Localised impedance monitoring device for the remote clinical assessment of home-based dialysis patients.

BioImpedance Spectroscopy (BIS) has been clinically used to determine the hydrational status of patients undergoing haemodialysis (HD). In the present project we are developing a calf-localised, integrated impedimetric device to periodically and conveniently measure and transmit information on the hydrational status of home-based patients to a remote clinic. Surprisingly, we have found that simple postural changes before or during measurement lead to significant fluid shifts in the lower leg that are as important and as long lasting as the effects of haemodialysis. These must be taken into account if potentially hazardous errors are not to be made in assessing a patient's hydrational status.

A wireless patch for sleep respiratory disorders applications.

This paper presents a conformable wireless patch and its mobile application for physical activity, spO2 and pCO2 recording associated to digital biomarkers that aim at providing the clinicians with a reliable computer-aided diagnosis tool for rapid and continuous monitoring of sleep respiratory disorders. Each part of the system is described and results are presented and discussed. The reflectance sp02 sensor has been tested in vivo on several body sites and several subjects then compared to a reference device. The electrochemical tcpO2 sensor has been validated in vitro. Based on these physiological parameters, the proposed algorithms to automatically identifying sleep respiratory events are compared to a reference index.

Estimating the bias field of MR images.

We propose a modification of Wells et al. technique for bias field estimation and segmentation of magnetic resonance (MR) images. We show that replacing the class other, which includes all tissue not modeled explicitly by Gaussians with small variance, by a uniform probability density, and amending the expectation-maximization (EM) algorithm appropriately, gives significantly better results. We next consider the estimation and filtering of high-frequency information in MR images, comprising noise, intertissue boundaries, and within tissue microstructures. We conclude that post-filtering is preferable to the prefiltering that has been proposed previously. We observe that the performance of any segmentation algorithm, in particular that of Wells et al. (and our refinements of it) is affected substantially by the number and selection of the tissue classes that are modeled explicitly, the corresponding defining parameters and, critically, the spatial distribution of tissues in the image. We present an initial exploration to choose automatically the number of classes and the associated parameters that give the best output. This requires us to define what is meant by "best output" and for this we propose the application of minimum entropy. The methods developed have been implemented and are illustrated throughout on simulated and real data (brain and breast MR).

Cone-beam SPECT with a tilted detector.

In this article we report on the TOMOCONIC project for cerebral SPECT using cone-beam collimators. First, we describe our experimental set-up. The cone-beam collimator improves both spatial resolution and sensitivity. We tilt the detector to center the focal point rotation plane on the region to reconstruct. Then, to minimize cone-beam artefacts, we use the Grangeat algorithm for image reconstruction. We describe here how it can be generated to this tilted acquisition geometry. Finally, we present our first experimental results and a comparison with parallel-beam SPECT. The improvement ratio on transverse spatial resolution is 1.5. We conclude with our first clinical images.

Recommendations for ICT use in Alzheimer's disease assessment: Monaco CTAD Expert Meeting.

Alzheimer disease (AD) and other related dementia represent a major challenge for health care systems within the aging population. It is therefore important to develop better instruments for assessing disease severity and disease progression to optimize patient's care and support to care providers, and also provide better tools for clinical research. In this area, Information and Communication Technologies (ICT) are of particular interest. Such techniques enable accurate and standardized assessments of patients' performance and actions in real time and real life situations. The aim of this article is to provide basic recommendation concerning the development and the use of ICT for Alzheimer's disease and related disorders. During he ICT and Mental Health workshop (CTAD meeting held in Monaco on the 30th October 2012) an expert panel was set up to prepare the first recommendations for the use of ICT in dementia research. The expert panel included geriatrician, epidemiologist, neurologist, psychiatrist, psychologist, ICT engineers, representatives from the industry and patient association. The recommendations are divided into three sections corresponding to 1/ the clinical targets of interest for the use of ICT, 2/ the conditions, the type of sensors and the outputs (scores) that could be used and obtained, 3/ finally the last section concerns specifically the use of ICT within clinical trials.

A wireless multichannel EEG recording platform.

A wireless multichannel data acquisition system is being designed for ElectroEncephaloGraphy (EEG) recording. The system is based on a custom integrated circuit (ASIC) for signal conditioning, amplification and digitization and also on commercial components for RF transmission. It supports the RF transmission of a 32-channel EEG recording sampled at 1 kHz with a 12-bit resolution. The RF communication uses the MICS band (Medical Implant Communication Service) at 402-405 Mhz. This integration is a first step towards a lightweight EEG cap for Brain Computer Interface (BCI) studies. Here, we present the platform architecture and its submodules. In vivo validations are presented with noise characterization and wireless data transfer measurements.

A modular 256-channel micro electrode array platform for in vitro and in vivo neural stimulation and recording: BioMEA.

In order to understand the dynamics of large neural networks, where information is widely distributed over thousands of cells, one of today's challenges is to successfully monitor the simultaneous activity of as many neurons as possible. This is made possible by using the Micro-Electrode Array (MEA) technology allowing neural cell culture and/or tissue slice experimentation in vitro. Thanks to development of microelectronics' technologies, a novel data acquisition system based on MEA technology has been developed, the BioMEA™. It combines the most advanced MEA biochips with integrated electronics, and a novel user-friendly software interface. To move from prototype (result of the RMNT research project NEUROCOM) to manufactured product, a number of changes have been made. Here, we present a 256-channel MEA data acquisition system with integrated electronics (BioMEA™) allowing simultaneous recording and stimulation of neural networks for in vitro and in vivo applications. This integration is a first step towards an implantable device for BCI (Brain Computer Interface) studies and neural prosthesis.

Estimation of respiratory waveform and heart rate using an accelerometer.

In this paper the use of an accelerometer to measure cardio-respiratory activity is presented. Movement of the chest was recorded by an accelerometer attached to a belt around the chest. The acquisition is realized in different status: normal, apnea, deep breathing or after exhaustion and also in different postures: vertical (sitting, standing) or horizontal (lying down). The resulting signal was compared with reference measurements. The results of experimental evaluation indicate that using a chest-accelerometer can correctly detect the respiratory waveform and heart rate (HR) signal. This method is therefore suitable for automatic identification some disease, for example arrhythmia or sleep apnea.

Evaluation of postural stability by means of a single inertial sensor.

Human posture control during standing is a combination of many complicated control processes. Physical therapists perform different clinical balance tests to either assess postural control or identify balance disorders that can ultimately cause a patient to fall. In this article, several standardized clinical exercises for balance assessment are executed together with an orientation tracker strapped onto the volunteer's sternum. The tracker estimates the 3-D orientation of the trunk in real-time using an efficient attitude determination algorithm. The device is fully portable and sensitive to anteroposterior and mediolateral sways. Analysis of the resulting angles provides several parameters that are useful in assessing and quantifying balance function. This approach could be a valuable tool for a therapist for patient's follow-up and could be combined with existing procedures such as force platforms or optical motion analysis systems. Also, statistical analysis on these parameters could help to characterize normal and pathological performances in a population.

ACTIDOM--a microsystem based on MEMS for activity monitoring of the frail elderly in their daily life.

A "ambulatory activity recorder" was developed, with 3 accelerometers and 3 magnetometers, to detect and qualify the elementary activities of a person, such as walking and transfers. The signal processing is explained, along with the preliminary results obtained on young and older healthy subjects. This work open the way to continuous and automatic monitoring of the level of mobility.