Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> An analysis of falls experienced by a stratified population sample of 553 subjects, 65 years and over, was performed. It is estimated that one third of people 65 years and over experience one or more falls in a year. To analyse the association of physical and social variables with falls, the falls were divided into pattern falls and occasional falls. Pattern falls were those which, on history and examination, were assessed as arising from only minimal external upset and primarily from a disorder of balance or postural stability in the subject. Occasional falls were those which had arisen under circumstances which would be liable to cause a fit person to fall. Bivariate analysis showed those having pattern falls tended to have more functional disability, to have increased impairment of mobility, to use more aids to mobility, to be more depressed, to have lower mental test scores and to need more professional support. Women experiencing pattern falls also tended to be older and have poorer vision, while men had lower systolic blood pressure. Discriminant analysis showed that the principal effective 'predictors' of pattern falls in women were functional disability, the need for support services and informal help and the use of walking aids. In men they were functional disability and the need for support services and informal help. <s> BIB001 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Abstract To study risk factors for falling, we conducted a one-year prospective investigation, using a sample of 336 persons at least 75 years of age who were living in the community. All subjects underwent detailed clinical evaluation, including standardized measures of mental status, strength, reflexes, balance, and gait; in addition, we inspected their homes for environmental hazards. Falls and their circumstances were identified during bimonthly telephone calls. During one year of follow-up, 108 subjects (32 percent) fell at least once; 24 percent of those who fell had serious injuries and 6 percent had fractures. Predisposing factors for falls were identified in linear-logistic models. The adjusted odds ratio for sedative use was 28.3; for cognitive impairment, 5.0; for disability of the lower extremities, 3.8; for palmomental reflex, 3.0; for abnormalities of balance and gait, 1.9; and for foot problems, 1.8; the lower bounds of the 95 percent confidence intervals were 1 or more for all variables. T... <s> BIB002 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Of 1042 individuals aged 65 years and over who were successfully interviewed in a community survey of health and physical activity, 35% (n = 356) reported one or more falls in the preceding year. Although the overall ratio of female fallers to male fallers was 2.7:1, this ratio approached unity with advancing age. Mobility was significantly impaired in those reporting falls. Asked to provide a reason for their falls, 53% reported tripping, 8% dizziness and 6% reported blackouts. A further 19% were unable to give a reason. There was no association between falls and the use of diuretics, antihypertensives or tranquilizers, but a significant association between falls and the use of hypnotics and antidepressants was found. Discriminant analysis of selected medical and anthropometric variables indicated that handgrip strength in the dominant hand and reported symptoms of arthritis, giddiness and foot difficulties were most influential in predicting reports of recent falls. <s> BIB003 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> BACKGROUND AND PURPOSE ::: The risk of falls is very high among stroke patients, and falling is a major complication in stroke rehabilitation. This study aimed to investigate the incidence, characteristics, and consequences of falls in an inpatient stroke rehabilitation setting. ::: ::: ::: METHODS ::: One hundred sixty-one patients consecutively admitted to a geriatric stroke rehabilitation unit were studied. Falls that occurred during their rehabilitation stay were prospectively registered and analyzed. ::: ::: ::: RESULTS ::: Sixty-two of the patients (39%) suffered falls. The total number of falls was 153, which corresponds to an incidence rate of 159 falls per 10,000 patient-days. Most falls occurred during transfers or from sitting in a wheelchair or on some other kind of furniture. Seventeen falls (11%) were classified as the result of extrinsic mechanisms, 49 (32%) were intrinsic falls, 39 (25%) occurred in a nonbipedal position (while sitting or lying), and 48 falls (31%) remained unclassified. No injury was observed in 109 of 153 incidents (71%), whereas 6 falls (4%) involved fractures or other serious injury. ::: ::: ::: CONCLUSIONS ::: Since falls are so frequent, they must be considered a significant problem in stroke rehabilitation. Fall prevention strategies should therefore be developed and included in rehabilitation programs. <s> BIB004 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> OBJECTIVES ::: To determine the incidence of falls on a stroke rehabilitation unit; to assess the frequency and nature of injuries; and to identify risk factors predictive of falls, functional outcomes, and impairments. ::: ::: ::: DESIGN ::: Retrospective cohort study. ::: ::: ::: SETTING ::: An inpatient stroke rehabilitation unit. ::: ::: ::: PARTICIPANTS ::: Two hundred thirty-eight consecutive stroke patient admissions. ::: ::: ::: INTERVENTIONS ::: Incident reports completed on patients who experienced a fall while on the unit were reviewed and resultant injuries categorized (abrasions, lacerations, fractures). ::: ::: ::: MAIN OUTCOME MEASURES ::: Stroke impairments and admission functional assessments, FIM instrument, Berg Balance Scale (BBS), and Chedoke-McMaster (CM) Stroke Impairment Inventory of fallers were compared with nonfallers. ::: ::: ::: RESULTS ::: Of the 238 patients, 88 (37%) experienced at least 1 fall, and almost half of these (45 patients [19%]) experienced at least 2 falls. A total of 180 falls were reported over the 5-year period. Of the 180 reported falls, 33% occurred when patients were using their wheelchairs. Injuries occurred in 22% of the reported falls. These consisted of contusions (49%) and abrasions (41%), primarily of the upper (30.8%) and lower (25.6%) extremities. Only 1 fracture was reported. Fallers tended to have lower admission BBS scores (50% of patients with a score <30 fell vs 18% with a score >30, P <.01) and a lower score on the admission arm, leg, and foot components of the CM (P <.05). Patients who fell were also more likely to be apraxic (P <.014) and suffer from cognitive deficits (P <.01). Repeat fallers had lower admission FIM scores (P <.01) when compared with nonfallers. ::: ::: ::: CONCLUSION ::: Although patients undergoing stroke rehabilitation experienced a significant number of falls, the incidence of serious injury was small. Patients who experienced at least 1 fall had significantly lower BBS, FIM, and CM arm, leg, and foot scores compared with nonfallers. These data suggest that groups of stroke patients who are at risk for falls within the rehabilitation setting can be identified by using a variety of impairment and functional assessments. This information may be potentially useful for designing interventions directed at reducing fall frequency among stroke survivors. <s> BIB005 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> OBJECTIVES ::: To evaluate how cognitive function and divided attention affect gait in Alzheimer's disease (AD). ::: ::: ::: DESIGN ::: Cross-sectional intervention study with subjects serving as their own controls. ::: ::: ::: SETTING ::: Inpatient unit and outpatient clinic for patients with dementia located at a Veterans Affairs Medical Center. ::: ::: ::: PARTICIPANTS ::: Twenty-eight patients diagnosed with probable AD. ::: ::: ::: INTERVENTION ::: Performance of a cognitive task (repeating random digits) while walking. ::: ::: ::: MEASUREMENTS ::: Neuropsychological measures including clock drawing, verbal fluency, and digit span were obtained along with the Clinical Dementia Rating and Mini-Mental State Examination, the measures of dementia severity. Gait speed and stride-to-stride variability of gait rhythm were measured, once during normal walking and once during dual-task walking. ::: ::: ::: RESULTS ::: During usual walking, subjects walked slowly and with greater gait variability than older adults without AD. Gait speed was significantly reduced (P<.012) and gait variability increased with dual-task walking (P<.007). The effect on gait variability was larger than the effect on gait speed (P<.015). Executive and neuropsychological function were significantly (P<.02) associated with the increased gait variability that occurred when walking with divided attention but not with gait speed or usual, single-task walking measures of gait. ::: ::: ::: CONCLUSION ::: Divided attention markedly impairs the ability of patients with AD to regulate the stride-to-stride variations in gait timing. This susceptibility to distraction and its effect on stride time variability, a measure of gait unsteadiness, could partially explain the predilection to falling observed in patients with dementia. The results also support the concept that persons with AD have significant impairments in the cognitive domain of attention and that locomotor function relies upon cognitive, especially executive, function. <s> BIB006 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Objective Falls are common in patients with Alzheimer’s disease (AD). Identification of the potential risk factors and developing preventive strategies for falls will have a significant impact in maintaining the quality of life in AD. Patients Clinical follow-up of 124 (74.1±6.1 years, range 62–88) mild to moderate AD patients in an outpatient memory clinic. Methods Postural sway, cognitive function, use of neuroleptics, severity of periventricular and deep white matter lesions, and the presence or absence of silent brain infarctions on magnetic resonance imaging were assessed at baseline. Results A total of 104 patients (84%) completed the study. Fall events were confirmed in 42.3% (44/104). After adjustment for age, gender, and cognitive status, a high grade of periventricular white matter lesions (odds ratio 8.7 [95%CI 1.5 to 51.8], p=0.017) and neuroleptic drug use (odds ratio 3.5 [95%CI 1.2 to 10.5], p=0.027) were significantly associated with an increased risk of falls. Conclusion Our results suggest that periventricular white matter lesions and the use of neuroleptics may be related to falls in mild to moderate AD. A comprehensive risk management of brain ischemia as well as the use of the smallest efficacious dose of neuroleptics in the treatment of behavioral and psychiatric symptoms of AD should be recommended to help reduce the risk of unexpected falls. (Internal Medicine 44: 717–721, 2005) <s> BIB007 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> The study of postural sway during quiet stance has proved a useful approach to investigate the function of the balance system. Recent studies have suggested that providing information on postural sway to vestibular patients through various biofeedback devices may improve their balance awareness and therefore reduce their risk of falling. One drawback common to these approaches is related to timing: informing a patient about current balance conditions may not allow enough time to react and avoid a fall. Here we propose a new technique for predicting relevant balance related variables based on the recording of inertial information on trunk movement using a wearable device. Our preliminary results show that such approach may allow predicting critical balance conditions with few hundreds of milliseconds advance and is thus promising for the development of a fall prevention device. <s> BIB008 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> OBJECTIVE ::: To examine incidence, associated factors, and health care provider (HCP) response to falls in persons with multiple sclerosis (MS). ::: ::: ::: DESIGN ::: Cross-sectional retrospective design. ::: ::: ::: SETTING ::: Community setting. ::: ::: ::: PARTICIPANTS ::: Four hundred seventy-four persons with MS. ::: ::: ::: METHODS ::: Mailed survey questionnaire examined incidence, risk factors, and HCP response to falls in persons with MS who were dwelling in the community. Univariate and multiple ordinal regression analysis identified variables associated with single and multiple falls. ::: ::: ::: MAIN OUTCOME MEASUREMENTS ::: Falls, causes and perceived reasons for falls, and HCP response. ::: ::: ::: RESULTS ::: A total of 265 participants (58.2%) reported one or more falls in the previous 6 months, and 58.5% of falls were medically injurious. Trips/slips while walking accounted for 48% of falls. Factors associated with falls included use of a cane or walker (odds ratio [OR] 2.62; 95% confidence interval [CI] 1.66-4.14), income <$25,000 (OR 1.85; 95% CI 1.13-3.04), balance problems (OR 1.28; 95% CI 1.11-1.49), and leg weakness (OR 1.26; 95% CI 1.09-1.46). Fifty-one percent of those who fell (135/265) reported speaking to an HCP about their falls; recommended strategies included safety strategies (53.2%), use of gait assistive devices (42.1%), exercise/balance training (22.2%), and home modifications (16.6%). ::: ::: ::: CONCLUSIONS ::: Factors associated with falls in persons with MS are similar to those in other populations with neurologic diseases. Despite the high incidence of falls, fewer than 50% of people with MS receive information about prevention of falls from an HCP. <s> BIB009 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> During gait the body is in a continuous state of imbalance, with each subsequent step preventing a fall. Gait balance is maintained by regulating the interactions between the center of mass (CoM) and base of support (BoS). The purpose of this study was to investigate the interaction of the CoM position and velocity (CoMv) in relation to the dynamically changing BoS throughout gait. This was quantified using: (1) The shortest distance from the CoM to the boundary of the BoS; (2) The distance from the CoM to the centroid of the BoS; and (3) The distance from the CoM to the BoS along the direction of the CoMv. These interactions were investigated in healthy young adults, healthy older adults, and elderly fallers, who performed level walking at a self-selected speed. Elderly fallers demonstrated a conservative CoM–BoS separation at toe off and reduced balance control ability, specifically a decreased time to contact, when compared to healthy young adults at heel strike. Decreased time available in responding to perturbations might result in a greater number of falls. Understanding foot position and CoM trajectories might allow for appropriate rehabilitation practices. <s> BIB010 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Fall prevention in elderly subjects is often based on training and rehabilitation programs that include mostly traditional balance and strength exercises. By applying such conventional interventions to improve gait performance and decrease fall risk, some important factors are neglected such as the dynamics of the gait and the motor learning processes. The EU project "Self Mobility Improvement in the eLderly by counteractING falls" (SMILING project) aimed to improve age-related gait and balance performance by using unpredicted external perturbations during walking through motorized shoes that change insole inclination at each stance. This paper describes the shoe-worn inertial module and the gait analysis method needed to control in real-time the shoe insole inclination during training, as well as gait spatio-temporal parameters obtained during long distance walking before and after the 8-week training program that assessed the efficacy of training with these motorized shoes. <s> BIB011 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Falls not only present a considerable health threat, but the resulting treatment and loss of working days also place a heavy economic burden on society. Gait instability is a major fall risk factor, particularly in geriatric patients, and walking is one of the most frequent dynamic activities of daily living. To allow preventive strategies to become effective, it is therefore imperative to identify individuals with an unstable gait. Assessment of dynamic stability and gait variability via biomechanical measures of foot kinematics provides a viable option for quantitative evaluation of gait stability, but the ability of these methods to predict falls has generally not been assessed. Although various methods for assessing gait stability exist, their sensitivity and applicability in a clinical setting, as well as their cost-effectiveness, need verification. The objective of this systematic review was therefore to evaluate the sensitivity of biomechanical measures that quantify gait stability among elderly individuals and to evaluate the cost of measurement instrumentation required for application in a clinical setting. To assess gait stability, a comparative effect size (Cohen's d) analysis of variability and dynamic stability of foot trajectories during level walking was performed on 29 of an initial yield of 9889 articles from four electronic databases. The results of this survey demonstrate that linear variability of temporal measures of swing and stance was most capable of distinguishing between fallers and non-fallers, whereas step width and stride velocity prove more capable of discriminating between old versus young (OY) adults. In addition, while orbital stability measures (Floquet multipliers) applied to gait have been shown to distinguish between both elderly fallers and non-fallers as well as between young and old adults, local stability measures (λs) have been able to distinguish between young and old adults. Both linear and nonlinear measures of foot time series during gait seem to hold predictive ability in distinguishing healthy from fall-prone elderly adults. In conclusion, biomechanical measurements offer promise for identifying individuals at risk of falling and can be obtained with relatively low-cost tools. Incorporation of the most promising measures in combined retrospective and prospective studies for understanding fall risk and designing preventive strategies is warranted. <s> BIB012 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> About 30% of individuals over the age of 65, and 50% over age 80, fall at least once per year [1]. Fall-related injuries cost the Canadian health care system $2.8 billion annually [2]. Risk for falls in older adults is commonly assessed in the clinical environment using tools such as the Short Physical Performance Battery (SPPB) [3], which include subjective assessments of postural sway while standing under various sensory conditions. This study uses wearable accelerometers and a force plate to quantify measures of postural stability during these tasks. Four participants were asked to maintain quiet stance in six different conditions, while their center of pressure (COP) and accelerations from six accelerometers were recorded. Standard deviations in signals were used as measures of postural sway. The sway observed in all sensors increased with the difficulty of the stance condition. Manipulation of vision and surface stiffness caused greater changes in sway in the AP than ML direction, while changes in stance configuration were more evident in the ML direction. Furthermore, the ankle sensor was the most sensitive in registering changes in sway when manipulating vision and surface stiffness (showing an increase of 236% over baseline values in AP sway with eyes closed and standing on foam), while the thigh was most sensitive to changes in stance width (showing an increase of 336% over baseline values in ML sway in the tandem stance condition). This study contributes in establishing the utility of wearable sensors for quantifying postural stability under various stance configurations in future studies with high-risk older adults. <s> BIB013 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> BackgroundFalls are a prevalent issue in the geriatric population and can result in damaging physical and psychological consequences. Fall risk assessment can provide information to enable appropriate interventions for those at risk of falling. Wearable inertial-sensor-based systems can provide quantitative measures indicative of fall risk in the geriatric population.MethodsForty studies that used inertial sensors to evaluate geriatric fall risk were reviewed and pertinent methodological features were extracted; including, sensor placement, derived parameters used to assess fall risk, fall risk classification method, and fall risk classification model outcomes.ResultsInertial sensors were placed only on the lower back in the majority of papers (65%). One hundred and thirty distinct variables were assessed, which were categorized as position and angle (7.7%), angular velocity (11.5%), linear acceleration (20%), spatial (3.8%), temporal (23.1%), energy (3.8%), frequency (15.4%), and other (14.6%). Fallers were classified using retrospective fall history (30%), prospective fall occurrence (15%), and clinical assessment (32.5%), with 22.5% using a combination of retrospective fall occurrence and clinical assessments. Half of the studies derived models for fall risk prediction, which reached high levels of accuracy (62-100%), specificity (35-100%), and sensitivity (55-99%).ConclusionsInertial sensors are promising sensors for fall risk assessment. Future studies should identify fallers using prospective techniques and focus on determining the most promising sensor sites, in conjunction with determination of optimally predictive variables. Further research should also attempt to link predictive variables to specific fall risk factors and investigate disease populations that are at high risk of falls. <s> BIB014 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Background Falls are a significant issue in people with multiple sclerosis (MS), with research demonstrating fall rates of more than 50%. ::: ::: Purpose The purpose of this study was to evaluate the risk factors associated with falling in people with MS. ::: ::: Data Sources Mixed search methods were used, including computer-based and manual searches. Additionally, hand searches of reference lists and conference abstracts were performed. All literature published from the source's earliest date to January 2012 was included; only full-text English-language sources (or those where a translation was available) were included. ::: ::: Study Selection Eligibility criteria specified articles evaluating any aspect of fall risk in adults with a confirmed MS diagnosis, where the incidence of falling as determined by prospective or retrospective participant report was included. ::: ::: Data Extraction Data were extracted independently by 2 reviewers using a written protocol and standardized extraction documentation. Detailed assessment of each article was independently undertaken by both reviewers, including assessment of study quality using an adaptation of the Newcastle Ottawa Scale plus extraction of key data (participant characteristics, fall incidence, and outcomes). ::: ::: Data Synthesis The final review comprised 8 articles with a total of 1,929 participants; 1,037 (53.75%) were classified as fallers. Eighteen different risk factors were assessed within the included studies. Meta-analysis demonstrated an increase in fall risk associated with impairments of balance and cognition, progressive MS, and use of a mobility aid. Narrative review of the qualitative articles and those factors where meta-analysis was not possible also was undertaken. ::: ::: Limitations Variation in assessment, analysis, and reporting methods allowed meta-analysis for only 4 factors. ::: ::: Conclusion There is limited evidence of the factors associated with fall risk in people with MS. Further methodologically robust studies are needed. <s> BIB015 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> The primary purpose of this study was to systematically evaluate and compare the predictive power of falls for a battery of stability indices, obtained during normal walking among community-dwelling older adults. One hundred and eighty seven community-dwelling older adults participated in the study. After walking regularly for 20 strides on a walkway, participants were subjected to an unannounced slip during gait under the protection of a safety harness. Full body kinematics and kinetics were monitored during walking using a motion capture system synchronized with force plates. Stability variables, including feasible-stability-region measurement, margin of stability, the maximum Floquet multiplier, the Lyapunov exponents (short- and long-term), and the variability of gait parameters (including the step length, step width, and step time), were calculated for each subject. Sensitivity of predicting slip outcome (fall vs. recovery) was examined for each stability variable using logistic regression. Results showed that the feasible-stability-region measurement predicted fall incidence among these subjects with the highest sensitivity (68.4%). Except for the step width (with an sensitivity of 60.2%), no other stability variables could differentiate fallers from those who did not fall for the sample included in this study. The findings from the present study could provide guidance to identify individuals at increased risk of falling using the feasible-stability-region measurement or variability of the step width. <s> BIB016 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> SUMMARY Falls in people with Parkinson's disease (PD) are frequent and recurrent events with devastating and widespread consequences. Despite this, understanding of the predictive and explanatory value of fall risk factors, as well as the development and testing of interventions aimed at reducing falls, are in their infancy. This review focuses on fall prediction and risk factors that are potentially remediable with physical interventions. We show that falls can be predicted with high accuracy using a simple three-step clinical tool. Evidence from recently published randomized controlled trials supports the implementation of balance-challenging exercises in reducing falls. Larger scale trials utilizing technologically advanced monitoring methods will further elucidate those interventions most likely to be cost effective according to individual risk factor profiles. <s> BIB017 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Freezing of gait (FOG) and falls are common and disabling phenomena in Parkinson's disease (PD) and related disorders as they may lead to loss of independence. Both are usually observed in the advanced stage of the disease, although they can also be seen in the early stage. FOG and falls have similar risk factors, such as axial motor disability and cognitive impairment, and FOG is one of the most common causes of falls. The objective of this review is to address recent ideas about the underlying pathophysiology of FOG and falls, and discuss the similarities, differences, and relationships between FOG and falls. Recent advances in studies that elucidate physical and cognitive risk factors to predict future falls are also reviewed. In addition to the history of prior falls and disease severity, the presence of FOG and cognitive dysfunction are associated with falls in PD. <s> BIB018 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Aging negatively impacts the ability to maintain postural stability due to degraded control systems. The entropic half-life, a non-linear variable that quantifies the transition of sample entropy with increasing time scales, quantifies the time that elapses before old positional information no longer influences, or is no longer related to, the control mechanisms that regulate the movement at the current center of pressure location. The entropic half-life provides a more representative and comprehendible way of detecting changes in complexity using measurement units of time. The purpose of this study was to determine the effects of aging on the magnitude and temporal structure of the center of pressure movement during quiet single-limb stance. Center of pressure data of 24 older and 24 younger subjects were analyzed. The complexity of the temporal structure of the center of pressure signal was quantified by calculating the entropic half-life of the center of pressure in the medio-lateral and anterior–poste... <s> BIB019 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Abstract Background Postural control in the medial–lateral (ML) direction is of particular interest regarding the assessment of changes in postural control, as it is highly related to the risk of falling. Objective To determine the postural strategies used to regain balance following a voluntary lateral step and compare these strategies between young and older adults. Methods Sixteen older adults (60–90 years) and 14 young adults (20–40 years) were asked to stand quietly for 30s, walk in place and then take a lateral step and stand quietly (30s). Balance Post was divided into 10s intervals. Center of pressure displacement (CoP) and velocity (VCoP) in the anterio-posterior (AP) and ML directions were analyzed. Results In both groups, CoP and VCoP in AP and ML increased in Post1 compared to Pre ( P P =0.01) in older adults. Age correlated with all VCoP (Pre and Post) in both ML ( P P Conclusions Dissimilar to young adults, older adults use different postural strategies in ML and AP directions and prioritized postural stability in the AP direction to recover balance after completing a lateral step. In the ML direction, older adults took up to 30s to regain balance. Considering that age was related to larger CoP displacement and velocity, the AP strategy to recover postural balance following a lateral step could become less efficient as older adults age and therefore increasing the risk of falls. <s> BIB020 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Abstract Early detection of balance impairment is crucial to identify individuals who may benefit from interventions aimed to prevent falls, which is a major problem in aging societies. Since mediolateral balance deteriorates with aging, we proposed a mediolateral balance assessment (MELBA) tool that uses a CoM-tracking task of predictable sinusoidal and unpredictable multisine targets. This method has shown to be reliable and sensitive to aging effect, however, it is not known whether it can predict performance on common daily-life tasks such as walking. This study aimed to determine whether MELBA is an ecologically valid tool by correlating its outputs with a measure of mediolateral gait stability known to be predictive of falls. Nineteen community-dwelling older adults (72 ± 5 years) tracked predictable and unpredictable target displacements at increasing frequencies with their CoM by shifting their weight sideward. Response delay (phase-shift) and amplitude difference (gain) between the CoM and target in the frequency domain were used to quantify performance. To assess gait stability, the local divergence exponent was calculated using mediolateral accelerations with an inertial sensor when walking on a treadmill (LDE TR ) and in daily-life (LDE DL ) for one week. Pearson product-moment correlation analyses were performed to determine correlations between performance on MELBA tasks and LDE. Results show that phase-shift bandwidth for the predictable target (range above −90°) was significantly correlated with LDE TR whereas phase-shift bandwidth for the unpredictable target was significantly correlated with LDE DL . In conclusion MELBA is an ecologically valid tool for mediolateral balance assessment in community-dwelling older adults who exhibit subtle balance impairments. <s> BIB021 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Monitoring biosignals has become more people-friendly since the development of wearable electro-conductive cloth. This paper proposes an application using wearable EMG sensors that estimates the fall risk of elderly people based on co-contraction of the lower limb during walking. Fifty-two healthy elderly people participated in a gait test with continuous EMG of the thigh (rectus femoris and biceps femoris) and cruris (tibialis anterior and gastrocnemius). The participants were categorized into a "faller group" and a "non-faller group" based on their experience of falls in the previous year. Co-contraction of thigh and cruris were determined based on EMG, and were then used to estimate the experience of falling using a linear discrimination method. The results showed that thigh co-contraction during the stance phase can be predictive of falling experience with 65% accuracy. <s> BIB022 </s> Type and Location of Wearable Sensors for Monitoring Falls during Static and Dynamic Tasks in Healthy Elderly: A Review <s> Introduction <s> Abstract Falls are the cause for more than half of the injury-related hospitalizations among older people. Accurate assessment of individuals’ fall risk could enable targeted interventions to reduce the risk. This paper presents a novel method for using wearable accelerometers to detect early signs of deficits in balance from gait. Gait acceleration data were analyzed from 35 healthy female participants (73.86±5.40 years). The data were collected with waist-mounted accelerometer and the participants performed three supervised balance tests: Berg Balance Scale (BBS), Timed-Up-and-Go (TUG) and 4 m walk. The follow-up tests with the same protocol were performed after one year. Altogether 43 features were extracted from the accelerometer signals. Sequential forward floating selection and ten-fold cross-validation were applied to determine models for 1) estimating the outcomes of BBS, TUG and 4 m walk tests and 2) predicting decline in balance during one-year follow-up indicated as decline in BBS total score and one leg stance. Normalized root-mean-square errors (RMSE) of the assessment scale result estimates were 0.28 for BBS score, 0.18 for TUG time, and 0.22 for 4 m walk test. Area under curve (AUC) was 0.78 for predicting decline in BBS total score and 0.82 for one leg stance, respectively. The results suggest that the gait features can be used to estimate the result of a clinical balance assessment scale and predict decline in balance. A simple walk test with wearable monitoring could be applicable as an initial screening tool to identify people with early signs of balance deficits. <s> BIB023
Falls and related accidents are a common and serious problem not only in a pathologic condition like Parkinson's Disease  , stroke BIB005 or multiple sclerosis BIB009 , in which they are due to the motor and cognitive characteristics of the specific disease, but also for healthy people aged 65 and over [4] . A fall is defined as coming to rest on the ground or floor or other lower level, suddenly and involuntarily BIB002  . Many epidemiological studies have reported a fall frequency of 28-35% in adults aged 65 and over BIB003  BIB001 , highlighting the need of developing effective and inexpensive ways to predict and prevent risk factors. BIB002   . Base of Support (BoS) BIB010 ), and in the control of alignment of Center of Pressure (CoP) with respect to the Center of Gravity (CoG)  . According to a biomechanical approach, the falls could be due to a change in position of the CoM projection beyond the BoS without any correction  . Even when standing, the body sways constantly and for this reason such posture is called static standing or stand still. The most common way to study the balance in static standing is through the trajectories of the CoP with respect to the CoG BIB019 BIB020  , although nonlinear measures have been proposed in some studies  BIB016 BIB021 . The assessment of the degree of postural sway during static standing could be useful to evaluate the ability to preserve balance control. For this reason, participants are commonly asked to perform a static upright task, on a force platform, in open-and closed-eyes condition, with both arms along the body BIB008 BIB013 . During this test, it is also possible to analyze the relationship between the CoM and CoP, it being useful for fall prediction BIB008 and risk assessment BIB013 . One of the major health issues for an older adult is the loss of stability or a slip and the subsequent fall during walking. For this reason, the evaluation of dynamic stability, the assessment of activity and mobility in daily living conditions (for example, through ADLs) or through tasks such as simple walk, "time up and go" (TUG) test BIB023 and the 6-minute walk test BIB011 , could provide useful motor outcomes to detect the early signs of balance alteration and then provide key information about fall risk BIB022 . The latter results could, however, be capitalized in a predictive fashion so as to accomplish fall detection/prediction. Many articles in the literature are focused on defining gait characteristics in the elderly with the aim of identifying the causes of fall. In the recent review article by BIB012 , the authors tried to evaluate the sensitivity of biomechanical measures that quantify gait stability in older populations. In detail, they analyzed different approaches to study gait stability based on two different classes: (i) linear variability of temporal measures (such as swing and stance time, step width, stride velocity), and (ii) (nonlinear) orbital or local stability measures (such as Floquet multipliers or Lyapunov exponents). They concluded that, although some biomechanical approaches for determining specific parameters of mobility can assess the function and stability in the elderly, they hardly have been taken up in clinical settings because of their unclear sensitivity and specificity, together with the time and effort required for their use. Within this framework, a key role is played by the adopted sensing technologies, both in terms of hardware and software approaches. Recently, the interest in falls is increased not only in healthy subjects, but also in pathological conditions such as Parkinson's disease  BIB017 BIB018 , multiple sclerosis BIB009 BIB015 , stroke BIB005 BIB004 and Alzheimer's disease BIB007 BIB006 . However, this review investigates the studies published in the last two decades in the field of stability control for fall risk assessment, prevention and detection based on wearable sensors in healthy elderly people only. This is because, in a pathologic condition, the stability, and therefore the fall risk, strongly depends on the motor and cognitive characteristics of the disease. An interesting review can be found in BIB014 , where the authors focus their attention on wearable inertial sensors for fall risk assessment in geriatric populations. Within this manuscript, we extend the analysis to other sensor typologies, such as pressure sensors, electromyographic sensors and cameras, and to fall detection and prevention. Therefore, the aim of our work is to provide an overview of the most adopted sensing technologies in these fields, with a focus on the type of sensors (rather than algorithms), their position on the body and the kind of tasks they are used in. The existing literature has been found by defining a search criteria and considering some of the most important publication databases. In more detail, the search criterion is reported in Section 2, and the search results are reported in Section 3. Starting from these outcomes, some trends are identified and reported in Section 4. Finally, conclusions are drawn in Section 5.