Mobile phone-based joint angle measurement for functional assessment and rehabilitation of proprioception

International audienceAssessment of joint functional and proprioceptive abilities is essential for balance, posture, and motor control rehabilitation. Joint functional ability refers to the capacity of movement of the joint. It may be evaluated thereby measuring the joint range of motion (ROM). Proprioception can be defined as the perception of the position and of the movement of various body parts in space. Its role is essential in sensorimotor control for movement acuity, joint stability, coordination, and balance. Its clinical evaluation is commonly based on the assessment of the joint position sense (JPS). Both ROM and JPS measurements require estimating angles through goniometer, scoliometer, laser-pointer, and bubble or digital inclinometer. With the arrival of Smartphones, these costly clinical tools tend to be replaced. Beyond evaluation, maintaining and/or improving joint functional and proprioceptive abilities by training with physical therapy is important for long-term management. This review aims to report Smartphone applications used for measuring and improving functional and proprioceptive abilities. It identifies that Smartphone applications are reliable for clinical measurements and are mainly used to assess ROM and JPS. However, there is lack of studies on Smartphone applications which can be used in an autonomous way to provide physical therapy exercises at home

Revealing buried information: Statistical processing techniques for ultracold gas image analysis

The techniques of principal and independent component analysis are applied to images of ultracold atoms. As an illustrative example, we present the use of these model-independent methods to rapidly determine the differential phase of a BEC interferometer from large sets of images of interference patterns. These techniques have been useful in the calibration of the experiment and in the investigation of phase randomization. The details of the algorithms are provided.Comment: v2: Many changes made to answer reviewer comments and improve clarity. 29 pages, 9 figures v3: Small change to emphasize role of models in result interpretation. 29 pages, 9 figure

An Atom Michelson Interferometer on a Chip Using a Bose-Einstein Condensate

An atom Michelson interferometer is implemented on an "atom chip." The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with atom propagation time of 10 ms

High efficiency symmetric beam splitter for cold atoms with a standing wave light pulse sequence

In a recent experiment [1], it was observed that a sequence of two standing wave square pulses can split a BEC at rest into +/- 2 h_bar k diffraction orders with almost 100% efficiency. By truncating the Raman-Nath equations to a 2-state model, we provide an intuitive picture that explains this double square pulse beamsplitter scheme. We further show it is possible to optimize a standingwave multi square pulse sequence to efficiently diffract an atom at rest to symmetric superposition of +/- 2n h_bar k diffraction order with n>1. The approach is considered to be qualitatively different from the traditional light pulse schemes in the Bragg or the Raman-Nath region, and can be extended to more complex atomic optical elements that produce various tailored output momentum states from a cold atom source.Comment: 22 pages, 4 figures, 1 tabl

Assessment of attention demand for balance control using a Smartphone: implementation and evaluation

International audienceDual-task paradigm studies strongly highlights the importance of considering attention demand when assessing the ability of an individual to control balance. This paper introduces the implementation of a Smartphone application for quantitative and independent assessment of attention demand for balance control. A proof-of-concept study was designed to evaluate the effectiveness of the iBalance system in assessing the attention demand for balance control. Eight young healthy adults voluntarily performed a dual-task paradigm procedure, in which they were asked to respond vocally as rapidly as possible to an unpredictable auditory stimulus while maintaining a stable seated posture and two standing postures of increasing difficulty: bipedal and unipedal. Trunk sway measurements were used as an index of postural performance, whereas reaction time measurements were used as an index of the attention demand allocated for executing the postural tasks. In line with the existing literature, results showed that, as the postural task increased in difficulty, trunk sway and attention demand used for controlling balance increased. Taken together, these results are promising, suggesting that the iBalance system could constitute a wireless, portable, lightweight, pervasive, low-cost, user-friendly Smartphone-based system for quantitative and independent assessment of attention demand for balance control suitable for home use

Method and System for Measuring, Monitoring, Controlling and Correcting a Movement or a Posture of a User

The invention relates to a method for measuring, monitoring, controlling, evaluating and correcting proprioceptive and/or postural and/or locomotor and/or motor and/or spatial orientation abilities of a user, said method comprising the steps of: measuring and processing (10, 20, 30) in order to detect an effective movement or an effective posture of the user; comparing (40) the effective movement or the effective posture to a theoretical movement or a theoretical posture; providing biological feedback (50) in order to allow the user to correct his effective movement or his effective posture with respect to the theoretical movement or the theoretical posture; calculating and storing (60) a score; transmitting (70) the score to a third party in order to allow the latter to monitor the performances of the user; and automatically or non-automatically updating (80) a level of difficulty

Assessment of attention demand for balance control using a Smartphone: implementation and evaluation

International audienceDual-task paradigm studies strongly highlights the importance of considering attention demand when assessing the ability of an individual to control balance. This paper introduces the implementation of a Smartphone application for quantitative and independent assessment of attention demand for balance control. A proof-of-concept study was designed to evaluate the effectiveness of the iBalance system in assessing the attention demand for balance control. Eight young healthy adults voluntarily performed a dual-task paradigm procedure, in which they were asked to respond vocally as rapidly as possible to an unpredictable auditory stimulus while maintaining a stable seated posture and two standing postures of increasing difficulty: bipedal and unipedal. Trunk sway measurements were used as an index of postural performance, whereas reaction time measurements were used as an index of the attention demand allocated for executing the postural tasks. In line with the existing literature, results showed that, as the postural task increased in difficulty, trunk sway and attention demand used for controlling balance increased. Taken together, these results are promising, suggesting that the iBalance system could constitute a wireless, portable, lightweight, pervasive, low-cost, user-friendly Smartphone-based system for quantitative and independent assessment of attention demand for balance control suitable for home use

High Resolution Spectroscopy on an X-ray Absorption Beamline

International audienceAbstract A bent crystal spectrometer based on the Rowland circle geometry has been tested on the BM30b/FAME beamline at the European Synchrotron Radiation Facility. The energy resolution of the spectrometer (1.3eV at the Cu K1 energy, i.e. 8047.78eV) allows to perform different kinds of measurements, including X-ray Absorption Spectroscopy, Resonant Inelastic X-ray Scattering and X-ray Raman Scattering experiments. The simplicity of the experimental device makes it easily implemented on a classical X-ray absorption beamline