Automatic signal quality assessment of raw trans-abdominal biopotential recordings for non-invasive fetal electrocardiography.

Introduction: Wearable monitoring systems for non-invasive multi-channel fetal electrocardiography (fECG) can support fetal surveillance and diagnosis during pregnancy, thus enabling prompt treatment. In these embedded systems, power saving is the key to long-term monitoring. In this regard, the computational burden of signal processing methods implemented for the fECG extraction from the multi-channel trans-abdominal recordings plays a non-negligible role. In this work, a supervised machine-learning approach for the automatic selection of the most informative raw abdominal recordings in terms of fECG content, i.e., those potentially leading to good-quality, non-invasive fECG signals from a low number of channels, is presented and evaluated. Methods: For this purpose, several signal quality indexes from the scientific literature were adopted as features to train an ensemble tree classifier, which was asked to perform a binary classification between informative and non-informative abdominal channels. To reduce the dimensionality of the classification problem, and to improve the performance, a feature selection approach was also implemented for the identification of a subset of optimal features. 10336 5-s long signal segments derived from a real dataset of multi-channel trans-abdominal recordings acquired from 55 voluntary pregnant women between the 21st and the 27th week of gestation, with healthy fetuses, were adopted to train and test the classification approach in a stratified 10-time 10-fold cross-validation scheme. Abdominal recordings were firstly pre-processed and then labeled as informative or non-informative, according to the signal-to-noise ratio exhibited by the extracted fECG, thus producing a balanced dataset of bad and good quality abdominal channels. Results and Discussion: Classification performance revealed an accuracy above 86%, and more than 88% of those channels labeled as informative were correctly identified. Furthermore, by applying the proposed method to 50 annotated 24-channel recordings from the NInFEA dataset, a significant improvement was observed in fetal QRS detection when only the channels selected by the proposed approach were considered, compared with the use of all the available channels. As such, our findings support the hypothesis that performing a channel selection by looking directly at the raw abdominal signals, regardless of the fetal presentation, can produce a reliable measurement of fetal heart rate with a lower computational burden.

Design and Usability Assessment of a Multi-Device SOA-Based Telecare Framework for the Elderly.

Telemonitoring is a branch of telehealth that aims at remotely monitoring vital signs, which is important for chronically ill patients and the elderly living alone. The available standalone devices and applications for the self-monitoring of health parameters largely suffer from interoperability problems; meanwhile, telemonitoring medical devices are expensive, self-contained, and are not integrated into user-friendly technological platforms for the end user. This paper presents the technical aspects and usability assessment of the telemonitoring features of the HEREiAM platform, which supports heterogeneous information technology systems. By exploiting a service-oriented architecture, the measured parameters collected by off-the-shelf Bluetooth medical devices are sent as XML documents to a private cloud that implements an interoperable health service infrastructure, which is compliant with the most recent healthcare standards and security protocols. This Android-based system is designed to be accessible both via TV and portable devices, and includes other utilities designed to support the elderly living alone. Four usability assessment sessions with quality-validated questionnaires were performed to accurately understand the ease of use, usefulness, acceptance, and quality of the proposed system. The results reveal that our system achieved very high usability scores even at its first use, and the scores did not significantly change over time during a field trial that lasted for four months, reinforcing the idea of an intuitive design. At the end of such a trial, the user-experience questionnaire achieved excellent scores in all aspects with respect to the benchmark. Good results were also reported by general practitioners who assessed the quality of their remote interfaces for telemonitoring.

Six-Month Assessment of a Hand Prosthesis with Intraneural Tactile Feedback.

OBJECTIVE: Hand amputation is a highly disabling event, which significantly affects quality of life. An effective hand replacement can be achieved if the user, in addition to motor functions, is provided with the sensations that are naturally perceived while grasping and moving. Intraneural peripheral electrodes have shown promising results toward the restoration of the sense of touch. However, the long-term usability and clinical relevance of intraneural sensory feedback have not yet been clearly demonstrated. METHODS: To this aim, we performed a 6-month clinical study with 3 transradial amputees who received implants of transverse intrafascicular multichannel electrodes (TIMEs) in their median and ulnar nerves. After calibration, electrical stimulation was delivered through the TIMEs connected to artificial sensors in the digits of a prosthesis to generate sensory feedback, which was then used by the subjects while performing different grasping tasks. RESULTS: All subjects, notwithstanding their important clinical differences, reported stimulation-induced sensations from the phantom hand for the whole duration of the trial. They also successfully integrated the sensory feedback into their motor control strategies while performing experimental tests simulating tasks of real life (with and without the support of vision). Finally, they reported a decrement of their phantom limb pain and a general improvement in mood state. INTERPRETATION: The promising results achieved with all subjects show the feasibility of the use of intraneural stimulation in clinical settings. ANN NEUROL 2019;85:137-154.