A double-blind study was undertaken to determine the relationship (if one exists) between the extent of postural sway in standing of individual elderly subjects and their frequency of falling. A total of 205 subjects were studied; their average age was 81.8 years. Thirty per cent of the men, and 46% of the women, had one or more falls; the proportion of all subjects with one or more falls was 42%. The average speed of sway was significantly greater ( P <0.05) for those who fell one or more times in a year than for those who did not fall. In this group of institutionalized elderly, there was no sex-related difference in the mean speed of sway; moreover, no age-related trend was demonstrated by the regression of mean speed upon age for all subjects. The mean speed of sway even for the non-fallers was found to be greater than that measured in a sample of non-institutional elderly subjects studied in the past. Thus, mean speed of postural sway was found to be only of statistical value for determining the risk of falling among these institutionalized elderly. We found postural sway to be an indicator of a tendency to fall, but the difference was less than might have been expected. No trend of increasing postural sway correlating with the increased frequency of falls was found.

This article presents criteria for the design of a lumbar intervertebral disc prosthesis that take into consideration issues of endurance, materials behavior, geometry, kinetics, motion constraints, fixation to bone, and safety. The criteria and design philosophies discussed are generally applicable in the synthesis of any new implant system. Specifications of the design of a disc prosthesis are presented along with an evaluation of the design based on some of the preliminary test data.

Older adults with dementia often cannot remember how to complete activities of daily living and require a caregiver to aid them through the steps involved. The use of a computerized guidance system could potentially reduce the reliance on a caregiver. This paper examines the design and preliminary evaluation of a planning system that uses Markov decision processes (MDPs) to determine when and how to provide prompts to a user with dementia for guidance through the activity of handwashing. Results from the study suggest that MDPs can be applied effectively to this type of guidance problem. Considerations for the development of future guidance systems are presented

Background. Age-related loss of foot-sole cutaneous sensation is very common and is associated with impaired balance control. This study investigated the effect of a balance-enhancing insole (designed to facilitate foot-sole sensation) on lateral gait stability and evaluated its effectiveness in daily life. Methods. Forty community-dwelling older adults (age 65–75) with moderate loss of foot-sole sensation (unrelated to neuropathy) were fitted with the same model of walking shoes. Half of the participants were assigned, at random, to wear the shoes with a facilitatory insole for 12 weeks; the other participants wore a conventional insole. A gait perturbation protocol, simulating uneven terrain, was performed at baseline and after wearing the assigned insoles for 12 weeks. Participants were tested with both types of insoles during each gait-testing session and sent in weekly postcards with information pertaining to insole comfort, hours of wear, and falls. Results. The facilitatory insole improved lateral stability during gait, and this benefit did not habituate after 12 weeks of wearing the insole in daily life. Nine participants who wore conventional insoles experienced one or more falls, whereas only five of the facilitatory group fell. Although there were initial reports of mild discomfort in 10 cases, all but one participant tolerated the facilitatory insole, and most indicated that they would like to continue wearing the insole on a long-term basis. Conclusions. A relatively simple change in insole design can help to counter effects of age-related (non-neuropathic) decline in foot-sole sensitivity, and is a viable intervention to enhance balance control.