Mooyeon Oh-Park

Exercise for the dialyzed: Aerobic and strength training during hemodialysis

Oh-Park M, Fast A, Gopal S, Lynn R, Frei G, Drenth R, Zohman L: Exercise for the dialyzed: Aerobic and strength training during hemodialysis. Am J Phys Med Rehabil 2002;81:814–821. Objective To investigate the safety and feasibility of aerobic and strength training during hemodialysis for end-stage renal disease patients and to evaluate its impact on their cardiac fitness, muscle strength, and functional status. Design A total of 22 patients undergoing hemodialysis for end-stage renal disease had assessment of their cardiac fitness with stress tests and walk tests, assessment of their muscle strength by one repetition maximum of knee extension, and assessment of their functional status by Medical Outcomes Study Short Form-36 before and after exercise training. Training, consisting of cycle ergometer exercise and strengthening of the knee extensors two to three times a week for 3 mo, was done during dialysis. Results Eighteen of 22 patients completed 3 mo of training and four dropped out due to knee pain or medical complications unrelated to exercise. No patient developed major complications from the program. After training, there was a significant improvement in the mental and physical components of the Short Form-36 and one repetition maximum of knee extension. Among 14 of 18 patients who agreed and completed a follow-up fitness testing, five showed improvement on the stress tests and eight on the walk tests. Conclusions A well designed exercise program during hemodialysis can be performed safely with proper supervision and patient education, improving muscle strength, mental and physical function, and possibly cardiac fitness.

Inflammatory Markers and Gait Speed Decline in Older Adults

BACKGROUND Increased inflammatory activity and gait speed decline are common with aging, but the association between the two is not well established. The objective of this study was to determine the influence of inflammatory markers, interleukin-6 (IL-6), and tumor necrosis factor alpha, on gait speed performance and decline in older adults. METHODS We conducted cross-sectional and longitudinal analyses of 333 adults aged 70 and older (61% women) with gait and biomarker assessments identified from participants in the Einstein Aging Study, a community-based aging study. Gait velocity measured at baseline and annual follow-up visits (median follow-up 2.3 years) was the main outcome. RESULTS At baseline, higher interleukin-6 levels were associated with slower gait velocity (estimate -4.90 cm/s, p = .008). Adjusted for age, gender, education, and medical illnesses, a one-unit increase in baseline log IL-6 levels was associated with a 0.98 cm/s faster gait speed decline per year (p = .002). The results remained significant after adjustments for additional potential confounders such as physical activity levels, body mass index, and medications. Participants in the highest IL-6 quartile had a 1.75 cm/s/year faster decline in gait velocity compared with those in the lowest quartile (p = .002). Tumor necrosis factor alpha was not associated with gait velocity at cross-section or with gait speed decline. CONCLUSIONS IL-6 levels are associated with gait performance in community residing seniors and predicts risk of gait speed decline in aging.

Conventional and Robust Quantitative Gait Norms in Community‐Dwelling Older Adults

OBJECTIVES: To develop and compare norms for widely used gait parameters in adults aged 70 and older using cross‐sectional (conventional) and longitudinal (robust) approaches accounting for important confounders such as disease effects on gait.

Multisensory integration across the senses in young and old adults.

Stimuli are processed concurrently and across multiple sensory inputs. Here we directly compared the effect of multisensory integration (MSI) on reaction time across three paired sensory inputs in eighteen young (M=19.17 years) and eighteen old (M=76.44 years) individuals. Participants were determined to be non-demented and without any medical or psychiatric conditions that would affect their performance. Participants responded to randomly presented unisensory (auditory, visual, somatosensory) stimuli and three paired sensory inputs consisting of auditory-somatosensory (AS) auditory-visual (AV) and visual-somatosensory (VS) stimuli. Results revealed that reaction time (RT) to all multisensory pairings was significantly faster than those elicited to the constituent unisensory conditions across age groups; findings that could not be accounted for by simple probability summation. Both young and old participants responded the fastest to multisensory pairings containing somatosensory input. Compared to younger adults, older adults demonstrated a significantly greater RT benefit when processing concurrent VS information. In terms of co-activation, older adults demonstrated a significant increase in the magnitude of visual-somatosensory co-activation (i.e., multisensory integration), while younger adults demonstrated a significant increase in the magnitude of auditory-visual and auditory-somatosensory co-activation. This study provides first evidence in support of the facilitative effect of pairing somatosensory with visual stimuli in older adults.

Transient Versus Persistent Fear of Falling in Community-Dwelling Older Adults: Incidence and Risk Factors

OBJECTIVES: To investigate the incidence of fear of falling (FOF) and the risk factors associated with transient versus persistent FOF in community‐dwelling older adults.

Depressive Symptoms and Gait Dysfunction in the Elderly

OBJECTIVE Assess the association between depressive symptoms (not meeting the criteria for major depression) and gait dysfunction in older adults. DESIGN Cross-sectional study. SETTING Einstein Aging Study, a community-based longitudinal aging study. PARTICIPANTS Six hundred ten nondemented and nondepressed community-residing adults age 70 and older. MEASUREMENTS Depressive symptoms measured using the 15-item Geriatric Depression Scale. To obtain a comprehensive assessment of gait, eight individual quantitative gait parameters were assessed: velocity (cm/s), stride length (cm), cadence (steps/min), swing phase (seconds), stance phase (seconds), double support phase (seconds), stride length variability (SD of stride length), and swing time variability (SD of swing time). Multiple linear regression analysis was applied to study the association of depressive symptoms with gait, adjusting for potential confounders including demographic variables, medical illnesses, and clinical gait abnormalities. RESULTS Increased level of depressive symptoms was associated with worse velocity, stride, and swing time variability. The relationship of the remaining five gait variables with depressive symptoms was not significant in the fully adjusted models. CONCLUSIONS Higher levels of depressive symptoms are associated with worse performance in specific quantitative gait variables in community-residing older adults.

Stair Negotiation Time in Community-Dwelling Older Adults: Normative Values and Association With Functional Decline

OBJECTIVES To establish reference values for stair ascent and descent times in community-dwelling, ambulatory older adults, and to examine their predictive validity for functional decline. DESIGN Longitudinal cohort study. Mean follow-up time was 1.8 years (maximum, 3.2y; total, 857.9 person-years). SETTING Community sample. PARTICIPANTS Adults 70 years and older (N=513; mean age, 80.8 ± 5.1y) without disability or dementia. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Time to ascend and descend 3 steps measured at baseline. A 14-point disability scale assessed functional status at baseline and at follow-up interviews every 2 to 3 months. Functional decline was defined as an increase in the disability score by 1 point during the follow-up period. RESULTS The mean±SD stair ascent and descent times for 3 steps were 2.78 ± 1.49 and 2.83 ± 1.61 seconds, respectively. The proportion of self-reported and objective difficulty was higher with longer stair ascent and descent times (P<.001 for trend for both stair ascent and descent). Of the 472 participants with at least 1 follow-up interview, 315 developed functional decline, with a 12-month cumulative incidence of 56.6% (95% confidence interval [CI], 52.1%-61.3%). The stair negotiation time was a significant predictor of functional decline after adjusting for covariates including gait velocity (adjusted hazard ratio [aHR] per 1-s increase: aHR=1.12 [95% CI, 1.04-1.21] for stair ascent time; aHR=1.15 [95% CI, 1.07-1.24] for stair descent time). Stair descent time was a significant predictor of functional decline among relatively high functioning older adults reporting no difficulty in stair negotiation (P=.001). CONCLUSIONS The stair ascent and descent times are simple, quick, and valid clinical measures for assessing the risk of functional decline in community-dwelling older adults including high-functioning individuals.

A simple walk test to guide exercise programming of the elderly.

Exercise training programs are usually based on a maximal exercise stress test; however, this test is often difficult and sometimes frightening to older persons. This preliminary study reports on a fixed-distance, submaximal walk test and compares its usefulness for exercise prescription to that of the traditional maximal stress test. Ten cardiac patients, with an average age of 72 years (4 men), had recently clinically indicated maximal graded stress tests. Within one week, each had the walk test, which consisted of walking three times up and back 100 feet in the hospital corridor (total of 600 feet) as rapidly as possible, with a blood pressure cuff on their arm and carrying the electrocardiogram cable. Resting and peak heart rate, blood pressure, symptoms, and exercise electrocardiograms were compared for the walk test v the maximal stress test. Oxygen consumption was calculated from the peak workload on the maximal stress test and from walking speed on the walk test. The peak heart rates after the walk test were within the target heart rate zone (70-85%) for exercise programming, as obtained from the maximal stress test, in all patients except one. The calculated peak oxygen consumption from the walk test was also within the training zone (60-80%) obtained from the maximal stress test in all patients except one. This pilot study shows that a submaximal, steady state timed walk of 600 feet can be a feasible method of providing the information for exercise programming, possibly avoiding the need for a maximal stress test. This walk test can be performed easily by health-related staff without sophisticated facilities in an inpatient rehabilitation unit or nursing home; however, further study with a larger number of patients is necessary before this method of exercise prescription can be recommended.

Clinically meaningful change in stair negotiation performance in older adults

Stair negotiation is a key marker for independence among older adults; however, clinically meaningful change has not been established. Our objective was to establish the values of clinically meaningful change in stair negotiation time using distribution- and anchor-based approaches. Study participants were 371 community residing older adults (age≥70) in the Einstein Aging Study with time to ascend and descend 3 steps measured at baseline and at one-year follow-up. Anchor-based estimates were obtained using functional decline (defined as one-point increment in disability score) and change in self-reported walking ability over the one-year follow-up period. Small, moderate, and large meaningful change estimates were 0.28, 0.71, and 1.15 s for stair ascent time (0.31, 0.78, and 1.25 s for stair descent time) using the distribution-based approach of effect size. The estimates of meaningful decline range from 0.47 to 0.53 s for stair ascent time (0.33-0.53 s for stair descent time) using the anchor-based approach. The estimates of meaningful improvement were smaller (0.13-0.18 s for stair ascent, 0.06-0.15 for stair descent) compared to those for decline. Based on general consistency between distribution- and anchor-based approaches, preliminary criteria suggested for stair negotiation time is 0.5 s for meaningful decline and 0.2 s for meaningful improvement.

Effect of treadmill training on specific gait parameters in older adults with frailty: case series.

Background and Purpose:Treadmill-walking training (TWT) as an intervention to improve the gait of frail older adults has not been well studied. In this pilot study, we describe the feasibility, tolerance, and effect of TWT on specific gait parameters during overground walking in 4 frail older adults as a prelude to developing larger-scale exercise intervention trials in this high-risk population. Case Description:Four community-residing frail older individuals (age > 70 years) with Mini-Mental State Examination score of 26 or higher and no activity limitations. Frailty was defined as the presence of at least 3 of the following 5 attributes: slow gait (<1 m/s); unintentional weight loss (>10 lb in prior year); self-report of poor grip strength; exhaustion; and low level of physical activity. Intervention:The TWT consisted of 24 sessions (3 times per week for 8 weeks). Five quantitative gait parameters (velocity, stride length, swing time, percentage of double support phase, and coefficient of variation [COV] of stride length) during overground walking were measured at baseline, weekly during training, and immediately post-TWT. Outcome:All participants tolerated TWT without significant complications. Following TWT, gait velocity increased in all participants by 6.4 to 26.8 cm/s, which was larger than the reported value for meaningful change in gait velocity (4 cm/s). Stride length and double support phase also showed improvement in all participants (mean percentage increase of 10.8% for stride length and 17.1% reduction for double support phase posttraining compared with baseline). Swing time improved in 3 participants (mean reduction of 4.5%). The COV of stride length did not show consistent improvement. Discussion:This case series shows that TWT is feasible and well tolerated by frail older adults and may improve most gait parameters in this high-risk population.