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.

The purpose of the present study was to describe the spatial-temporal parameters of the centre of pressure (COP) trajectory during the single-support phase of gait among stroke survivors and relate these parameters to the severity of sensorimotor impairment. Fifty-seven participants were asked to walk at their preferred and fast speed over a pressure sensitive mat. Outcome measures included anterior-posterior(AP) COP displacement. AP-COP velocity, medial-lateral (ML) COP variability and foot region COP time. The results demonstrated an asymmetrical AP-COP displacement in favour of the non-paretic limb for the majority of participants. The inter-limb difference scores for AP-COP displacement and AP-COP velocity were related to the severity of sensorimotor impairment and greater among gait aid users. ML-COP variability was greater under the non-paretic limb, possibly suggesting difficultly with paretic limb swing phase. Reduced or absent forefoot COP time suggests difficulty with forward progression and modified foot function during push-off. The inter-limb difference in COP parameters highlights the asymmetrical nature of post-stroke gait and the challenge of maintaining single limb support. We view this information as potentially important to clinicians as an outcome measure for gait rehabilitation. (C) 2010 Elsevier B.V. All rights reserved.

Skin sensory input from the foot soles is coupled with vestibular input to facilitate body orientation in a gravitational environment. Anecdotal observations suggest that foot sole skin becomes hypersensitive following space flight. The veritable level of skin sensitivity and its impact on postural disequilibrium observed post space flight have not been documented. Skin sensitivity of astronauts (n = 11) was measured as vibration perception at the great toe, fifth metatarsal and heel. Frequencies targeted four classes of receptors: 3 and 25 Hz for slow-adapting (SA) receptors and 60 and 250 Hz for fast-adapting (FA) receptors. Data were collected pre– and post–space flight. We hypothesized that skin sensitivity would increase post–space flight and correlate to balance measures. Decreased skin sensitivity was found on landing day at 3 and 25 Hz on the great toe. Hypersensitivity was found for a subset of astronauts (n = 6) with significantly increased sensitivity to 250 Hz at the heel. This subset displayed a greater reduction in computerized dynamic posturography (CDP) equilibrium (EQ) scores (−54%) on landing vs. non-hypersensitive participants (−11%). Observed hyposensitivity of SA (pressure) receptors may indicate a strategy to reduce pressure input during periods of unloading. Hypersensitivity of FAs coupled with reduced EQ scores may reflect targeted sensory reweighting. Altered gravito-inertial environments reduce vestibular function in balance control which may trigger increased weighting of FAs (that signal foot contact, slips). Understanding modulations to skin sensitivity has translational implications for mitigating postural disequilibrium following space flight and for on-Earth preventative strategies for imbalance in older adults.