Interpersonal-level discrimination indices, sociodemographic factors, and telomere length in African-Americans and Whites

OBJECTIVE

Studies have linked self-reported discrimination to telomere attrition, a biological marker of accelerated cellular aging. However, it is unknown whether intersections between social categories-race, socioeconomic status (SES), sex, and age-influence the association of varying forms of discrimination with telomere length. We examined these associations in a socioeconomically and racially/ethnically diverse urban sample.

METHODS

Cross-sectional data were from 341 middle-aged (30-64 years) African American and White, community participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span Study (HANDLS). Multiple regression models examined up to 3-way interactions between a discrimination measure (i.e., everyday, racial, gender, lifetime burden, and frequency of discrimination across sources) and two social categories.

RESULTS

After adjusting for depressive symptoms, waist circumference, and lifetime substance use, two themes emerged: 1) among women with higher SES, a) greater lifetime discrimination burden (b = -0.23, p =  .011), gender discrimination (b = -0.29, p =  .040), and racial discrimination (b = -0.24, p = 0.023) and 2) among younger adults, irrespective of race and sex, greater frequency of discrimination across sources (b = 0.002, p =  .008) was associated with shorter telomeres.

CONCLUSIONS

Irrespective of race, women with higher SES and younger adults reporting greater discrimination may be at particular risk for accelerated aging. Telomere attrition promotes and accelerates chronic health conditions for which there are health disparities. Future research explicating intersections among specific discrimination indices and social categories is warranted.

Lifetime discrimination burden, racial discrimination, and subclinical cerebrovascular disease among African Americans

OBJECTIVE

Explore interactive relations of lifetime discrimination burden and racial discrimination-chronic stressors among African Americans (AAs)-and age with MRI-assessed white matter lesion volume (WMLV), a prognostic indicator of poor clinical brain health outcomes.

METHOD

AAs (N = 71; 60.6% female, mean age = 50) participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study underwent quantitative magnetic resonance imaging coded for WMLV. Participants self-reported lifetime discrimination burden and racial discrimination approximately 5 years earlier. Multivariable regression models assessed interactions of linear and quadratic effects of discrimination and age with WMLV adjusted for sex and socioeconomic status.

RESULTS

Findings revealed significant interactive relations of age and (a) quadratic, lifetime discrimination burden, B = .05, p = .014, ηpartial2 = .092, and (b) quadratic, racial discrimination, B = .03, p = .001, ηpartial2 = .155, with WMLV. Among older AA, increases in lifetime discrimination burden and racial discrimination were associated with increases in WMLV (ps < .03); in younger AA, decreasing levels of racial discrimination were related to increases in WMLV (p = .006).

CONCLUSIONS

Among older AA, as lifetime discrimination burden and racial discrimination increased, so did WMLV. However, in younger AA, decreases in racial discrimination were associated with increased WMLV. Elucidation of complex mechanistic underpinnings, including potentially differential impacts of the acknowledgment versus suppression or underreporting of discriminatory experiences, among AA of different age cohorts, is critical to understanding the present pattern of findings. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Dorsolateral prefrontal cortex volume as a mediator between socioeconomic status and executive function

OBJECTIVE

Lower socioeconomic status (SES) is related to poorer cognitive performance, but the neural underpinnings of this relation are not fully understood. This study examined whether SES-linked decrements in executive function were mediated by smaller dorsolateral prefrontal cortex (DLPFC) volumes. Given the literature demonstrating that SES-brain relations differ by race, we examined whether race moderated these mediations.

METHOD

Participants were 190 socioeconomically diverse, self-identified African American (AA) and White adults from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Regional brain volumes were derived using T1-weighted MP-RAGE images. Adjusting for age and sex, moderated mediation analyses examined if the DLPFC mediated SES-executive function relations differently across racial groups. Executive function was measured using Trail Making Test part B (Trails B), Digit Span Backwards (DSB), and verbal fluency.

RESULTS

Moderated mediation demonstrated that DLPFC volume significantly mediated the association between SES and Trails B in Whites (lower confidence interval [CI] = 0.01; upper CI = 0.07), but not in AAs (lower CI = -0.05; upper CI = 0.01). No mediations were found for DSB or verbal fluency, although SES was related to all tests.

CONCLUSION

The DLPFC may be important in the association of SES and mental flexibility for White, but not AA adults. It is possible that the well-replicated advantages of high SES among Whites do not readily translate, on average, to AAs. These findings highlight the importance of brain volume for cognitive functioning, while adding to the literature on sociodemographic health disparities. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Changes in Function After a 6-Month Walking Intervention in Patients With Intermittent Claudication Who Are Obese or Nonobese

BACKGROUND AND PURPOSE

Both obesity and peripheral artery disease (PAD) limit function and may work additively to reduce mobility. The purpose of this study was to compare the effects of a 6-month, center-based walking program on mobility function between adults who are weight-stable obese and nonobese with PAD.

METHODS

This is a secondary data analysis of 2 combined studies taken from previous work. Fifty-three adults with PAD and intermittent claudication participated in 6 months of treadmill training or standard of care. Patients were divided into 4 groups for analyses: exercise nonobese (Ex), exercise obese (ExO), standard-of-care nonobese (SC), and standard-of-care obese (SCO). Mobility was assessed by a standardized treadmill test to measure claudication onset time (COT) and peak walking time (PWT) as well as the distance walked during a 6-minute walk distance (6MWD) test.

RESULTS

There was a significant (P < .001) interaction (intervention × obesity) effect on 6MWD, wherein both exercise groups improved (Ex = 7%, ExO = 16%; P < .02), the SC group did not change (0.9%; P > .05), and the SCO group tended to decline (-18%; P = .06). Both exercise intervention groups significantly improved COT (Ex = 92%, ExO = 102%; P < .01) and PWT (Ex = 54%, ExO = 103%; P < .001). There was no change (P > .05) in either standard-of-care group.

CONCLUSIONS

Individuals who are obese and nonobese with PAD made similar improvements after a 6-month, center-based walking program. However, patients who are obese with PAD and do not exercise may be susceptible to greater declines in mobility. Exercise may be particularly important in patients who are obese with PAD to avoid declines in mobility.

A pilot randomized aerobic exercise trial in older HIV-infected men: Insights into strategies for successful aging with HIV

BACKGROUND

HIV-infected adults have increased risk for age-related diseases and low cardiorespiratory fitness that can be prevented and improved with exercise. Yet, exercise strategies have not been well studied in older adults with HIV and may require substantial adaptation to this special population.

OBJECTIVE

To determine the safety and efficacy of aerobic exercise in older HIV-infected men in a randomized trial comparing different levels of exercise intensity.

METHODS

We conducted a pilot exercise trial in 22 HIV-infected men ≥50 years of age receiving antiretroviral therapy who were randomized 1:1 to moderate-intensity aerobic exercise (Mod-AEX) or high-intensity aerobic exercise (High-AEX) that was performed three times weekly for 16 weeks in a supervised setting. Primary outcome was cardiorespiratory fitness (VO2peak) measured by treadmill testing. Secondary outcomes were exercise endurance, six-minute walk distance (6-MWD), body composition measured by Dual-energy X-ray absorptiometry (DXA), and fasting plasma levels of lipids and glucose.

RESULTS

VO2peak increased in the High-AEX group (3.6 ±1.2 mL/kg/min, p = 0.02) but not in the Mod-AEX group (0.4 ±1.4 mL/kg/min, p = 0.7) with a significant between group difference (p<0.01). Exercise endurance increased in both the High-AEX group (27 ±11%, p = 0.02) and the Mod-AEX group (11 ±4%, p = 0.04). The 6-MWD increased in both the High-AEX (62 ±18m, p = 0.01) and the Mod-AEX group (54 ±14m, p = 0.01). Changes in VO2peak and 6-MWD were clinically relevant. There were no serious exercise-related adverse events. Dropouts were similar between group (27% overall) and were related to joint pain.

CONCLUSIONS

This pilot exercise trial demonstrates that moderate to high-intensity aerobic exercise in older HIV-infected men increases endurance and ambulatory function. However, increased cardiorespiratory fitness was observed only with high-intensity aerobic exercise despite substantial baseline impairment. Future research is needed to determine exercise strategies in older HIV-infected adults that address advanced aging and comorbidity yet are durable and feasible.

Sarcopenia in Peripheral Arterial Disease: Prevalence and Effect on Functional Status

OBJECTIVES

(1) To determine the prevalence of sarcopenia in older men with peripheral arterial disease (PAD); (2) to compare a subgroup of the group with age-, race-, sex-, and body mass index (BMI)-matched non-PAD control counterparts, and (3) to compare the functional status of those with PAD with and without sarcopenia.

DESIGN

Cohort study.

SETTING

Medical center.

PARTICIPANTS

Sedentary community-dwelling men (N=108; age, >50y) with a confirmed diagnosis of PAD (44% blacks; BMI, 27.8±0.4kg/m²; ankle-brachial index, .62±.01).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry scans were used to assess appendicular lean mass and determine the prevalence of sarcopenia by/height². Treadmill tests were used to determine claudication onset time, peak walking time, and claudication recovery time. 6-Minute walk distance was also measured.

RESULTS

Sarcopenia prevalence in our PAD cohort was 25%. The PAD subgroup (n=42) matched with control counterparts in terms of race, sex, age, and BMI had higher prevalence rates than did their non-PAD counterparts (23.8% vs 2.4%; P<.05). Individuals with sarcopenia (n=28) had a shorter 6-minute walk distance (326±18.8m vs 380±9.7m; P<.05) and higher claudication recovery time (592±98s vs 395±29s; P<.05) than did individuals with PAD but without sarcopenia (n=80). There was no difference in claudication onset time or peak walking time between the PAD groups.

CONCLUSIONS

Men with PAD demonstrate a high prevalence of sarcopenia. Those with sarcopenia and PAD demonstrate decreased mobility function.

Strength Training for Skeletal Muscle Endurance after Stroke

BACKGROUND AND PURPOSE

Initial studies support the use of strength training (ST) as a safe and effective intervention after stroke. Our previous work shows that relatively aggressive, higher intensity ST translates into large effect sizes for paretic and non-paretic leg muscle volume, myostatin expression, and maximum strength post-stroke. An unanswered question pertains to how our unique ST model for stroke impacts skeletal muscle endurance (SME). Thus, we now report on ST-induced adaptation in the ability to sustain isotonic muscle contraction.

METHODS

Following screening and baseline testing, hemiparetic stroke participants were randomized to either ST or an attention-matched stretch control group (SC). Those in the ST group trained each leg individually to muscle failure (20 repetition sets, 3× per week for 3 months) on each of three pneumatic resistance machines (leg press, leg extension, and leg curl). Our primary outcome measure was SME, quantified as the number of submaximal weight leg press repetitions possible at a specified cadence. The secondary measures included one-repetition maximum strength, 6-minute walk distance (6MWD), 10-meter walk speeds, and peak aerobic capacity (VO₂ peak).

RESULTS

ST participants (N = 14) had significantly greater SME gains compared with SC participants (N = 16) in both the paretic (178% versus 12%, P < .01) and non-paretic legs (161% versus 12%, P < .01). These gains were accompanied by group differences for 6MWD (P < .05) and VO₂ peak (P < .05).

CONCLUSION

Our ST regimen had a large impact on the capacity to sustain submaximal muscle contraction, a metric that may carry more practical significance for stroke than the often reported measures of maximum strength.

Nonlinear associations between plasma cholesterol levels and neuropsychological function

OBJECTIVE

Although both high and low levels of total and low-density lipoprotein (LDL) cholesterol have been associated with poor neuropsychological function, little research has examined nonlinear effects. We examined quadratic relations of cholesterol to performance on a comprehensive neuropsychological battery.

METHOD

Participants were 190 older adults (53% men, ages 54-83) free of major medical, neurologic, and psychiatric disease. Measures of fasting plasma total and high-density lipoprotein (HDL) cholesterol were assayed, and LDL cholesterol was calculated. Participants completed neuropsychological measures of attention, executive function, memory, visuospatial judgment, and manual speed and dexterity. Multiple regression analyses examined cholesterol levels as quadratic predictors of each measure of cognitive performance, with age (dichotomized as <70 vs. 70+) as an effect modifier.

RESULTS

A significant quadratic effect of Total Cholesterol² × Age was identified for Logical Memory II (b = -.0013, p = .039), such that the 70+ group performed best at high and low levels of total cholesterol than at midrange total cholesterol (U-shaped) and the <70 group performed worse at high and low levels of total cholesterol than at midrange total cholesterol (inverted U shape). Similarly, significant U- and J-shaped effects of LDL Cholesterol² × Age were identified for Visual Reproduction II (b = -.0020, p = .026) and log of the Trail Making Test, Part B (b = .0001, p = .044). Quadratic associations between HDL cholesterol and cognitive performance were nonsignificant.

CONCLUSIONS

Results indicate differential associations between cholesterol and neuropsychological function across different ages and domains of function. High and low total and LDL cholesterol may confer both risk and benefit for suboptimal cognitive function at different ages. (PsycINFO Database Record

Relations of blood pressure and head injury to regional cerebral blood flow

Hypertension confers increased risk for cognitive decline, dementia, and cerebrovascular disease. These associations have been attributed, in part, to cerebral hypoperfusion. Here we posit that relations of higher blood pressure to lower levels of cerebral perfusion may be potentiated by a prior head injury. Participants were 87 community-dwelling older adults - 69% men, 90% white, mean age=66.9years, 27.6% with a history of mild traumatic brain injury (mTBI) defined as a loss of consciousness ≤30min resulting from an injury to the head, and free of major medical (other than hypertension), neurological or psychiatric comorbidities. All engaged in clinical assessment of systolic and diastolic blood pressure (SBP, DBP) and single photon emission computed tomography (SPECT). Computerized coding of the SPECT images yielded relative ratios of blood flow in left and right cortical and select subcortical regions. Cerebellum served as the denominator. Sex-stratified multiple regression analyses, adjusted for age, education, race, alcohol consumption, smoking status, and depressive symptomatology, revealed significant interactions of blood pressure and head injury to cerebral blood flow in men only. Specifically, among men with a history of head injury, higher systolic blood pressure was associated with lower levels of perfusion in the left orbital (β=-3.21, p=0.024) and left dorsolateral (β=-2.61, p=0.042) prefrontal cortex, and left temporal cortex (β=-3.36, p=0.014); higher diastolic blood pressure was marginally associated with lower levels of perfusion in the left dorsolateral prefrontal cortex (β=-2.79, p=0.051). Results indicate that men with a history of head injury may be particularly vulnerable to the impact of higher blood pressure on cerebral perfusion in left anterior cortical regions, thus potentially enhancing risk for adverse brain and neurocognitive outcomes.

Sarcopenia Is Associated With Lower Skeletal Muscle Capillarization and Exercise Capacity in Older Adults

BACKGROUND

Skeletal muscle capillary rarefaction limits the transcapillary transport of nutrients and oxygen to muscle and may contribute to sarcopenia and functional impairment in older adults. We tested the hypothesis that skeletal muscle capillarization and exercise capacity (VO2max) are lower in sarcopenic than in nonsarcopenic older adults and that the degree of sarcopenia is related to lower skeletal muscle capillarization.

METHODS

Body composition, VO2max, and vastus lateralis capillarization were determined in 76 middle-aged and older men and women (age = 61±1 years, body mass index [BMI] = 30.7±0.5kg/m(2) [mean ± SEM]). Participants were classified as sarcopenic if appendicular lean mass divided by BMI (ALMBMI) was less than 0.789 for men or less than 0.512 for women.

RESULTS

Sarcopenic subjects (ALMBMI = 0.65±0.04, n = 16) had 20% lower capillary-to-fiber ratio, as well as 13% and 15% lower VO2max expressed as mL/kg/min or L/min, respectively, compared with sex-, race-, and age-matched participants without sarcopenia (ALMBMI = 0.81±0.05, n = 16; p < .05). In all 76 subjects, ALMBMI, thigh muscle cross-sectional area, and VO2max correlated directly with capillarization (r = .30-.37, p ≤ .05), after accounting for age, sex, and race.

CONCLUSIONS

These findings suggest that low skeletal muscle capillarization is one factor that may contribute to sarcopenia and reduced exercise capacity in older adults by limiting diffusion of substrates, oxygen, hormones, and nutrients. Strategies to prevent the aging-related decline in skeletal muscle capillarization may help to prevent or slow the progression of sarcopenia and its associated functional declines in generally healthy older adults.

Aging, Fitness, and Marathon Times in a 91 Year-old Man Who Competed in 627 Marathons

Aging is associated with a decline in maximal aerobic capacity (VO_2max) that may be attenuated by chronic endurance exercise. This case study chronicles the changes in marathon times in a 91 year old man who completed 627 marathons and 117 ultramarathons over 42 years. He began running marathons at age 48. His yearly best times remained fairly constant at ~240 minutes from age 50 – 64 years and then gradually rose to about 260 minutes in his early seventies followed by a curvilinear deterioration as he approached his ninth decade. His times plateaued at ~ 600 minutes in his late eighties. Between ages 68 and 89 his VO_2max declined from 43 to 20 ml/kg/min. His marathon times were highly correlated with his VO_2max (r²=0.87). The decline in marathons times and VO_2max may reflect the contributions of biological aging, changes in exercise training volume and intensity, injuries, and comorbid disease.

Fasting glucose and glucose tolerance as potential predictors of neurocognitive function among nondiabetic older adults

INTRODUCTION

Significant evidence has demonstrated that Type 2 diabetes mellitus and related precursors are associated with diminished neurocognitive function and risk of dementia among older adults. However, very little research has examined relations of glucose regulation to neurocognitive function among older adults free of these conditions. The primary aim of this investigation was to examine associations among fasting glucose, glucose tolerance, and neurocognitive function among nondiabetic older adults. The secondary aim was to examine age, gender, and education as potential effect modifiers.

METHOD

The study employed a cross-sectional, correlational study design. Participants were 172 older adults with a mean age of 64.43 years (SD = 13.09). The sample was 58% male and 87% White. Participants completed an oral glucose tolerance test as part of a larger study. Trained psychometricians administered neuropsychological tests that assessed performance in the domains of response inhibition, nonverbal memory, verbal memory, attention and working memory, visuoconstructional abilities, visuospatial abilities, psychomotor speed and executive function, and motor speed and manual dexterity. Linear multiple regressions were run to test study aims.

RESULTS

No significant main effects of fasting glucose and 2-hour glucose emerged for performance on any neurocognitive test; however, significant interactions were present. Higher fasting glucose was associated with poorer short-term verbal memory performance among men, but unexpectedly better response inhibition and long-term verbal memory performance for participants over age 70. Higher 2-hour glucose values were associated with reduced divided attention performance among participants with less than a high school education.

CONCLUSIONS

Mixed findings suggest that glucose levels may be both beneficial and deleterious to neurocognition among nondiabetic older adults. Additional studies with healthy older adults are needed to confirm this unexpected pattern of associations; however, findings have implications for the importance of maintaining healthy glucose levels in older adulthood.

Distinct functions of social support and cognitive function among older adults

BACKGROUND/STUDY CONTEXT: Social support has been shown to buffer cognitive decline in older adults; however, few studies have examined the association of distinct functions of perceived social support and cognitive function. The current study examined the relations between distinct functions of social support and numerous cognitive domains in older adults.

METHODS

Data were derived from a cross-sectional, correlational study of cardiovascular risk factors, cognitive function, and neuroimaging. The participants were 175 older adults with a mean age of 66.32. A number of neuropsychological tests and the Interpersonal Support Evaluation List were administered. Multiple linear regression analyses were conducted to determine cross-sectional relations of social support to cognitive function after controlling for age, gender, education, depressive symptomatology, systolic blood pressure, body mass index, total cholesterol, and fasting glucose.

RESULTS

No significant positive relations were found between distinct functions of social support and cognitive function in any domain; however, inverse relations emerged such that greater social support across several functions was associated with poorer nonverbal memory and response inhibition.

CONCLUSION

Results suggest that the receipt of social support may be a burden for some older adults. Within the current study, fluid cognitive abilities reflected this phenomenon. The mechanism through which social support is associated with poorer cognitive function in some domains deserves further exploration.

Aerobic exercise plus weight loss improves insulin sensitivity and increases skeletal muscle glycogen synthase activity in older men

The purpose of this study was to determine the effects of 6-month aerobic exercise training + weight loss (AEX + WL) on basal and insulin activation of glycogen synthase, basal citrate synthase activity, and Akt and AS160 phosphorylation in older, overweight/obese insulin-resistant men (n = 14; 63 ± 2 years; body mass index, 32 ± kg/m(2)). Muscle samples of the vastus lateralis were collected before and during a 3-hour 80 mU/m(2)/min hyperinsulinemic-euglycemic clamp. AEX + WL increased VO2max by 11% (p < .05) and decreased body weight (-9%, p < .001). AEX + WL increased basal citrate synthase activity by 46% (p < .01) and insulin activation of independent (2.9-fold) and fractional (2.3-fold) activities (both p < .001) of glycogen synthase. AEX + WL had no effect on phosphorylation of Akt or AS160. Glucose utilization (M) improved 25% (p < .01), and the change tended to be related to the increase in insulin activation of glycogen synthase fractional activity (r = .50, p = .08) following AEX + WL. In summary, AEX + WL has a robust effect on insulin activation of skeletal muscle glycogen synthase activity that likely contributes to improved glucose utilization in older insulin-resistant men.

Increased skeletal muscle capillarization after aerobic exercise training and weight loss improves insulin sensitivity in adults with IGT

OBJECTIVE

Transcapillary transport of insulin is one determinant of glucose uptake by skeletal muscle; thus, a reduction in capillary density (CD) may worsen insulin sensitivity. Skeletal muscle CD is lower in older adults with impaired glucose tolerance (IGT) compared with those with normal glucose tolerance and may be modifiable through aerobic exercise training and weight loss (AEX+WL). We tested the hypothesis that 6-month AEX+WL would increase CD to improve insulin sensitivity and glucose tolerance in older adults with IGT.

RESEARCH DESIGN AND METHODS

Sixteen sedentary, overweight-obese (BMI 27-35 kg/m2), older (63 ± 2 years) men and women with IGT underwent hyperinsulinemic-euglycemic clamps to measure insulin sensitivity, oral glucose tolerance tests, exercise and body composition testing, and vastus lateralis muscle biopsies to determine CD before and after 6-month AEX+WL.

RESULTS

Insulin sensitivity (M) and 120-min postprandial glucose (G120) correlated with CD at baseline (r = 0.58 and r = -0.60, respectively, P < 0.05). AEX+WL increased maximal oxygen consumption (VO2max) 18% (P = 0.02) and reduced weight and fat mass 8% (P < 0.02). CD increased 15% (264 ± 11 vs. 304 ± 14 capillaries/mm(2), P = 0.01), M increased 21% (42.4 ± 4.0 vs. 51.4 ± 4.3 µmol/kg FFM/min, P < 0.05), and G120 decreased 16% (9.35 ± 0.5 vs. 7.85 ± 0.5 mmol/L, P = 0.008) after AEX+WL. Regression analyses showed that the AEX+WL-induced increase in CD independently predicted the increase in M (r = 0.74, P < 0.01) as well as the decrease in G120 (r = -0.55, P < 0.05).

CONCLUSIONS

Six-month AEX+WL increases skeletal muscle CD in older adults with IGT. This represents one mechanism by which AEX+WL improves insulin sensitivity in older adults with IGT.

Psychometric limitations of the mini-mental state examination among nondemented older adults: an evaluation of neurocognitive and magnetic resonance imaging correlates

BACKGROUND/STUDY CONTEXT: Although many of the Mini-Mental State Examination's (MMSE) limitations are well accepted among geriatricians, neuropsychologists, and other interested clinicians and researchers, its continued use in psychometrically unsound ways suggests that additional investigation and dissemination of information are sorely needed. The authors aimed to describe the reliability and validity of the MMSE as a measure of cognitive function among healthy older adults.

METHODS

The authors examined MMSE performance in 124 stroke- and dementia-free, community-dwelling older adults (65% male; mean age = 66.5 years). All participants were administered an extensive neuropsychological battery composed of measures of attention, executive function, memory, and visuospatial function. A subset of 99 participants also underwent magnetic resonance imaging (MRI). MMSE test-retest reliability was examined among 65 participants who underwent repeat MMSE testing over an average interval of 83.2 days.

RESULTS

Spearman test-retest correlation for total MMSE scores was r S = .35 (p = .004), for Serial Sevens was r S = .40 (p = .001), and for Word Recall was r S = -.01 (p = .96). Total MMSE performance correlated significantly with a minority of neuropsychological tests and MRI-derived indices of white matter disease and brain atrophy. A subset of 17% of participants demonstrated inappropriate intrusion of MMSE Pentagon Copy during another test of visuospatial recall.

CONCLUSIONS

Overall, MMSE scores exhibited ceiling effects, poor test-retest reliability, limited sensitivity to subtle brain abnormalities, and a high rate of intrusion elsewhere in the neuropsychological battery. Individual MMSE items demonstrated poor construct validity. These qualities illustrate the serious limitations of the MMSE in detecting individual differences in cognitive function among healthy older adults.

Test-retest reliability of portable metabolic monitoring after disabling stroke

PURPOSE

Impaired economy of gait, prevalent in chronic stroke secondary to residual gait deficits, is associated with intolerance for performing activities of daily living. Gait economy/efficiency is traditionally assessed by determining the rate of oxygen consumption during submaximal treadmill walking. However, the mechanics and energetics of treadmill versus overground walking are very different in stroke survivors with ambulatory deficits. Clearly, overground cardiopulmonary measures are needed to accurately profile movement economy after stroke. An obstacle to obtaining such measures after stroke has been the absence of reliable portable metabolic monitoring equipment. The purpose of this study was to establish the test-retest reliability of a portable metabolic monitoring device during overground walking in hemiparetic stroke survivors.

METHODS

Twenty-three chronic hemiparetic stroke survivors underwent two 6-minute walk tests while wearing a COSMED K4b(2) portable metabolic measurement system. Intraclass correlations coefficients (ICC) were calculated for both cardiopulmonary parameters and distance covered to determine test-retest reliability. An ICC of ≥ 0.85 was considered reliable.

RESULTS

ICCs for relative Vo2 (0.90), absolute Vo2 (0.93), Vco2 (0.93), and minute ventilation (0.95) demonstrated high reliability, but not for heart rate (0.76) or respiratory exchange ratio (0.64). There was no significant difference in the distance each participant walked between the first and second tests, eliminating distance as a potential confounder of our analyses (ICC = 0.99).

CONCLUSIONS

Our results strongly support the reliability of the K4b(2) for quantifying overground gait efficiency after stroke. Use of this device may enable researchers to study how varying poststroke rehabilitation interventions affect this central measure of health and function.

The Unified Parkinson's Disease Rating Scale as a predictor of peak aerobic capacity and ambulatory function

The Unified Parkinson's Disease Rating Scale (UPDRS) is a widely applied index of disease severity. Our objective was to assess the utility of UPDRS for predicting peak aerobic capacity (VO2 peak) and ambulatory function. Participants (n = 70) underwent evaluation for UPDRS (Total and Motor ratings), VO2 peak, 6-minute walk distance (6MW), and 30-foot self-selected walking speed (SSWS). Using regression, we determined the extent to which the Total and Motor UPDRS scores predicted each functional capacity measure after adjusting for age and sex. We also tested whether adding the Hoehn and Yahr scale (H-Y) to the model changed predictive power of the UPDRS. Adjusted for age and sex, both the Total UPDRS and Motor UPDRS subscale failed to predict VO2 peak. The Total UPDRS did weakly predict 6MW and SSWS (both p < 0.05), but the Motor UPDRS subscale did not predict these ambulatory function tests. After adding H-Y to the model, Total UPDRS was no longer an independent predictor of 6MW but remained a predictor of SSWS. We conclude that Total and Motor UPDRS rating scales do not predict VO2 peak, but that a weak relationship exists between Total UPDRS and measures of ambulatory function.

Gender differences in the relation of hypertension to cognitive function in older adults

Here we examined potential interactive relations of hypertension and gender to cognitive function in 98 healthy, older adults (ages 55-83 years; 64% male; 92% White). After statistical adjustment for age and education, hypertensives performed significantly more poorly than normotensives on tests of motor speed and manual dexterity (p < 0.05). The adverse consequences of hypertension in older adults was more pronounced for female than male hypertensives on tests of delayed visual memory, visual attention and working memory, visuoconstructional ability, motor speed and manual dexterity for the non-dominant hand (p < 0.05); these are dimensions of performance for which female gender may be a relative disadvantage. The findings suggest the need to further examine subgroups that are vulnerable to the cognitive correlates of hypertension. The results also highlight the need for increased attention to blood pressure control in older adults for the preservation of cognitive function.

Association between physical performance and all-cause mortality in CKD

In older adults, measurements of physical performance assess physical function and associate with mortality and disability. Muscle wasting and diminished physical performance often accompany CKD, resembling physiologic aging, but whether physical performance associates with clinical outcome in CKD is unknown. We evaluated 385 ambulatory, stroke-free participants with stage 2-4 CKD enrolled in clinic-based cohorts at the University of Washington and University of Maryland and Veterans Affairs Maryland Healthcare systems. We compared handgrip strength, usual gait speed, timed up and go (TUAG), and 6-minute walking distance with normative values and constructed Cox proportional hazards models and receiver operating characteristic curves to test associations with all-cause mortality. Mean age was 61 years and the mean estimated GFR was 41 ml/min per 1.73 m(2). Measures of lower extremity performance were at least 30% lower than predicted, but handgrip strength was relatively preserved. Fifty deaths occurred during the median 3-year follow-up period. After adjustment, each 0.1-m/s decrement in gait speed associated with a 26% higher risk for death, and each 1-second longer TUAG associated with an 8% higher risk for death. On the basis of the receiver operating characteristic analysis, gait speed and TUAG more strongly predicted 3-year mortality than kidney function or commonly measured serum biomarkers. Adding gait speed to a model that included estimated GFR significantly improved the prediction of 3-year mortality. In summary, impaired physical performance of the lower extremities is common in CKD and strongly associates with all-cause mortality.

Randomized clinical trial of 3 types of physical exercise for patients with Parkinson disease

OBJECTIVE

To compare the efficacy of treadmill exercises and stretching and resistance exercises in improving gait speed, strength, and fitness for patients with Parkinson disease.

DESIGN

A comparative, prospective, randomized, single-blinded clinical trial of 3 types of physical exercise.

SETTING

The Parkinson's Disease and Movement Disorders Center at the University of Maryland and the Baltimore Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center.

PATIENTS

A total of 67 patients with Parkinson disease who had gait impairment were randomly assigned to 1 of 3 arms of the trial. INTERVENTIONS; (1) A higher-intensity treadmill exercise (30 minutes at 70%-80% of heart rate reserve), (2) a lower-intensity treadmill exercise (50 minutes at 40%-50% of heart rate reserve), and (3) stretching and resistance exercises (2 sets of 10 repetitions on each leg on 3 resistance machines [leg press, leg extension, and curl]). These exercises were performed 3 times a week for 3 months.

MAIN OUTCOME MEASURES

The primary outcome measures were gait speed (6-minute walk), cardiovascular fitness (peak oxygen consumption per unit time [$$ VO2], and muscle strength (1-repetition maximum strength).

RESULTS

All 3 types of physical exercise improved distance on the 6-minute walk: lower-intensity treadmill exercise (12% increase; P=.001), stretching and resistance exercises (9% increase; P<.02), and higher-intensity treadmill exercise (6% increase; P=.07), with no between-group differences. Both treadmill exercises improved peak $$ VO2 (7%-8% increase; P<.05) more than did the stretching and resistance exercises. Only stretching and resistance improved muscle strength (16% increase; P<.001).

CONCLUSIONS

The effects of exercise were seen across all 3 exercise groups. The lower-intensity treadmill exercise resulted in the greatest improvement in gait speed. Both the higher- and lower-intensity treadmill exercises improved cardiovascular fitness. Only the stretching and resistance exercises improved muscle strength. Therefore, exercise can improve gait speed, muscle strength, and fitness for patients with Parkinson disease. The combination of treadmill and resistance exercises may result in greater benefit and requires further investigation.

Judgment of Line Orientation: an examination of eight short forms

The Judgment of Line Orientation (JLO) test is a commonly used measure of visuospatial perception. Because of its length, several short forms have appeared in the literature. We examined the internal consistency of the JLO and eight of its published short forms among 128 undergraduates, 203 healthy older adults, and 55 chronic kidney disease patients. The full test demonstrated good reliability for traditional neuropsychological assessment, but the majority of short forms were adequate only for screening purposes, where greater measurement error is typically permitted in exchange for brevity. In contrast, a recently developed short form based upon item response theory demonstrated promise as a stand-alone measure.

The short physical performance battery as a predictor of functional capacity after stroke

BACKGROUND

The short physical performance battery is a widely used instrument for quantifying lower extremity function in older adults. However, its utility for predicting endurance-based measures of functional performance that are more difficult to conduct in clinical settings is unknown. An understanding of this could be particularly relevant in mobility impaired stroke survivors, for whom establishing the predictive strength of simpler to perform measures would aid in tracking broader categories of functional disability. This cross-sectional study was conducted to determine whether the short physical performance battery is related to functional measures with a strong endurance component.

METHODS

Functional measures (short physical performance battery, peak aerobic capacity, and 6-minute walk) were obtained and compared for the first time in stroke survivors with hemiparetic gait. Pearson correlation coefficients were used to assess strength of the relationships (α P < .05).

RESULTS

Forty-three stroke participants performed a standardized short physical performance battery. Forty-one of the subjects completed a 6-minute walk, and 40 completed a peak treadmill test. Mean short physical performance battery (6.3 ± 2.5 [mean ± SD]), 6-minute walk (242 ± 115 meters), and peak aerobic capacity (17.4 ± 5.4 mL/kg/min) indicated subjects had moderate to severely impaired lower extremity functional performance. The short physical performance battery was related to both 6-minute walk (r = 0.76; P < .0001) and peak fitness (r = 0.52; P < .001).

CONCLUSIONS

Our results show that the short physical performance battery may be reflective of endurance-based, longer-distance performance measures that would be difficult to perform in standard clinical stroke settings. Additional studies are needed to explore the value of using the short physical performance battery to assess rehabilitation-related functional progression after stroke.

Repeatability of aerobic capacity measurements in Parkinson disease

PURPOSE

Maximal or peak aerobic capacity (VO(2peak)) during a maximal-effort graded exercise test is considered by many to be the "gold standard" outcome for assessing the effect of exercise training on cardiorespiratory fitness. The reliability of this measure in Parkinson disease (PD) has not been established, where the degree of motor impairment can vary greatly and is influenced by medications. This study examined the reliability of VO(2peak) during a maximal-effort graded exercise test in subjects with PD.

METHODS

Seventy healthy middle-aged and older subjects with PD Hoehn and Yahr stage 1.5-3 underwent a screening/acclimatization maximal-effort treadmill test followed by two additional maximal-effort treadmill tests with repeated measurements of VO(2peak). A third VO(2peak) test was performed in a subset of 21 subjects.

RESULTS

The mean VO(2peak) measurement was 2.4% higher in the second test compared with the first test (21.42 ± 4.3 vs 21.93 ± 4.50 mL·kg(-1)·min(-1), mean ± SD, P = 0.03). The intraclass correlation coefficients (ICC) for VO(2peak) expressed either as milliliters per kilogram per minute or as liters per minute were highly reliable, with ICC of 0.90 and 0.94, respectively. The maximum HR (ICC of 0.91) and final speed achieved during the tests (ICC of 0.94) were also highly reliable, with the respiratory quotient being the least reliable of the parameters measured (ICC of 0.65).

CONCLUSIONS

Our results demonstrate that measurement of VO(2peak) is reliable and repeatable in subjects with mild to moderate PD, thereby validating use of this parameter for assessing the effects of exercise interventions on cardiorespiratory fitness.