Evaluation of a smartphone human activity recognition application with able-bodied and stroke participants.

BACKGROUND: Mobile health monitoring using wearable sensors is a growing area of interest. As the world's population ages and locomotor capabilities decrease, the ability to report on a person's mobility activities outside a hospital setting becomes a valuable tool for clinical decision-making and evaluating healthcare interventions. Smartphones are omnipresent in society and offer convenient and suitable sensors for mobility monitoring applications. To enhance our understanding of human activity recognition (HAR) system performance for able-bodied and populations with gait deviations, this research evaluated a custom smartphone-based HAR classifier on fifteen able-bodied participants and fifteen participants who suffered a stroke. METHODS: Participants performed a consecutive series of mobility tasks and daily living activities while wearing a BlackBerry Z10 smartphone on their waist to collect accelerometer and gyroscope data. Five features were derived from the sensor data and used to classify participant activities (decision tree). Sensitivity, specificity and F-scores were calculated to evaluate HAR classifier performance. RESULTS: The classifier performed well for both populations when differentiating mobile from immobile states (F-score > 94 %). As activity recognition complexity increased, HAR system sensitivity and specificity decreased for the stroke population, particularly when using information derived from participant posture to make classification decisions. CONCLUSIONS: Human activity recognition using a smartphone based system can be accomplished for both able-bodied and stroke populations; however, an increase in activity classification complexity leads to a decrease in HAR performance with a stroke population. The study results can be used to guide smartphone HAR system development for populations with differing movement characteristics.

Hip loading asymmetry in Lenke type 1 idiopathic scoliosis: Effect of spinal fusion and sex.

BACKGROUND: Thoracic curvatures are most common in patients with idiopathic scoliosis. The literature highlights an imbalance of hip joint moments in the frontal plane quantified with a symmetry index. Spinal arthrodesis can reduce this symmetry index which then tends towards 0. Furthermore, asymptomatic women present lower hip moment in the frontal plane than asymptomatic men. This difference could influence the symmetry index in the case of patients with idiopathic scoliosis. Therefore, the main objective of this study was to show a significant positive effect of spinal arthrodesis on the symmetry index. The secondary objective was to compare the symmetry index between sexes before spinal fusion. METHOD: The retrospective study included 20 patients with Type-1 Lenke curve idiopathic scoliosis, who performed a gait analysis before and one year after spinal fusion. The gait analysis consisted of walking back and forth at spontaneous speed. FINDINGS: While significantly lower curvatures were depicted, the symmetry index showed a significantly lower value after spinal fusion (p < 0.03). The symmetry index showed no significant difference between sexes (p > 0.05). INTERPRETATION: The study shows the effect of surgical fusion on the symmetry index, although the latter remains significant compared to the norm. Literature reveals that spinal fusion tends to the symmetrisation of the body's center of mass and increases ranges of motion on the trunk and pelvis. This could favour symmetry of hip moment in the frontal plane. Future research should investigate other Type Lenke curves before and after surgery, and the effect of braces on this symmetry index.

Effects of Unity Prosthetic Elevated Vacuum Suspension System on Minimum Swing Toe Clearance.

BACKGROUND: The risk of tripping in people with amputation is greater than that of able-bodied individuals due to reduced toe clearance during the swing phase. Appropriate prosthetic suspension may increase toe clearance by providing more secured attachment between the residual limb and prosthetic socket. Research is lacking on the Unity suspension system's effect on swing toe clearance. METHODS: Twelve people with transtibial amputation were fitted with the Unity suspension system. After one month accommodation period, the person walked with active (ON) or inactive vacuum (OFF) in a CAREN-Extended virtual reality system, across multiple simulated real-world scenarios. Prosthetics minimum swing toe clearance, and kinematic data, while the vacuum was ON or OFF, were compared with the intact side and a group of 12 able-bodied individuals. RESULTS: Minimum swing toe clearance (MSTC) and knee flexion angle were larger on the prosthetic side (active and inactive vacuum) compared to both the intact side and the control group. However, hip flexion angle on the prosthetic side was approximately 17% smaller than the control group. Unlike the control group, MSTC with active and inactive vacuum suspension was not significantly different between level walking and other walking conditions. Finally, among all walking conditions, the lowest swing toe clearance for both control and the amputee groups was recorded when the limb was at the top of a side-slope. CONCLUSION: An effective suspension system could improve toe clearance; however, significant differences were not found between active and inactive vacuum conditions. The likelihood of inappropriate foot contact on side-slope ground might be greater than other walking conditions for both able-bodied and amputee groups, possibly leading to stumbling or falling.

A Novel Quick Release Mechanism for Ankle Foot Orthosis Struts.

BACKGROUND: A posterior dynamic element ankle-foot orthosis (PDEAFO) uses a stiff carbon fibre strut to store and release energy during various mobility tasks, with the strut securely attached to the foot and shank-cuff sections. A design that allows the user to swap struts for specific activities could improve mobility by varying PDEAFO stiffness, but current approaches where bolts securely connect the strut to the orthosis make quick strut swapping time-consuming and impractical. OBJECTIVES: Design a novel quick release AFO (QRAFO) that can enable daily living strut-swapping and thereby enable better ankle biomechanics for the person's chosen activity. METHODOLOGY: The novel QRAFO enables device stiffness changes through a quick release mechanism that includes a quick-release key, weight-bearing pin, receptacle anchor, and immobilization pin. A prototype was modelled and simulated with SolidWorks. Mechanical tests were performed with an Instron 4482 machine to evaluate quick release mechanism strength with running and 20° slope downhill walking loads. Quick release efficiency was then evaluated via two quick release functional tests, with four participants wearing a 3D printed QRAFO. FINDINGS: Simulated stress on the weight bearing pin, anchor, and surrounding carbon fibre structure under running and downhill walking loads did not exceed the yielding stress. Mechanical tests verified the simulation results. Four participants successfully swapped the strut within 25.01 ± 3.66 seconds, outperforming the 60.48 ± 10.88 seconds result for the hand-tightened bolted strut. A learning evaluation with one participant showed that, after approximately 30 swapping iterations, swap time was consistently below 10 seconds. CONCLUSION: The quick release mechanism accommodated running and slope walking loads, and allowed easy and fast strut removal and attachment, greatly reducing strut swap time compared to screw-anchor connections. Overall, the novel quick release AFO improved strut-swapping time without sacrificing device strength, thereby enabling people to use the most appropriate AFO stiffness for their current activity and hence improve mobility and quality of life.

Passive Rotation Angle Motion Validation for an Ankle-Foot Orthosis Multi-Jointed Surrogate Lower Limb Design.

Ankle-foot orthoses (AFO) are devices that assist lower limb motion. Mechanical testing an AFO would ideally load the device while worn on the leg, since AFO function is dependent on intimate leg contact. However, this is not appropriate for cyclic or load-to-failure applications. A surrogate lower limb (SLL) was designed for this AFO testing application, to provide anthropometric 3D movement when subjected to standard test loads. This novel four-joint SLL was inspired by the Rizzoli foot model, which segments the lower limb into five sections. SLL joint prototypes were validated by measuring rotation angles and comparing with typical anatomical ranges of motion. The 3D printed models were within acceptable variability of human joint movement and, therefore, were appropriate for use in the final SSL.

Transtibial amputee gait with the unity suspension system.

Study Design: Experimental study.Objectives: Research is lacking on the Unity suspension system's effect on gait performance. The purpose of this study was to evaluate the effects of the Unity elevated vacuum system on level walking performance while the vacuum was active (ON) and inactive (OFF).Methods: Twelve unilateral transtibial amputees were fit with the Ossur elevated vacuum suspension system (Unity) and Pro-flex XC foot. After one month accommodation period, 3D motion analysis was performed using the CAREN-Extended system. Temporal-spatial, kinematics, and kinetics were examined during level walking to understand the effect of the elevated vacuum, separate trials were completed with the vacuum active (ON) or inactive (OFF).Results: Significant differences were found between vacuum conditions (ON and OFF) for some temporal-spatial gait parameters, but differences were very small and may not be clinically significant. Differences between vacuum conditions on most kinetic and kinematic gait parameters were also low. However, step length symmetry between intact and prosthetic limbs improved with active elevated vacuum (ON).Conclusions: Elevated vacuum suspension's effect on level walking gait is small if a well-fitting liner-based socket is provided.Implications for rehabilitationStep length symmetry between intact and prosthetic limbs improved with an active vacuum system.Differences between vacuum conditions on most gait parameters were small during level walking.Subjective feedback showed improved proprioception and comfort with an active vacuum system.

DC conductivity of a suspension of insulating particles with internal rotation.

We analyse the consequences of Quincke rotation on the conductivity of a suspension. Quincke rotation refers to the spontaneous rotation of insulating particles dispersed in a slightly conducting liquid and subject to a high DC electric field: above a critical field, each particle rotates continuously around itself with an axis pointing in any direction perpendicular to the DC field. When the suspension is subject to an electric field lower than the threshold one, the presence of insulating particles in the host liquid decreases the bulk conductivity since the particles form obstacles to ion migration. But for electric fields higher than the critical one, the particles rotate and facilitate ion migration: the effective conductivity of the suspension is increased. We provide a theoretical analysis of the impact of Quincke rotation on the apparent conductivity of a suspension and we present experimental results obtained with a suspension of PMMA particles dispersed in weakly conducting liquids.

Size effect in Quincke rotation: a numerical study.

This paper deals with the Quincke rotation of small insulating particles. This dc electrorotation of insulating objects immersed in a slightly conducting liquid is usually explained by looking at the action of the free charges present in the liquid. Under the effect of the dc electric field, the charges accumulate at the surface of the insulating particle which, in turn, acquires a dipole moment in the direction opposite to that of the field and begins to rotate in order to flip its dipole moment. In the classical Quincke model, the charge distribution around the rotor is supposed to be purely superficial. A consequence of this assumption is that the angular velocity does not depend on the rotor size. Nevertheless, this hypothesis holds only if the rotor size is much larger than the characteristic ion layer thickness around the particle. In the opposite case, we show thanks to numerical calculations that the bulk charge distribution has to be accounted for to predict the electromechanical behavior of the rotor. We consider the case of an infinite insulating cylinder whose axis is perpendicular to the dc electric field. We use the finite element method to solve the conservation equations for the positive and the negative ions coupled with Navier-Stokes and Poisson equations. Doing so, we compute the bulk charge distribution and the velocity field in the liquid surrounding the cylinder. For sufficiently small cylinders, we show that the smaller the cylinder is, the smaller its angular velocity is when submitted to a dc electric field. This size effect is shown to originate both in ion diffusion and electromigration in the charge layer. At last, we propose a simple analytical model which allows calculating the angular velocity of the rotor when electromigration is present but weak and diffusion can be neglected.

Mechanical Evaluation Of Unity Elevated Vacuum Suspension System.

BACKGROUND: Small residual limb-socket displacement is a good indicator of prosthetic suspension system quality. Active vacuum suspension systems can decrease vertical movement inside the socket, compared to non-active suction systems. This study mechanically evaluated limb-socket displacement with the Össur Unity active vacuum system. METHOD: Forty-eight conditions were evaluated: four cylindrical and four conical sockets (polypropylene, polyethylene terephthalate glycol-modified (PETG), thermoset resin (acrylic), Thermolyn soft materials); two Iceross Seal-In V liners (standard, high profile); three vacuum conditions (active vacuum, inactive vacuum, no suction with valve open). An Instron 4428 test machine applied 0-100N linear ramped tensile loads to each positive mold, with the socket secured in place, while displacement between the mold and socket was recorded. Following the displacement tests, the load before failure (i.e., 10 mm displacement) was measured. RESULTS: Average and standard deviations for movement between the mold and sockets were small. The displacement average for all conditions was 0.30±0.16mm for active vacuum, 0.32±0.16mm for inactive vacuum, and 0.39±0.22mm for no suction. Across all trials, active vacuum systems tolerated significantly (p<0.001) more load before failure (812±221N) compared to inactive vacuum (727±213N), and no suction (401±184N). The maximum load before failure (1142±53N) was for the cylindrical polypropylene socket and high-profile liner. CONCLUSION: The Unity system successfully controlled pistoning inside the socket for regular activity loads and also controlled the greatest traction loads. While relative movement was smallest for Unity, all conditions (inactive vacuum, no suction) were viable for loads less than 100N. Furthermore, similar results can be achieved when using different socket fabrication materials.

Dysphagia 27 years after cervical disc arthroplasty.

INTRODUCTION: Dysphagia is a frequent postoperative symptom after anterior cervical disc arthroplasty. However, onset of dysphagia and neck pain a long time after surgery should suggest a diagnosis of prosthesis dislocation. CARE REPORT: A 65-year-old man with a history of cervical disc arthroplasty 27 years previously consulted for rapidly progressive dysphagia with no other associated symptoms. Physical examination and CT scan confirmed the diagnosis of anterior dislocation of the prosthesis with no signs of perforation. Surgical extraction via a neck incision allowed resolution of the symptoms. DISCUSSION: Prosthesis dislocation should be considered in a patient with a history of cervical disc arthroplasty presenting with dysphagia and neck pain. The clinical and radiological assessment confirmed the diagnosis and early surgical management allowed resolution of the symptoms and avoided complications such as pharyngo-oesophageal perforation.

Acute submaxillitis: Etiological data and etiological management.

OBJECTIVES: The objective of the present study was to test the hypothesis that acute submaxillitis involves salivary duct obstruction. Obstacle characteristics and treatment were analyzed. MATERIAL AND METHODS: Patients presenting with an episode of acute submaxillitis between 2009 and 2015 were retrospectively included. All underwent salivary duct imaging and/or sialendoscopy, with pathologic examination if the salivary gland was removed for etiologic diagnosis. For etiological treatment, if the causal lesion could not be treated by isolated sialendoscopy, surgery used a direct approach assisted by sialendoscope. In case of failure of these procedures, submaxillectomy was indicated. RESULTS: Twenty-nine patients were included, 28 of whom showed salivary duct abnormality. At least 1 calculus was found in 27 patients; calculi were usually single (n=20), situated in the mid-third (n=21), and large (mean 7.7mm). Ten patients showed stenosis, associated with salivary calculus in 9 cases. Twenty-five patients with salivary duct obstruction underwent sialendoscopy. Isolated sialendoscopy was used in 5 cases, and a combined approach in 13 cases. CONCLUSION: An episode of submaxillitis requires salivary duct exploration by sialendoscopy, to enable early treatment given the prevalence of associated calculi and high success rate of conservative management by sialendoscopy.

A secure web-based approach for accessing transitional health information for people with traumatic brain injury.

A web-based transitional health record was created to provide regional healthcare professionals with ubiquitous access to information on people with brain injuries as they move through the healthcare system. Participants included public, private, and community healthcare organizations/providers in Eastern Ontario (Canada). One hundred and nineteen service providers and 39 brain injury survivors registered over 6 months. Fifty-eight percent received English and 42% received bilingual services (English-French). Public health providers contacted the regional service coordinator more than private providers (52% urban centres, 26% rural service providers, and 22% both areas). Thirty-five percent of contacts were for technical difficulties, 32% registration inquiries, 21% forms and processes, 6% resources, and 6% education. Seventeen technical enquiries required action by technical support personnel: 41% digital certificates, 29% web forms, and 12% log-in. This web-based approach to clinical information sharing provided access to relevant data as clients moved through or re-entered the health system. Improvements include automated digital certificate management, institutional health records system integration, and more referral tracking tools. More sensitive test data could be accessed on-line with increasing consumer/clinician confidence. In addition to a strong technical infrastructure, human resource issues are a major information security component and require continuing attention to ensure a viable on-line information environment.

[Medico legal issues related to driving: the role of the general practitionner]. / Restrictions médico-légales a la conduite automobile rôle du médecin généraliste.

The Belgian law requires that the physician informs his/her patient when he diagnoses a medical reason that makes him/her unfit to drive a vehicle. This paper lists, as they appear in the official texts, the physical conditions and diseases which may be responsible for the inaptitude to drive. Thus are detailed the rules applied in the presence of neurological diseases, psychic disorders, epilepsia, pathological sleepiness, locomotive disorders, cardiovascular disease, rhythm or conduction disturbances, blood pressure abnormalities, coronary or myocardial disease, and hearing loss or vestibular problems. The reader will also find a summary of the rules related to visual ability, alcohol use, driving under the influence of psychotropic drugs, or medicines in general, renal or hepatic diseases, and to the patient who received an organ transplant or an artificial implant. The responsibility of the physician, primarily the general practionner, may be involved in these matters; this issue is discussed.

[Management of intrafamily violence issues by general practitioners]. / Gestion sur le terrain de la violence intra-familiale par le médecin généraliste.

General practitioners often come upon intrafamily abuse cases in their practice. They are either specifically consulted because of these instances of abuse or they discover them by accident. When this happens, they are often unsure of the appropriate procedure to follow, for fear of committing a medical fault or breaking the law. The aim of this short article is not to dwell on the diagnostic methodologies, but to provide a series of general guidelines to follow in everyday practice.

The evidence-base for elevated vacuum in lower limb prosthetics: Literature review and professional feedback.

BACKGROUND: An optimal suspension system can improve comfort and quality of life in people with limb loss. To guide practice on prosthetic vacuum suspension systems, assessment of the current evidence and professional opinion are required. METHODS: PubMed, Web of Science, and Google Scholar databases were explored to find related articles. Search terms were amputees, artificial limb, prosthetic suspension, prosthetic liner, vacuum, and prosthesis. The results were refined by vacuum socket or vacuum assisted suspension or sub-atmospheric suspension. Study design, research instrument, sample size, and outcome measures were reviewed. An online questionnaire was also designed and distributed worldwide among professionals and prosthetists (www.ispoint.org, OANDP-L, LinkedIn, personal email). FINDINGS: 26 articles were published from 2001 to March 2016. The number of participants averaged 7 (SD=4) for transtibial and 6 (SD=6) for transfemoral amputees. Most studies evaluated the short-term effects of vacuum systems by measuring stump volume changes, gait parameters, pistoning, interface pressures, satisfaction, balance, and wound healing. 155 professionals replied to the questionnaire and supported results from the literature. Elevated vacuum systems may have some advantages over the other suspension systems, but may not be appropriate for all people with limb loss. INTERPRETATION: Elevated vacuum suspension could improve comfort and quality of life for people with limb loss. However, future investigations with larger sample sizes are needed to provide strong statistical conclusions and to evaluate long-term effects of these systems.

Transilluminated powered phlebectomy. Mid-term clinical experience.

AIM: Transilluminated powered phlebectomy (TIPP) was first described in 1996 by Sptiz et al. and was designed to allow minimally invasive surgical treatment of varicose veins (VV). We report our updated experience with TIPP technique. METHODS: Between January 2001 and February 2004, 84 patients underwent treatment by TIPP technique for primary symptomatic VV. Saphenofemoral junction with complete stripping of the great saphenous vein was performed in all patients. Incompetent perforating veins was ligated and prominent VV were ablated with TIPP technique. RESULTS: Mean age of patients was 50.6 years (range 29-79 years) and most of patients were women (73%). The major varicose vein risk factors were standing position and parity. Heaviness (62%), pain (57%) and unsightly veins (30%) were the most common indications for surgery. The mean number of surgical incisions was 6 (range 3-10), the average operative time was 59 min (range 30-100 min) and the mean cosmetic score (out of 10) at 6 weeks was 8 (range 2-10). The mean pain score (out of 10) was at 2 days, 7 days and 6 weeks was 5, 3 and 0, respectively. All the complications were documented. CONCLUSIONS: The TIPP technique is safe without any adverse events, presents advantages and inconvenient which are discussed in this paper.

Cohesion induced by a rotating magnetic field in a granular material.

We report experiments on a magnetic cohesive granular material made of steel spheres in the millimeter range. A magnetic field magnetizes the spheres, so that an interaction force between grains appears. A rotating magnetic field is applied parallel to plane of the quasi-two-dimensional cell containing the spheres so that only the time averaged force between two particles will be considered. Both maximum angle of stability and angles of repose are measured. The maximum angle of stability is found to depend linearly on the interaction force. Another noticeable feature is the lack of dependence of the maximum angle of stability on the initial height of the heap. We show that the angle of repose is less sensitive to the magnetic interaction force than the maximum of stability. At last, we discuss the importance of using a rotating field rather than a constant one. In particular, we report some measurements of both the maximum angle of stability and the angle of repose in constant field, which show a strong dependence of the angles of avalanche on the direction of the field.

Electrohydrodynamic instabilities and orientation of dielectric ellipsoids in low-conducting fluids.

We study the dynamics of an ellipsoidal particle in a weakly conducting dielectric liquid when submitted to a dc electric field. At low field intensities, the particle long axis is aligned in the field direction. When the field strength is increased, we show that, depending on the initial orientation of the particle, there exist two stable orientations: the one with the long axis parallel to the field direction remains possible while a spinning state with the long axis perpendicular to the field appears. This last striking orientation is due to the finite Maxwell-Wagner polarization relaxation time. For sufficiently high field intensities, each state loses its stability and the particle dynamics becomes chaotic. Those conclusions from the theoretical model are supported by experimental observations.

Clinical analysis of a CAD/CAM system for custom seating: a comparison with hand-sculpting methods.

A CAD/CAM system for manufacturing custom seating inserts was evaluated within a moderately to severely disabled population. Using the Otto Bock Shape System, 25 CAD/CAM seats were manufactured at a remote facility and compared to 9 seats manufactured using hard-sculpting techniques. Clinician and client questionnaires were completed for each seat to assess satisfaction, fitting/manufacturing times, and to collect demographic data. The CAD/CAM method was significantly better (p < 0.05) than the hand-sculpting method in terms of on-site fabrication time. No significant differences were found for initial fitting time, final fitting time, clinician insert rating, and client satisfaction. These results support the CAD/CAM method as an effective and clinically efficient technique for making custom wheelchair seats.

A technique for the determination of center of gravity and rolling resistance for tilt-seat wheelchairs.

A balance platform setup was defined for use in the determination of the center of gravity in the sagittal plane for a wheelchair and patient. Using the center of gravity information, measurements from the wheelchair and patient (weight, tire coefficients of friction), and various assumptions (constant speed, level-concrete surface, patient-wheelchair system is a rigid body), a method for estimating the rolling resistance for a wheelchair was outlined. The center of gravity and rolling resistance techniques were validated against criterion values (center of gravity error = 1 percent, rolling resistance root mean square error = 0.33 N, rolling resistance Pearson correlation coefficient = 0.995). Consistent results were also obtained from a test dummy and five subjects. Once the center of gravity is known, it is possible to evaluate the stability of a wheelchair (in terms of tipping over) and the interaction between the level of stability and rolling resistance. These quantitative measures are expected to be of use in the setup of wheelchairs with a variable seat angle and variable wheelbase length or when making comparisons between different wheelchairs.