Phosphatidylinositol 5‐phosphate (PtdIns5P), the least characterized among the three phosphatidylinositol monophosphates, is emerging as a bioactive lipid involved in the control of several cellular functions. Similar to PtdIns3P, it is present in low amounts in mammalian cells, and can be detected at the plasma membrane and endomembranes as well as in the nucleus. Changes in PtdIns5P levels are observed in mammalian cells following specific stimuli or stresses, and in human diseases. Recently, the contribution of several enzymes such as PIKfyve, myotubularins, (...) and type II PtdInsP‐kinases to PtdIns5P metabolism has gained a strong experimental support. Here, we provide a picture emerging from recent studies showing how this lipid can be generated and act as a regulator of membrane and cytoskeleton dynamics, and as a modulator of gene expression. We briefly summarize the current methods and tools for studying PtdIns5P, and discuss how PtdIns5P can integrate and coordinate different functions in a spatiotemporal manner. (shrink)

The activism of institutional investors tends more and more toward the supervision and control of the behavior of the managers of big companies. In this article, we present a model based on the creation of an activism index that lets us evaluate such activism's effect on the sensitivity of the investment policies of a company in the face of financial variables and market variables. To test our assertions, we analyze firm-level data for United Kingdom, Germany, France, Denmark, and Spain during (...) the period 1995-2004. Our results point to a significant reduction in the sensitivity of company investment decisions in the face of these variables, especially relative to intangible capital, as a result of the neutralizing effect of activism on the high agency costs of free cash flow and on the information asymmetries of the market. (shrink)

The activism of institutional investors tends more and more toward the supervision and control of the behavior of the managers of big companies. In this article, we present a model based on the creation of an activism index that lets us evaluate such activism's effect on the sensitivity of the investment policies of a company in the face of financial variables and market variables . To test our assertions, we analyze firm-level data for United Kingdom , Germany, France, Denmark, and (...) Spain during the period 1995-2004. Our results point to a significant reduction in the sensitivity of company investment decisions in the face of these variables, especially relative to intangible capital, as a result of the neutralizing effect of activism on the high agency costs of free cash flow and on the information asymmetries of the market. (shrink)

The activism of institutional investors tends more and more toward the supervision and control of the behavior of the managers of big companies. In this article, we present a model based on the creation of an activism index that lets us evaluate such activism’s effect on the sensitivity of the investment policies of a company in the face of financial variables (such as cash flow and liquidity ratio) and market variables (ownership concentration and value creation index). To test our assertions, (...) we analyze firm-level data for United Kingdom (U.K.), Germany, France, Denmark, and Spain during the period 1995–2004. Our results point to a significant reduction in the sensitivity of company investment decisions in the face of these variables, especially relative to intangible capital, as a result of the neutralizing effect of activism on the high agency costs of free cash flow and on the information asymmetries of the market. (shrink)

We examine whether the behavior of institutional investors representatives on boards leads to observable differences in corporate finance. We find that directors representing pressure-sensitive investors prefer lower financial leverage whereas pressure-resistant directors show no particular preference. When analyzed separately, directors appointed by banks and insurance firms have different attitudes. Bank representatives on boards increase both the financial leverage and the banking debt. This result suggests that some types of institutional directors provide financial resources to the firms on whose board they (...) sit, supporting the view that boards manage the uncertainty associated with strategic decision making and provide firms with preferential access to resources and financial expertise. This research has interesting academic and policy implications for the debate over the proper degree of institutional involvement in corporate governance. Different institutional investors have different agendas and incentives for corporate governance, and, therefore, both researchers and policy makers should no longer consider institutional investors as a whole. In addition, our paper calls for new research on the causes and implications of institutional investor involvement in the corporate governance of nonfinancial firms. This new research could require new insights on the dynamics within the boards and on the interplay among the knowledge, incentives and attitudes of quite different directors. (shrink)

In this paper I present a case study of mathematical explanation in science that is new to the philosophical literature, and that arises in the context of estimating the energetic costs of running in bipedal animals. I refer to this as the Bipedal Gait Costs explanation. I argue that it is important for examples of applied mathematics to be driven not just by philosophical and mathematical concerns but also by scientific concerns. After a detailed presentation of the BGC case (...) study, I discuss ways in which it is different from standard examples of MES. One distinctive aspect of BGC is that substantive mathematics occurs at two different levels. I argue for a distinction to be drawn between the mathematical modeling that occurs at one level, which is non-explanatory, and the mathematical theorem which is applied to results gleaned from these models, which is explanatory. I conclude by drawing some connections with broader indispensability-based arguments for platonism in the philosophy of mathematics. (shrink)

GraphicalPatients with early- to middle-stage PD were enrolled for C-Gait assessment and traditional walking ability assessments. The correlation of C-Gait assessment and traditional walking tests were studied. Two models were established based on C-Gait assessment and traditional walking tests to explore the value of C-Gait assessment in predicting freezing of gait.ObjectiveEfficient methods for assessing walking adaptability in individuals with Parkinson’s disease are urgently needed. Therefore, this study aimed to assess C-Gait for detecting freezing of (...) gait in patients with early- to middle-stage PD.MethodPeople with PD diagnosis were recruited from April 2019 to November 2019 in Beijing Rehabilitation Hospital. The participants performed six items of walking adaptability on an instrumented treadmill augmented with visual targets and obstacles. The patient’s walking adaptability was evaluated by C-Gait assessment and traditional walking tests, and FOG-related indexes were collected as outcome measures. Two discriminant models were established by stepwise discriminant analysis; area under the receiver operating characteristic curve was used to validate the models.ResultIn total, 53 patients were included in this study. Most C-Gait assessment items had no or low correlations with traditional walking tests. The obstacle avoidance and speed of adaptation items could lead to FOG with high sensitivity. In addition, the C-Gait assessment model had slightly better discrimination of freezers from non-freezers compared with traditional walking test models ; specifically, obstacle avoidance and speed of adaptation have uniquely discriminant potential.ConclusionC-gait assessment could provide additional value to the traditional walking tests for PD. Gait adaptability assessment, as measured by C-Gait, may be able to help identify freezers in a PD population. (shrink)

Deep brain stimulation of the subthalamic nucleus or the globus pallidus is an established treatment for Parkinson’s disease that yields a marked and lasting improvement of motor symptoms. Yet, DBS benefit on gait disturbances in PD is still debated and can be a source of dissatisfaction and poor quality of life. Gait disturbances in PD encompass a variety of clinical manifestations and rely on different pathophysiological bases. While gait disturbances arising years after DBS surgery can be related (...) to disease progression, early impairment of gait may be secondary to treatable causes and benefits from DBS reprogramming. In this review, we tackle the issue of gait disturbances in PD patients with DBS by discussing their neurophysiological basis, providing a detailed clinical characterization, and proposing a pragmatic programming approach to support their management. (shrink)

Taking regular walks when living with Parkinson’s disease has beneficial effects on movement and quality of life. Yet, patients usually show reduced physical activity compared to healthy older adults. Using auditory stimulation such as music can facilitate walking but patients vary significantly in their response. An individualized approach adapting musical tempo to patients’ gait cadence, and capitalizing on these individual differences, is likely to provide a rewarding experience, increasing motivation for walk-in PD. We aim to evaluate the observance, safety, (...) tolerance, usability, and enjoyment of a new smartphone application. It was coupled with wearable sensors and delivered individualized musical stimulation for gait auto-rehabilitation at home. Forty-five patients with PD underwent a 1-month, outdoor, uncontrolled gait rehabilitation program, using the BeatWalk application. The music tempo was being aligned in real-time to patients’ gait cadence in a way that could foster an increase up to +10% of their spontaneous cadence. Open-label evaluation was based on BeatWalk use measures, questionnaires, and a six-minute walk test. Patients used the application 78.8% of the prescribed duration and enjoyed it throughout the program. The application was considered “easy to use” by 75% of the patients. Pain, fatigue, and falls did not increase. Fear of falling decreased and quality of life improved. After the program, patients improved their gait parameters in the six-minute walk test without musical stimulation. BeatWalk is an easy to use, safe, and enjoyable musical application for individualized gait rehabilitation in PD. It increases “walk for exercise” duration thanks to high observance.Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT02647242. (shrink)

Human gait is a complex activity that requires high coordination between the central nervous system, the limb, and the musculoskeletal system. More research is needed to understand the latter coordination's complexity in designing better and more effective rehabilitation strategies for gait disorders. Electroencephalogram and functional near-infrared spectroscopy are among the most used technologies for monitoring brain activities due to portability, non-invasiveness, and relatively low cost compared to others. Fusing EEG and fNIRS is a well-known and established methodology proven (...) to enhance brain–computer interface performance in terms of classification accuracy, number of control commands, and response time. Although there has been significant research exploring hybrid BCI involving both EEG and fNIRS for different types of tasks and human activities, human gait remains still underinvestigated. In this article, we aim to shed light on the recent development in the analysis of human gait using a hybrid EEG-fNIRS-based BCI system. The current review has followed guidelines of preferred reporting items for systematic reviews and meta-Analyses during the data collection and selection phase. In this review, we put a particular focus on the commonly used signal processing and machine learning algorithms, as well as survey the potential applications of gait analysis. We distill some of the critical findings of this survey as follows. First, hardware specifications and experimental paradigms should be carefully considered because of their direct impact on the quality of gait assessment. Second, since both modalities, EEG and fNIRS, are sensitive to motion artifacts, instrumental, and physiological noises, there is a quest for more robust and sophisticated signal processing algorithms. Third, hybrid temporal and spatial features, obtained by virtue of fusing EEG and fNIRS and associated with cortical activation, can help better identify the correlation between brain activation and gait. In conclusion, hBCI system is not yet much explored for the lower limb due to its complexity compared to the higher limb. Existing BCI systems for gait monitoring tend to only focus on one modality. We foresee a vast potential in adopting hBCI in gait analysis. Imminent technical breakthroughs are expected using hybrid EEG-fNIRS-based BCI for gait to control assistive devices and Monitor neuro-plasticity in neuro-rehabilitation. However, although those hybrid systems perform well in a controlled experimental environment when it comes to adopting them as a certified medical device in real-life clinical applications, there is still a long way to go. (shrink)

The Hospital for Rehabilitation, Stavern, in Norway has treated patients with physical symptoms with no organic cause, so called conversion disorder patients, for over a decade. For four years research on the treatment has been carried out. Patients with conversion disorder seem not to fit in traditional somatic hospitals because their patienthood depends upon psychiatric diagnosis. Ironically, they appear not to belong in psychiatric hospitals because of their physical symptoms. The treatment offered these patients at hospitals for rehabilitation is adapted (...) physical activity consisting of behaviour elements such as positive reinforcement of normal function and lack of positive reinforcement at dysfunction. The pedagogical approach is seen as crucial in the successful rehabilitation of the patients. The disorder and treatment can be understood by using theories about the ecstatic body, radical behaviourism and phenomenology. When patients have problems in behaviour concerning both body and mind, it would be natural to employ both in the road to recovery. This article describes the various treatments and discusses them from phenomenological, ethical and philosophical perspectives. (shrink)

The Gait Deviation Index is a multivariate measure of overall gait pathology based on 15 gait features derived from three-dimensional kinematic data. GDI aims at providing a comprehensive, easy to interpret, and clinically meaningful metric of overall gait function. It has been used as an outcome measure to study gait in several conditions: cerebral palsy, post-stroke hemiparetic gait, Duchenne muscular dystrophy, and Parkinson’s disease, among others. Nevertheless, its use in population with Spinal Cord Injury (...) has not been studied yet. The aim of the present study was to investigate the applicability of the GDI to SCI through the assessment of the relationship of the GDI with the Walking Index for Spinal Cord Injury II. 3D gait kinematics of 34 patients with incomplete SCI was obtained. Besides, 3D gait kinematics of a sample of 50 healthy volunteers was also gathered with Codamotion motion capture system. A total of 302 and 446 strides were collected. GDI was calculated for each stride and grouped for each WISCI II level. HV data were analyzed as an additional set. Normal distribution for each group was assessed with Kolmogorov-Smirnov tests. Afterward, ANOVA tests were performed between each pair of WISCI II levels to identify differences among groups. The results showed that the GDI was normally distributed across all WISCI II levels in both iSCI and HV groups. Furthermore, our results showed an increasing relationship between the GDI values and WISCI II levels in subjects with iSCI, but only discriminative in WISCI II levels 13, 19, and 20. The index successfully distinguished HV group from all the individuals with iSCI. Findings of this study indicated that the GDI is not an appropriate multivariate walking metric to represent the deviation of gait pattern in adult population with iSCI from a normal gait profile when it is compared with the levels of walking impairment described by the WISCI II. Future work should aim at defining and validating an overall gait index derived from 3D kinematic gait variables appropriate for SCI, additionally taking into account other walking ability outcome measures. (shrink)

Name der Zeitschrift: Cognitive Linguistics Jahrgang: 25 Heft: 4 Seiten: 701-741.

Background and ObjectiveAbsolute angle represents the inclination of a body segment relative to a fixed reference in space. This work compares the absolute and relative angles for exploring biomechanical gait constraints.MethodsGait patterns of different neuromotor conditions were analyzed using 3D gait analysis: normal gait, Cerebral Palsy, Charcot Marie Tooth and Duchenne Muscular Dystrophy, representing central and peripheral nervous system and muscular disorders, respectively. Forty-two children underwent gait analysis: 10 children affected by CP, 10 children by CMT, (...) 10 children by DMD and 12 healthy children. The kinematic and kinetic parameters were collected to describe the biomechanical pattern of participants’ lower limbs. The absolute angles of thigh, leg and foot were calculated using the trigonometric relationship of the tangent. For each absolute series, the mean, range, maximum, minimum and initial contact were calculated. Kinematic and kinetic gait data were studied, and the results were compared with the literature.ResultsStatistical analysis of the absolute angles showed how, at the local level, the single segments behave differently depending on the pathology. However, if the lower limb is studied globally, a biomechanical constraint emerges.ConclusionEach segment compensates separately for the disease deficit so as to maintain a global biomechanical invariance. Using a model of inter-joint co-variation could improve the interpretation of the clinical gait pattern. (shrink)

PurposeThe purpose of this study was to introduce an orthogonal experimental design to improve the efficiency of building and optimizing models for freezing of gait prediction.MethodsA random forest model was developed to predict FOG by using acceleration signals and angular velocity signals to recognize possible precursor signs of FOG. An OED was introduced to optimize the feature extraction parameters.ResultsThe main effects and interaction among the feature extraction hyperparameters were analyzed. The false-positive rate, hit rate, and mean prediction time were (...) 27%, 68%, and 2.99 s, respectively.ConclusionThe OED was an effective method for analyzing the main effects and interactions among the feature extraction parameters. It was also beneficial for optimizing the feature extraction parameters of the FOG prediction model. (shrink)

Many patients were surprised or confused by their first visit to Dr. Freud's office. Lying on the famous couch, they found themselves surrounded by a plethora of objects and images they would never have associated with the business of the psychoanalytic cure. Statuettes, masks, and portraits from ancient times were arranged in showcases, on the shelves and on desks within a room whose walls were covered with depictions of mythological scenes and portraits of Freud's mentors . The patient's first impressions (...) of this peculiar display, which has been faithfully preserved by Anna Freud in their last London home at Maresfield Gardens, were frequently strong ones. One of the most articulate of Freud's patients, Hilda Doolittle, herself a lover of antiquities, did not hesitate to tell him how “overwhelmed and upset” she was to find him “surrounded by these treasures, in a museum, a temple.” During her own analysis, a variety of these “toys,” as she called them, seemed to act as replicas or “ghosts” of the figures appearing in her dreams or memories: “We are all haunted houses.”1 · 1. H. D. [Hilda Doolittle], “Advent,” Tribute to Freud , pp. 119, 146. (shrink)

BackgroundThe interpretation of clinical gait data in children with cerebral palsy (CP) is time-consuming, requires extensive expertise and often lacks transparency. Here we aimed to develop a set of look-up tables to support this process, linking typical gait features as present in CP to their potential underlying impairments.MethodsWe developed an initial core set of gait features and their potential underlying impairments based on biomechanical reasoning, literature and clinical experience. This core set was further specified through a Delphi (...) process in a multidisciplinary group of experts in gait analysis of children with CP and evaluated on 20 patient cases. The likelihood of the listed gait feature–impairment relationships was scored by the expert panel on a five-point scale.ResultsThe final core set included 120 relevant gait feature–impairment relations including likelihood scores. This set was presented in the form of look-up tables in both directions, i.e., sorted by gait features with potential underlying impairment, and sorted by impairments with potential related gait features. The average likelihood score for the relations was 3.5 ± 0.6 (range 2.1–4.6).ConclusionThe developed set of look-up tables linking gait features and impairments, can assist gait analysts and clinicians in standardized biomechanical reasoning, to support treatment decision-making for gait impairments in children with CP. (shrink)

BackgroundAlthough gait patterns disturbances are known to be related to cognitive decline, there is no consensus on the possibility of predicting one from the other. It is necessary to find the optimal gait features, experimental protocols, and computational algorithms to achieve this purpose.PurposesTo assess the efficacy of the Stable Sparse Classifiers procedure for discriminating young and healthy older adults, as well as healthy and cognitively impaired elderly groups from their gait patterns. To identify the walking tasks or (...) combinations of tasks and specific spatio-temporal gait features that allow the best prediction with SSC.MethodsA sample of 125 participants was studied. They underwent assessment with five neuropsychological tests that explore different cognitive domains. A summarized cognitive index, based on the Mahalanobis distance from normative data, was calculated. The sample was divided into three groups using k-means clustering of MDCog in addition to Age. The participants executed four walking tasks and their gait patterns, measured with a body-fixed Inertial Measurement Unit, were used to calculate 16 STGF and dual-task costs. SSC was then employed to predict which group the participants belonged to. The classification's performance was assessed using the area under the receiver operating curves and the stable biomarkers were identified.ResultsThe discrimination HE vs. MCI-E revealed that the combination of the easy dual-task and the fast walking task had the best prediction performance. The features related to gait variability and to the amplitude of vertical acceleration had the largest predictive power. SSC prediction accuracy was better than the accuracies obtained with linear discriminant analysis and support vector machine classifiers.ConclusionsThe study corroborated that the changes in gait patterns can be used to discriminate between young and healthy older adults and more importantly between healthy and cognitively impaired adults. A subset of gait tasks and STGF optimal for achieving this goal with SSC were identified, with the latter method superior to other classification techniques. (shrink)

Objective: Gait adaptation to environmental challenges is fundamental for independent and safe community ambulation. The possibility of precisely studying gait modulation using standardized protocols of gait analysis closely resembling everyday life scenarios is still an unmet need.Methods: We have developed a fully-immersive virtual reality environment where subjects have to adjust their walking pattern to avoid collision with a virtual agent crossing their gait trajectory. We collected kinematic data of 12 healthy young subjects walking in real world (...) and in the VR environment, both with and without the VA perturbation. The VR environment closely resembled the RW scenario of the gait laboratory. To ensure standardization of the obstacle presentation the starting time speed and trajectory of the VA were defined using the kinematics of the participant as detected online during each walking trial.Results: We did not observe kinematic differences between walking in RW and VR/A-, suggesting that our VR environment per se might not induce significant changes in the locomotor pattern. When facing the VA all subjects consistently reduced stride length and velocity while increasing stride duration. Trunk inclination and mediolateral trajectory deviation also facilitated avoidance of the obstacle.Conclusions: This proof-of-concept study shows that our VR/A+ paradigm effectively induced a timely gait modulation in a standardized immersive and realistic scenario. This protocol could be a powerful research tool to study gait modulation and its derangements in relation to aging and clinical conditions. (shrink)

The aim of the experiment was to evaluate the adaptive responses of biomechanical and electromyographic parameters to vertical unloading when walking during the 4-month isolation experiment SIRIUS-19 in the ground-based space station model. The study involved 6 healthy international crew members of the SIRIUS-19 project aged 34 ± 6.2 years. Body Weight Unloading conditions was created by the h/p/cosmos airwalk system. The locomotor test included walking with a sequential change of BWU modes: 5-min walking with 0% BWU, 5-min walking with (...) 65% BWU and 5-min walking with 85% BWU. Ground Reaction Force was recorded by the h/p/cosmos treadmill device. Muscle Lab Model 4000e device was used to record the electromyographic signals of the hip and shin muscles. The locomotor test was performed twice before GBI, monthly during GBI and 1 week after leaving isolation. The results obtained before GBI demonstrate that the changes of support and proprioceptive afferentation signals play significant role in reorganizing of the biomechanical structure of motor acts and the development of new movement patterns. The results of the study are consistent with the previously obtained results of other studies in this direction. Despite the fact that during the GBI the participants of the experiment performed regular physical training, a decrease in the performance indicators values was detected, especially pronounced after 100 days of GBI. This is probably due to limited space of a space station model, as well as the development of a special motor stereotype in it. Noteworthy are the results obtained after the 4th session of the experiment, indicating the effect of sensorimotor learning. We think that the data obtained in this study will be useful in research both in gravitational physiology and in clinical medicine. (shrink)

Background: Previous studies have investigated the effects of dance interventions on Parkinson’s motor and non-motor symptoms in an effort to develop an integrated view of dance as a therapeutic intervention. This within-subject study questions whether dance can be simply considered a form of exercise by comparing a Dance for Parkinson’s class with a matched-intensity exercise session lacking dance elements like music, metaphorical language, and social reality of art-partaking.Methods: In this repeated-measure design, 7 adults with Parkinson’s were tested four times; before (...) and after a Dance for Parkinson’s class, as well as before and after a matched-intensity exercise session. Physiological measures included heart rate and electrodermal activity. Self-reported affect and body self-efficacy were collected. Gait symmetry and dual task cost were analyzed using the 6 min walking test and Timed-Up-and-Go test, respectively.Results: Average heart rate was the same for both conditions, while electrodermal activity was higher during Dance for Parkinson’s. Significant differences were found in body self-efficacy, beauty subscale, symmetry of gait, and dual task performance.Conclusion: Dance, compared to an exercise intervention of matched intensity, yields different outcomes through the means of intrinsic artistic elements, which may influence affective responses, the experience of beauty, self-efficacy, and gait performance. (shrink)