Introduction: With the growing population of older adults, predicting survival through clinical examinations has gained an increased interest. We aimed to evaluate the relationship between balance measures, such as postural sway and voluntary stepping performance and survival. METHODS:This study analyzed balance parameters, collected from previous studies conducted between 2005 and 2011, including postural sway, stabilogram diffusion analysis (SDA) in standing, and voluntary step execution. Cox proportional hazards regression analyses were performed to examine associations between balance parameters and mortality. RESULTS:Voluntary stepping performance, especially under dual-task (DT) condition, was associated with survival. Slower step initiation time was associated with higher mortality risk; with every 0.100 s increase, the survival hazard rate ratios decreased by 28%. Postural sway parameters, particularly increase in anterior-posterior sway velocity, demonstrated predictive ability but less effective than voluntary stepping test parameters. Among SDA measures, higher critical displacement tended to show an association with lower survival in older adults. CONCLUSION:These findings align with prior research regarding physical performance indicators, such as gait speed, to survival. Voluntary stepping under DT conditions extends this understanding by capturing both physical and cognitive functions, offering a more integrated survival assessment. Voluntary stepping performance, in DT conditions, may be a valuable predictor of survival in older adults. Incorporating DT-based assessments into clinical evaluations could improve survival prediction and guide early interventions targeting cognitive-motor health. Future studies should explore the longitudinal impact of voluntary stepping on survival, assessing whether cognitive-motor training for balance rehabilitation can enhance survival rates. .

Long-duration bedrest impairs upright postural and locomotor control, prompting the need for assessment tools to predict the effects of deconditioning on post-bedrest outcome measures. We developed a tilt board mounted vertically with a horizontal air-bearing sled as a potential supine assessment tool for a future bedrest study. The purpose of this pilot study was to examine the association between supine proprioceptive assessments on the tilt board and upright functional mobility. Seventeen healthy participants completed variations of a supine tilt board task and an upright functional mobility task (FMT), which is an established obstacle avoidance course. During the supine tasks, participants lay on the air-bearing sled with axial loading toward the tilt board. Participants tilted the board to capture virtual targets on an overhead monitor during 30 s trials. The tasks included two dynamic tasks (i.e., double-leg stance matching mediolateral tilt targets over ±3° or ±9° ranges) and two static tasks (i.e., single-leg stance maintaining a central target position). The performances during the dynamic tasks were significantly correlated with the FMT time to completion. The dominant-leg static task performance showed a moderate trend with the FMT time to completion. The results indicate that supine proprioceptive assessments may be associated with upright ambulation performance, and thus, support the proposed application in bedrest studies.

Background Mounting evidence suggests that wearable technologies using peripheral neuromodulation can provide novel ways of improving mobility and gait function in various patient populations including older adults. The purpose of this narrative review is to provide an overview of wearable technologies/devices to improve mobility and gait function through noninvasive peripheral neuromodulation in older adults over the age of 65 and to indicate the suggested mechanism of action behind these technologies. Methods We performed searches for articles and conference abstracts written in English, using the following databases: Embase Classic+Embase from 1947 to July 15, 2021; Ovid MEDLINE; Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations, Daily and Versions from 1946 to July 15, 2021; PubMed; and Scopus. Results Forty-one technologies met the inclusion/exclusion criteria. We found that the primary implementation of the 41 technologies can be divided into 3 main categories: sensory substitution, sensory augmentation (open loop, closed loop), and motor stimulation. Using these technologies, various aspects of mobility are treated or addressed, including, gait function, fall risk, foot drop, navigating environment, and postural control. Conclusions This narrative review summarizes wearable technologies that are currently commercially available and in stages of research and development. Overall, studies suggest that wearable peripheral neuromodulation technologies can improve aspects of mobility for older adults. Existing literature suggests that these technologies may lead to physiological changes in the brain through sensory reweighting or other neuroplastic mechanisms to enhance the performance of mobility and gait function in older adults over the age of 65.

BackgroundWe recently reported that individuals with impaired plantar sensation and high fall risk due to sensory peripheral neuropathy (PN) improved gait and balance function following 10 weeks of use of Walkasins®, a wearable lower limb sensory prosthesis that provides directional specific mechanical tactile stimuli related to plantar pressure measurements during standing and walking (RxFunction Inc., Eden Prairie, MN, United States). Here, we report 26-week outcomes and compare pre- and in-study fall rates. We expected improvements in outcomes and reduced fall rates reported after 10 weeks of use to be sustained.Materials and methodsParticipants had clinically diagnosed PN with impaired plantar sensation, high fall risk (Functional Gait Assessment, FGA score < 23) and ability to sense tactile stimuli above the ankle at the location of the device. Additional outcomes included 10 m Gait Speed, Timed Up and Go (TUG), Four-Stage Balance Test, and self-reported outcomes, including Activities-Specific Balance Confidence scale and Vestibular Disorders Activities of Daily Living Scale. Participants tracked falls using a calendar.ResultsWe assessed falls and self-reported outcomes from 44 individuals after 26 weeks of device use; 30 of them conducted in-person testing of clinical outcomes. Overall, improvements in clinical outcomes seen at 10 weeks of use remained sustained at 26 weeks with statistically significant increases compared to baseline seen in FGA scores (from 15.0 to 19.2), self-selected gait speed (from 0.89 to 0.97 m/s), and 4-Stage Balance Test (from 25.6 to 28.4 s), indicating a decrease in fall risk. Non-significant improvements were observed in TUG and fast gait speed. Overall, 39 falls were reported; 31 of them did not require medical treatment and four caused severe injury. Participants who reported falls over 6 months prior to the study had a 43% decrease in fall rate during the study as compared to self-report 6-month pre-study (11.8 vs. 6.7 falls/1000 patient days, respectively, p < 0.004), similar to the 46% decrease reported after 10 weeks of use.ConclusionA wearable sensory prosthesis can improve outcomes of gait and balance function and substantially decreases incidence of falls during long-term use. The sustained long-term benefits in clinical outcomes reported here lessen the likelihood that improvements are placebo effects.Clinical trial registrationClinicalTrials.gov, identifier #NCT03538756.

Astronauts experience post-flight disturbances in postural and locomotor control due to sensorimotor adaptations during spaceflight. These alterations may have adverse consequences if a rapid egress is required after landing. Although current exercise protocols can effectively mitigate cardiovascular and muscular deconditioning, the benefits to post-flight sensorimotor dysfunction are limited. Furthermore, some exercise capabilities like treadmill running are currently not feasible on exploration spaceflight vehicles. Thus, new in-flight operational countermeasures are needed to mitigate postural and locomotor control deficits after exploration missions. Data from spaceflight and from analog studies collectively suggest that body unloading decreases the utilization of proprioceptive input, and this adaptation strongly contributes to balance dysfunction after spaceflight. For example, on return to Earth, an astronaut’s vestibular input may be compromised by adaptation to microgravity, but their proprioceptive input is compromised by body unloading. Since proprioceptive and tactile input are important for maintaining postural control, keeping these systems tuned to respond to upright balance challenges during flight may improve functional task performance after flight through dynamic reweighting of sensory input. Novel approaches are needed to compensate for the challenges of balance training in microgravity and must be tested in a body unloading environment such as head down bed rest. Here, we review insights from the literature and provide observations from our laboratory that could inform the development of an in-flight proprioceptive countermeasure.

Background: Peripheral neuropathy (PN) can result in either partial or complete loss of distal sensation resulting in an increased fall risk. Walkasins® uses a shoe insert to detect the magnitude and direction of sway and sends signals to a leg unit that provides sensory balance cues. The objective of this case report is to describe the long-term influence of the Walkasins® lower limb sensory neuroprosthesis on balance and gait for an individual with diabetic PN. Case Description: A 51-year-old male with a 3-year history of PN and a 10-year history of type II diabetes mellitus was fitted bilaterally with Walkasins® and utilized them 8–10 hours/day for more than 2 years. Although, vibration and tactile sensation thresholds were severely impaired at his 1st metatarsophalangeal joint and the lateral malleolus bilaterally he could perceive tactile stimuli from the Walkasins® above the ankles. Outcomes: Following Walkasins® use, his Activities-specific Balance Confidence Scale (ABC) scores improved from 33 to 80%. His mean Vestibular Activities of Daily Living (VADL) scores decreased from 3.54 to 1. His Functional Gait Assessment (FGA) scores increased from 13/30 to 28/30 and his miniBESTest scores improved from 15/28 to 26/28. Gait speed increased from 0.23 to 1.5 m/s. The patient described a decrease in pain and cramping throughout his lower extremities and an increase in function. Discussion: Gait and balance improved with the use of the Walkasins® and participation in a wellness program. This improvement suggests that the use of sensory substitution devices, such as the Walkasins®, may replace sensory deficits related to gait and balance dysfunction experienced by patients with PN. Further research is needed to determine if other patients will have a similar response and what the necessary threshold of sensory function is to benefit from use of the Walkasins®.

To investigate long-term effects of using a sensory neuroprosthesis (Walkasins®) providing tactile stimuli of foot pressure on clinical outcomes of gait and balance function in community dwelling individuals with peripheral neuropathy (PN) who have balance problems. We hypothesize the Functional Gait Assessment (FGA) will increase by at least four.

BackgroundSensory peripheral neuropathy (PN) is associated with gait, balance problems and high fall risk. The walk2Wellness trial investigates effects of long-term, home-based daily use of a wearable sensory prosthesis on gait function, balance, quality of life and fall rates in PN patients. The device (Walkasins®, RxFunction Inc., MN, United States) partially substitutes lost nerve function related to plantar sensation providing directional tactile cues reflecting plantar pressure measurements during standing and walking. We tested the null hypothesis that the Functional Gait Assessment (FGA) score would remain unchanged after 10 weeks of use.MethodsParticipants had PN with lost plantar sensation, gait and balance problems, an FGA score < 23 (high fall risk), and ability to sense tactile stimuli above the ankle. Clinical outcomes included FGA, Gait Speed, Timed Up&Go (TUG) and 4-Stage Balance Test. Patient-reported outcomes included Activities-Specific Balance Confidence (ABC) scale, Vestibular Disorders Activities of Daily Living Scale, PROMIS participation and satisfaction scores, pain rating, and falls. Evaluations were performed at baseline and after 2, 6, and 10 weeks. Subjects were not made aware of changes in outcomes. No additional balance interventions were allowed.ResultsForty-five participants of 52 enrolled across four sites completed in-clinic assessments. FGA scores improved from 15.0 to 19.1 (p < 0.0001), normal and fast gait speed from 0.86 m/s to 0.95 m/s (p < 0.0001) and 1.24 m/s to 1.33 m/s (p = 0.002), respectively, and TUG from 13.8 s to 12.5 s (p = 0.012). Four-Stage Balance Test did not improve. Several patient-reported outcomes were normal at baseline and remained largely unchanged. Interestingly, subjects with baseline ABC scores lower than 67% (high fall risk cut-off) increased their ABC scores (49.9% to 59.3%, p = 0.01), whereas subjects with ABC scores above 67% showed a decrease (76.6% to 71.8%, p = 0.019). Subjects who reported falls in the prior 6 months (n = 25) showed a decrease in the number of fall-risk factors (5.1 to 4.3, p = 0.023) and a decrease in fall rate (13.8 to 7.4 falls/1000 days, p = 0.014). Four pre-study non-fallers (n = 20) fell during the 10 weeks.ConclusionA wearable sensory prosthesis presents a new way to treat gait and balance problems and manage falls in high fall-risk patients with PN.Trial registrationClinicalTrials.gov (#NCT03538756).

Sunday, April 26April 14, 2020Free AccessA Wearable Sensory Neuroprosthesis to Improve Gait and Balance Function in Persons with Sensory Peripheral Neuropathy – the walk2Wellness Trial (1170)Lars Oddsson, Teresa Bisson, Helen Cohen, Ikechukwu Iloputaife, Sara Koehler-McNicholas, Doris Kung, Lewis Lipsitz, Brad Manor, Patricia McCracken, and Diane WrisleyAuthors Info & AffiliationsApril 14, 2020 issue94 (15_supplement)https://doi.org/10.1212/WNL.94.15_supplement.1170 Letters to the Editor

Peripheral neuropathy may cause loss of sensory information from plantar cutaneous mechanoreceptors that is important for balance control and falls management. The current study investigated short-term effects of using Walkasins, an external lower-limb sensory neuroprosthesis, on clinical outcomes of balance and gait in persons who reported peripheral neuropathy and balance problems. The device replaces lost plantar sensation with tactile balance information that modulates cutaneous mechanoreceptors above the ankle where sensation is intact. Thirty-one male community-dwelling Veterans, 56-84 years old with insensate feet and balance problems participated. Initial Functional Gait Assessment, gait speed, and 4-Stage Balance Test outcomes were assessed. After initial assessment, subjects were randomly assigned to either wearing Walkasins turned ON, or OFF, and outcomes were re-assessed following a set of standardized balance exercises. Following a one-hour rest and washout period, treatments were crossed-over between groups and a third outcomes assessment was performed. Before cross-over, 10 of 15 subjects in the ON-then-OFF group improved their Functional Gait Assessment score by at least four points, the Minimal Clinically Important Difference, compared to 5 of 16 in the OFF-then-ON group. After cross-over, 7 of 16 subjects in the OFF-then-ON group improved by at least four points versus 2 of 15 in the ON-then-OFF group. ON treatment was associated with a Functional Gait Assessment improvement of 4.4 +/- 3.7 points versus 1.5 +/- 1.2 for the OFF treatment (p<0.01). Overall, Functional Gait Assessment scores changed from 15.2 +/- 4.8 at initial assessment to 21.1 +/- 5.2 after final assessment (p<0.001). At the end of the two treatment sessions, 16 of the 31 individuals had improved their Functional Gait Assessment score beyond 23, indicating normal fall-risk status. Future studies should investigate long-term benefits of the device to reduce fall risk and actual falls in patients with peripheral neuropathy and balance problems.

To investigate whether vibrotactile feedback of foot pressure can enhance the effect of a brief balance therapy session with a physical therapist on Functional Gait Assessment (FGA) and normal gait speed in elderly community dwelling individuals diagnosed with peripheral neuropathy (PN) and have balance problems.

Supporting body weight and balance control are foundations of our ability to move and function independently. However, neurological disease, injury, and aging often threaten these prerequisites of functional independence, leading to a decrease in quality of life. In the United States alone, 7.5 million individuals have survived stroke, traumatic brain injury (TBI), or spinal cord injury (SCI), and over a million new patients are diagnosed every year [1–2]. To improve gait function in these patient populations, partial body weight-supported gait training is a widely-used rehabilitation therapy. In general, the therapeutic quality of partial body weight-supported gait training is directly proportional to the amount of time patients are able to tolerate an upright posture (either standing or walking). To achieve an upright posture, therapists must first attach a support system (e.g., gait belt, harness lift system, exoskeleton), then several therapists must assist the patient into a standing position. Depending on the patient’s level of impairment, several therapists may also be needed to support and assist the patient while standing and walking, then again to remove the support system at the end of therapy. Accordingly, multiple therapists are often needed to provide a small quantity of upright physical therapy time with standard support systems. Furthermore, use of standard support systems can be uncomfortable and fatiguing for the patient, further reducing their actual therapeutic treatment time [3].

Although much research has been done on repetitive transcranial magnetic stimulation (rTMS) in chronic stroke, only sparse research has been done in acute stroke despite the particularly rich potential for neuroplasticity in this stage. We attempted a preliminary clinical trial in one active, high-quality inpatient rehabilitation facility (IRF) in the -United States. But after enrolling only 4 patients in the grant period, the study was stopped because of low enrollment. The purpose of this paper is to offer a perspective describing the important physiologic rationale for including rTMS in the early phase of stroke, the reasons for our poor patient enrollment in our attempted study, and recommendations to help future studies succeed. We conclude that, if scientists and clinicians hope to enhance stroke outcomes, more attention must be directed to leveraging conventional rehabilitation with neuromodulation in the acute phase of stroke when the capacity for neuroplasticity is optimal. Difficulties with patient enrollment must be addressed by reassessing traditional inclusion and exclusion criteria. Factors that shorten patients’ length of stay in the IRF must also be reassessed at all policy-making levels to make ethical decisions that promote higher functional outcomes while retaining cost consciousness.

Peripheral neuropathy (PN), commonly caused by diabetes mellitus, is a debilitating condition that currently affects approximately 20 million Americans. Chronic symptoms of PN often involve pain and weakness of the lower limbs, with eventual sensation loss on the plantar surfaces of the feet. According to epidemiological studies, reduced foot sole sensation has been linked to decreased standing stability [1] and an increased risk of falling [2]. Consequently, cost-effective interventions are needed to improve balance and mobility in this population. A growing body of research suggests that vibrotactile cues delivered to sensate areas of the lower limb may be an effective way to provide information about foot sole pressure to PN patients who experience poor balance control. Indeed, sensory substitution devices that provide vibrotactile feedback have been shown to aid in balance and improve postural control in various patient populations [3–7]. However, none of these technologies have been based on measurements of foot pressure nor have they been used as a balance prosthesis. The goal of this study was to investigate the effect of a new external lower-limb sensory prosthesis, the Walkasins™, on the balance and gait of individuals with PN who experience balance problems [8]. Walkasins™ consist of two parts: a leg unit and a foot pad (Figure 1). The leg unit wraps around the lower leg of the user and contains electronics for reading foot pad pressure signals, a microprocessor, and four vibrating motors that provide gentle tactile sensory cues to the front, back, medial, and lateral surfaces of the user’s leg. These cues reflect real-time foot pressure information at a location above the ankle where skin sensation is still present. The leg unit has a power button, two status LEDs, and a reset button (not shown in Figure 1). Power is supplied by a rechargeable internal battery. The foot pad is a thin consumable sole insert that can be cut to size and fit into a regular shoe. The foot pad connects to the leg unit through a physical cable. In this study, subjects performed gait and balance assessments with and without the Walkasins™ turned on in order to determine its short-term effects.

Multisensory-visual, vestibular and somatosensory information is integrated for appropriate postural control. The primary goal of this study was to assess somatosensory utilization during a functional motor task of unipedal postural control, in normal healthy adults. Assessing individual bias in the utilization of individual sensory contributions during postural control may help customization of rehabilitation protocols. In this study, a test paradigm of unipedal stance control in supine orientation with and without vision was assessed. Postural control in this test paradigm was hypothesized to utilize predominantly contributions of somatosensory information from the feet and ankle joint, with minimal vestibular input. Fourteen healthy subjects "stood" supine on their dominant leg while strapped to a backpack frame that was freely moving on air-bearings, to remove available otolith tilt cues with respect to gravity that influences postural control when standing upright. The backpack was attached through a cable to a pneumatic cylinder that provided a gravity-like load. Subjects performed three trials each with Eyes-open (EO) and Eyes-closed (EC) while loaded with 60% body weight. There was no difference in unipedal stance time (UST) across the two conditions with EC condition challenging the postural control system greater than the EO condition. Stabilogram-diffusion analysis (SDA) indicated that the critical mean square displacement was significantly different between the two conditions. Vestibular cues, both in terms of magnitude and the duration for which relevant information was available for postural control in this test paradigm, were minimized. These results support our hypothesis that maintaining unipedal stance in supine orientation without vision, minimizes vestibular contribution and thus predominantly utilizes somatosensory information for postural control.

Astronauts experience Postflight disturbances in postural and locomotor control due to sensorimotor adaptation to the unique environment of spaceflight. These alterations might have adverse consequences if a rapid egress were required following a Mars landing or on return to Earth after a water landing. Currently, no operational countermeasure is targeted to mitigate Postflight balance and locomotor dysfunction.

Objective:To evaluate long-term effects of balance-training on concerns about falling, gait, balance performance, and physical function in older adults with osteoporosis and increased risk of falling.Design:Randomized controlled trial, including three groups (training, training+physical activity, and control group), with follow-ups at three, nine, and 15 months. Short-term, three-month follow-up, benefits for those who fulfilled the first follow-up ( n = 69) have previously been reported.Setting:Stockholm, Sweden.Participants:A total of 96 elderly, age 66–87, with verified osteoporosis.Interventions:Balance-training programme including dual- and multitasks, with or without supplementary physical activity, three times/week over 12 weeks.Measurements:Concerns about falling Falls Efficacy Scale -International (FES-I), walking at preferred speed with and without a cognitive dual-task and at fast speed, balance tests (one-leg stance and modified figure-of-eight), and physical function Late-Life Function and Disability Instrument (LLFDI).Results:Participants in the training group maintained positive effects throughout the study period for concerns about falling (baseline vs. 15 months, median 27.5 vs. 23 points, p < 0.001) and walking performance (baseline vs. 15 months, p ⩽ 0.05 with an improvement of 0.9–1.4 m/s). The Training+physical activity group declined to baseline values at the nine-month follow-up, and were even lower at the 15-month follow-up for concerns about falling (median 26 vs. 26 points), walking performance (changes of −0.02 to 0.04 m/s), and physical function (mean 44.0 vs. 42.9 points). The control group remained unchanged throughout the study period.Conclusions:This balance-training programme reduced concerns about falling, and also improved gait in older adults with osteoporosis and increased risk of falling in a long-term perspective – important issues for fall prevention.