Background: the identification of specific risk factors for falls in community-dwelling elderly persons is required to identify older people at risk of falling. Objective: the aim of the study was to determine the ability of various biomechanical measures of postural stability to identify fallers in the elderly population. Method: 19 subjects (78.4 ± 1.3 years old) who reported having fallen unexpectedly at least twice in the last 6 months, and 124 non-fallers (77.8 ± 0.53 years old) participated in the study. Balance measurements were made in the upright position in six different conditions using a force platform, and the Limits of Stability Test was carried out. Static two-point discrimination (TPD) testing to the underside of the first toe was made to evaluate the innervation density of the slowly adapting receptors. Finally, maximal isometric lower limb strength was measured in major muscle groups. Repeated measures analysis of variance tests were performed to assess the mean differences between the two groups (fallers and non-fallers). The level of significance was set to 0.05. Results and discussion: results suggest that control of balance in narrow base stance may be an important tool in identifying elderly fallers. The findings show an increase in mediolateral sway in narrow base stance in older people who experienced recurrent falls. Also, TPD appears to be impaired in elderly fallers (14.93 ± 1.1 mm versus 12.98 ± 0.3 mm). Conclusions: simple and safe laboratory quantitative tests were able to differentiate between elderly fallers and elderly individuals who did not fall, suggesting a possible clinical application as a preliminary screening tool for predicting future risk of falling.

Background: Postural control and falls in the elderly constitute a major health problem. The interest in balance deficits is growing, as concern about the rising costs of health care increases. This issue is particularly relevant to the elderly population in which falls occur most frequently. Postural control in the elderly was studied using a cognitive approach. Objective: The purpose of this study was to study the characteristics of central processing of postural control while performing cognitive tasks. Methods: A dual-task procedure was developed to estimate the level of automaticity of a quiet upright standing task. The effect of a concurrent attention-demanding task (modified Stroop test) on the efficiency of balance control in the elderly was determined using force platform and electromyography measurements. Results: It was found that there is an increase in postural sway in old subjects compared with young subjects when performing single tasks and dual-task tests. The results of the study demonstrate that postural adjustments require cognitive processing; young and old subjects showed similar interference effects on postural steadiness (postural sway) caused by the concurrent attention-demanding task. The results are corroborated by the hypothesis that a dual task gives information on the restoration of automaticity of postural control in old age by a central reorganization process. When performing a dual task tested on a narrow base of support, the old subjects decreased their body sway, while the younger did not. According to electromyography measurements, the older subjects increased their muscle activity in the tibialis anterior and soleus muscles, using slow-twitch motor units compared with the younger subjects. Conclusions: Both alterations (cognitive and base of support) have a substantially greater effect on the elderly than on the young. The older subjects decreased their body sway by activating a cocontraction strategy of postural control around the ankle joint, probably because of the danger to their postural stability.

Background. Peripheral sensation is the most important sensory system in the maintenance of upright posture in all age groups. With aging, visual and somatosensory processing change their prospective contribution to the maintenance of quiet standing, at debated percentages. Aging is associated with a decrease in balance abilities that, in turn, increases the risk of falling. We used force plate data to show that, with aging, while vision plays a significant role in regulating postural stability (PS), the individual's perception of his/her stability becomes more significant than vision. Moreover, under experimental conditions, electromyography (EMG) of the ankle musculature of elderly people reveals the adoption of a different strategy, a cocontraction strategy, with or without visual input. The aim of this study was to look at two distinct age groups to determine whether or not a shift takes place in the sensory modality typically relied on while maintaining PS during a static, postural-related task. Method. The participants comprised two groups: a “young” (Y) group of 20 people aged 20–35, and an “old” (O) group of 32 people aged 65–84. The role of vision was tested with regard to two differently sized bases of support. They were tested during quiet upright standing on a single force plate in wide base and then in narrow base conditions. Surface EMG was recorded from the tibialis anterior, soleus, rectus femoris, and semitendinous muscles. Results. The older group differed from the younger group when performing the task under the narrow base condition. When participants stood naturally, our EMG data indicated that, unlike the Y group, the O group used cocontraction around the ankle in order to deal with changing conditions and sensory inputs. Significant increases were found in the area, length, and mean velocity of body sway in the older group as compared with the younger group. Discussion. The visual contribution to postural stabilization is significantly greater in the younger population than in the elderly population. Across the older group, lack of vision seemed to interfere less with PS; however, the EMG data indicated that, unlike the Y group, the O participants used cocontraction around the ankle in order to deal with changing conditions and sensory inputs. Conclusion. To cope with the deterioration in their sensory input and processing ability, elderly individuals seemed to have developed a strategy of stiffening and freezing their lower legs during upright standing.

SIR—Loss of balance and falls in the elderly constitute a major problem associated with human suffering as well as high costs for society [1]. Falls might occur during various daily activities, such as tripping or tangling the feet, reaching movements or bending [2]. Many of these activities are constrained by limits of stability (LOS). LOS can be described as the maximum distance a person can intentionally displace his/her centre of gravity, and lean his/her body in a given direction without losing balance, stepping or grasping. Accordingly, one's LOS capacity is likely to be an important prerequisite for the successful planning and execution of movements such as using a step stool to reach into a high cabinet as well as bending over from standing position to pick up an object from the floor.