Ellen L. McGough

Associations Between Physical Performance and Executive Function in Older Adults With Mild Cognitive Impairment: Gait Speed and the Timed “Up & Go” Test

Background Older adults with amnestic mild cognitive impairment (aMCI) are at higher risk for developing Alzheimer disease. Physical performance decline on gait and mobility tasks in conjunction with executive dysfunction has implications for accelerated functional decline, disability, and institutionalization in sedentary older adults with aMCI. Objectives The purpose of this study was to examine whether performance on 2 tests commonly used by physical therapists (usual gait speed and Timed “Up & Go” Test [TUG]) are associated with performance on 2 neuropsychological tests of executive function (Trail Making Test, part B [TMT-B], and Stroop-Interference, calculated from the Stroop Word Color Test) in sedentary older adults with aMCI. Design The study was a cross-sectional analysis of 201 sedentary older adults with memory impairment participating in a longitudinal intervention study of cognitive function, aging, exercise, and health promotion. Methods Physical performance speed on gait and mobility tasks was measured via usual gait speed and the TUG (at fast pace). Executive function was measured with the TMT-B and Stroop-Interference measures. Results Applying multiple linear regression, usual gait speed was associated with executive function on both the TMT-B (β=−0.215, P=.003) and Stroop-Interference (β=−0.195, P=.01) measures, indicating that slower usual gait speed was associated with lower executive function performance. Timed “Up & Go” Test scores (in logarithmic transformation) also were associated with executive function on both the TMT-B (β=0.256, P<.001) and Stroop-Interference (β=0.228, P=.002) measures, indicating that a longer time on the TUG was associated with lower executive function performance. All associations remained statistically significant after adjusting for age, sex, depressive symptoms, medical comorbidity, and body mass index. Limitations The cross-sectional nature of this study does not allow for inferences of causation. Conclusions Physical performance speed was associated with executive function after adjusting for age, sex, and age-related factors in sedentary older adults with aMCI. Further research is needed to determine mechanisms and early intervention strategies to slow functional decline.

Physical exercise and cognitive performance in the elderly: current perspectives

In an aging population with increasing incidence of dementia and cognitive impairment, strategies are needed to slow age-related decline and reduce disease-related cognitive impairment in older adults. Physical exercise that targets modifiable risk factors and neuroprotective mechanisms may reduce declines in cognitive performance attributed to the normal aging process and protect against changes related to neurodegenerative diseases such as Alzheimer’s disease and other types of dementia. In this review we summarize the role of exercise in neuroprotection and cognitive performance, and provide information related to implementation of physical exercise programs for older adults. Evidence from both animal and human studies supports the role of physical exercise in modifying metabolic, structural, and functional dimensions of the brain and preserving cognitive performance in older adults. The results of observational studies support a dose-dependent neuroprotective relationship between physical exercise and cognitive performance in older adults. Although some clinical trials of exercise interventions demonstrate positive effects of exercise on cognitive performance, other trials show minimal to no effect. Although further research is needed, physical exercise interventions aimed at improving brain health through neuroprotective mechanisms show promise for preserving cognitive performance. Exercise programs that are structured, individualized, higher intensity, longer duration, and multicomponent show promise for preserving cognitive performance in older adults.

Association of cognitive domains with postural instability/gait disturbance in Parkinson's disease

INTRODUCTION Research suggests an association between global cognition and postural instability/gait disturbance (PIGD) in Parkinson disease (PD), but the relationship between specific cognitive domains and PIGD symptoms is not clear. This study examined the association of cognition (global and specific cognitive domains) with PIGD symptoms in a large, well-characterized sample of individuals with PD. METHODS Cognitive function was measured with a detailed neuropsychological assessment, including global cognition, executive function, memory, visuospatial function, and language. PIGD symptoms were measured using the Movement Disorder Society Unified Parkinsons Disease Rating Scale (MDS-UPDRS) Part III, Motor Examination subscale. Multiple linear regression analyses were performed to assess the relationship between cognition and PIGD symptoms with models adjusting for age, sex, education, enrollment site, disease duration, and motor symptom severity. RESULTS The analysis included 783 participants, with mean (standard deviation) age of 67.3 (9.7) years and median (interquartile range) MDS-UPDRS Motor Subscale score of 26 (17, 35). Deficits in global cognition, executive function, memory, and phonemic fluency were associated with more severe PIGD symptoms. Deficits in executive function were associated with impairments in gait, freezing, and postural stability, while visuospatial impairments were associated only with more severe freezing, and poorer memory function was associated only with greater postural instability. DISCUSSION While impairments in global cognition and aspects of executive functioning were associated with more severe PIGD symptoms, specific cognitive domains were differentially related to distinct PIGD components, suggesting the presence of multiple neural pathways contributing to associations between cognition and PIGD symptoms in persons with PD.

Development of Evidence-Based Exercise Recommendations for Older HIV-Infected Patients

&NA; Advances in antiretroviral therapy (ART) have decreased HIV‐related morbidity and mortality and contributed to rapidly increasing numbers of older people living with HIV. Successful management of ART‐related side effects (metabolic syndrome) and age‐related comorbidities (frailty) are major challenges for patients and providers. Exercise has proven beneficial for younger HIV‐infected patients, but we know little about which exercise regimens to recommend to the elderly. Our goal was to develop age‐appropriate, evidence‐based exercise recommendations for older HIV‐infected adults (age > 50). We reviewed randomized controlled trials on the effects of physical exercise for: (a) HIV‐infected young adults, (b) frail older adults, and (c) elderly individuals with metabolic syndrome. We recommend a combination of endurance and resistance exercises 3 times per week for at least 6 weeks to improve cardiovascular, metabolic, and muscle function. Further research is warranted to study the benefits and risks of physical exercise in older HIV‐infected patients.

Dimensions of physical frailty and cognitive function in older adults with amnestic mild cognitive impairment.

OBJECTIVE The objective of this study was to examine relationships between dimensions of physical frailty and severity of cognitive impairment in older adults with amnestic mild cognitive impairment (aMCI). PATIENTS AND METHODS The prevalence of physical frailty dimensions including slow gait speed, low physical activity, and low grip strength was examined among 201 sedentary older adults with aMCI. Associations between dimensions of physical frailty and severity of cognitive impairment, as measured with the Alzheimers Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and individual dimensions of cognitive function were examined using multiple linear regression models. RESULTS Greater than 50% of participants met physical frailty criteria on dimensions of slow gait speed, low physical activity and low grip strength. Slower gait speed was associated with elevated severity of cognitive impairment. Both gait speed and physical activity were associated with individual dimensions cognitive function. CONCLUSIONS Dimensions of physical frailty, particularly gait speed, were associated with severity of cognitive impairment, after adjusting for age, sex and age-related factors. Further studies are needed to investigate mechanisms and early intervention strategies that assist older adults with aMCI to maintain function and independence.

Functional mobility limitations and falls in assisted living residents with dementia: physical performance assessment and quantitative gait analysis

Background and Purpose:The prevalence of functional mobility limitations and falls is higher in people with dementia compared with cognitively healthy older adults, and both are associated with gait and motor impairments. The aims of this study were to examine concurrent validity of physical performance assessments and spatiotemporal gait measures in older adults with advanced dementia and to prospectively examine their relationship to functional mobility limitations and falls over a 4-month period. Methods:Thirty-one older adults living in dementia-specific assisted living residences participated. Correlations were examined between a modified Berg Balance Scale (mod-Berg), the Short Physical Performance Battery (SPPB), and spatiotemporal gait measures using the GAITRite Walkway system. Over 4-months, functional mobility limitations were rated, and falls were recorded by nursing supervisors. Differences in functional mobility limitations and falls were examined in relation to baseline balance and gait measures. Results:Partial correlations between spatiotemporal gait measures and the mod-Berg as well as the SPPB were statistically significant (P < .05) after adjusting for age and Mini-Mental State Examination scores. Participants with low functional mobility ratings had significantly lower scores on the mod-Berg (P ⩽ .001) and SPPB (P ⩽ .001). They also demonstrated slower gait speed, lower cadence, higher stride time variability, and a greater percentage of gait cycle in double support (P ⩽ .01). Participants with at least 1 fall, compared with those who did not fall, had lower scores on the mod-Berg (P = .02), lower cadence (P = .048), and greater stride length variability (P = .035). Discussion:The mod-Berg and SPPB were strongly correlated with reliable gait measures associated with instability and increased fall risk. The modified Berg Balance Scale demonstrates potential as a predictor of falls in older adults living in dementia-specific assisted living. Conclusion:The results of this study provide support for the application of brief physical performance assessments by physical therapists to identify functional mobility limitations and fall risk in older adults with advanced dementia.

A Tandem Cycling Program: Feasibility and Physical Performance Outcomes in People With Parkinson Disease

Background and Purpose: Individuals with Parkinson disease (PD) have motor and nonmotor impairments that interfere with exercise participation. The purpose of this study was to examine the feasibility and physical performance outcomes of a community-based indoor tandem cycling program that was designed to facilitate a higher cadence, consistency, and intensity of training. Methods: Forty-one participants with mild to moderate PD were enrolled. A high-cadence cycling protocol using mechanically augmented (or forced) exercise on a tandem bicycle was adapted for our program. Participants cycled 3 times per week for 10 weeks. Feasibility measures included program retention, attendance, and adverse events, as well as the ability to reach training goals for heart rate (HR) and cadence. Physical performance outcomes included the Berg Balance Scale (BBS), Short Physical Performance Battery (SPPB), Five-Times-Sit-to-Stand (FTSTS) Test, Timed Up and Go (TUG), and gait parameters during usual and fast-paced walking. Results: Program feasibility was demonstrated with a high attendance rate (96%) and retention rate (100%). There were no adverse events. The majority of participants reached their exercise training goals for target HR (87%) and cadence (95%). Statistically significant physical performance improvement (P < 0.05) was observed across domains of gait, balance, and mobility, suggesting a slowing or reversal of functional decline as a result of this cycling program. Discussion and Conclusion: Program feasibility and improved physical performance outcomes were demonstrated in individuals with mild to moderate PD participating in a community-based indoor tandem cycling program. Video Abstract available for more insights from the authors (see supplemental digital content 1, http://links.lww.com/JNPT/A146).

Posterior Cingulate Lactate as a Metabolic Biomarker in Amnestic Mild Cognitive Impairment

Mitochondrial dysfunction represents a central factor within the pathogenesis of the Alzheimers disease (AD) spectrum. We hypothesized that in vivo measurements of lactate (lac), a by-product of glycolysis, would correlate with functional impairment and measures of brain health in a cohort of 15 amnestic mild cognitive impairment (aMCI) individuals. Lac was quantified from the precuneus/posterior cingulate (PPC) using 2-dimensional J-resolved magnetic resonance spectroscopy (MRS). Additionally, standard behavioral and imaging markers of aMCI disease progression were acquired. PPC lac was negatively correlated with performance on the Wechsler logical memory tests and on the minimental state examination even after accounting for gray matter, cerebral spinal fluid volume, and age. No such relationships were observed between lac and performance on nonmemory tests. Significant negative relationships were also noted between PPC lac and hippocampal volume and PPC functional connectivity. Together, these results reveal that aMCI individuals with a greater disease progression have increased concentrations of PPC lac. Because lac is upregulated as a compensatory response to mitochondrial impairment, we propose that J-resolved MRS of lac is a noninvasive, surrogate biomarker of impaired metabolic function and would provide a useful means of tracking mitochondrial function during therapeutic trials targeting brain metabolism.

Integrating Health Promotion into Physical Therapy Practice to Improve Brain Health and Prevent Alzheimer Disease

BACKGROUND AND PURPOSE Alzheimer disease is the most common cause of dementia, and brain pathology appears years before symptoms are evident. Primary prevention through health promotion can incorporate lifestyle improvement across the lifespan. Risk factor assessment and identifying markers of disease might also trigger preventive measures needed for high-risk individuals and groups. SUMMARY OF KEY POINTS Many potential risk factors are modifiable through exercise, and may be responsive to early intervention strategies to reduce the downward slope toward disability. Through the use of common clinical tests to identify cognitive and noncognitive functional markers of disease, detection and intervention can occur at earlier stages, including preclinical stages of disease. Physical activity and exercise interventions to address modifiable risk factors and impairments can play a pivotal role in the prevention and delay of functional decline, ultimately reducing the incidence of dementia. This article discusses prevention, prediction, plasticity, and participation in the context of preserving brain health and preventing Alzheimer disease and related dementias in aging adults. RECOMMENDATIONS FOR CLINICAL PRACTICE Rehabilitation professionals have opportunities to slow disease progression through research, practice, and education initiatives. From a clinical perspective, interventions that target brain health through lifestyle changes and exercise interventions show promise for preventing stroke and associated neurovascular diseases in addition to dementia. Physical therapists are well positioned to integrate primary health promotion into practice for the prevention of dementia and other neurological conditions in older adults.

Lifestyle Changes in the Prevention of Mobility Disability

The prevention of functional decline with aging is essential for maintaining independent mobility for daily living and community access. The onset of mobility disability may be progressive or catastrophic in nature. Self-reported and performance-based clinical measures can be valuable for identifying the onset of mobility disability. Identification of modifiable lifestyle factors and preclinical predictors of mobility disability can be utilized in preventive care. Modifiable lifestyle factors related to mobility disability include physical activity (PA) level, smoking, nutrition, and body mass index (BMI). Age-related comorbid conditions including cardiovascular health, sarcopenia, metabolic dysregulation, cognitive impairment, and multi-morbidity influence the trajectory of decline toward mobility disability. This clinical review summarizes current knowledge about the onset and prevention of mobility disability, reviews intervention studies related to decreasing the risk for mobility disability, and provides suggestions for clinicians related to predicting and preventing mobility disability in older adults. Special attention is given to useful clinical measures, modifiable lifestyle factors, and delivering care in the context of age-related comorbid conditions in older adults.