Development of a Wearable Cardiac Monitoring System for Behavioral Neurocardiac Training: A Usability Study.

BACKGROUND: Elevated blood pressure is one of the main risk factors for death globally. Behavioral neurocardiac training (BNT) is a complementary approach to blood pressure and stress management that is intended to exercise the autonomic reflexes, improve stress recovery, and lower blood pressure. BNT involves cognitive-behavioral therapy with a paced breathing technique and heart rate variability biofeedback. BNT is limited to in-clinic delivery and faces an accessibility barrier because of the need for clinical oversight and the use of complex monitoring tools. OBJECTIVE: The objective of this project was to design, develop, and evaluate a wearable electrocardiographic (ECG) sensor system for the delivery of BNT in a home setting. METHODS: The wearable sensor system, Beat, consists of an ECG sensor and a mobile app. It was developed iteratively using the principles of test-driven Agile development and user-centered design. A usability study was conducted at Toronto General Hospital to evaluate feasibility and user experience and identify areas of improvement. RESULTS: The Beat sensor was designed as a modular patch to be worn on the user's chest and uses standard ECG electrodes. It streams a single-lead ECG wirelessly to a mobile phone using Bluetooth Low Energy. The use of small, low-power electronics, a low device profile, and a tapered enclosure allowed for a device that can be unobtrusively worn under clothing. The sensor was designed to operate with a mobile app that guides users through the BNT exercises to train them to a slow-paced breathing technique for stress recovery. The BNT app uses the ECG captured by the sensor to provide heart rate variability biofeedback in the form of a real-time heart rate waveform to complement and reinforce the impact of the training. Usability testing (n=6) indicated that the overall response to the design and user experience of the system was perceived positively. All participants indicated that the system had a positive effect on stress management and that they would use it at home. Areas of improvement were identified, which focused primarily on the delivery of training and education on BNT through the app. CONCLUSIONS: The outcome of this project was a wearable sensor system to deliver BNT at home. The system has the potential to offer a complementary approach to blood pressure and stress management at home and reduce current accessibility barriers.

Comparative evaluation of an ambulatory EEG platform vs. clinical gold standard.

Electroencephalography (EEG) testing in clinical labs makes use of large amplifiers and complex software for data acquisition. While there are new ambulatory electroencephalogram (EEG) systems, few have been directly compared to a gold standard system. Here, an ultra-low power wireless EEG system designed by Imec is tested against the gold standard Neuroscan SynAmps2 EEG system, recording simultaneously from the same laboratory cap prepared with electrode gel. The data was analyzed using correlation analysis for both time domain and frequency domain data. The analysis indicated a high Pearson's correlation coefficient (mean=0.957, median=0.985) with high confidence (mean P=0.002) for 10-second sets of data transformed to the frequency domain. The time domain results had acceptable Pearson's coefficient (mean=0.580, median =0.706) with high confidence (mean P=0.008).

A contact-free respiration monitor for smart bed and ambulatory monitoring applications.

The development of a contact-free respiration monitor has a broad range of clinical applications in the home and hospital setting. Current approaches suffer from a variety of problems including unreliability, low sensitivity, and high cost. This work describes a novel approach to contact-free respiration monitoring that addresses these shortcomings by employing a highly sensitive capacitance sensor to detect variations in capacitive coupling caused by breathing. A prototype system consisting of a synthetic-metallic pad, sensor electronics, and iPhone interface was built and its performance compared experimentally to the gold standard technique (Respiratory Inductance Plethysmography) on both a healthy volunteer and SimMan robotic mannequin. The prototype sensor effectively captured respiratory movements over breathing rates of 5-55 bpm; achieving an average spectral correlation of 0.88 (CI: 0.86-0.90) and 0.95 (CI: 0.95-0.96) to the gold standard using the SimMan and healthy volunteer respectively.

A mobile phone based remote patient monitoring system for chronic disease management.

Rising concern over the poor state of chronic disease management led to the user-informed design and development of a home tele-monitoring system. Focus groups with patients and primary care providers guided the research team towards a design that would accommodate the workflow and concerns of the healthcare providers and the low use and comfort with technology found among the patient population. The system was trialed in a before-and-after pilot study of 34 patients with diabetes and hypertension. Findings demonstrate a significant improvement in systolic and diastolic blood pressure. An RCT beginning in 2007 is being conducted to confirm these findings. It is hypothesized that this user-centred approach, utilizing focus groups, iterative design and human factors methods of evaluation, will lead to the next-generation of home tele-monitoring applications that are more intuitive, less cumbersome, and ultimately bring about greater patient compliance and better physician management.