Impaired local dynamic stability during treadmill walking predicts future falls in patients with multiple sclerosis:A prospective cohort study

Background: Falling is a significant problem in patients with multiple sclerosis (MS) and the majority of falls occur during dynamic activities. Recently, there have been evidences focusing on falls and local stability of walking based on dynamic system theory in the elderly as well as patients with cerebral concussion. However, in patient with MS, this relationship has not been fully investigated. The aim of this study was to investigate local stability of walking as a risk factor for falling in patients with MS. Methods: Seventy patients were assessed while walking at their preferred speed on a treadmill under single and dual task conditions. A cognitive task (backward counting) was used to assess the importance of dual tasking to fall risk. Trunk kinematics were collected using a cluster marker over the level of T7 and a 7-camera motion capture system. To quantify local stability of walking, maximal finite-time Lyapunov exponent was calculated from a 12-dimensional state space reconstruction based on 3-dimensional trunk linear and angular velocity time series. Participants were classified as fallers (≥1) and non-fallers based on their prospective fall occurrence. Findings: 30 (43%) participants recorded ≥1 falls and were classified as fallers. The results of multiple logistic regression analysis revealed that short-term local dynamic stability in the single task condition (P < 0.05, odds ratio = 2.214 (1.037–4.726)) was the significant fall predictor. Interpretation: The results may indicate that the assessment of local stability of walking can identify patients who would benefit from gait retraining and fall prevention programs

Development of the Persian version of gross motor function measure-88 (GMFM-88): A study of reliability

The aims of this study were to cross-culturally translate and equivalence of Gross Motor Function Measure 88 (GMFM-88) in to Persian and to evaluate its reliability in the 50 children with Cerebral Palsy (CP). Our investigation was a none-experimental and methodological study which developed a Persian translation of GMFM-88 based on International Quality of Life Assessment (IQLA) guidelines. Inter-rater reliability was perfumed by comparison of scores recorded by two expert physiotherapists in a blind pattern while inter-rater reliability was assessed by comparison of scores recorded by an expert physiotherapist in two continuous weeks. Intra-class Correlation Coefficient (ICC) was used to evaluate both reliabilities. Additionally internal consistency was calculated using Cronbach's alpha coefficient. The ICC was 0.99 for both inter-rater reliability and intra-rater reliability with 95 Confidence Interval (CI) = 0.99-1. Cronbach�s alpha coefficients for all dimensions of GMFM-88 were ranged 0.78-0.94, which showed an acceptable internal consistency. The Persian version of GMFM-88 which indicated high internal consistency is a reliable instrument to quantifying gross motor function in children with CP and to following efficacy of various rehabilitation and medical treatments in these patients. © 2015 Academic Journals Inc

Discrepancy of target sites between clinician and cytopathological reports in head neck fine needle aspiration: Did I miss the target or did the clinician mistake the organ site?

The diagnostic accuracy of fine needle aspiration cytology (FNAC) of head and neck lesions is relatively high, but cytologic interpretation might be confusing if the sample is lacking typical cytologic features according to labeled site by physician. These errors may have an impact on pathology search engines, healthcare costs or even adverse outcomes. The cytology archive database of multiple institutions in southern Iran and Australia covering the period 2001–2011, were searched using keywords: salivary gland, head, neck, FNAC, and cytology. All the extracted reports were reviewed. The reports which showed discordance between the clinician’s impression of the organ involved and subsequent fine needle biopsy request, and the eventual cytological diagnosis were selected. The cytological diagnosis was confirmed by histology or cell block, with assistance from imaging, clinical outcome, physical examination, molecular studies, or microbiological culture. The total number of 10,200 head and neck superficial FNAC were included in the study, from which 48 cases showed discordance between the clinicians request and the actual site of pathology. Apart from the histopathology, the imaging, clinical history, physical examination, immunohistochemical study, microbiologic culture and molecular testing helped to finalize the target organ of pathology in 23, 6, 7, 8, 2, and 1 cases respectively. The commonest discrepancies were for FNAC of “salivary gland” [total: 20 with actual final pathology in: bone (7), soft tissue (5), lymph node (3), odontogenic (3) and skin (2)], “lymph node” [total: 12 with final pathology in: soft tissue (3), skin (3), bone (1) and brain (1)], “soft tissue” [total: 11 with final pathology in: bone (5), skin (2), salivary gland (1), and ocular region (1)] and “skin” [total: 5 with final pathology in: lymph node (2), bone (1), soft tissue (1) and salivary gland (1)]. The primary physician requesting FNAC of head and neck lesions are incorrect in their clinical impression of the actual site in nearly 0.5 percent of cases, due to the overlapping clinical and imaging findings or possibly due to inadequate history taking or physical examination

Predicting falls among patients with multiple sclerosis:Comparison of patient-reported outcomes and performance-based measures of lower extremity functions

Background Accurate fall screening tools are needed to identify those multiple sclerosis (MS) patients at high risk of falling. The present study aimed at determining the validity of a series of performance-based measures (PBMs) of lower extremity functions and patient-reported outcomes (PROs) in predicting falls in a sample of MS patients (n = 84), who were ambulatory independent. Methods Patients were assessed using the following PBMs: timed up and go (TUG), timed 25-foot walk (T25FW), cognitive T25FW, 2-min walk (2MW), and cognitive 2MW. Moreover, a series of valid and reliable PROs were filled in by participants including the activities-specific balance confidence (ABC), 12-item multiple sclerosis walking scale (MSWS-12), fall efficacy scale international (FES-I), and modified fatigue impact scale (MFIS). The dual task cost (DTC) of 2MW and T25FW tests were calculated as a percentage of change in parameters from single to dual task conditions. Participants were classified as none-fallers and fallers (⩾1) based on their prospective fall occurrence. Results In the present study, 41(49%) participants recorded ≥ 1 fall and were classified as fallers. The results of logistic regression analysis revealed that each individual test, except DTC of 2MW and T25FW, significantly predicted future falls. However, considering the area under the curves (AUCs), PROs were more accurate compared to PBMs. In addition, the results of multiple logistic regression with the first two factors extracted from principal component analysis revealed that both factor 1 (PROs) and factor 2 (PBMs) significantly predicted falls with a greater odds ratio (OR) for factor 1 (factor 1: P = <0.0001, OR = 63.41 (6.72–597.90)) than factor 2 (P <0.05, OR = 5.03 (1.33–18.99)). Conclusions The results of this study can be used by clinicians to identify and monitor potential fallers in MS patients

Comparison of postural balance between subgroups of nonspecific low-back pain patients based on O'Sullivan classification system and normal subjects during lifting

Background: Balance disorder is one of the most-studied fields in low-back pain patients (LBP). However, there is insufficient information regarding the effect of LBP subgrouping on postural control. The purpose of the present study was to compare postural control between subgroups of chronic nonspecific LBP and healthy subjects during lifting. Methods: A total of 35 men with chronic LBP (19 active extension pattern AEP and 16 flexion pattern FP) and 15 healthy controls were enrolled in this cross-sectional study. Pooled LBP was subdivided based on the O'Sullivan's classification system (OCS). The participants were asked to lift a box from the ground to the waist level and hold it for 20 seconds. The load was 10% of the subject's weight. Force plate system was used to record balance parameters, including standard deviations (SDs) of center of pressure (COP) amplitude and COP velocity in anterior-posterior and medial-lateral directions and mean total velocity. The test was divided into two static and dynamic phases. Data were analyzed using one-way analysis of variance and independent t-test. Results: There were no significant differences between pooled LBP and control groups in any of the variables, except for the SD of the anterior-posterior direction velocity in the X-plane in the static phase (P=0.017). After classifying LBP, the results showed that the healthy and AEP groups were significantly different in SD of COP velocity in the frontal plane (P=0.021), mean total velocity (P=0.010), and SD of COP velocity in the sagittal plane (P=0.039). Conclusion: The present study showed that postural control was not different between the pooled LBP and normal groups. After classifying pooled LBP based on OCS, we found that the AEP showed different postural control as compared to healthy controls in the dynamic phase. The FP and AEP exhibited different postural control relative to the healthy controls in the static phase, and COP velocity was lower in those groups compared to the control group. The results of this study support the concept of LBP classification. © 2019 BY THE ARCHIVES OF BONE AND JOINT SURGERY

Reliability of center of pressure measures of postural stability in patients with unilateral anterior cruciate ligament injury

The aim of this study was to estimate the test-retest reliability of some commonly used center of pressure measures in postural control investigations of sport injuries under the diverse stressful postural conditions. Twelve patients with anterior cruciate ligament injury were evaluated on two separate sessions. The center of pressure was recorded from force platform and the following measures were calculated (1) standard deviation of amplitude (2) mean velocity (3) standard deviation of velocity (4) phase plane parameters and (5) area (95 confidence ellipse). Relative and absolute reliability was assessed using intra-class correlation coefficient and coefficient of variation, respectively. Mean velocity and total phase plane parameters were the most reliable measures having high to very high correlation across all postural conditions. The mean and range of intra-class correlation coefficient for mean velocity and total phase plane parameters were 0.88 (range: 0.80 to 0.96) and 0.81 (range: 0.71 to 0.88), respectively. Interestingly, pattern of the coefficient of variation values was, to a great extent, consistent with the intra-class correlation coefficients. Therefore, mean velocity and total phase plane parameters may be sensitive center of pressure measures to differentiate balance between Anterior Cruciate Ligament (ACL) injured patients and to evaluate the effect of a rehabilitation program in this population. © 2008 Asian Network for Scientific Information

Reliability and validity of the Persian version of Foot and Ankle Ability Measure (FAAM) to measure functional limitations in patients with foot and ankle disorders

Objective: To translate the Foot and Ankle Ability Measure (FAAM) into Persian and to evaluate the psychometric properties of the Persian version of FAAM. Methods: 93 patients with a range of foot and ankle disorders, completed the Persian version of the FAAM and Short-Form 36 Health Survey (SF-36) in the test session. With an interval of 2-6 days, 60 patients filled out the FAAM in the retest session. The FAAM is composed of two subscales including activities of daily living (ADL) and SPORTS. Internal consistency was assessed using Cronbach's alpha, test-retest reliability using intraclass correlation coefficient (ICC) and standard error of measurement (s.e.m.), item internal consistency and discriminant validity using Spearman's correlation coefficient and construct validity using Spearman's correlation coefficient and Independent t-test. Results: Cronbach's alpha coefficient of 0.97 and 0.94 was obtained for ADL and SPORTS subscales, respectively. The ICC and s.e.m. were 0.98 and 3.13 for ADL and 0.98 and 3.53 for SPORTS subscale. Items were stronger measures of their hypothesized subscale than of other subscale. The ADL and SPORTS subscales had stronger correlation with SF-36 physical function (r=0.60, 0.53) and physical health summary measure (r=0.61, 0.48) than with SF-36 mental health (r=0.21, 0.10) and mental health summary measure (r=0.36, 0.27). A high correlation was found between FAAM scores and global scale of functional status for SPORTS (r=0.73) but not for ADL (r=0.42). FAAM scores were greater in individuals who rated their function as normal or nearly normal compared with those who rated as abnormal or severely abnormal for SPORTS (P=0.04) but not for ADL (P=0.15). Conclusion: The Persian version of FAAM is a reliable and valid measure to quantify physical functioning in patients with foot and ankle disorders. © 2010 Osteoarthritis Research Society International

Low Complexity Regularization of Linear Inverse Problems

Inverse problems and regularization theory is a central theme in contemporary signal processing, where the goal is to reconstruct an unknown signal from partial indirect, and possibly noisy, measurements of it. A now standard method for recovering the unknown signal is to solve a convex optimization problem that enforces some prior knowledge about its structure. This has proved efficient in many problems routinely encountered in imaging sciences, statistics and machine learning. This chapter delivers a review of recent advances in the field where the regularization prior promotes solutions conforming to some notion of simplicity/low-complexity. These priors encompass as popular examples sparsity and group sparsity (to capture the compressibility of natural signals and images), total variation and analysis sparsity (to promote piecewise regularity), and low-rank (as natural extension of sparsity to matrix-valued data). Our aim is to provide a unified treatment of all these regularizations under a single umbrella, namely the theory of partial smoothness. This framework is very general and accommodates all low-complexity regularizers just mentioned, as well as many others. Partial smoothness turns out to be the canonical way to encode low-dimensional models that can be linear spaces or more general smooth manifolds. This review is intended to serve as a one stop shop toward the understanding of the theoretical properties of the so-regularized solutions. It covers a large spectrum including: (i) recovery guarantees and stability to noise, both in terms of $\ell^2$-stability and model (manifold) identification; (ii) sensitivity analysis to perturbations of the parameters involved (in particular the observations), with applications to unbiased risk estimation ; (iii) convergence properties of the forward-backward proximal splitting scheme, that is particularly well suited to solve the corresponding large-scale regularized optimization problem

One-Pass Ranking Models for Low-Latency Product Recommendations

Purchase logs collected in e-commerce platforms provide rich information about customer preferences. These logs can be leveraged to improve the quality of product recommenda-tions by feeding them to machine-learned ranking models. However, a variety of deployment constraints limit the näıve applicability of machine learning to this problem. First, the amount and the dimensionality of the data make in-memory learning simply not possible. Second, the drift of customers’ preference over time require to retrain the ranking model regularly with freshly collected data. This limits the time that is available for training to prohibitively short intervals. Third, ranking in real-time is necessary whenever the query complexity prevents us from caching the predictions. This constraint requires to minimize prediction time (or equiva

Customer’s Acceptance of Humanoid Robots in Services: The Moderating Role of Risk Aversion

The emerging introduction of humanoid robots in service encounters is becoming a reality in the present and the short-term. Owing to this unstoppable advance, there is a need to better understand customers’ perceptions and reactions toward humanoid agents in service encounters. To shed some light on this underexplored phenomenon, this research investigates how the interaction between robot and customer’s features may contribute to a successful introduction of this disruptive innovation. Results of an empirical study with a sample of 168 US customers reveal that customer’s perceptions of robot’s human-likeness increase the intentions to use humanoid service robots. Interestingly, customers’ risk aversion moderates this relationship. Specifically, the study found that highly risk-averse customers tend to avoid using humanoids when they are perceived as highly mechanical-like. The discussion highlights the main contributions of the research, which combine previous knowledge on human–robot interaction and risk aversion from a marketing approach. Managerial implications derived from the research findings and the avenues opened for further research are described at the end