Miho Sugiura

Walking speed as a good predictor for maintenance of I‐ADL among the rural community elderly in Japan: A 5‐year follow‐up study from TMIG‐LISA

Background  A population‐based prospective cohort study was undertaken to examine the predictors of functional decline in instrumental activities of daily living (I‐ADL) among non‐disabled older Japanese subjects living in a rural community during a five‐year interval from 1992 to 1997.

Longitudinal Change in the Physical Performance of Older Adults in the Community

The primary purposes of this study were 1) to confirm age-related deterioration of physical performance in older adults longitudinally, and 2) to predict future functional status and mortality by initial level of physical performances. The subjects were 517 older adults examined both in 1992 and 1996 in the Tokyo Metropolitan Institute of Gerontology, Longitudinal Interdisciplinary Study on Aging. The same battery consisting of muscle strength, balance, walking, and manual speed was administered to the subjects in the baseline and follow-up examinations. A significant longitudinal decline was observed in all physical performances except for grip strength. The age-related decline accelerated with aging for preferred walking velocity. Inter-subject variability in walking velocity significantly increased for 4 years period. Maximum walking velocity was a common predictor for functional status and mortality. The results suggest that physical performance measures, especially maximum walking velocity, is a valid means for physical therapy to evaluate physical functioning of community-living older persons.

Effects of an automated stride assistance system on walking parameters and muscular glucose metabolism in elderly adults

Objective: To identify the effects of an automated stride assistance system (SAS) on walking scores and muscle activities in the lower extremities of elderly people. Methods: Seven healthy elderly men (73–81 years) participated in this study. Subjects walked continuously at a constant speed for 50 min on a treadmill with and without the SAS, which is a device to control the walk ratio (step length/cadence) and to add support power to the thigh during walking. A step counter equipped with an infrared device was used to record walking data. The average speeds during treadmill walking were 2.89–3.82 km/h without the SAS and 3.03–4.03 km/h with the SAS. Positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG) evaluation of glucose metabolism were conducted on each subject twice after walking with and without the SAS. Results: Walk ratio, walking speed and step length were significantly improved in all subjects by the SAS, while cadence was significantly decreased by the SAS in all subjects except one. The SAS did not have a significant effect on glucose metabolism of the muscles of the lower extremities. There were no significant correlations between change in walking speed and change in glucose metabolism in each muscle without the SAS and with the SAS. In contrast, significant correlations between walking speed and glucose metabolism were shown in gluteus minimus (r = −0.929), hip-related muscles (r = −0.862), soleus (r = −0.907), and medial gastrocnemius (r = −0.952) without the SAS. With the SAS, there were significant correlations in gluteus medius (r = −0.899), hip-related muscles (r = −0.819), and medial gastrocnemius (r = −0.817) in the elderly subjects. Conclusions: The SAS increases walking scores in elderly people without increasing energy consumption of lower-extremity muscles. The elderly subjects with low walking speed showed higher glucose metabolism in hip-related muscles and triceps surae. Thus, this association suggested that decreased walking speed in elderly adults has a higher metabolic cost in these muscle regions.

Association between change in bone mineral density and decline in usual walking speed in elderly community-dwelling Japanese women during 2 years of follow-up.

OBJECTIVES: To investigate the association between change in bone mineral density (BMD) and change in usual walking speed in elderly community‐living Japanese women during 2 years of follow‐up.

The Use of Positron Emission Tomography and

The aim of this study was to investigate the use of [18F] fluoro deoxyglucose and positron emission tomography (FDG PET) for quantitative evaluation of glucose metabolism in skeletal muscle during walking. Ten young males underwent FDG PET twice during walks, which were done with or without an automated stride assistance system (SAS). Walk ratios were significantly increased by the SAS in seven subjects. Regional glucose metabolism in muscles between the crista iliaca and the planta was clearly visualized in all ten subjects. Glucose utilization increased significantly in the tibialis posterior and medial gastrocnemius muscles of the seven subjects in whom walk ratios were increased by the SAS. FDG PET is useful for analysis of muscle activity during exercise and rehabilitation.

[^{18}{\rm F}]

Background and aims: Recent studies have revealed that there are critical differences between participants and non-participants in health examinations. The aim of this study was to examine mortality differences between participants and non-participants in a comprehensive health examination for prevention of geriatric syndromes among community-dwelling elderly people, using a three-year prospective cohort study. Methods: The study population included 854 adults aged 70 to 84 at baseline. The following items were all studied: the status of participation in the comprehensive health examination as an independent variable, age, gender, number of years of education, living alone, presence of chronic diseases, experience of falls over one year, history of hospitalization over one year, self-rated health, body mass index, instrumental activities of daily living, and subjective well-being as covariates; and all-cause mortality during a three-year follow-up as a dependent variable. Results: In an adjusted Cox’s proportional hazard regression model, the mortality risk for participants in the comprehensive health examination was significantly lower than that of non-participants (Risk Ratio (for participants)=0.44, 95% confidence interval=0.24 to 0.78). Conclusions: The present study shows that there is a large mortality difference between participants and non-participants. Our findings suggest two possible interpretations: 1) There is a bias due to self-selection for participation in the trial, which was not eliminated by adjustment for the covariates in the statistical model; 2) There is an intervention effect associated with participation in the comprehensive health examination which reduces the mortality risk.

Fluorodeoxyglucose for Functional Imaging of Muscular Activity During Exercise With a Stride Assistance System

Background:  A study was conducted to clarify the characteristics of cognitive function among physically independent very old people dwelling in an urban community in Japan.

A mortality comparison of participants and non-participants in a comprehensive health examination among elderly people living in an urban Japanese community

In this study, we examined the factorial structure of the physical performance measures and the longitudinal invariance of elderly people in the community. The subjects were investigated in Akita as part of TMG‐LISA. Data used in this study were from 463 older adults who participated in all the physical performance tests, both in the baseline (1992) and the 4‐year follow‐up (1996) investigation. The test battery consisted of six items (hand power, walking, and balance). There were longitudinal aging changes in gender and age in all of the measurements between the baseline research and the follow‐up research, except for the one‐leg standing with eyes closed test. The factorial invariance of the structure in these measures taken in 1992 and 1996 was confirmed through the confirmatory factor analysis (CFA) of the structural equation modeling, controlled for gender and age. As a preliminary step for analysis of factorial invariance, we analyzed the fitting basic motor ability model to cross‐sectional data of the baseline and follow‐up. As a result of the analysis, the fitness levels of each data of the models were good. Then, we applied simultaneous analysis and analyzed longitudinal changes in the factorial structure of measurements. The results were that there were the same factors in the factorial structure model of physical performance measured in both the baseline and follow‐up investigation, and that their arrangements were identical. Furthermore, we find that there was no difference in all factor‐loading in both models being investigated. These results statistically indicated that there were no signs of aging changes in factorial structure of the measures between the baseline investigations and the follow‐up 4 years later in spite of the longitudinal decline of the values of physical performance tests. Moreover, it was indicated that the simultaneous analysis, which this research used, was applicable for statistical analysis procedure of factorial invariance of various repeated measures on studies of aging, as a longitudinal study.