Effects Of Pelvis Impact Angle And Hip Muscle Forces On Hip Fracture Risk During A Fall Using An Advanced Hip Impact Simulator

Over 90% of hip fractures in older adults are caused by falls [1]. Whether a given fall will cause hip fracture depends on bone strength, and on the impact force and stress applied to the bone during impact [2]. Improved understanding is required on how peak bone stresses during a fall depend on the mechanics of a fall, and on the state of contraction at the moment of impact of the muscles spanning the hip. Recently, Choi et al showed that, for lateral impact to the hip, peak stresses decrease with increases in hip abductor muscle force [3]. In the current study, we used an advanced hip impact simulator to examine the independent and interacting effects of both hip muscle force and pelvis impact angle on peak bone stresses during a fall

Pressure Distribution Over the Palm Region During Forward Falls on the Outstretched Hands

Falls on the outstretched hands are the cause of over 90% of wrist fractures, yet little is known about bone loading during this event. We tested how the magnitude and distribution of pressure over the palm region during a forward fall is affected by foam padding (simulating a glove) and arm configuration, and by the faller’s body mass index (BMI) and thickness of soft tissues over the palm region. Thirteen young women with high (n=7) or low (n=6) BMI participated in a “torso release experiment” that simulated falling on both outstretched hands with the arm inclined either at 20° or 40° from the vertical. Trials were acquired with and without a 5 mm thick foam pad secured to the palm. Outcome variables were the magnitude and location of peak pressure (d, θ) with respect to the scaphoid, total impact force, and integrated force applied to three concentric areas, including “danger zone” of 2.5 cm radius centered at the scaphoid. Soft tissue thickness over the palm was measured by ultrasound. The 5 mm foam pad reduced peak pressure, and peak force to the danger zone, by 83% and 13%, respectively. Peak pressure was 77% higher in high BMI when compared with low BMI participants. Soft tissue thickness over the palm correlated positively with distance (d) (R=0.79, p=0.001) and force applied outside the danger zone (R=0.76, p=0.002), but did not correlate with BMI (R=0.43, p=0.14). The location of peak pressure was shunted 4 mm further from the scaphoid at 20° than that of 40° falls (d=25 mm (SD 8), θ= −9° (SD 17) in the 20° falls versus d=21 mm (SD 8), θ= −5° (SD 24) in the 40° falls). Peak force to the entire palm was 11% greater in 20° compared with 40° falls. These results indicate that even a 5 mm thick foam layer protects against wrist injury, by attenuating peak pressure over the palm during forward falls. Increased soft tissue thickness shunts force away from the scaphoid. However, soft tissue thickness is not predicted by BMI, and peak pressures are greater in high individuals than that of low BMI individuals. These results contribute to our understanding of the mechanics and prevention of wrist and hand injuries during falls

Influence Of Pelvis Impact Angle During A Fall: On The Protective Benefit Of Hip Protectors

Over 90% of hip fractures are due to falls [1]. Laboratory measures have shown that wearable hip protectors reduce impact forces to the proximal femur during a simulated sideways fall on the hip [2, 3]. However, clinical evidence suggests that hip fractures still occur when hip protectors are worn [4]. Furthermore, while falls in real life result in a variety of impact configurations, biomechanical tests to date have focused only on lateral impact to the pelvis. In the current study, we examined how the force reduction provided by wearable hip protectors is affected by pelvis impact configuration during simulated sideways falls

Pressure Distribution Over the Palm During Falls on the Outstretched Hands

Over 90% of wrist fractures are caused by falls on the outstretched hands (Palvanen et al., Osteoporos Int, 2000). Along with bone strength, fracture risk depends on the magnitude and distribution of force to soft and hard tissues during impact. In the current study, we examined how pressure distribution over the palm during a fall is affected by impact configuration, body mass index (BMI), palmer soft tissue thickness, and a 5 mm thick foam pad (simulating a protective glove)

Performance of a Hip Protector Depends on its Position During a Fall

Hip protectors are designed to attenuate and redistribute the force applied to the hip region during a fall, and thereby reduce risk for hip fracture [1]. However, little information exists on the effectiveness of hip protectors in achieving these goals, and how this is altered by displacement of the hip protector relative to the greater trochanter (GT). In the current study, we tested these issues

Cardiovascular Responses to Orthostasis and Their Association With Falls in Older Adults

Background Orthostatic hypotension (OH) refers to a marked decline in blood pressure when upright. OH has a high incidence and prevalence in older adults and represents a potential intrinsic risk factor for falls in these individuals. Previous studies have not included more recent definitions for blood pressure responses to orthostasis, including initial, delayed, and recovery blood pressure responses. Furthermore, there is little research examining the relationships between cerebrovascular functioning and falling risk. Therefore, we aimed to: (i) test the association between different blood pressure responses to orthostatic stress and retrospective falling history and; (ii) test the association between cerebrovascular responses to orthostatic stress and falling history. Methods We tested 59 elderly residents in long term care facilities who underwent a passive seated orthostatic stress test. Beat-to-beat blood pressure and cerebral blood flow velocity (CBFV) responses were assessed throughout testing. Risk factors for falls and falling history were collected from facility records. Cardiovascular responses to orthostasis were compared between retrospective fallers (≥1 fall in the previous year) and non-fallers. Results Retrospective fallers had larger delayed declines in systolic arterial pressure (SAP) compared to non-fallers (p  = 0.015). Fallers also showed poorer early (2 min) and late (15 min) recovery of SAP. Fallers had a greater decline in systolic CBFV. Conclusions Older adults with a positive falling history have impaired orthostatic control of blood pressure and CBFV. With better identification and understanding of orthostatic blood pressure impairments earlier intervention and management can be implemented, potentially reducing the associated risk of morbidity and mortality. Future studies should utilize the updated OH definitions using beat-to-beat technology, rather than conventional methods that may offer less accurate detection

Accuracy of Kinovea Software in Estimating Body Segment Movements During Falls Captured on Standard Video: Effects of Fall Direction, Camera Perspective and Video Calibration Technique

Falls are a major cause of unintentional injuries. Understanding the movements of the body during falls is important to the design of fall prevention and management strategies, including exercise programs, mobility aids, fall detectors, protective gear, and safer environments. Video footage of real-life falls is increasingly available, and may be used with digitization software to extract kinematic features of falls. We examined the validity of this approach by conducting laboratory falling experiments, and comparing linear and angular positions and velocities measured from 3D motion capture to estimates from Kinovea 2D digitization software based on standard surveillance video (30 Hz, 640x480 pixels). We also examined how Kinovea accuracy depended on fall direction, camera angle, filtering cut-off frequency, and calibration technique. For a camera oriented perpendicular to the plane of the fall (90 degrees), Kinovea position data filtered at 10 Hz, and video calibration using a 2D grid, mean root mean square errors were 0.050 m or 9% of the signal amplitude and 0.22 m/s (7%) for vertical position and velocity, and 0.035 m (6%) and 0.16 m/s (7%) for horizontal position and velocity. Errors in angular measures averaged over 2-fold higher in sideways than forward or backward falls, due to out-of-plane movement of the knees and elbows. Errors in horizontal velocity were 2.5-fold higher for a 30 than 90 degree camera angle, and 1.6-fold higher for calibration using participants’ height (1D) instead of a 2D grid. When compared to 10 Hz, filtering at 3 Hz caused velocity errors to increase 1.4-fold. Our results demonstrate that Kinovea can be applied to 30 Hz video to measure linear positions and velocities to within 9% accuracy. Lower accuracy was observed for angular kinematics of the upper and lower limb in sideways falls, and for horizontal measures from 30 degree cameras or 1D height-based calibration

Relationships between Orthostatic Hypotension, Frailty, Falling and Mortality in Elderly Care Home Residents

Background: Orthostatic hypotension (OH; profound falls in blood pressure when upright) is a common deficit that increases in incidence with age, and may be associated with falling risk. Deficit accumulation results in frailty, regarded as enhanced vulnerability to adverse outcomes. We aimed to evaluate the relationships between OH, frailty, falling and mortality in elderly care home residents. Methods: From the Minimum Data Set (MDS) document, a frailty index (FI-MDS) was generated from a list of 58 deficits, ranging from 0 (no deficits) to 1.0 (58 deficits). OH was evaluated from beat-to-beat blood pressure and heart rate (finger plethysmography) collected during a 15-min supine-seated orthostatic stress test. Retrospective and prospective falling rates (falls/year) were extracted from facility falls incident reports. All-cause 3-year mortality was determined. Data are reported as mean ± standard error. Results: Data were obtained from 116 older adults (aged 84.2 ± 0.9 years; 44% males) living in two long term care facilities. The mean FI-MDS was 0.36 ± 0.01; FI-MDS was correlated with age (r = 0.277; p = 0.003). Those who were frail (FI ≥ 0.27) had larger Initial (− 17.8 ± 4.2 vs − 6.1 ± 3.3 mmHg, p = 0.03) and Consensus (− 22.7 ± 4.3 vs − 11.5 ± 3. 3 mmHg, p = 0.04) orthostatic reductions in systolic arterial pressure. Frail individuals had higher prospective and retrospective falling rates and higher 3-year mortality. Receiver operating characteristic curves evaluated the ability of FI-MDS alone to predict prospective falls (sensitivity 72%, specificity 36%), Consensus OH (sensitivity 68%, specificity 60%) and 3-year mortality (sensitivity 77%, specificity 49%). Kaplan Meier survival analyses showed significantly higher 3-year mortality in those who were frail compared to the non-frail (p = 0.005). Conclusions: Frailty can be captured using a frailty index based on MDS data in elderly individuals living in long term care, and is related to susceptibility to orthostatic hypotension, falling risk and 3-year mortality. Use of the MDS to generate a frailty index may represent a simple and convenient risk assessment tool for older adults living in long term care. Older adults who are both frail and have impaired orthostatic blood pressure control have a particularly high risk of falling and should receive tailored management to mitigate this ris

Validation of Accuracy of SVM-Based Fall Detection System Using Real-World Fall and Non-Fall Datasets

Falls are a major cause of injuries and deaths in older adults. Even when no injury occurs, about half of all older adults who fall are unable to get up without assistance. The extended period of lying on the floor often leads to medical complications, including muscle damage, dehydration, anxiety and fear of falling. Wearable sensor systems incorporating accelerometers and/or gyroscopes are designed to prevent long lies by automatically detecting and alerting care providers to the occurrence of a fall. Research groups have reported up to 100% accuracy in detecting falls in experimental settings. However, there is a lack of studies examining accuracy in the real-world setting. In this study, we examined the accuracy of a fall detection system based on real-world fall and non-fall data sets. Five young adults and 19 older adults went about their daily activities while wearing tri-axial accelerometers. Older adults experienced 10 unanticipated falls during the data collection. Approximately 400 hours of activities of daily living were recorded. We employed a machine learning algorithm, Support Vector Machine (SVM) classifier, to identify falls and non-fall events. We found that our system was able to detect 8 out of the 10 falls in older adults using signals from a single accelerometer (waist or sternum). Furthermore, our system did not report any false alarm during approximately 28.5 hours of recorded data from young adults. However, with older adults, the false positive rate among individuals ranged from 0 to 0.3 false alarms per hour. While our system showed higher fall detection and substantially lower false positive rate than the existing fall detection systems, there is a need for continuous efforts to collect real-world data within the target population to perform fall validation studies for fall detection systems on bigger real-world fall and non-fall datasets

Association between Sedentary Behaviour and Physical, Cognitive, and Psychosocial Status among Older Adults in Assisted Living

Objective. Identification of the factors that influence sedentary behaviour in older adults is important for the design of appropriate intervention strategies. In this study, we determined the prevalence of sedentary behaviour and its association with physical, cognitive, and psychosocial status among older adults residing in Assisted Living (AL). Methods. Participants (, mean age = 86.7) from AL sites in British Columbia wore waist-mounted activity monitors for 7 consecutive days, after being assessed with the Timed Up and Go (TUG), Montreal Cognitive Assessment (MoCA), Short Geriatric Depression Scale (GDS), and Modified Fall Efficacy Scale (MFES). Results. On average, participants spent 87% of their waking hours in sedentary behaviour, which accumulated in 52 bouts per day with each bout lasting an average of 13 minutes. Increased sedentary behaviour associated significantly with scores on the TUG (, ) and MFES (, ), but not with the MoCA or GDS. Sedentary behaviour also associated with male gender, use of mobility aid, and multiple regression with increased age. Conclusion. We found that sedentary behaviour among older adults in AL associated with TUG scores and falls-related self-efficacy, which are modifiable targets for interventions to decrease sedentary behaviour in this population