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By Benny Lo

Aiming to develop pervasive sensing technologies to address the increasing demands on the healthcare services caused by the demographic shifts, Body Sensor Networks (BSN) has attracted many interests in both academic and industrial communities. Together with the advances in sensing, computing and wireless communication technologies, extensive numbers of BSN sensing technologies have been proposed, ranging from activity sensors, behaviour monitors, to physiological and biomechanical sensors. One of the major challenges in BSN research is to take the concept and translate it for clinical applications. This article highlights the standards and regulatory requirements on clinical translation.

Body Sensor Networks

The concept of Body Sensor Networks (BSN) outlines the technological challenges on the development of pervasive sensing systems for health, wellbeing and sport applications. Following the rapid growth in mobile phone technologies, significant advancements have been made in associated technologies, such as sensing, wireless networking, ultra-low power processing, energy harvesting, etc. Recent developments in BSN have progressed from technology oriented research to clinical applications. In the following sections, some of the key standards and regulatory requirements on translating BSN technologies for clinical applications will be discussed, such as biocompatibility, wireless communication standards, security and privacy, and ethics approval

Biocompatibility

As body worn sensors often have direct contact with the users, sensors have to be packaged with biocompatible material to avoid injury or allergic reactions prior to human trials. The ISO10993 standardises the evaluation of biocompatibility of medical devices [1]. With the recent development in rapid prototyping and 3D printing technologies, sensor packaging can be built and prototyped using a 3D printer with biocompatible materials. It has significantly shortened the design and validation process and lowered cost for developing prototypes for clinical use.

Wireless Communication Standards

The FCC (Federal Communications Commission) and Ofcom (Office of Communication) regulate the use of radio frequency bands in the US and UK respectively. The majority of BSN development relies on the use of the ISM (Industrial, Scientific and Medical) band. Early BSN sensors were mainly developed based on WSN (Wireless Sensor Networks) platforms and used the IEEE 802.15.4 or ZigBee as the wireless link. With the emerging ultra-low power wireless technologies, new wireless standards, such as the Bluetooth Low Energy (BLE or Bluetooth SMART) and the new IEEE802.15.6 Wireless Body Area Networks (WBAN), are introduced for BSN and associated applications. Similar to Bluetooth, BLE operates at 2.4GHz, but instead of optimising for media streaming, BLE is designed for low power sensing applications. WBAN, on the other hand, introduces the use of ultra-wide band (UWB) for short range communication, and it will enable more energy efficient wireless communication with smaller form factor.

Security and Privacy

Due to the sensitive nature of patient data, the handling of the data is strictly regulated. In the UK, all patient data is regulated by the 1998 Data Protection Act. Consents shall be sought from patients prior to the collection of data, and any record held shall be kept secured at all times and only those people concerned can have access to them. The patient has the right to access and to prevent access to their information. In the US, the access to health information is protected by the Health Information Portability and Accountability Act (HIPAA) and the Health Information Technology for Economic and Clinical Health (HITECH) Act. Similarly to the UK, appropriate mechanisms have to be implemented to ensure privacy and security of patient data, and patients shall be informed if the privacy and security of their data is compromised [2]. Recent developments on privacy and digital identities focus on the concept of you own your data that you have the right to possess, use, dispose or distribute your data. [3]

Ethics approval

Before any clinical trial, studies have to be assessed and approved by an independent research ethics committee. The process is designed to ensure that the rights and interests of the people involved in the trial will be protected. In addition to ethics, before a new device can be trialed clinically, approval shall be sought from MHRA (Medicines and Healthcare products Regulatory Agency) in the UK (similar to the FDA (Food and Drugs Agency) in the US). Depends on the complexity of the study, ethics applications could take a few months.

Opportunities

The miniaturised wearable low cost BSN sensors have facilitated the development of novel sensing modalities and enabled long-term measurements of physiological, activity, biochemical, biomechanical and context awareness parameters. Instead of snap-shot measurements, the continuous measurement concept of BSN has provided an unprecedented opportunity in gathering detailed extensive information on the patients. It has facilitated the identification of novel biomarkers and surrogate signs for capturing clinically relevant episodes. For instance, it has been shown that a miniaturised ear-worn sensor can capture activities, energy expenditure and gait parameters [4][5][6]. Poh et al. showed that electrodermal activity (EDA) sensor can be used to capture sympathetic nervous system activities during epileptic seizures [7]. With the rapid advancement of BSN technologies together with large-scale initiatives, such as the UK BioBank[8], in gathering long-term patient data from a large population, extensive health information will become available. It could better our understanding on physiology and pathology, which will enable the development of new effective diagnostic and therapeutic strategies for better patient care.

For Further Reading

1., 2., 3. http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/ GuidanceDocuments/UCM348890.pdf

4.L. Atallah, J. Leong, B. Lo and G-Z. Yang, “Energy expenditure prediction using a miniaturised ear worn sensor”, Medicine and Science in Sport and Exercise, July 2011 – Volume 43 – Issue 7 – pp 1369-1377

5.Benny Lo, Julien Pansiot, Guang-Zhong Yang, “Bayesian Analysis of Sub-Plantar Ground Reaction Force with BSN”, IEEE Proceedings of the 6th International Conference on Body Sensor Networks 2009 (BSN 2009), pp.135-139, June 2009

6. Benny Lo, Louis Atallah, Omer Aziz, Mohammed El ElHew, Ara Darzi and Guang-Zhong Yang, “Real-Time Pervasive Monitoring for Postoperative Care”, Proceeding of the International Workshop on Wearable and Implantable Body Sensor Networks 2007 (BSN 2007), pp.122-127, 2007.

7. Poh, Ming-Zher, et al. “Continuous monitoring of electrodermal activity during epileptic seizures using a wearable sensor.” Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE. IEEE, 2010.

8. http://www.ukbiobank.ac.uk/

Contributor

Benny Ping Lai Lo is Lecturer at the Hamlyn Centre and the Department of Surgery and Cancer, Imperial College London. He also acts as the Programmer Manager of the ESPRIT Programme, a UK EPSRC and UK Sport funded programme. Dr. Lo received his PhD in Computing from Imperial College London. His research interests include Body Sensor Networks, Pervasive Computing, Microelectronics, Bayesian Networks, Computer Vision, Temporal Tracking, Machine Learning, Image segmentation, and stochastic inferencing. Read more