Frailty is an important geriatric syndrome strongly linked to falls risk as well as increased mortality and morbidity. Taken alone, falls are the most common cause of injury and hospitalization and one of the principal causes of death and disability in older adults worldwide. Reliable determination of older adults' frailty state in concert with their falls risk could lead to targeted intervention and improved quality of care. We report a mobile assessment platform employing inertial and pressure sensors to quantify the balance and mobility of older adults using three physical assessments (timed up and go (TUG), five times sit to stand (FTSS) and quiet standing balance). This study examines the utility of each individual assessment, and the novel combination of assessments, to screen for frailty and falls risk in older adults.Data were acquired from inertial and pressure sensors during TUG, FTSS and balance assessments using a touchscreen mobile device, from 124 community dwelling older adults (mean age 75.9 ± 6.6 years, 91 female). Participants were given a comprehensive geriatric assessment which included questions on falls and frailty. Methods based on support vector machines (SVM) were developed using sensor-derived features from each physical assessment to classify patients at risk of falls risk and frailty.In classifying falls history, combining sensor data from the TUG, Balance and FTSS tests to a single classifier model per gender yielded mean cross-validated classification accuracy of 87.58% (95% CI: 84.47-91.03%) for the male model and 78.11% (95% CI: 75.38-81.10%) for the female model. These results compared well or exceeded those for classifier models for each test taken individually. Similarly, when classifying frailty status, combining sensor data from the TUG, balance and FTSS tests to a single classifier model per gender, yielded mean cross-validated classification accuracy of 93.94% (95% CI: 91.16-96.51%) for the male model and 84.14% (95% CI: 82.11-86.33%) for the female model (mean 89.04%) which compared well or exceeded results for physical tests taken individually.Results suggest that the combination of these three tests, quantified using body-worn inertial sensors, could lead to improved methods for assessing frailty and falls risk.

Context:No researchers, to our knowledge, have investigated the immediate postinjury-movement strategies associated with acute first-time lateral ankle sprain (LAS) as quantified by center of pressure (COP) and kinematic analyses during performance of the Star Excursion Balance Test (SEBT).Objective: To analyze the kinematic and COP patterns of a group with acute first-time LAS and a noninjured control group during performance of the SEBT.Design: Case-control study. Intervention: Participants performed the anterior (ANT), posterolateral (PL), and posteromedial (PM) reach directions of the SEBT.Main Outcome Measure(s): We assessed 3-dimensional kinematics of the lower extremity joints and associated fractal dimension (FD) of the COP path during performance of the SEBT.Results: The LAS group had decreased normalized reach distances in the ANT, PL, and PM directions when compared with the control group on their injured (ANT: 58.16% 6 6.86% versus 64.86% 6 5.99%; PL: 85.64% 6 10.62% versus 101.14% 6 8.39%; PM: 94.89% 6 9.26% versus 107.29 6 6.02%) and noninjured (ANT: 60.98% 6 6.74% versus 64.76% 6 5.02%; PL: 88.95% 6 11.45% versus 102.36% 6 8.53%; PM: 97.13% 6 8.76% versus 106.62% 6 5.78%) limbs (P , .01). This observation was associated with altered temporal sagittal-plane kinematic profiles throughout each reach attempt and at the point of maximum reach (P , .05). This result was associated with a reduced FD of the COP path for each reach direction on the injured limb only (P , .05).Conclusions: Acute first-time LAS was associated with bilateral deficits in postural control, as evidenced by the bilateral reduction in angular displacement of the lower extremity joints and reduced reach distances and FD of the COP path on the injured limb during performance of the SEBT.Key Words: ankle joint, biomechanics, kinematics, kinetics, postural balance Key PointsIndividuals with acute, first-time lateral ankle sprain injuries exhibited bilateral deficits in dynamic postural control as assessed using the reach distances achieved during the anterior, posterolateral, and posteromedial directions of the Star Excursion Balance Test. These deficits are underpinned by both local and global modifications in the movement patterns adopted at the point of maximum reach by the joints of the lower extremity. A trend toward reduced sagittal-plane range-of-motion displacement was also noted at the hip, knee, and ankle joints throughout each reach attempt in the injured group. These deficits were associated with an apparently reduced capacity to exploit the available base of support, as illustrated by a reduced fractal dimension of the stance-limb center-of-pressure path of the injured limb. Researchers need to determine if some deficits observed in the acute phase of lateral ankle sprain precede or predispose an athlete to the initial injury and to clarify whether these deficits are central to the onset of chronic injury.

Falls are the most common cause of injury and hospitalization and one of the principal causes of death and disability in older adults worldwide. Measures of postural stability have been associated with the incidence of falls in older adults. The aim of this study was to develop a model that accurately classifies fallers and non-fallers using novel multi-sensor quantitative balance metrics that can be easily deployed into a home or clinic setting. We compared the classification accuracy of our model with an established method for falls risk assessment, the Berg balance scale. Data were acquired using two sensor modalities--a pressure sensitive platform sensor and a body-worn inertial sensor, mounted on the lower back--from 120 community dwelling older adults (65 with a history of falls, 55 without, mean age 73.7 ± 5.8 years, 63 female) while performing a number of standing balance tasks in a geriatric research clinic. Results obtained using a support vector machine yielded a mean classification accuracy of 71.52% (95% CI: 68.82-74.28) in classifying falls history, obtained using one model classifying all data points. Considering male and female participant data separately yielded classification accuracies of 72.80% (95% CI: 68.85-77.17) and 73.33% (95% CI: 69.88-76.81) respectively, leading to a mean classification accuracy of 73.07% in identifying participants with a history of falls. Results compare favourably to those obtained using the Berg balance scale (mean classification accuracy: 59.42% (95% CI: 56.96-61.88)). Results from the present study could lead to a robust method for assessing falls risk in both supervised and unsupervised environments.

lateral ankle sprain copers, 1-year following a first-time lateral ankle sprain injury. AbstractPurpose: To quantify the dynamic balance deficits that characterize a group with chronic ankle instability compared to lateral ankle sprain copers and non-injured controls using kinematic and kinetic outcomes.Methods: Forty-two participants with chronic ankle instability and twenty-eight ankle sprain copers were initially recruited within 2-weeks of sustaining a first-time, acute lateral ankle sprain and required to attend our laboratory one-year following to complete the current studyprotocol. An additional group of non-injured individuals were also recruited to act as a control group. All participants completed the anterior, posterior-lateral and posterior-medial reach directions of the Star Excursion Balance Test. Sagittal plane kinematics of the lower extremity and associated fractal dimension of the center of pressure path were also acquired. Results:Participants with chronic ankle instability displayed poorer performance in the anterior, posterior-medial and posterior-lateral reach directions compared to controls bilaterally, and in the posterior-lateral direction compared to ankle sprain copers on their 'involved' limb only. These performance deficits in the posterior-lateral and posterior-medial directions were associated with reduced flexion and dorsiflexion displacements at the hip, knee and ankle at the point of maximum reach, and coincided with reduced complexity of the center of pressure path. Conclusion:In comparison to ankle sprain copers and controls, participants with chronic ankle instability were characterized by dynamic balance deficits as measured using the SEBT. This was attested to reduced sagittal plane motions at the hip, knee and ankle joints, and reduced capacity of the stance limb to avail of its supporting base. Level of evidence: Level III