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Falling is a leading cause of serious injury, loss of independence and nursing home admission in seniors. Arm reactions induced by a sudden loss of balance can play an important role in preventing falls and protecting against injury. The aim of this study was to investigate the effect of unpredictable perturbation characteristics on perturbation-triggered early-onset balance-recovery and impact-protection arm reactions. Twelve healthy young adults (20-28 yrs.; 5 women) and twelve healthy older adults (65-74 yrs.; 8 women) were tested and compared. Participants were exposed to forward/backward platform translations with/without a handrail available, while perturbation magnitudes were varied over a wide range that either allowed balance recovery or resulted in a "fall" (into a safety harness). Barriers were used to deter stepping reactions, so as to simplify interpretation of the arm reactions. Early-onset arm reactions (deltoid/biceps latency <200 ms) occurred in 91% of trials. When a handrail was present, the majority of responses (71%) involved a reach-to-grasp reaction. In the absence of a handrail, the induced arm movement was consistent with efforts to either counterbalance the falling motion (27% of trials) or to protect against impact (13% of trials). In contrast to suggestions that early-onset arm reactions may be generic startle-like responses, the present results supported our hypothesis that early-onset arm reactions would be dependent on task conditions. The results also supported our hypothesis that early-onset impact-protection reactions would occur in some trials; however, these reactions were relatively infrequent and the frequency did not increase even in trials where large perturbation magnitude precluded any possibility of recovering balance. Age-related differences were limited to an increase in fall frequency among older adults (59%) compared to younger adults (44%) and a small (12 ms) delay in EMG onset latency of the right medial deltoid. Further work is needed to fully understand the complex interaction (and possible sequencing) of upper- and lower-limb balance-recovery and impact-protection reactions, and the effects of co-morbidities and other factors.

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We investigated the effect of handrail height on the timing and speed of reach-to-grasp balance reactions during slope descent, in fourteen younger and thirteen older adults. Participants walked along an 8° slope mounted to a robotic platform. Platform perturbations evoked reach-to-grasp reactions. Handrail height did not significantly affect handrail contact time (i.e., time from perturbation onset to handrail contact) or movement time (i.e., time from EMG latency to handrail contact). Participants appeared to compensate for the increased hand-handrail distance with higher rails via increased peak upward hand speed, and decreased vertical handrail overshoot. Aging was associated with slower EMG latency, reduced hand acceleration time, and increased hand deceleration time. Our findings suggest that participants were not disadvantaged by higher handrails from reach-to-grasp timing or speed perspectives, and that other metrics (e.g., center-of-mass control after grasping) may be more important when evaluating handrail designs for balance recovery.

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OBJECTIVE: Perturbation-evoked stepping reactions are infrequently assessed directly in clinical settings even though stepping reactions in response to a sudden loss-of-balance perturbation ultimately determine whether a fall occurs. Individuals with acquired brain injury (ABI) due to stroke who are ambulatory and awaiting hospital discharge have been found to exhibit delayed stepping reactions but are typically discharged without assessment of perturbation-evoked stepping. Tests that specifically target the capacity to perform perturbation-evoked stepping reactions are important to identify those at risk for falls and to direct intervention strategies. The aim of this study was to evaluate agreement and reliability of two assessment methods used to assess rapid stepping reactions, specifically in individuals with ABI due to stroke or other causes. A secondary aim was to compare perturbation-triggered biomechanics of the two assessment methods. METHODS: Thirty-five participants who were less than 4 months post-ABI were evaluated in an inpatient unit at the Toronto Rehabilitation Institute. Stepping reactions were assessed using manual release-from-lean and cable release-from-lean perturbation-based assessment methods. RESULTS: There was moderate agreement between the assessment scores resulting from the two assessment methods (κ = 0.55) and substantial test-retest reliability (κ's > 0.61) for both assessment methods. There was no evidence that the assessment score was affected by assessment method, test-retest, or assessment order. However, the cable release from lean resulted in a more rapid release of the lean support force (2 ms vs. 125 ms) and earlier foot-off times (340 ms vs. 401 ms) compared with the manual release from lean. CONCLUSION: Delays in foot-off time associated with the manual release-from-lean perturbation raise concerns that the manual assessment method may not provide a perturbation that is sufficiently challenging to reveal a patient's balance-recovery capacity and associated fall risk. However, the manual assessment requires no equipment and the assessment score may provide a useful indication of gross reactive balance control.

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Well-designed handrails significantly enhance balance recovery, by allowing users to apply high forces to the rail and stabilize their center of mass. However, data on user-applied handrail forces during balance recovery are limited. We characterized the peak forces that 50 young adults applied to a handrail during forward and backward falling motions; quantified effects of handrail height (34, 38, 42 inches) and position prior to balance loss (standing beside the rail with or without hand contact, or facing the handrail with two-handed contact); and examined the relationship between handrail forces and individual mass. The testing environment consisted of a robotic platform that translated rapidly to destabilize participants, and a height-adjustable handrail that was mounted to the platform. Our findings support our hypotheses that starting position and handrail height significantly affect peak handrail forces in most axes. The highest handrail forces were applied when participants faced the handrail and grasped with two hands. In these cases, increased handrail height was associated with increased anterior forces and decreased downward, upward and resultant forces. As hypothesized, peak handrail forces correlated strongly with individual weight in most axes. Implications of these findings for handrail design are discussed.

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Conventional winter-safety footwear devices, such as crampons, can be effective in preventing slips on icy surfaces but the protruding studs can lead to other problems such as trips. A new hybrid (rough and smooth) rubber outsole was designed to provide high slip resistance without use of protruding studs or asperities. In the present study, we examined the slip resistance of the hybrid rubber outsole on both dry (-10 °C) and wet (0 °C) icy surfaces, in comparison to three conventional strap-on winter anti-slip devices: 1) metal coils ("Yaktrax Walker"), 2) gritted (sandpaper-like) straps ("Rough Grip"), and 3) crampons ("Altagrips-Lite"). Drag tests were performed to measure static (SCOF) and dynamic (DCOF) coefficients of friction, and gait trials were conducted on both level and sloped ice surfaces (16 participants). The drag-test results showed relatively high SCOF (≧0.37) and DCOF (≧0.31) values for the hybrid rubber sole, at both temperatures. The other three footwear types exhibited lower DCOF values (0.06-0.20) when compared with the hybrid rubber sole at 0 °C (p < 0.01). Slips were more frequent when wearing the metal coils, in comparison to the other footwear types, when descending a slope at -10 °C (6% of trials vs 0%; p < 0.05). There were no other significant footwear-related differences in slip frequency, distance or velocity. These results indicate that the slip-resistance of the hybrid rubber sole on icy surfaces was comparable to conventional anti-slip footwear devices. Given the likely advantages of the hybrid rubber sole (less susceptibility to tripping, better slip resistance on non-icy surfaces), this type of sole should contribute to a decrease in fall accidents; however, further research is needed to confirm its effectiveness under a wider range of test conditions.

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BACKGROUND: Standing balance is imperative for mobility and avoiding falls. Use of an excessive number of standing balance measures has limited the synthesis of balance intervention data and hampered consistent clinical practice. OBJECTIVE: To develop recommendations for a core outcome set (COS) of standing balance measures for research and practice among adults. METHODOLOGY: A combination of scoping reviews, literature appraisal, anonymous voting and face-to-face meetings with fourteen invited experts from a range of disciplines with international recognition in balance measurement and falls prevention. Consensus was sought over three rounds using pre-established criteria. DATA SOURCES: The scoping review identified 56 existing standing balance measures validated in adult populations with evidence of use in the past five years, and these were considered for inclusion in the COS. RESULTS: Fifteen measures were excluded after the first round of scoring and a further 36 after round two. Five measures were considered in round three. Two measures reached consensus for recommendation, and the expert panel recommended that at a minimum, either the Berg Balance Scale or Mini Balance Evaluation Systems Test be used when measuring standing balance in adult populations. LIMITATIONS: Inclusion of two measures in the COS may increase the feasibility of potential uptake, but poses challenges for data synthesis. Adoption of the standing balance COS does not constitute a comprehensive balance assessment for any population, and users should include additional validated measures as appropriate. CONCLUSIONS: The absence of a gold standard for measuring standing balance has contributed to the proliferation of outcome measures. These recommendations represent an important first step towards greater standardization in the assessment and measurement of this critical skill and will inform clinical research and practice internationally.

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OBJECTIVE: To examine whether depression predicts less improvement in fear of falling and falls efficacy in older adults attending a falls prevention program (FPP). METHODS: Using a prospective observational design in an academic medical center, the authors studied 69 nondemented adults aged 55 years or older (mean age: 77.8±8.9 years) who had experienced at least one fall in the previous year and who attended the FPP. The primary outcome variable was change in severity of fear of falling during the FPP. Secondary outcome variables were change in falls efficacy and fear-related restriction of activities during the FPP. Independent variables were baseline depressive disorders and depressive symptom severity. RESULTS: Twenty-one of 69 study participants (30.4%) had a depressive disorder at baseline. Depressive disorder and depressive symptoms were not associated with change in severity of fear of falling or restriction of activity. On the other hand, depressive disorder was associated with improvement in falls efficacy, although this finding was not significant in multivariate analysis. Among participants with a depressive disorder, improvement in falls efficacy was significantly correlated with improvement in depressive symptoms. CONCLUSION: There was no association between baseline depression and change in fear of falling in this FPP. The correlation between improvement in depressive symptoms and improvement in falls efficacy raises the question as to whether a cognitive-behavioral intervention that simultaneously targets both depression and falls efficacy would be a useful component of a FPP.

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BACKGROUND: Age-related difficulty in controlling lateral stability is of crucial importance because lateral falls increase risk of debilitating hip-fracture injury. This study examined whether a small increase in footwear sole width can improve ability of older adults to regain lateral stability subsequent to balance perturbation. METHODS: The study involved sixteen healthy, ambulatory, community-dwelling older adults (aged 65-78). Widened base-of-support (WBOS) footwear was simulated by affixing polystyrene-foam blocks (20mm wide) on the medial and lateral sides of rubber overshoes; unaltered overshoes were worn in normal (NBOS) trials. Balance perturbations were applied using a motion platform. RESULTS: Gait, mobility and agility tests revealed no adverse effects of wearing the WBOS footwear. Lateral-perturbation tests showed that the WBOS footwear improved ability to stabilize the body without stepping (p=0.002). Depending on the perturbation magnitude, the frequency of stepping was reduced by up to 25% (64% of NBOS trials vs 39% of WBOS trials). In addition, the WBOS footwear appeared to improve ability to maintain lateral stability during forward-step reactions, as evidenced by reduced incidence of additional lateral steps (p=0.04) after stepping over an obstacle in response to a forward-fall perturbation. CONCLUSIONS: A small increase in sole width can improve certain aspects of lateral stability in older adults, without compromising mobility and agility. This finding supports the viability of WBOS footwear as an intervention to improve balance. Further research is needed to test populations with more severe balance impairments, examine user compliance, and determine if WBOS footwear actually reduces falling risk in daily life.

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A recent study involving young adults showed that rapid perturbation-evoked reach-to-grasp balance-recovery reactions can be guided successfully with visuospatial-information (VSI) retained in memory despite: 1) a reduction in endpoint accuracy due to recall-delay (time between visual occlusion and perturbation-onset, PO) and 2) slowing of the reaction when performing a concurrent cognitive task during the recall-delay interval. The present study aimed to determine whether this capacity is compromised by effects of aging. Ten healthy older adults were tested with the previous protocol and compared with the previously-tested young adults. Reactions to recover balance by grasping a small handhold were evoked by unpredictable antero-posterior platform-translation (barriers deterred stepping reactions), while using liquid-crystal goggles to occlude vision post-PO and for varying recall-delay times (0-10 s) prior to PO (the handhold was moved unpredictably to one of four locations 2 s prior to vision-occlusion). Subjects also performed a spatial- or non-spatial-memory cognitive task during the delay-time in a subset of trials. Results showed that older adults had slower reactions than the young across all experimental conditions. Both age groups showed similar reduction in medio-lateral end-point accuracy when recall-delay was longest (10 s), but differed in the effect of recall delay on vertical hand elevation. For both age groups, engaging in either the non-spatial or spatial-memory task had similar (slowing) effects on the arm reactions; however, the older adults also showed a dual-task interference effect (poorer cognitive-task performance) that was specific to the spatial-memory task. This provides new evidence that spatial working memory plays a role in the control of perturbation-evoked balance-recovery reactions. The delays in completing the reaction that occurred when performing either cognitive task suggest that such dual-task situations in daily life could increase risk of falling in seniors, particularly when combined with the general age-related slowing that was observed across all experimental conditions.

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INTRODUCTION: It appears that age-related changes in visual attention may impair ability to acquire the visuospatial information needed to grasp a handrail effectively in response to sudden loss of balance. This, in turn, may increase risk of falling. To counter this problem, we developed a proximity-triggered cueing system that provides a visual cue (flashing lights) and/or verbal cue ("attention use the handrail") to attract attention to the handrail. This study examined the effect of handrail cueing on grasping of the rail and associated gaze behavior in a large cohort (n=160) of independent and ambulatory older adults (age 64-80). METHODS: The handrail and cueing system was mounted on a large (2 m×6 m) motion platform configured to simulate a real-life environment. Subjects performed a daily-life task that required walking to the end of the platform, which was triggered to perturb balance by moving suddenly when they were adjacent to the rail. To prevent adaptation, each subject performed only one trial, and a deception was used to ensure that the perturbation was truly unexpected. Each subject was assigned to one of four cue conditions: visual, verbal, multimodal (visual-plus-verbal) or no cue. RESULTS: Verbal cueing attracted overt visual attention to the handrail and markedly increased proactive grasping (prior to the onset of the balance perturbation) particularly when delivered unimodally. Subjects were otherwise much more likely to grasp the rail in reaction to the perturbation. A possible trend for visual cueing to improve the accuracy of these reactions was offset by adverse effects on reaction speed and on frequency of proactive grasping. CONCLUSIONS: The results support the viability of using unimodal verbal cueing to reduce fall risk by increasing proactive handrail use. Conversely, they do not strongly support use of visual cueing (either alone or in combination with verbal cueing) and suggest that it may even have adverse effects. Further study is needed to evaluate effects of handrail cueing in a wide range of populations and real-life settings.

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Recent findings suggest that rapid perturbation-evoked reach-to-grasp balance-recovery reactions can be (and often are) guided by visuospatial information stored in working memory. To further our understanding, the present study examined the influence of memory-decay and concurrent cognitive-task performance on the speed, accuracy and effectiveness of these reactions by using liquid-crystal goggles to initiate occlusion of vision at various "recall-delay" times prior to perturbation-onset, in ten healthy young-adults. A small handhold was moved unpredictably to one of four locations 2s prior to vision-occlusion; reactions to recover balance by grasping the handhold were evoked by unpredictable antero-posterior platform-translation perturbations. Recall-delay time (0s/2s/5s/10s) was randomized, and subjects performed a spatial- or non-spatial-memory task during the delay-time in a subset of trials. Consistent with studies of volitional reach-to-grasp, recall-delay led to some reduction in endpoint accuracy; however, unlike those studies, the present results showed no evidence that recall-delay led to slowing of the arm movement. Both spatial and non-spatial cognitive tasks had similar effects (slowing of movement initiation and execution), suggesting these effects were related to generic attentional demands rather than competition for specific resources related to spatial working memory. Further work is needed to determine effects of age-related impairments in visuospatial memory and attentional capacity.

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Perturbation of whole-body stability often evokes rapid arm reactions. It has been suggested that the earliest arm activation is a generic (e.g. startle-like) response to which a later stabilizing (e.g. counterweight or reach-to-grasp) or impact-protection component can be appended. To examine whether the initial part of the reaction is generic, we examined arm reactions evoked by small balance perturbations in 12 healthy young adults while varying perturbation direction (rightward or forward platform translation) and environmental conditions (handrail present or absent). The perturbation magnitude was selected to be sufficiently small to obviate the need to use the arms for stabilization. To avoid adaptation or habituation, analysis focused on each subject's very first exposure to the perturbation. Most subjects exhibited active movement of both arms in reaction to the perturbation, but there was large (non-stereotypical) inter-subject variation in muscle-onset latency and arm kinematics. Furthermore, the velocity and direction of the initial arm movement were affected by perturbation direction, in a manner consistent with functional strategies (counterweight strategy in backward falls, hybrid counterweight/protective strategy in leftward falls). Although subjects never contacted the handrail, responses were slower when it was present. These results are not consistent with a generic stereotyped response, but suggest instead that even the earliest component of first-trial arm reactions was functionally modulated.

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BACKGROUND: Rapid reach-to-grasp reactions are a prevalent response to sudden loss of balance and play an important role in preventing falls. A previous study indicated that young adults are able to guide functionally effective grasping reactions using visuospatial information (VSI) stored in working memory. The present study addressed whether healthy older adults are also able to use "stored" VSI in this manner or are more dependent on "online" visual control. METHODS: Liquid-crystal goggles were used to force reliance on either stored or online VSI while reaching to grasp a small handhold in response to unpredictable platform perturbations. A motor-driven device varied the handhold location unpredictably for each trial. Twelve healthy older adults (65-79 years) were compared with 12 young adults (19-29 years) tested in a previous study. RESULTS: Reach-to-grasp reactions were slower and more variable in older adults, regardless of the nature of the available VSI. When forced to rely on stored VSI, both age groups showed a reduction in reach accuracy; however, a tendency to undershoot the handhold was exacerbated in the older adults. Forced reliance on online VSI led to similar delays in both age groups; however, the older adults were more likely to reach with the "wrong" limb (contralateral to the handhold) and/or raise both arms initially (possibly to "buy" more time for final limb selection). CONCLUSION: Situations that force the central nervous system to rely on either stored or online VSI tend to exacerbate age-related reductions in speed and accuracy of reach-to-grasp balance-recovery reactions. Further work is needed to determine if this increases risk of falling in daily life.

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Reaching to grasp an object for support is a common and functionally important response to sudden balance perturbation. The need to react very rapidly (to prevent falling) imposes temporal constraints on acquisition and processing of the visuospatial information (VSI) needed to guide the reaching movement. Previous results suggested that the CNS may deal with these constraints by using VSI stored in memory proactively, prior to perturbation onset; however, the extent to which online visual control is necessary or sufficient to guide these reactions has not been established. This study examined the speed, accuracy, and effectiveness of perturbation-evoked reach-to-grasp reactions when forced to rely entirely on either online- or stored-VSI by using liquid-crystal goggles to occlude vision either before or after perturbation onset. The reactions were evoked, in twelve healthy young adults, via sudden unpredictable antero-posterior platform translation (barriers deterred stepping reactions). Prior to perturbation onset, a small cylindrical handhold was positioned unpredictably (by a motor-driven device) at one of four locations in front of the subject. Results indicated that equilibrium could be recovered successfully by grasping the handhold using either online-VSI or stored-VSI to guide the arm reaction; however, both sources of VSI were required for optimal performance. Reach initiation and arm movement were slowed when dependent on online-VSI, whereas reach accuracy and grip formation were impaired when dependent on stored-VSI. Comparison with normal-VSI trials suggests that both sources of VSI are utilized when grasping a small handhold for support under normal visual conditions, with stored-VSI predominating during initiation/transport and online-VSI contributing primarily to final target acquisition/prehension.

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PROBLEM: Falling is a leading cause of serious injury, loss of independence, and nursing-home admission in older adults. Impaired balance control is a major contributing factor. METHODS: Results from our balance-control studies have been applied in the development of new and improved interventions and assessment tools. Initiatives to facilitate knowledge-translation of this work include setting up a new network of balance clinics, a research-user network and a research-user advisory board. RESULTS: Our findings support the efficacy of the developed balance-training methods, balance-enhancing footwear, neuro-prosthesis, walker design, handrail-cueing system, and handrail-design recommendations in improving specific aspects of balance control. IMPACT ON KNOWLEDGE USERS: A new balance-assessment tool has been implemented in the first new balance clinic, a new balance-enhancing insole is available through pharmacies and other commercial outlets, and handrail design recommendations have been incorporated into 10 Canadian and American building codes. Work in progress is expected to have further impact.

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Despite widespread acceptance of clinical benefits, empirical evidence to evaluate the advantages and limitations of ambulation aids for balance control is limited. The current study investigates the upper limb biomechanical contributions to the control of frontal plane stability while using a 4-wheeled walker in quiet standing. We hypothesized that: (1) upper limb stabilizing moments would be significant, and (2) would increase under conditions of increased stability demand. Factors influencing upper limb moment generation were also examined. Specifically, the contributions of upper limb center-of-pressure (COP(hands)), vertical and horizontal loads applied to the assistive device were assessed. The results support a significant mechanical role for the upper limbs, generating 27.1% and 58.8% of overall stabilizing moments under baseline and challenged stability demand conditions, respectively. The increased moment was achieved primarily through the preferential use of phasic upper limb control, reflected by increased COP(hands) (baseline vs. challenged conditions: 0.29 vs. 0.72cm). Vertical, but not horizontal, was the primary force direction contributing to stabilizing moments in quiet standing. The key finding that the upper limbs play an important role in effecting frontal plane balance control has important implications for ambulation aid users (e.g., elderly, stroke, and traumatic brain injury).

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A fundamental principle that has emerged from studies of natural gaze behavior is that goal-directed arm movements are typically guided by a saccade to the target. In this study, we evaluated a hypothesis that this principle does not apply to rapid reach-to-grasp movements evoked by sudden unexpected balance perturbations. These perturbations involved forward translation of a large (2 × 6 m) motion platform configured to simulate a "real-life" environment. Subjects performed a common "daily-life" visuo-cognitive task (find a telephone and make a call) that required walking to the end of the platform, which was triggered to move as they approached a handrail mounted alongside the travel path. A deception was used to ensure that the perturbation was truly unexpected. Eleven of 18 healthy young-adult subjects (age 22-30) reached to grasp or touch the rail in response to the balance perturbation. In support of the hypothesis, none of these arm reactions was guided by concurrent visual fixation of the handrail. Seven of the 11 looked at the rail upon first entering the environment, and hence may have used "stored" central-field information about the handrail location to guide the subsequent arm reaction. However, the other four subjects never looked directly at the rail, indicating a complete reliance on peripheral vision. These findings add to previous evidence of distinctions in the CNS control of volitional and perturbation-evoked arm movements. Future studies will determine whether similar visuo-motor behavior occurs when the available handhold is smaller or when subjects are not engaged in a concurrent visuo-cognitive task.

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For a reach-to-grasp reaction to prevent a fall, it must be executed very rapidly, but with sufficient accuracy to achieve a functional grip. Recent findings suggest that the CNS may avoid potential time delays associated with saccade-guided arm movements by instead relying on peripheral vision (PV). However, studies of volitional arm movements have shown that reaching is slower and/or less accurate when guided by PV, rather than central vision (CV). The present study investigated how the CNS resolves speed-accuracy trade-offs when forced to use PV to guide perturbation-evoked reach-to-grasp balance-recovery reactions. These reactions were evoked, in 12 healthy young adults, via sudden unpredictable antero-posterior platform translation (barriers deterred stepping reactions). In PV trials, subjects were required to look straight-ahead at a visual target while a small cylindrical handhold (length 25%> hand-width) moved intermittently and unpredictably along a transverse axis before stopping at a visual angle of 20°, 30°, or 40°. The perturbation was then delivered after a random delay. In CV trials, subjects fixated on the handhold throughout the trial. A concurrent visuo-cognitive task was performed in 50% of PV trials but had little impact on reach-to-grasp timing or accuracy. Forced reliance on PV did not significantly affect response initiation times, but did lead to longer movement times, longer time-after-peak-velocity and less direct trajectories (compared to CV trials) at the larger visual angles. Despite these effects, forced reliance on PV did not compromise ability to achieve a functional grasp and recover equilibrium, for the moderately large perturbations and healthy young adults tested in this initial study.

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BACKGROUND: Compensatory stepping and grasping reactions are prevalent responses to sudden loss of balance and play a critical role in preventing falls. The ability to execute these reactions effectively is impaired in older adults. OBJECTIVE: The purpose of this study was to evaluate a perturbation-based balance training program designed to target specific age-related impairments in compensatory stepping and grasping balance recovery reactions. DESIGN: This was a double-blind randomized controlled trial. SETTING: The study was conducted at research laboratories in a large urban hospital. PARTICIPANTS: Thirty community-dwelling older adults (aged 64-80 years) with a recent history of falls or self-reported instability participated in the study. INTERVENTION: Participants were randomly assigned to receive either a 6-week perturbation-based (motion platform) balance training program or a 6-week control program involving flexibility and relaxation training. MEASUREMENTS: Features of balance reactions targeted by the perturbation-based program were: (1) multi-step reactions, (2) extra lateral steps following anteroposterior perturbations, (3) foot collisions following lateral perturbations, and (4) time to complete grasping reactions. The reactions were evoked during testing by highly unpredictable surface translation and cable pull perturbations, both of which differed from the perturbations used during training. RESULTS: /b> Compared with the control program, the perturbation-based training led to greater reductions in frequency of multi-step reactions and foot collisions that were statistically significant for surface translations but not cable pulls. The perturbation group also showed significantly greater reduction in handrail contact time compared with the control group for cable pulls and a possible trend in this direction for surface translations. LIMITATIONS: Further work is needed to determine whether a maintenance program is needed to retain the training benefits and to assess whether these benefits reduce fall risk in daily life. CONCLUSION: Perturbation-based training shows promise as an effective intervention to improve the ability of older adults to prevent themselves from falling when they lose their balance.

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A computer-based 'Useful Field of View' (UFOV) training program has been shown to be effective in improving visual processing in older adults. Studies of young adults have shown that playing video games can have similar benefits; however, these studies involved realistic and violent 'first-person shooter' (FPS) games. The willingness of older adults to play such games has not been established. OBJECTIVES: To determine the degree to which older adults would accept playing a realistic, violent FPS-game, compared to video games not involving realistic depiction of violence. METHODS: Sixteen older adults (ages 64-77) viewed and rated video-clip demonstrations of the UFOV program and three video-game genres (realistic-FPS, cartoon-FPS, fixed-shooter), and were then given an opportunity to try them out (30 minutes per game) and rate various features. RESULTS: The results supported a hypothesis that the participants would be less willing to play the realistic-FPS game in comparison to the less violent alternatives (p's<0.02). After viewing the video-clip demonstrations, 10 of 16 participants indicated they would be unwilling to try out the realistic-FPS game. Of the six who were willing, three did not enjoy the experience and were not interested in playing again. In contrast, all 12 subjects who were willing to try the cartoon-FPS game reported that they enjoyed it and would be willing to play again. A high proportion also tried and enjoyed the UFOV training (15/16) and the fixed-shooter game (12/15). DISCUSSION: A realistic, violent FPS video game is unlikely to be an appropriate choice for older adults. Cartoon-FPS and fixed-shooter games are more viable options. Although most subjects also enjoyed UFOV training, a video-game approach has a number of potential advantages (for instance, 'addictive' properties, low cost, self-administration at home). We therefore conclude that non-violent cartoon-FPS and fixed-shooter video games warrant further investigation as an alternative to the UFOV program for training improved visual processing in seniors.