To utilize cervical auscultation as a means of screening for risk of dysphagia, we must first determine how the signal differs between healthy subjects and subjects with swallowing disorders. In this experiment we gathered swallowing sound and vibration data from 53 (13 with stroke, 40 without) patients referred for imaging evaluation of swallowing function with videofluoroscopy. The analysis was limited to non-aspirating swallows of liquid with either thin (< 5 cps) or viscous (≈300cps\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\approx 300\,{\text{cps}}$$\end{document}) consistency. After calculating a selection of generalized time, frequency, and time frequency features for each swallow, we compared our data against our findings in a previous experiment that investigated identical features for a different group of 56 healthy subjects. We found that nearly all of our chosen features for both vibrations and sounds showed significant differences between the healthy and disordered swallows despite the absence of aspiration. We also found only negligible differences between dysphagia as a symptom of stroke and dysphagia as a symptom of another condition. Non-aspirating swallows from healthy controls and patients with dysphagia have distinct feature patterns. These findings should greatly help the development of the cervical auscultation field and serve as a reference for future investigations into more specialized characterization methods.

BackgroundTo utilize cervical auscultation as a means of screening for risk of dysphagia, we must first determine how the signal differs between healthy subjects and subjects with swallowing disorders.MethodsIn this experiment we gathered swallowing sound and vibration data from 53 (13 with stroke, 40 without) patients referred for imaging evaluation of swallowing function with videofluoroscopy. The analysis was limited to non-aspirating swallows of liquid with either thin (< 5 cps) or viscous ($$\approx 300\,{\text{cps}}$$≈300cps) consistency. After calculating a selection of generalized time, frequency, and time frequency features for each swallow, we compared our data against our findings in a previous experiment that investigated identical features for a different group of 56 healthy subjects.ResultsWe found that nearly all of our chosen features for both vibrations and sounds showed significant differences between the healthy and disordered swallows despite the absence of aspiration. We also found only negligible differences between dysphagia as a symptom of stroke and dysphagia as a symptom of another condition.ConclusionNon-aspirating swallows from healthy controls and patients with dysphagia have distinct feature patterns. These findings should greatly help the development of the cervical auscultation field and serve as a reference for future investigations into more specialized characterization methods.

Wirelessly powered implantable medical devices require efficient power transfer through biological tissue within safety constraints on energy absorption, often in the presence of environmental variability. Accurate modeling of the tissue medium is essential to evaluate the performance and sensitivity of transcutaneous powering systems. Here, we investigate loop and dipole antenna topologies in proximity to simulated tissue models and experimental phantoms, with emphasis on representing heterogeneous tissue with functionally equivalent simplified models, and modeling variability in tissue properties for sensitivity analyses. We first present a modified phantom formulation that provides greater control over frequency-dependent properties. We then show that homogeneous phantoms have limited use at representing input impedance and energy absorption at ultrahigh operating frequency by analyzing each antenna topology in proximity to layered or homogeneous tissue across frequency. We compare loop and dipole antenna topologies in terms of specific absorption rate and impedance, and show that frequency-dependent tissue behavior must be considered even at fixed operating frequencies. Finally, we discuss the dual utility of a transmitting antenna as a resonator to detect changes in tissue properties in addition to powering an implanted device.

A vertex-varying spectral content on graphs challenges the assumption of vertex invariance and requires vertex-frequency representations for an adequate analysis. In this letter, we introduce a class of vertex-frequency energy distributions inspired by traditional time-frequency energy distributions. These newly introduced distributions do not use localization windows. Their efficiency in energy concentration is illustrated through examples.

Recent developments in personal and mobile healthcare have shown promising results in term of patients' quality of life and quality of care improvements. This can be achieved through continuous monitoring of patients' physiological functions using wearable non-invasive biomedical sensors. The remote collection and processing of such data can then be used to provide rapid medical response if a problem is detected or to offer preventive measures. However, the integration of wearable sensors into wider-scale framework is still a major challenge, as real-time data collection and remote configuration capabilities must be integrated to strongly constrained devices. Here, we show how such requirements can be integrated into a multiparameter, cardiorespiratory wearable sensor and how this sensor can be integrated into wide-scale Internet-based frameworks. We thus manufactured a biomedical-grade heart rate, instantaneous heart-rate variability and respiratory sensor. The sensor was tested in real life ambulatory condition, and we showed an Internet-based proof of concept exhibiting the integration of our sensor into wide-scale healthcare frameworks. Finally, we anticipate that wearable healthcare will greatly improve patients' quality-of-life by using IoT-based wearable devices similar to the sensor developed in this paper.

Recent developments in personal and mobile healthcare have shown promising results in term of patients' quality of life and quality of care improvements. This can be achieved through continuous monitoring of patients' physiological functions using wearable non-invasive biomedical sensors. The remote collection and processing of such data can then be used to provide rapid medical response if a problem is detected or to offer preventive measures. However, the integration of wearable sensors into wider-scale framework is still a major challenge, as real-time data collection and remote configuration capabilities must be integrated to strongly constrained devices. Here, we show how such requirements can be integrated into a multiparameter, cardiorespiratory wearable sensor and how this sensor can be integrated into wide-scale Internet-based frameworks. We thus manufactured a biomedical-grade heart rate, instantaneous heart-rate variability and respiratory sensor. The sensor was tested in real life ambulatory condition, and we showed an Internet-based proof of concept exhibiting the integration of our sensor into wide-scale healthcare frameworks. Finally, we anticipate that wearable healthcare will greatly improve patients' quality-of-life by using IoT-based wearable devices similar to the sensor developed in this paper.

Objective: Up to 10% of free flap cases are compromised, and without prompt intervention, amputation and even death can occur. Hourly monitoring improves salvage rates, but the gold standard for monitoring requires experienced personnel to operate and suffers from high false-positive rates as high as 31% that result in costly and unnecessary surgeries. In this paper, we investigate free flap patency monitoring using automatic hardware-only classification systems that eliminate the need for experienced personnel. The expected flow ranges of the antegrade and retrograde veins for breast reconstruction are studied using a syringe pump to create the laminar flow seen in veins. Methods: Feature data extracted from the Doppler blood flow signals are analyzed for sensitivity, specificity, and false-positive rates. Hardware is built to perform the classification automatically in real-time and output a decision at the end of the observation period. Results: Experimental results using the hardware-only classifier for a 50 ms window size show high sensitivity (96.75%), specificity (90.20%), and low false-positive rate (9.803%). The experimental and theoretical classification results show close agreement. Conclusion: This work indicates that automatic hardware-only classifiers can eliminate the need for experienced personnel to monitor free flap patency. Significance: The hardware-only classification is amenable to a monolithic implementation and future studies should study a totally implantable wirelessly-powered blood flow classifier. The high classifier performance in a short window period indicates that duty-cycled powering can be used to extend the safe operational depth of an implant. This is particularly relevant for the difficult buried free flap applications.