Contralateral Effects of Unilateral Strength and Skill Training: Modified Delphi Consensus to Establish Key Aspects of Cross-Education

Background

Cross-education refers to increased motor output (i.e., force generation, skill) of the opposite, untrained limb following a period of unilateral exercise training. Despite extensive research, several aspects of the transfer phenomenon remain controversial.

Methods

A modified two-round Delphi online survey was conducted among international experts to reach consensus on terminology, methodology, mechanisms of action, and translational potential of cross-education, and to provide a framework for future research.

Results

Through purposive sampling of the literature, we identified 56 noted experts in the field, of whom 32 completed the survey, and reached consensus (75% threshold) on 17 out of 27 items.

Conclusion

Our consensus-based recommendations for future studies are that (1) the term ‘cross-education’ should be adopted to refer to the transfer phenomenon, also specifying if transfer of strength or skill is meant; (2) functional magnetic resonance imaging, short-interval intracortical inhibition and interhemispheric inhibition appear to be promising tools to study the mechanisms of transfer; (3) strategies which maximize cross-education, such as high-intensity training, eccentric contractions, and mirror illusion, seem worth being included in the intervention plan; (4) study protocols should be designed to include at least 13–18 sessions or 4–6 weeks to produce functionally meaningful transfer of strength, and (5) cross-education could be considered as an adjuvant treatment particularly for unilateral orthopedic conditions and sports injuries. Additionally, a clear gap in views emerged between the research field and the purely clinical field.

The present consensus statement clarifies relevant aspects of cross-education including neurophysiological, neuroanatomical, and methodological characteristics of the transfer phenomenon, and provides guidance on how to improve the quality and usability of future cross-education studies.

Electronic supplementary material

The online version of this article (10.1007/s40279-020-01377-7) contains supplementary material, which is available to authorized users.

Associations between symptoms of pain, insomnia and depression, and frailty in older adults: A cross-sectional analysis of a cohort study

BACKGROUND

Frailty is prevalent in older adults and has adverse effects on multiple health outcomes. Pain, insomnia, and depressive symptoms are commonly seen and treatable symptoms in older adults and are associated with frailty. However, it is unknown whether these symptoms are independently associated with frailty and how they interact with each other creating a greater impact on frailty than individual symptoms. It is important to understand these associations for nurses to provide high-quality patient-centered care for older adults with frailty.

OBJECTIVES

To determine independent associations of pain, insomnia, and depressive symptoms with frailty and examine their synergistic impact on frailty among older adults.

DESIGN

A cross-sectional analysis of a cohort study.

SETTING

Communities in the United States.

PARTICIPANTS

Community-dwelling older adults from the National Health and Aging Trend Study (N = 7,609), a nationally representative survey of Medicare Beneficiaries in the United States.

METHODS

Frailty status was determined by five criteria of the Physical Frailty Phenotype: exhaustion, low physical activity, weakness, slowness, and shrinking. Pain was determined by self-reports of bothersome pain in the last month. Insomnia included self-reports of difficulty initiating sleep and difficulty maintaining sleep. Depressive symptom was assessed by the Patient Health Questionnaire-2. Logistic regression models were used adjusting for sociodemographic, health-related and behavioral covariates.

RESULTS

The sample was mainly under 80 years old (72%), female (57%), and non-Hispanic White (81%). Approximately 53% experienced bothersome pain, 11% had difficulty initiating sleep, 6% had difficulty maintaining sleep, and 15% had depressive symptom; 46% were pre-frail and 14% were frail. Independent associations with pre-frailty and frailty were found in pain (odds ratio [OR]: 1.81, 95% CI: 1.60, 2.04), difficulty initiating sleep (OR: 1.23, 95% CI: 1.04, 1.46) and depressive symptom (OR: 2.29, 95% CI: 1.85, 2.84). Interaction terms between pain and depressive symptom (OR: 1.87, 95% CI: 1.14, 3.07), and between difficulty initiating sleep and depressive symptom (OR: 2.66, 95% CI: 1.15, 6.13) were significant, suggesting a synergistic impact on pre-frailty and frailty.

CONCLUSIONS

Pain, difficulty initiating sleep, and depressive symptoms are independent risk factors of frailty and may have a synergistic impact on frailty. Interventions should be developed to address these symptoms to reduce the adverse effects of frailty.

Pain in persons with dementia and the direct and indirect impacts on caregiver burden

OBJECTIVES

Unresolved pain is related to neuropsychiatric symptoms (NPS) in persons living with dementia (PLWD), and an increase in NPS is distressing for PLWD and their caregivers. Hence, we examined whether pain in PLWD was related to caregiver burden and whether caregiver upset with NPS mediated this relationship.

METHOD

We examined, cross-sectionally, the relationships among pain in PLWD, caregiver burden, and upset with NPS. Data from 272 PLWD and their caregivers who participated in the Advancing Caregiver Training (ACT) trial were analyzed using structural equation modeling (SEM).

RESULTS

Model fit was satisfactory, and caregiver upset with NPS fully mediated the association between pain in PLWD and caregiver burden.

CONCLUSION

Caregiver upset with NPS helps explain the relationship between pain in PLWD and burden in their caregivers. Pain and NPS are amenable to modification, as is caregiver burden, suggesting great opportunity to impact the lives of PLWD and their caregivers.

Place of Death for Persons With and Without Cognitive Impairment in the United States

BACKGROUND/OBJECTIVES

There is increasing recognition that place of death is an important component of quality of end-of-life care (EOLC) and quality of death. This study examined where older persons with and without cognitive impairment die in the United States, what factors contribute to place of death, and whether place of death influences satisfaction with EOLC.

DESIGN

Cross-sectional secondary data analysis.

SETTING

In-person interviews with community-dwelling proxy respondents.

PARTICIPANTS

Data were collected from 1,500 proxies for deceased participants in the National Health and Aging Trends Study (NHATS), a nationally-representative sample of community-dwelling Medicare beneficiaries aged 65 and older.

MEASUREMENTS

Study variables were obtained from the NHATS "last month of life" interview data. Survey weights were applied to all analyses.

RESULTS

Persons with cognitive impairment (CI) most often died at home, while cognitively healthy persons (CHP) were equally likely to die at home or in a hospital. Persons with CI who utilized the Medicare Hospice Benefit were 14.5 times more likely to die at home than in a hospital, and 3.4 times more likely to die at home than a nursing home. CHP who use this benefit were over six times more likely to die at home than in a hospital, and more than twice as likely to die at home than a nursing home. Place of death for CHP was also associated with age and race. Proxies of persons with CI who died at home rated EOLC as more favorable, while proxies of CHP rated in-home and hospital care equally.

CONCLUSION

Findings add to the scant literature identifying factors associated with place of death for older adults with and without CI and results suggest that place of death is a quality of care indicator for these populations. These findings may inform EOLC planning and policy-making and facilitate greater well-being at end-of-life.

"All I know is that there is a lot of discrimination": Older African immigrants' experiences of discrimination in the United States

Discrimination is implicated in the disproportionate burden of disease and health disparities in racial/ethnic minorities. This qualitative descriptive study explored the experiences of discrimination and its impact on the health of older African immigrants. Semi-structured interviews were conducted with 15 participants. Three main themes and six sub-themes were identified. These included: (1) types of discrimination which were: (a) accent-based, (b) unfair treatment during routine activities, (c) experience with systems; (2) consequences of discrimination; and (3) surviving and thriving with discrimination: (a) "blind eye to it", (b) reacting to it, (c) avoiding it. These themes described common experiences of discrimination, current strategies used to deal with discrimination, and the impact of discrimination on this sample. Health care providers should be aware of discrimination experiences, how to assess for it, and identify when to refer patients to appropriate community resources that include mental health, employment, cultural groups and legal services.

"So I am Stuck, but it´s OK": Residential Reasoning and Housing Decision-Making of Low-Income Older Adults with Disabilities in Baltimore, Maryland

Housing preferences and housing decision-making in later life are critical aspects of aging in place, which is a public health priority in many Western countries. However, few studies have examined the economic, social, and health factors that guide older adults' preferences and decisions about where to live, and even less so among older adults with low income or disabilities who may face greater barriers to aging in place. We sought to understand what housing decision-making and residential reasoning means for low-income older adult homeowners in Baltimore, Maryland. Using a grounded theory approach, we interviewed 12 adults with disabilities in June 2017 and February 2018. Our findings revealed how the strong desire to age in place turned into the realization that they had to age in place due to limited resources and options. The core category "shifting between wanting to age in place and having to age in place" was influenced by family needs, being a homeowner, the neighborhood, and coping at home. In conclusion, for low-income older adults with disabilities, it is important to acknowledge that sometimes aging in place may be equivalent to being stuck in place.

Prevalence of motor impairment in residents of New South Wales, Australia aged 55 years and over: cross-sectional survey of the 45 and Up cohort

BACKGROUND

The population prevalence of many diseases is known. However, little is known of the population prevalence of motor impairments.

METHODS

The aim of this study was to determine the point prevalence of specific motor impairments (weakness, fatigue, contracture, impaired balance and impaired coordination) in the population aged 55 years and older resident in New South Wales, Australia in 2018. 55,210 members of the 45 and Up cohort were invited to participate in a follow-up survey that included questions on motor impairment. Responses were received from 20,141 people (36%). Calibrated estimates of prevalence of specific motor impairments, and of having at least one motor impairment, were obtained using survey weights based on the known multivariate distributions of age, gender and geographical location (28 regions) in the population.

RESULTS

More than one-third of adults aged over 55 residing in New South Wales have difficulty using their hands, arms or legs. The prevalence of each motor impairment (muscle weakness, fatigue, contracture, impaired balance or impaired coordination) in this population is between 4 and 12%. The prevalence of at least one of these impairments is 21%. The prevalence of at least one impairment in people aged 85 and over is 42%. Women consistently had more difficulty using hands, arms and legs, and more motor impairment, than men. Difficulty using hands, arms and legs and the prevalence of all motor impairments, especially poor balance, greatly increased with age.

CONCLUSION

The prevalence of specific motor impairments in older Australian adults is high - comparable to that of the most prevalent diseases. There may be merit in considering motor impairment as a significant public health problem in its own right.

Exergames and Depressive Symptoms in Older Adults: A Systematic Review

To synthesize and critique studies that examined the impact of exergames on depressive symptoms in older adults. Articles were retrieved from the databases CINAHL, Embase, PsychINFO, and Medline. Studies were included in the review if they involved a physical activity/videogame intervention and measured outcomes of depressive symptoms in older adults. The search generated 957 articles for consideration, which were narrowed to 17 articles after applying exclusion criteria. In studies that required depressive symptoms as an inclusion criterion, there was an improvement in depressive symptoms in older adults following the exergame intervention. In studies that did not require depressive symptoms as an inclusion criterion, researchers found mixed results. Future older adult exergame research should measure depression as a primary outcome, utilize control groups with random sampling, consist of larger sample sizes, and include people with disabilities.

Advances in Understanding the Causes and Consequences of Health Disparities in Aging Minorities

PURPOSE OF REVIEW

The purpose was to discuss appropriate methods for advancing our understanding of health disparities or minority aging including life-course perspectives, biological measures, pain measurement, and generational approaches.

RECENT FINDINGS

Life course perspectives provide an orientation for studying older minorities that concomitantly captures exposures and stressors that may lead to earlier onset of disease and premature mortality. The use of biological markers to study health disparities in older minorities is necessary in order to identify pathways between psychosocial factors and health outcomes. Work focusing on pain disparities should include explorations of relationships between psychosocial factors, and subjective and objective measures of pain. Studying families can provide insight into genetic associations and coping styles in older minorities.

SUMMARY

Methodological approaches that take life course, biology, and social factors into account may help identify causal pathways between social determinants of health and health outcomes among older minorities. Once these causal pathways have been identified, more strategies and interventions that strive toward health equity across older adults of all race/ethnic groups can be developed.

Quality and Quantity of Social Support Show Differential Associations With Stress and Depression in African Americans

Social support (SS) is typically associated with lower emotional distress (e.g., stress and depression) in individuals. However, SS is a multifaceted construct that can vary by quality, quantity (amount), and type (i.e., it can be emotional or instrumental in nature).

OBJECTIVE

The current study examined the relationships between characteristics of SS, stress, and depression in aging African Americans.

PARTICIPANTS

Analyses focused on data from 705 participants aged 22-92 years from the Carolina African American Twin Study of Aging.

MEASUREMENTS

Measures included the quality and quantity of emotional and instrumental support received, as well as stress and depression.

DESIGN

A series of univariate and increasingly complex multivariate regression models were conducted in MPlus (using the cluster option to control for family structure) to examine the relationships between SS and emotional distress variables.

RESULTS

Overall, better quality of emotional SS predicted fewer depression symptoms and less perceived stress, after controlling for age, gender, socioeconomic status variables, and the other subtypes of SS. However, more instances of emotional SS were associated with higher levels of perceived stress, depression symptoms, and more stressful life events within the past year. Likewise, more instrumental SS predicted more perceived stress, while holding the other variables constant.

CONCLUSION

African Americans who experience more emotional distress report more SS, but the quality of emotional support appears to play an important role in the association between reduced levels of stress and depression. These findings suggest that interventions should include approaches to reduce emotional distress as well as enhance the quality SS.

Pain in low-income older women with disabilities: a qualitative descriptive study

The purpose of this qualitative study was to identify how low-income older women with disabilities perceive pain, pain management, and communication with healthcare providers. We interviewed 26 low-income women (average age 75 years; SD 7.0), eliciting the following overarching themes: "Invisibility of Pain: Unnoticed or Undetected," "Escalating Pain Leads to Help Seeking," "Communication with Healthcare Providers and Outcomes," "Pain Management Facilitates Function and Accomplishment," and "The Intersection of Pain, Disability, and Depressive Symptoms." Study findings support the ways in which behavior changes from pain can impede pain management.

1137 Sleep Duration, Physical Activity And Cognitive Decline In Chinese Older Adults: Findings From The CHARLS

Introduction

Lack of physical activity and disturbed sleep have been linked to older adult’s poor cognitive outcomes; however, little is unknown how they interact to affect cognition long-term. The purpose of this study was to examine the association of baseline sleep duration and physical activity (PA) with change in cognition independently and interactively over four years.

Methods

The sample included 1126 community-dwelling older adults aged 60+ (mean age 67.1±5.9 years, 51% female) from the 2011 baseline and 2015 follow-up data of the China Health and Retirement Longitudinal Study (CHARLS). All variables were assessed through interviews. Sleep duration was measured with hours per 30-minute interval and categorized as very-short (<5h), short (5-6.5h), normal (7-8.5h), and long (≥9h). PA was calculated based on PA intensity, duration, and number of days. Cognition was a composite score of mental capacity, episodic memory, and visuospatial abilities. Data were analyzed using multiple regression (primary outcome: change in cognition; main independent variables: baseline sleep, PA, and sleep PA interaction).

Results

At baseline, 19% of participants had very-short sleep duration, 34.4% had short sleep, 39.2% had normal sleep, and 7.2% had long sleep. At follow-up, 57.5% of participants experienced cognitive decline (-3.5±2.5). After controlling for age, gender, education, region, body mass index, smoking, drinking, number of chronic conditions, pain, depression, and cognition at baseline, compared to participants reporting 7-8.5h sleep, those with ≥9h sleep had significantly greater decline in cognition [β=-1.4, 95% CI=2.4, -0.4], while those with <5h sleep [β=-0.5, 95% CI=-1.2, 0.2] and 5-6.5h sleep did not [β=-0.1, 95% CI=-0.7, 0.5]. PA was neither associated with cognitive decline, nor moderated the relationship between sleep duration and cognitive decline.

Conclusion

Long sleep might be a marker of cognitive decline in older adults. Prospective analysis, using objectively measured PA and sleep should be conducted to further examine these associations.

Support

National Institute of Nursing Research R00NR016484

Unlike voluntary contractions, stimulated contractions of a hand muscle do not reduce voluntary activation or motoneuronal excitability

Voluntary force declines during sustained, maximal voluntary contractions (MVC) due to changes in muscle and central nervous system properties. Central fatigue, an exercise-induced reduction in voluntary activation, is influenced by multiple processes. Some may occur independently of descending voluntary drive. To differentiate the effects associated with voluntary drive from other central and peripheral influences, we measured voluntary activation and motoneuron excitability following fatiguing contractions produced voluntarily or by electrical stimulation. On two separate days, participants performed either a 2-min MVC of adductor pollicis muscle or received 2-min continuous supramaximal electrical stimulation of the ulnar nerve. In study 1 (n = 14), the superimposed twitch elicited by ulnar nerve stimulation during brief MVCs was increased, and, hence, voluntary activation was reduced, up to 240 s after the 2-min MVC [-20 ± 12% (SD), P = 0.002] but not the 2-min stimulated contraction (-4 ± 7%), despite large reductions in MVC force (voluntary, -54 ± 18%; stimulated, -46 ± 16%). In study 2 (n = 12), F-waves recorded from the adductor pollicis were reduced in area for 150 s following the 2-min MVC (-21 ± 16%, P = 0.007) but not after the stimulated contraction (5 ± 27%). Therefore, voluntary activation and motoneuron excitability decreased only when descending voluntary drive was present during the fatiguing task. The findings do not exclude a cortical or brain stem contribution to the reduced voluntary activation but suggest that neither sensory feedback from the fatigued muscle nor repetitive activation of motoneurons underlie the changes, whereas they are consistent with motoneuronal inhibition by released factors linked to voluntary drive.NEW & NOTEWORTHY We demonstrate that reductions in voluntary activation and motoneuron excitability following 2-min isometric maximal contractions in humans occur only when fatigue is produced through voluntary contractions and not through electrically stimulated contractions. This is contrary to studies that suggest that changes in the superimposed twitch and therefore voluntary activation are explained by changes in peripheral factors alone. Thus, the interpolated twitch technique remains a viable tool to assess voluntary activation and central fatigue.

The role of social support on the effects of stress and depression on African American tobacco and alcohol use

OBJECTIVES

The current study explored whether social support (SS) from family and peers, influences the relationship between depressed mood (DM) and substance use (SU). We hypothesized that SS would have a protective effect on DM, and moderate the association between DM and SU.

PARTICIPANTS AND METHODS

Analyses focused on 703 individuals from the Carolina African American Twin Study on Aging (mean age = 49.78 years, STD = 14.52; 51% female). Participants reported on past year frequency of cigarettes and alcohol consumption, depressed mood, and stressful life events. Social support (SS) was assessed on two domains (i.e., emotional and instrumental), as well as for perceived quality and quantity of each type. Hypotheses were tested using ordinal logistic regression in Mplus while controlling for socioeconomic status, age, and gender.

RESULTS

Quality of emotional support was negatively associated with drinking. Smoking, but not drinking was associated with depressed mood. While individuals with high levels of depressed mood received more support, receiving better quality emotional support was associated with fewer mood and stress symptoms. Individuals who reported receiving better quality emotional support typically smoked fewer cigarettes.

CONCLUSION

Quantity of emotional support was associated with higher levels of negative emotionality, whereas the opposite was found for quality of emotional support. Emotional support may indirectly influence smoking via depressed mood. Effecting the perceived quality of support appears to be the mechanism by which emotional support helps to reduce smoking in adult African Americans.

RJ, Whitfield KE. THE RELATIONSHIP BETWEEN PAIN AND STRESS IN OLDER BLACKS

Older Blacks have higher rates of undermanaged and undertreated pain than other racial/ethnic groups. Pain can lead to disability and poor quality of life. It is essential that we identify modifiable factors related to pain in this population. This study examined if stress was associated with pain among older Blacks. Data were taken from the Baltimore Study on Black Aging, (N=602, mean age 69 [SD= 9.76]). A total of 78% of participants reported bodily pain in the past month. Women had an increased odds of reporting bodily pain (OR 1.89, 95% CI 1.17, 3.07) compared to men. Using logistic regression controlling for age, self-rated health, sex, depressive symptoms, and chronic conditions, higher levels of stress were associated with increased odds of bodily pain (OR 1.04, 95% CI 1.00, 1.07). Identification of effective coping mechanisms to combat stress may lead to pain relief among older Blacks, particularly Black women.

Achieving self-management goals among low income older adults with functional limitations

Although self-management interventions can improve symptoms and disease among older adults, there is a dearth of literature on how self-management behaviors may improve factors related to the older adults' physical function. To fill this gap in the literature, we describe the patient-directed self-management goals in nursing visits that relate to physical function as part of a multi-component program. We analyze the self-management goals and outcomes of 367 low- income older adults with functional limitations who participated in the CAPABLE program: a program to reduce the health effects of impaired physical function in low-income older adults. We focus on the following self-management goals that participants chose with the nurses: pain management, depressive symptoms, incontinence, fall prevention, and communication with healthcare providers. The majority of participants chose pain (50%) or fall prevention (51%) as goals and partially or fully met their goals. Improvements across these areas may lead to improved physical function.

The association of pain, race and slow gait speed in older adults

Gait speed is an important indicator of mobility and quality of life in older adults. Pain is related to gait speed; however, it is unknown if this relationship varies by race in a population based national sample. The aim of this study was to examine if the association between slow gait speed and pain differed between 7,025 older African Americans and non Hispanic Whites in the National Health and Aging Trends Study. Those with pain in the last month had higher odds of slow gait speed (odds ratio = 1.38, 95% confidence interval = 1.10 - 1.73) than those without pain. The relationship between pain and slow gait speed did not vary by race (interaction p = 0.6). This is important because it points to the underlying racial disparities in pain and gait speed being factors such as disparate opportunities and living conditions, and healthcare rather than attributes intrinsic to race.

Effects of acute isometric resistance exercise on cervicomedullary motor evoked potentials

Cervicomedullary motor evoked potentials (CMEPs) in relaxed biceps brachii have been reported to facilitate after acute isometric exercise of the elbow flexors. This facilitation, which reflects either enhanced corticospinal transmission or increased motoneurone excitability, has only been documented in the limb posture used during exercise. In Experiment 1, we tested if these spinal changes "transfer" to a second posture. Fourteen individuals completed 12 sets of high-force isometric contractions of the elbow flexors with the forearm pronated. Before and after exercise, biceps CMEPs were acquired with the forearm either pronated or supinated. CMEPs in pronation and supination were facilitated after exercise, indicating transfer (57.5 ± 55.5% and 53.9 ± 54.9%, respectively; mean ± SD). In Experiment 2, we examined if exercise posture influences the effect that exercise has on CMEPs. A different sample of 14 individuals performed isometric exercise in 2 sessions. In one, exercise was performed in supination. In the other, exercise was performed in pronation. Exercise intensity and volume were the same as in Experiment 1, as were participant characteristics. CMEPs were unchanged after exercise in supination (13.6 ± 31.2%) and pronation (7.7 ± 41.5%). The absence of an effect differs from the finding of Experiment 1. Thus, effects of acute isometric resistance exercise on corticospinal transmission and/or motoneurone excitability are not as consistent as previously thought. When exercise induces this spinal change, the effect is not specific to the posture used for exercise. However, the change does not always occur, and the reasons for this remain unknown.