Body Weight Shift Research Articles

Skill Extraction from Nursing Care Service Using Sliding Sheet

Back pain has been a serious problem for novice nurses who care for bedridden patients. To avoid back pain, placing a slippery sliding sheet beneath a patient has been suggested so that nurses can pull it when repositioning the patient rather than lifting the patient. However, inappropriate use of the sheet may not reduce lumbar pain. Therefore, it is important to identify skills required for novice nurses to perform bed care movements using a sliding sheet. This study firstly performed interview to obtain useful knowledge from expert nurses who are skilled in using a sliding sheet. Next, a simulation study was then conducted to determine specific bed care movements that would minimize lumbar joint moment associated with lumbar pain. The simulated and expert movements were compared to validate whether expert movements decreases lumbar joint moment. Finally, a novice participant was taught these expert movements, and the educational effect of using these skills was validated. Our results showed that the experts used characteristic movements, keeping the upper arm and trunk stabilized and utilizing a shift in body weight, when performing bed care movements with the sliding sheet. Additionally, the expert movements and simulated movements were shown to be similar. This result confirmed that expert movements could contribute to reducing lumbar joint moments. Moreover, a novice participant could decrease lumbar moment using skills derived from effective education.

Carryover effect of compelled body weight shift technique to facilitate rehabilitation of individuals with stroke-an assessor blinded randomized controlled trial.

Carryover effect of compelled body weight shift technique to facilitate rehabilitation of individuals with stroke-an assessor blinded randomized controlled trial.

A Physical Health Profile of Youths Living with a "Hikikomori" Lifestyle.

A cross-sectional study was designed to understand the impacts of “hikikomori” lifestyle on physical health. A total of 104 eligible hikikomori cases were recruited from the social services network of Hong Kong with a mean age of 19.02 ± 3.62 (ranged 13–31) year-old, and had completed the set of questionnaires and a series of anthropometric and physical health measurements. Despite SF36 score of 84.0 indicated good physical functioning in general, participants were lived sedentarily with high incidence of hypertension at 15.4% and prehypertension at 31.7%. Occurrence of hypertension and prehypertension in cases living as hikikomori >6 months were 3 times and 1.5 times higher than those newly onset cases, respectively. The blood pressure levels were correlated with age and all obesity index parameters measured including waist circumference and body mass index. Results also observed a shift of body weight from underweight to overweight and obesity along the hikikomori duration. Half of the hypertensive cases involved the elevation of systolic blood pressure, which suggested higher odds of cardiovascular complications. In conclusion, the hikikomori lifestyle could be a risk behavior that may harm the younger generation physically by promoting obesity and hypertension and probably other chronic illnesses.

Synthesis of Size-Tunable Hollow Polypyrrole Nanostructures and Their Assembly into Folate-Targeting and pH-Responsive Anticancer Drug-Delivery Agents.

Chemotherapeutic drugs currently used in clinical settings have high toxicity, low specificity, and short half-lives. Herein, polypyrrole-based anticancer drug nanocapsules were prepared by tailoring the size of the nanoparticles with a template method, controlling drug release by means of an aromatic imine, increasing nanoparticle stability through PEGylation, and improving tumor-cell selectivity by folate mediation. The nanoparticles were characterized by TEM and dynamic light scattering. α-Folate receptor expression levelsof tumor cells and normal cells were investigated by western blot and quantitative polymerase chain reaction analyses. Flow cytometry and fluorescence imaging were used to verify the cell uptake of the different-sized nanoparticles. From the different-sized polypyrrole nanoparticles, the optimally functionalized nanoparticles of 180 nm hydrodynamic diameter were chosen and further usedfor in vitroandin vivotests. The nanoparticles showed excellent biocompatibility and the drug-loaded nanoparticles exhibited effective inhibition of tumor cell growth in vitro. Moreover, the drug-loaded nanoparticles showed substantially enhanced accumulation in tumor regions and effectively inhibitedin vivotumor growth. Furthermore, the nanoparticles showed reduced doxorubicin-induced toxicity andno significant side effects in normal organs of tumor-bearing mice, as measured by body-weight shifts and evaluationof drug distribution. Overall, the functionalized nanoparticles are promising nanocarriers for tumor-targeting drug delivery.

Effects of continuous visual feedback during sitting balance training in chronic stroke survivors

BackgroundPostural control deficits are common in stroke survivors and often the rehabilitation programs include balance training based on visual feedback to improve the control of body position or of the voluntary shift of body weight in space. In the present work, a group of chronic stroke survivors, while sitting on a force plate, exercised the ability to control their Center of Pressure with a training based on continuous visual feedback. The goal of this study was to test if and to what extent chronic stroke survivors were able to learn the task and transfer the learned ability to a condition without visual feedback and to directions and displacement amplitudes different from those experienced during training.MethodsEleven chronic stroke survivors (5 Male - 6 Female, age: 59.72 ± 12.84 years) participated in this study. Subjects were seated on a stool positioned on top of a custom-built force platform. Their Center of Pressure positions were mapped to the coordinate of a cursor on a computer monitor. During training, the cursor position was always displayed and the subjects were to reach targets by shifting their Center of Pressure by moving their trunk. Pre and post-training subjects were required to reach without visual feedback of the cursor the training targets as well as other targets positioned in different directions and displacement amplitudes.ResultsDuring training, most stroke survivors were able to perform the required task and to improve their performance in terms of duration, smoothness, and movement extent, although not in terms of movement direction. However, when we removed the visual feedback, most of them had no improvement with respect to their pre-training performance.ConclusionsThis study suggests that postural training based exclusively on continuous visual feedback can provide limited benefits for stroke survivors, if administered alone. However, the positive gains observed during training justify the integration of this technology-based protocol in a well-structured and personalized physiotherapy training, where the combination of the two approaches may lead to functional recovery.

Assessment of Fall Characteristics From Depth Sensor Videos.

Falls are a major source of death and disability in older adults; little data, however, are available about the etiology of falls in community-dwelling older adults. Sensor systems installed in independent and assisted living residences of 105 older adults participating in an ongoing technology study were programmed to record live videos of probable fall events. Sixty-four fall video segments from 19 individuals were viewed and rated using the Falls Video Assessment Questionnaire. Raters identified that 56% (n = 36) of falls were due to an incorrect shift of body weight and 27% (n = 17) from losing support of an external object, such as an unlocked wheelchair or rolling walker. In 60% of falls, mobility aids were in the room or in use at the time of the fall. Use of environmentally embedded sensors provides a mechanism for real-time fall detection and, ultimately, may supply information to clinicians for fall prevention interventions. [Journal of Gerontological Nursing, 43(7), 13-19.].

Preparation, characterization, biotoxicity, and biodistribution of thermo-responsive magnetic complex micelles formed by Mn0.6Zn0.4Fe2O4 and a PCL/PEG analogue copolymer for controlled drug delivery.

A thermo-responsive PCL/PEG analogue copolymer (PCL-[b-P(MEO2MA-co-OEGMA)]2) with a lower critical solution temperature (LCST) of 40.4 °C at an MEO2MA/OEGMA molar ratio of 87 : 13 was designed and synthesized. The copolymer was subsequently labeled by coupling with fluorescein isothiocyanate (FITC). Thermo-responsive magnetic PCL-[b-P(MEO2MA-co-OEGMA)]2/Mn0.6Zn0.4Fe2O4 (MZF) complex micelles were prepared by a self-assembly method. Doxorubicin (DOX) was loaded into the magnetic complex micelles as a model drug, and the DOX-MZF-micelles showed well-controlled thermo-responsive release both at externally fixed temperatures and in the presence of an alternating magnetic field (AMF). Both the blank polymer micelles and the magnetic complex micelles exhibited excellent stability in normal saline and serum. Based on the detection of the FITC fluorescence signal, the micelles were found to be effectively labeled by FITC. Furthermore, the biological toxicity of micelles was studied in vitro and in vivo. In vitro toxicity studies to evaluate cell viability and cell toxicity were performed by employing WST-1 and LDH release assays using HL7702 cells, respectively. In vivo biotoxicity studies were conducted in ICR mice through a series of tests: general conditions, body weight shifts, serum biochemistry profiles, and organ coefficient tests. All the biological toxicity results obtained from the blank polymer micelles and the magnetic complex micelles indicated their good biocompatibility and nontoxicity. The in vivo biodistribution studies of the FITC-labeled magnetic complex micelles were performed in the ICR mice. The copolymer was cleared by the kidney and spleen, while the MZF nanoparticles were cleared by the liver in time, causing no adverse effects on organisms. The thermo-responsive magnetic complex micelles were shown to be an ideal nanocarrier for anticancer drug delivery in terms of controlled release, stability, biocompatibility and safety.

Randomized comparison trial of gait training with and without compelled weight-shift therapy in individuals with chronic stroke

Objective: To compare the effects of gait training combined with compelled weight-shift therapy and gait training alone on velocity and gait symmetry in patients with chronic stroke. Design: Single-blind randomized controlled trial. Participants: Patients (N=28) with chronic stroke and stance asymmetry toward the non-paretic side. Interventions: Six weeks of gait training combined with compelled weight-shift therapy via a shoe lift applied under the non-paretic leg (experimental group, n=14) or gait training alone (control group, n=14). Main measures: Percentage of total body weight carried by the paretic limb, gait velocity and gait spatiotemporal symmetry ratios including step symmetry, stance symmetry, swing symmetry and overall temporal symmetry. Results: When comparing the two groups, weight bearing on the affected side increased more significantly in experimental group than in control group (40.14±3.77, 38.28±4.06) after the end of treatment and also after a three-month follow-up (44.42±3.5, 38.5±3.77) (P<0.05). Among the experimental and control groups, there were no significant differences of gait velocity (cm/s) after six weeks of treatment (49.82±16.82, 42.66±18.75) and also after a three-month follow-up (50.94±16.27, 41.66±17.58) (P>0.05). There were no significant differences of gait spatiotemporal symmetry ratios including step symmetry, stance symmetry, swing symmetry and overall temporal symmetry between the two groups after six weeks of treatment and also at three-month follow-up (P>0.05). Conclusions: This study did not confirm that the effect of gait training combined with compelled body weight shift therapy was better than gait training alone on improving velocity and gait symmetry in patients with chronic stroke.

The force output of handle and pedal in different bicycle-riding postures

The purpose of this study was to analyse the force output of handle and pedal as well as the electromyography (EMG) of lower extremity in different cycling postures. Bilateral pedalling asymmetry indices of force and EMG were also determined in this study. Twelve healthy cyclists were recruited for this study and tested for force output and EMG during steady state cycling adopting different pedalling and handle bar postures. The standing posture increased the maximal stepping torque (posture 1: 204.2 47.0 Nm; posture 2: 212.5 46.1 Nm; posture 3: 561.5 143.0 Nm; posture 4: 585.5 139.1 Nm), stepping work (posture 1: 655.2 134.6 Nm; posture 2: 673.2 116.3 Nm; posture 3: 1852.3 394.4 Nm; posture 4: 1911.3 432.9 Nm), and handle force (posture 1: 16.6 3.6 N; posture 2: 16.4 3.6 N; posture 3: 26.5 8.2 N; posture 4: 41.4 11.1 N), as well as muscle activation (posture 1: 13.6–25.1%; posture 2: 13.0–23.9%; posture 3: 23.6–61.8%; posture 4: 22.5–65.8%) in the erector spine, rectus femoris, tibialis anterior, and soleus. However, neither a sitting nor a standing riding posture affected the hamstring. The riding asymmetry was detected between the right and left legs only in sitting conditions. When a cyclist changes posture from sitting to standing, the upper and lower extremities are forced to produce more force output because of the shift in body weight. These findings suggest that cyclists can switch between sitting and standing postures during competition to increase cycling efficiency in different situations. Furthermore, coaches and trainers can modify sitting and standing durations to moderate cycling intensity, without concerning unbalanced muscle development.

Postural strategy and trunk muscle activation during prolonged standing in chronic low back pain patients

Prolonged standing has been associated with development and aggravation of low back pain (LBP). However, the underlying mechanisms are not well known. The aim of the present study was to investigate postural control and muscle activation during and as a result of prolonged standing in chronic LBP (cLBP) patients compared to healthy controls (HCs). Body weight shifts and trunk and hip muscle activity was measured during 15min standing. Prior and after the standing trial, strength, postural sway, reposition error (RE), flexion relaxation ratio (FRR), and pain were assessed and after the prolonged standing, ratings of perceived exertion. During prolonged standing, the cLBP patients performed significantly more body weight shifts (p<.01) with more activated back and abdominal muscles (p=.01) and similar temporal variability in muscle activation compared to HCs, while the cLBP patients reported more pain and perceived exertion at the end of prolonged standing. Moreover, both groups had a similar change in strength, postural sway, RE and FRR from before to after prolonged standing, where changes in HC were towards pre-standing values of cLBP patients. Thus, despite a more variable postural strategy, the cLBP patients did not have higher muscle activation variability, but a general increased muscle activation level. This may indicate a reduced ability to individually deactivate trunk muscles. Plausibly, due to the increased variable postural strategy, the cLBP patients could compensate for the relatively high muscle activation level, resulting in normal variation in muscle activation and normal reduction in strength, RE and FRR after prolonged standing.

A COMPARATIVE STUDY ON THE EFFECT OF COMPELLED BODY WEIGHT SHIFT THERAPY (CBWST) AND MODIFIED CONSTRAINT INDUCED MOVEMENT THERAPY (m CIMT) ON WEIGHT BEARING SYMMETRY AND BALANCE IN STROKE PATIENTS

Abstract: Background and Purpose: Falls are highly prevalent and it is a one of the complications in post stroke patients. One of the reasons for impaired balance and high risk of falls is asymmetry weight bearing between both the legs. The aim of this study is to compare the effect of Compelled Body Weight Shift Therapy and Modified Constraint Induced Movement Therapy on weight bearing symmetry and balance in post stroke patients. Methodology: A Randomized Clinical Trial. Twenty two subacute and chronic patients were randomly allocated into two groups. Group A received Compelled Body Weight Shift Therapy and group B received Modified Constraint Induced Movement Therapy. Intervention was given for 1 hour a day for 6 days a week for 2 weeks. Outcome Measure: Weight bearing symmetry and balance was assessed using two weighing scales and Berg Balance Scale. Results: There was a significant difference in pre post intervention values of both the groups (p=0.00001) in terms of affected leg, unaffected leg, difference in weight distribution between both the legs and balance. Between the group A and B, the post values of both the groups there was a statically significance difference in terms of weight distribution on affected leg (p=0.001), unaffected leg (p=0.0119) and difference between both the legs (p=0.0099) Conclusion: Compelled Body Weight Shift Therapy and Modified Constraint Induced Movement Therapy are both effective in improving weight bearing symmetry and balance in post stroke patients. However, Modified Constraint Induced Movement Therapy has showed more statistically significant improvement compared to Compelled Body Weight Shift Therapy in terms of weight bearing symmetry.

English

Introduction: Stroke related hemiparesis also exhibit asymmetry in standing posture and walking. Chronic stroke survivors represent with asymmetric gait pattern due to altered weight distribution. Altered weight distribution of lower limbs that is less weight is taken on affected side, fewer excursions on the weaker side, is seen during static and dynamic balance as well as external perturbation. Objective: To evaluate the effect of Compelled Body Weight Shift Therapy on weight bearing symmetry and balance in post stroke patients. Methods: Total 22 participants were included in the study. All patients received 10mm shoe insole which is to be used on their unaffected side and along with this conventional rehabilitation program were given for 1 hour per day for 2 weeks. Results: There was significant difference in pre-post weight bearing distribution (p<0.001) and balance (p<0.001). There was also significant difference in all the component of Berg Balance Scale (p<0.001). Conclusion: Compelled Body Weight Shift Therapy can be easily administrated in the daily rehabilitation protocol, while treating stroke patients with balance problems due to asymmetrical weight bearing. With more symmetrical weight bearing, balance can be improved for better ambulation and reduced risk of falls.

Effect of compelled body weight shift therapy on weight bearing symmetry and balance in post stroke patients: an experimental pre-post study

Introduction: Stroke related hemiparesis also exhibit asymmetry in standing posture and walking. Chronic stroke survivors represent with asymmetric gait pattern due to altered weight distribution. Altered weight distribution of lower limbs that is less weight is taken on affected side, fewer excursions on the weaker side, is seen during static and dynamic balance as well as external perturbation. Objective: To evaluate the effect of Compelled Body Weight Shift Therapy on weight bearing symmetry and balance in post stroke patients. Methods: Total 22 participants were included in the study. All patients received 10mm shoe insole which is to be used on their unaffected side and along with this conventional rehabilitation program were given for 1 hour per day for 2 weeks. Results: There was significant difference in pre-post weight bearing distribution (p<0.001) and balance (p<0.001). There was also significant difference in all the component of Berg Balance Scale (p<0.001). Conclusion: Compelled Body Weight Shift Therapy can be easily administrated in the daily rehabilitation protocol, while treating stroke patients with balance problems due to asymmetrical weight bearing. With more symmetrical weight bearing, balance can be improved for better ambulation and reduced risk of falls.

Amphiphilic peptide dendritic copolymer-doxorubicin nanoscale conjugate self-assembled to enzyme-responsive anti-cancer agent

Peptide dendrimer drug conjugate based nanoparticles are recently developed as a potential candidate for drug delivery vehicle. In this study, we prepared and characterized the enzyme-sensitive amphiphilc mPEGylated dendron-GFLG-DOX conjugate via two-step highly efficient click reaction. Dynamic light scattering (DLS) and transmission electron microscope (TEM) studies demonstrated the mPEGylated dendron-GFLG-DOX conjugate self-assembled into compact nanoparticles with negatively charged surface. The nanoparticles with 9.62 wt% (weight percent) of DOX showed enzyme-sensitive property by drug release tests. The nanoparticles were shown to effectively kill cancer cells in vitro. The fluorescent image indicated that the nanoparticles could accumulate and retain within tumor for a long time. Moreover, the nanoparticles substantially enhanced antitumor efficacy compared to the free DOX, exhibiting much higher effects on inhibiting proliferation and inducing apoptosis of the 4T1 murine breast cancer model confirmed as the evidences from tumor growth curves, tumor growth inhibition (TGI), immunohistochemical analysis and histological assessment. The nanoparticles reduced DOX-induced toxicities and presented no significant side effects to normal organs of both tumor bearing and healthy mice as measured by body weight shifts and histological analysis. Therefore, the mPEGylated dendron-GFLG-DOX conjugate based nanoparticle serves as a potential drug delivery vehicle for breast cancer therapy.

Body size perception and weight control in youth: 9-year international trends from 24 countries.

ObjectivesTo examine nine-year trends and relationships regarding misperceptions of body size and dieting for weight loss among adolescents from 24 countries, and explore the influence of country-level overweight prevalence.MethodsSocio-demographic characteristics, body size perception, and dieting for weight loss were assessed in the Health Behaviour in School-aged Children survey conducted in 24 countries cross-sectionally at three time points (2001/02, 2005/06, 2009/10). Logistic regression models examined change over time in overestimation of body size in non-overweight adolescents, underestimation of body size in overweight adolescents, dieting for weight loss in non-overweight and overweight adolescents, and relationships between body size perception and dieting. Analyses were stratified by weight status and sex. Covariates included country-level overweight prevalence, family affluence, and country level of development. Body mass index was only included in models examining dieting for weight loss.ResultsCountry-level overweight prevalence increased over time (11.6% to 14.7%). Compared to Time 1, overweight adolescents had greater odds of body size underestimation at Time 3 (OR=1.68 for girls, OR=1.10 for boys), while non-overweight adolescents had lower odds of body size overestimation at Time 3 (OR=0.87 for girls, OR=0.89 for boys). Controlling for country-level overweight prevalence attenuated these relationships. Compared to Time 1, overweight and non-overweight boys were 10% more likely to diet at Time 3, while overweight and non-overweight girls were 19% and 16%, respectively, less likely to diet at Time 3. Controlling for country-level overweight prevalence did not impact trends in dieting for weight loss. Additionally, the association of self-perceived overweight with increased odds of dieting diminished over time.ConclusionsBody size perceptions among adolescents may have changed over time concurrent with shifts in country-level body weight. However, controlling for country-level overweight prevalence did not impact trends in dieting for weight loss, suggesting a potentially stronger impact of social comparison on weight-related perceptions than on behavior.

Peptide Dendrimer–Doxorubicin Conjugate‐Based Nanoparticles as an Enzyme‐Responsive Drug Delivery System for Cancer Therapy

Peptide dendrimers have shown promise as an attractive platform for drug delivery. In this study, mPEGylated peptide dendrimer-doxorubicin (dendrimer-DOX) conjugate-based nanoparticle is prepared and characterized as an enzyme-responsive drug delivery vehicle. The drug DOX is conjugated to the periphery of dendrimer via an enzyme-responsive tetra-peptide linker Gly-Phe-Leu-Gly (GFLG). The dendrimer-DOX conjugate can self-assemble into nanoparticle, which is confirmed by dynamic light scattering, scanning electron microscopy, and transmission electron microscopy studies. At equal dose, mPEGylated dendrimer-DOX conjugate-based nanoparticle results in significantly high antitumor activity, and induces apoptosis on the 4T1 breast tumor model due to the evidences from tumor growth curves, an immunohistochemical analysis, and a histological assessment. The in vivo toxicity evaluation demonstrates that nanoparticle substantially avoids DOX-related toxicities and presents good biosafety without obvious side effects to normal organs of both tumor-bearing and healthy mice as measured by body weight shift, blood routine test, and a histological analysis. Thus, the mPEGylated peptide dendrimer-DOX conjugate-based nanoparticle may be a potential nanoscale drug delivery vehicle for the breast cancer therapy.

Immediate effects of two attention strategies on trunk control on patients after stroke. A randomized controlled pilot trial

Objective: To compare the immediate effects of an external focus to enhance lateral body weight shift after stroke. Design: Randomized controlled trial. Setting: Inpatient rehabilitation hospital. Subjects: Twenty patients after stroke (11 males; mean (SD) age 72.2 (7.4) years; duration of illness 56 (14) days; there were 9 (45%) left-sided strokes) with impaired sitting balance were randomly allocated into two groups either external focus (n = 10) or internal focus (n = 10). Intervention: Patients in the external focus group, while sitting, were instructed to shift as much weight as they could sidewards to an external point next to their hip. Patients in the internal focus group were instructed to shift as much weight as they could sidewards to their hip. Main outcome measures: Immediate lateral body weight shift as well as anterior–posterior deviation was measured in centimetres with a sensor mat. Results: Patients in the external focus group achieved greater lateral body weight shift than those in the internal focus group (mean shift (SD) 8.7 (2.6) cm vs. 4.5 (3.3) cm, respectively; P = 0.006). However, there were no significant differences in anterior–posterior deviation (mean shift (SD) 2.3 (1.3) cm vs. 1.2 (1.2) cm, respectively; P = 0.08). Conclusion: Using an external focus may lead immediately to an enhanced lateral body weight shift while sitting, without increasing anterior–posterior deviation.

Preparation and Biosafety Evaluation of the Peptide Dendron Functionalized Mesoporous Silica Nanohybrid

AbstractMesoporous silica nanoparticles (MSNs) have been extensively studied and proposed as promising candidates for numerous biomedical applications. In this study, we report the design, preparation, characterization and biosafety evaluation of peptide dendron functionalized mesoporous silica nanohybrid. This nanohybrid was prepared by surface modification of MSNs via click reaction of azido‐MSNs with alkynyl peptide dendrons, and characterized by TEM, SEM, TGA, dynamic light scattering (DLS). In vitro cytotoxicity of the nanohybrid was evaluated against different cell lines by CCK‐8 assay. The in vivo toxicity evaluation was measured by body weight shift, blood routine test and histological analysis, suggesting that the peptide functionalized nanohybrid possessed good biocompatibility due to the non‐observed significant side effects to normal organs of healthy mice. Overall, considering our results we believe that the peptide dendron functionalized mesoporous silica nanohybrid is very promising in further biomedical applications.

EVALUATION OF THE BALANCE OF OBESE AND NON-OBESE ELDERLY WOMEN BY COMPUTED DYNAMIC POSTUROGRAPHY

Background: One of the main factors that currently limit the life of the elderly is the imbalance. Computed dynamic posturography, assesses the oscillation of the body by recording the pressure exerted by the feet on the force platform, and allows analyzing the postural reactions secondary to the shift of body weight. Objectives: Evaluate and compare the balance of obese and non-obese elderly women without vestibular symptoms by computed dynamic posturography. Design: prospective trial. Setting: data collected in a university hospital. Participants: 50 elderly females divided into 2 groups according to body mass index (BMI), between 18.5 and 24.9 kg/m2 for the non-obese group and greater than 30 kg/m2 for the obese group. Intervention: the participants were submitted to the Synapsys Static &amp; Dynamic Posturography® test. Measurements: Sensory Organization Test calculates the average proprioceptive, visual and vestibular functions. Data were analyzed statistically by the Fisher exact test. Results: significant differences were observed between the obese and non-obese subjects regarding: maximum amplitude of the anteroposterior displacement of the patient with eyes open and closed, length and surface area used by the patient with eyes open, energy spent with eyes open and closed, proprioceptive activity in the anteroposterior direction, and vestibular activity in the lateral direction. There were a higher percentage of changes in the anteroposterior tests compared to the lateral tests in the obese subjects. Conclusion: The obesity interferes with the body balance in elderly women, especially in situations that require postural control in the AP direction, proprioceptive cues in the AP direction and vestibular cues in the LAT direction.

Distinguishing the causes of falls in humans using an array of wearable tri-axial accelerometers

Falls are the number one cause of injury in older adults. Lack of objective evidence on the cause and circumstances of falls is often a barrier to effective prevention strategies. Previous studies have established the ability of wearable miniature inertial sensors (accelerometers and gyroscopes) to automatically detect falls, for the purpose of delivering medical assistance. In the current study, we extend the applications of this technology, by developing and evaluating the accuracy of wearable sensor systems for determining the cause of falls. Twelve young adults participated in experimental trials involving falls due to seven causes: slips, trips, fainting, and incorrect shifting/transfer of body weight while sitting down, standing up from sitting, reaching and turning. Features (means and variances) of acceleration data acquired from four tri-axial accelerometers during the falling trials were input to a linear discriminant analysis technique. Data from an array of three sensors (left ankle+right ankle+sternum) provided at least 83% sensitivity and 89% specificity in classifying falls due to slips, trips, and incorrect shift of body weight during sitting, reaching and turning. Classification of falls due to fainting and incorrect shift during rising was less successful across all sensor combinations. Furthermore, similar classification accuracy was observed with data from wearable sensors and a video-based motion analysis system. These results establish a basis for the development of sensor-based fall monitoring systems that provide information on the cause and circumstances of falls, to direct fall prevention strategies at a patient or population level.