Women ◽  
Young Women ◽  
Blood Donors ◽  
Sodium Citrate ◽  
Older Men ◽  
Reference Intervals ◽  
Female Adult ◽  
Experimental Animals ◽  
Age Related ◽  
Younger Men

Abstract We measured lipoperoxides, as malondialdehyde (MDA), by liquid chromatography in plasma from 230 male and 148 female adult blood donors, to establish reliable reference values and to compare possible sex-, age-, and specimen-related differences. Our studies show that mean have higher MDA concentrations in plasma than do women (P less than 0.05), older men have higher values than younger men (P less than 0.05), and older women have higher values than young women (P less than 0.001). These age-related results support earlier studies in experimental animals that lipid peroxidation increases with increasing age. In addition, plasma from liquid EDTA-anti-coagulated blood has significantly lower MDA concentrations than does serum or plasma from blood treated with lithium heparin, sodium citrate, or CPDA-1 (P less than 0.001).

Correlation between age and MMSE in schizophrenia

2015 ◽  
Vol 27 (11) ◽  
pp. 1769-1775 ◽  
Author(s):  
Jean-Robert Maltais ◽  
Geneviève Gagnon ◽  
Marie-Pierre Garant ◽  
Jean-François Trudel
Keyword(s):  
Age Groups ◽  
Community Dwelling ◽  
Screening Tools ◽  
Cognitive Screening ◽  
Cognitive Changes ◽  
Institutional Settings ◽  
Age Related ◽  
Schizophrenic Patients ◽  
Meta Regression Analysis ◽  
Institutionalized Patients

ABSTRACTBackground:The Mini-Mental State Examination (MMSE) is widely used in schizophrenia, although normative data are lacking in this population. This review and meta-regression analysis studies the effect of aging on MMSE scores in schizophrenic patients.Methods:We entered the search terms schizophrenia and MMSE in PubMed and PsychInfo. Bibliographies of pertinent articles were also examined. We included every study presenting the MMSE scores in schizophrenic patients along with a corresponding mean age. We conducted our analyses using simple linear regression weighted for the inverse of within-trial variance of the age variable, thus conferring more importance to studies with narrower age groups.Results:We identified 56 articles (n = 5,588) published between 1990 and 2012. The MMSE scores of schizophrenic patients decline by approximately 1 point for every four years (y = 34.939−0.247x, 95% Confidence Interval (CI) [−0.304, −0.189], R2 = 0,545), which is five times the rate in the general population. Institutionalized patients account for a large proportion of this decline (y = 37.603–0.308x, 95% CI [−0.349, −0.267], R2 = 0.622) whereas community-dwelling patients are relatively stable throughout aging (y = 27.591–0.026x, 95% CI [−0.074, 0.023], R2 = 0.037).Conclusions:Subgroup analyses show different trajectories between institutionalized and outpatients with schizophrenia. The deterioration observed in institutionalized patients may have to do with greater illness severity, heavier medication load, vascular risk factors, and lack of stimulation in institutional settings. Studies documenting the role of these variables would be useful. Cognitive screening tools that assess executive functions would be interesting to study in schizophrenics, as they may reveal more subtle age-related cognitive changes not measured by the MMSE.

Effect of age on heat-activated sweat gland density and flow during exercise in dry heat

1987 ◽  
Vol 63 (3) ◽  
pp. 1089-1094 ◽  
Author(s):  
R. K. Anderson ◽  
W. L. Kenney
Keyword(s):  
Older Women ◽  
Sweat Gland ◽  
Age Groups ◽  
Whole Body ◽  
Moderate Intensity ◽  
Exercise Session ◽  
Sweat Glands ◽  
Moderate Intensity Exercise ◽  
Age Related ◽  
Eccrine Glands

Physiological responses of eight postmenopausal older women (age 52–62 yr) and eight younger women (age 20–30 yr) were compared during moderate intensity exercise in a hot dry environment (48 degrees C dry bulb, 25 degrees C wet bulb). The age groups were matched on the basis of maximal O2 consumption (VO2max), body surface area, and body fatness. After heat acclimation the women walked at 40% VO2max for up to 2 h in the hot dry environment while heart rate (HR), rectal temperature (Tre), mean skin temperature (Tsk), whole-body sweating rate (Msw), and local sweating rates (msw; forearm, chest, and scapula) were measured. Additionally, the density of heat-activated sweat glands (HASG) was determined and average sweat gland flow (SGF) was calculated for the scapular area. Although no differences between age groups were found in HR response (when analyzed as percent of maximal HR) or Tsk, the older women had a significantly higher Tre throughout the heat-exercise session. The greater heat storage of the older women may be explained by their significantly lower Msw and msw. There were no differences between the younger and older women in the density of HASG after 30 min; therefore, the lower msw reflects a diminished output per HASG rather than a decrease in the number of sweat glands recruited. The diminished thermoregulatory ability of the older women, unrelated to differences in VO2max, appears to reflect either 1) a diminished response of the sweat glands to central and/or peripheral stimuli, or 2) an age-related structural alteration in the eccrine glands or surrounding skin cells.

The Role of Sensory Processing in the Everyday Lives of Older Adults

2003 ◽  
Vol 23 (3) ◽  
pp. 99-106 ◽  
Author(s):  
Patricia S. Pohl ◽  
Winnie Dunn ◽  
Catana Brown
Keyword(s):  
Older Adults ◽  
Sensory Processing ◽  
Sensory Input ◽  
Age Groups ◽  
Community Dwelling ◽  
Sensory Profile ◽  
Middle Aged ◽  
Age In Place ◽  
Sensory Experiences ◽  
Age Related

This study investigated whether there are age-related differences in sensory processing within daily life. Participants included 404 community-dwelling adults divided into three age groups: 19 to 34 years old (127 individuals), 35 to 64 years old (126 individuals), and 65 years and older (151 individuals). Each participant completed the Adolescent/Adult Sensory Profile. There was a difference in sensory processing between the three groups (p = .000), with the older adults noticing sensory input less than the young and middle aged adults (p = .002 for both groups). Both middle aged and older adults engaged in less sensory seeking behaviors than did young adults (p = .012 and p = .000, respectively). In an additional analysis, the older group was subdivided into four age groups (65 to 69 years, 70 to 74 years, 75 to 79 years, and 80 years and older). There was an age-related difference between the four groups (p = .000). Those 75 to 79 years old and those 80 years and older noticed sensory input less than did those younger than 70 years (p = .002 and p = .001, respectively). Those 80 years and older were also less apt to seek sensory experiences than were those younger than 70 years (p = .011). The authors propose hypotheses about the meaning of these findings and provide recommendations for the application of this knowledge to support older adults to age in place successfully.

scholarly journals Effect of aging on carotid baroreflex control of blood pressure and leg vascular conductance in women

2014 ◽  
Vol 306 (10) ◽  
pp. H1417-H1425 ◽  
Author(s):  
Daniel P. Credeur ◽  
Seth W. Holwerda ◽  
Leryn J. Boyle ◽  
Lauro C. Vianna ◽  
Areum K. Jensen ◽  
...  
Keyword(s):  
Older Women ◽  
Young Women ◽  
Vascular Changes ◽  
Vascular Conductance ◽  
Response Latencies ◽  
Baroreflex Control ◽  
Age Related ◽  
Carotid Baroreflex ◽  
Duplex Doppler ◽  
Neck Pressure

Recent work suggests that β-adrenergic vasodilation offsets α-adrenergic vasoconstriction in young women, but this effect is lost after menopause. Given these age-related vascular changes, we tested the hypothesis that older women would exhibit a greater change in vascular conductance following baroreflex perturbation compared with young women. In 10 young (21 ± 1 yr) and 10 older (62 ± 2 yr) women, mean arterial pressure (MAP; Finometer), heart rate (HR), cardiac output (CO; Modelflow), total vascular conductance (TVC), and leg vascular conductance (LVC, duplex-Doppler ultrasound) were continuously measured in response to 5-s pulses of neck suction (NS; −60 Torr) and neck pressure (NP; +40 Torr) to simulate carotid hypertension and hypotension, respectively. Following NS, decreases in MAP were similar between groups; however, MAP peak response latency was slower in older women ( P < 0.05). Moreover, at the time of peak MAP, increases in LVC (young, −11.5 ± 3.9%LVC vs. older, +19.1 ± 7.0%LVC; P < 0.05) and TVC were greater in older women, whereas young women exhibited larger decreases in HR and CO (young, −10 ± 3% CO vs. older, +0.8 ± 2% CO; P < 0.05). Following NP, increases in MAP were blunted (young, +14 ± 1 mmHg vs. older, +8 ± 1 mmHg; P < 0.05) in older women, whereas MAP response latencies were similar. Interestingly, decreases in LVC and TVC were similar between groups, but HR and CO (young, +7.0 ± 2% CO vs. older, −4.0 ± 2% CO; P < 0.05) responses were attenuated in older women. These findings suggest that older women have greater reliance on vascular conductance to modulate MAP via carotid baroreflex, whereas young women rely more on cardiac responsiveness. Furthermore, older women demonstrate a blunted ability to increase MAP to hypotensive stimuli.

Access to contraception and HIV testing among young women in a peri-urban district of Uganda

2012 ◽  
Vol 24 (4) ◽  
pp. 301-306 ◽  
Author(s):  
Anthony K. Mbonye ◽  
Felix Wamono
Keyword(s):  
Hiv Testing ◽  
Older Women ◽  
Young Women ◽  
Age Groups ◽  
Reproductive Age ◽  
Human Immune Deficiency Virus ◽  
Care Seeking ◽  
Urban District ◽  
Hiv Test ◽  
Hiv Testing Services

Abstract Objective: The purpose of the study was to assess care-seeking practices for contraception and human immune deficiency virus (HIV) testing services among young women (14–24 years) in a peri-urban district of Uganda. Methods: A formative study assessed care-seeking practices among women in Wakiso district, Central Uganda. A survey was carried out in 11 randomly selected parish clusters targeting women in the reproductive age group. Data on current use of contraception, information from women who had been tested for HIV, future desire for an HIV test, and choice of care were captured. Results: A total of 10,993 women were interviewed of whom young women were 5384 (49.0%). The proportion of young women using a method of contraception was less, 2446 (45.8%), compared with 2832 (54.3%) for older women, p=0.0001. Few adolescents (14–19 years), 850 (45.3%), had tested for HIV compared with older women, p=0.0001, whereas majority of the young women, 1321 (75.5%), wished to have an HIV test compared with older women, 742 (66.0%), p=0.0001. Fear for an HIV test was common among women of both age groups, p=0.9. Data further show that young women were less likely to deliver at hospitals, 1582 (50.8%), compared with older women, 2586 (53.3%), p=0.0001. Similarly, a lesser proportion of young women, 845 (50.4%), sought contraception at hospitals compared with older women, 1432 (54.4%), p=0.004. The factors that most influenced access to services were age, educational level, source of care, marital status, and future intention to use a particular service. Conclusions: Young women are less likely to access contraception and HIV testing services in this district. These results will be useful in designing and evaluating future interventions targeting young women.

Age-Related Differences in Performance Using a Mouse and Trackball

1998 ◽  
Vol 42 (2) ◽  
pp. 152-155 ◽  
Author(s):  
Michael Bohan ◽  
Alex Chaparro
Keyword(s):  
Older Adults ◽  
Motor Control ◽  
Performance Measures ◽  
Significant Interaction ◽  
Age Groups ◽  
Error Rates ◽  
Experimental Conditions ◽  
Younger Adults ◽  
Age Related ◽  
Target Characteristics

Aging is marked by changes in motor control which may be expected to affect performance using computer pointing devices. In this experiment, we compared older and younger adults' ability to acquire on-screen targets of varying distance and size using a mouse and trackball. The older adults moved consistently slower than their younger counterparts with both devices, particularly when making large amplitude movements. Error rates were equivalent for both age groups across all conditions. Analysis of throughput values indicated a significant interaction between age and device in which the younger adults' performance was more degraded when using the trackball than the mouse, while the older adults' performance did not vary across devices. These results are discussed in terms of potential error-averse strategies employed by the older participants in an attempt to compensate for age-related declines in motor control. Although the performance measures obtained in this study imply that older adults would perform equivalently using either the mouse or the trackball, it is not known whether these results generalize to other experimental conditions including different movement tasks, and target characteristics.

scholarly journals Age-Related Differences in Home Experiences and Worries During COVID-19

2020 ◽  
Author(s):  
Amanda Hunsaker ◽  
Eszter Hargittai
Keyword(s):  
Older Adults ◽  
Age Groups ◽  
Personal Space ◽  
Community Dwelling ◽  
Living Alone ◽  
Supportive Services ◽  
Age Related ◽  
Home Based ◽  
Single Person ◽  
At Home

The Coronavirus pandemic differentially impacted older adults in comparison to other age groups, creating extended time at home and even limiting interaction with others. In order to understand how individuals are coping with extensive time at home, we used a representative sample of community-dwelling adults to examine how home experiences and personal worries during the COVID-19 pandemic may differ across age groups, including among older adults. Overall, we find fewer older adults experienced home-based stressors (e.g. household conflict, lack of personal space) and fewer worries (e.g. related to finances or boredom) that may arise during a disease outbreak with lockdown measures. Those ages 70+ who were living alone also faced fewer negative home experiences and worries than individuals 60-69 years old living in single-person households. Supportive services to manage such home stressors and worries might benefit all age groups.

scholarly journals Muscle synergy differences between voluntary and reactive backward stepping

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuaijie Wang ◽  
Gonzalo Varas-Diaz ◽  
Tanvi Bhatt
Keyword(s):  
Older Adults ◽  
Age Groups ◽  
Neuromuscular Control ◽  
Potential Effect ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Limited Effect ◽  
Healthy Older Adults ◽  
Different Populations ◽  
Reactive Stepping

AbstractReactive stepping responses are essential to prevent falls after a loss of balance. It has previously been well described that both voluntary and reactive step training could improve the efficacy of reactive stepping in different populations. However, the effect of aging on neuromuscular control during voluntary and reactive stepping remains unclear. Electromyography (EMG) signals during both backward voluntary stepping in response to an auditory cue and backward reactive stepping elicited by a forward slip-like treadmill perturbation during stance were recorded in ten healthy young adults and ten healthy older adults. Using muscle synergy analysis, we extracted the muscle synergies for both voluntary and reactive stepping. Our results showed that fewer muscle synergies were used during reactive stepping than during voluntary stepping in both young and older adults. Minor differences in the synergy structure were observed for both voluntary and reactive stepping between age groups. Our results indicate that there is a low similarity of muscle synergies between voluntary stepping and reactive stepping and that aging had a limited effect on the structure of muscle synergies. This study enhances our understanding of the neuromuscular basis of both voluntary and reactive stepping as well as the potential effect of aging on neuromuscular control during balance tasks.

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