Casson, AJ

Logesparan, L

Rodriguez-Villegas, E

This talk will provide an introduction to the "Towards future truly wearable medical devices: from application to ASIC" mini-symposium. For user comfort and acceptance long term physiological sensors must be discrete, comfortable and easy to use. These requirements place stringent limits on all aspects of the system design: from the overall application aim, to power generation issues, to low power electronic design techniques. For successful devices design issues in all of these areas must be solved simultaneously. The work here presents an overview and introduction to these topics.Accepted versio

Rodriguez Villegas, E

Spiral - Imperial College Digital Repository

An introduction to future truly wearable medical devices—fromapplication to ASICAlexander J. Casson, Lojini Logesparan and Esther Rodriguez-VillegasAbstract—This talk will provide an introduction to the “To-wards future truly wearable medical devices: from applicationto ASIC” mini-symposium. For user comfort and acceptancelong term physiological sensors must be discrete, comfortableand easy to use. These requirements place stringent limits onall aspects of the system design: from the overall applicationaim, to power generation issues, to low power electronic designtechniques. For successful devices design issues in all of theseareas must be solved simultaneously. The work here presentsan overview and introduction to these topics.I. INTRODUCTIONA large number of members of the IEEE Engineeringin Medicine and Biology Society are interested in someform of prolonged physiological monitoring. This couldbe ECG (electrocardiogram) for heart monitoring; EEG(electroencephalogram) for brain monitoring; breathing ratemonitoring; blood pressure monitoring; fall detection; orone of many others. From the end user perspective, theseprolonged monitors must have a wide range of features. Theymust be:• small, discrete, socially acceptable, easy to use, longlasting, accurate, reliable, and ubiquitous.Devices satisfying all of these criteria are termed wearablemedical devices to distinguish them from current deviceswhich are only portable. The development of wearablemedical technology will be essential for future personalisedand preventative medical care.From the researcher perspective satisfying all of theserequirements simultaneously is daunting, and this is withoutincluding the medical and electronic requirements of the de-vice. Sampling rates, signal-to-noise ratios, safety regulationsand other specifications must also all be met. This mini-symposium will provide an overview of the major challengesaffecting wearable device development, and recent progresstowards their solution. We will discuss: what are the chal-lenges?; what is the state-of-the-art?; and what are the futureresearch questions?II. OBSTACLES TO WEARABLE TECHNOLOGYFor the design of wearable sensor nodes three major areaswill be considered. As will become apparent, these majorobstacles to wearable technology development cannot beThe authors are with the Department of Electrical andElectronic Engineering, Imperial College London, UK. Email:{acasson,ll704,e.rodriguez}@imperial.ac.uk.The research leading to these results has received funding from the Eu-ropean Research Council under the European Community’s 7th FrameworkProgramme (FP7/2007-2013) / ERC grant agreement no. 239749.overcome in isolation. Applications specific requirements,guides, specifications and aims are essential.A. Low power electronics and signal processingA classical wearable physiological sensor must containa front-end analogue amplifier, an analogue-to-digital con-verter, and a wireless transmitter. It has been estimated thatfor truly wearable systems all of these stages must operatewith an average power consumption of less than 140 µW [1].This is a challenging aim. Online signal processing, also onthe wearable sensor, can be used to help meet this challenge,but at the cost of requiring detailed algorithm developmentand verification [2]. Even then, a successful algorithm mustoperate with very low power consumption.B. Power autonomyThe power consumption budget can be increased by theuse of physically larger batteries at the cost of systemsize. Historically the capacity of off-the-shelf batteries hasdoubled only every 5–20 years [3], and so capacities of suffi-ciently small, and medically approved, batteries are unlikelyto reach satisfactory values in the near future. Instead, longterm autonomous operation can be achieved using power-scavenging techniques. Here energy is harvested from theambient environment of the user, for example from bodyheat or movement [4], and it is believed that such techniquesmay harvest up to 100 µW significantly relaxing the powerconstraints. However, there are open research questions overthe amount of power that can be produced, the physical sizeof the energy harvester and the non-constant nature of thepower source.C. Physiological applicationWearable technology has potential applications in manydifferent medical areas. Even taking just one, say wearableEEG for brain monitoring, there are many potential endusage situations. The requirements for Brain-Computer In-terface (BCI) EEG systems may be very different to thosefor epilepsy diagnosis. This will require different processingelectronics, with differing power budgets. Also, keepinga medical device attached to the body for days, weeksor months at a time is not a trivial problem. In recentyears there has been significant progress on dry electrodes(for example [5]) which do not require conductive gel, butchanging any part of the electrode attachment stage will alsoaffect the specifications required for the following circuitstages.III. REALISING WEARABLE TECHNOLOGYThe “Towards future truly wearable medical devices: fromapplication to ASIC” mini-symposium will investigate thestate-of-the-art in all of the above areas: wearable applica-tions, energy harvesting, and low power signal processingand transceiver electronics, in a holistic manner.To realise truly wearable technologies this holistic ap-proach is essential, breaking traditional discipline bound-aries. For example, it is not enough to solve issues A) and B)above without simultaneously considering C); the particularapplication sets detailed requirements which must drive andguide the entire system design, so that an integrated solutionis achieved at all of the design levels. Multiple, differentsystems may be necessary for each overall application aim,and a different approach taken in each case.REFERENCES[1] A. J. Casson, D. C. Yates, S. J. Smith, J. S. Duncan, and E. Rodriguez-Villegas, “Wearable electroencephalography,” IEEE Eng. Med. Biol.Mag., vol. 29, no. 3, pp. 44–56, 2010.[2] A. J. Casson and E. Rodriguez-Villegas, “Toward online data reductionfor portable electroencephalography systems in epilepsy,” IEEE Trans.Biomed. Eng., vol. 56, no. 12, pp. 2816–2825, 2009.[3] A. Wang and A. Chandrakasan, “Energy-efficient DSPs for wirelesssensor networks,” IEEE Signal Processing Mag., vol. 19, no. 4, pp.68–78, 2002.[4] T. von Buren, P. D. Mitcheson, T. C. Green, E. M. Yeatman, A. S.Holmes, and G. Troster, “Optimization of inertial micropower gener-ators for human walking motion,” IEEE Sensors J., vol. 6, no. 1, pp.28–38, 2006.[5] R. Matthews, N. J. McDonald, P. Hervieux, P. J. Turner, and M. A.Steindorf, “A wearable physiological sensor suite for unobtrusive mon-itoring of physiological and cognitive state,” in IEEE EMBC, Lyon,August 2007.

English

An introduction to future truly wearable medical devices—from application to ASIC

A J Casson

L Logesparan

E Rodriguez-Villegas

Crossref

An introduction to future truly wearable medical devices&amp;#x2014;From application to ASIC

Casson, Alexander J

Logesparan, Lojini

Rodriguez-Villegas, Esther

The University of Manchester - Institutional Repository

The University of Manchester ResearchAn introduction to future truly wearable medical devices -from application to ASICLink to publication record in Manchester Research ExplorerCitation for published version (APA):Casson, A. J., Logesparan, L., & Rodriguez-Villegas, E. (2010). An introduction to future truly wearable medicaldevices - from application to ASIC. In Engineering in Medicine and Biology Society (EMBC), 2010 AnnualInternational Conference of the IEEE (pp. 3430-3431)Published in:Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEECiting this paperPlease note that where the full-text provided on Manchester Research Explorer is the Author Accepted Manuscriptor Proof version this may differ from the final Published version. If citing, it is advised that you check and use thepublisher's definitive version.General rightsCopyright and moral rights for the publications made accessible in the Research Explorer are retained by theauthors and/or other copyright owners and it is a condition of accessing publications that users recognise andabide by the legal requirements associated with these rights.Takedown policyIf you believe that this document breaches copyright please refer to the University of Manchester’s TakedownProcedures [http://man.ac.uk/04Y6Bo] or contact uml.scholarlycommunications@manchester.ac.uk providingrelevant details, so we can investigate your claim.Download date:30. Jun. 2022An introduction to future truly wearable medical devices—fromapplication to ASICAlexander J. Casson, Lojini Logesparan and Esther Rodriguez-VillegasAbstract—This talk will provide an introduction to the “To-wards future truly wearable medical devices: from applicationto ASIC” mini-symposium. For user comfort and acceptancelong term physiological sensors must be discrete, comfortableand easy to use. These requirements place stringent limits onall aspects of the system design: from the overall applicationaim, to power generation issues, to low power electronic designtechniques. For successful devices design issues in all of theseareas must be solved simultaneously. The work here presentsan overview and introduction to these topics.I. INTRODUCTIONA large number of members of the IEEE Engineeringin Medicine and Biology Society are interested in someform of prolonged physiological monitoring. This couldbe ECG (electrocardiogram) for heart monitoring; EEG(electroencephalogram) for brain monitoring; breathing ratemonitoring; blood pressure monitoring; fall detection; orone of many others. From the end user perspective, theseprolonged monitors must have a wide range of features. Theymust be:• small, discrete, socially acceptable, easy to use, longlasting, accurate, reliable, and ubiquitous.Devices satisfying all of these criteria are termed wearablemedical devices to distinguish them from current deviceswhich are only portable. The development of wearablemedical technology will be essential for future personalisedand preventative medical care.From the researcher perspective satisfying all of theserequirements simultaneously is daunting, and this is withoutincluding the medical and electronic requirements of the de-vice. Sampling rates, signal-to-noise ratios, safety regulationsand other specifications must also all be met. This mini-symposium will provide an overview of the major challengesaffecting wearable device development, and recent progresstowards their solution. We will discuss: what are the chal-lenges?; what is the state-of-the-art?; and what are the futureresearch questions?II. OBSTACLES TO WEARABLE TECHNOLOGYFor the design of wearable sensor nodes three major areaswill be considered. As will become apparent, these majorobstacles to wearable technology development cannot beThe authors are with the Department of Electrical andElectronic Engineering, Imperial College London, UK. Email:{acasson,ll704,e.rodriguez}@imperial.ac.uk.The research leading to these results has received funding from the Eu-ropean Research Council under the European Community’s 7th FrameworkProgramme (FP7/2007-2013) / ERC grant agreement no. 239749.overcome in isolation. Applications specific requirements,guides, specifications and aims are essential.A. Low power electronics and signal processingA classical wearable physiological sensor must containa front-end analogue amplifier, an analogue-to-digital con-verter, and a wireless transmitter. It has been estimated thatfor truly wearable systems all of these stages must operatewith an average power consumption of less than 140 µW [1].This is a challenging aim. Online signal processing, also onthe wearable sensor, can be used to help meet this challenge,but at the cost of requiring detailed algorithm developmentand verification [2]. Even then, a successful algorithm mustoperate with very low power consumption.B. Power autonomyThe power consumption budget can be increased by theuse of physically larger batteries at the cost of systemsize. Historically the capacity of off-the-shelf batteries hasdoubled only every 5–20 years [3], and so capacities of suffi-ciently small, and medically approved, batteries are unlikelyto reach satisfactory values in the near future. Instead, longterm autonomous operation can be achieved using power-scavenging techniques. Here energy is harvested from theambient environment of the user, for example from bodyheat or movement [4], and it is believed that such techniquesmay harvest up to 100 µW significantly relaxing the powerconstraints. However, there are open research questions overthe amount of power that can be produced, the physical sizeof the energy harvester and the non-constant nature of thepower source.C. Physiological applicationWearable technology has potential applications in manydifferent medical areas. Even taking just one, say wearableEEG for brain monitoring, there are many potential endusage situations. The requirements for Brain-Computer In-terface (BCI) EEG systems may be very different to thosefor epilepsy diagnosis. This will require different processingelectronics, with differing power budgets. Also, keepinga medical device attached to the body for days, weeksor months at a time is not a trivial problem. In recentyears there has been significant progress on dry electrodes(for example [5]) which do not require conductive gel, butchanging any part of the electrode attachment stage will alsoaffect the specifications required for the following circuitstages.III. REALISING WEARABLE TECHNOLOGYThe “Towards future truly wearable medical devices: fromapplication to ASIC” mini-symposium will investigate thestate-of-the-art in all of the above areas: wearable applica-tions, energy harvesting, and low power signal processingand transceiver electronics, in a holistic manner.To realise truly wearable technologies this holistic ap-proach is essential, breaking traditional discipline bound-aries. For example, it is not enough to solve issues A) and B)above without simultaneously considering C); the particularapplication sets detailed requirements which must drive andguide the entire system design, so that an integrated solutionis achieved at all of the design levels. Multiple, differentsystems may be necessary for each overall application aim,and a different approach taken in each case.REFERENCES[1] A. J. Casson, D. C. Yates, S. J. Smith, J. S. Duncan, and E. Rodriguez-Villegas, “Wearable electroencephalography,” IEEE Eng. Med. Biol.Mag., vol. 29, no. 3, pp. 44–56, 2010.[2] A. J. Casson and E. Rodriguez-Villegas, “Toward online data reductionfor portable electroencephalography systems in epilepsy,” IEEE Trans.Biomed. Eng., vol. 56, no. 12, pp. 2816–2825, 2009.[3] A. Wang and A. Chandrakasan, “Energy-efficient DSPs for wirelesssensor networks,” IEEE Signal Processing Mag., vol. 19, no. 4, pp.68–78, 2002.[4] T. von Buren, P. D. Mitcheson, T. C. Green, E. M. Yeatman, A. S.Holmes, and G. Troster, “Optimization of inertial micropower gener-ators for human walking motion,” IEEE Sensors J., vol. 6, no. 1, pp.28–38, 2006.[5] R. Matthews, N. J. McDonald, P. Hervieux, P. J. Turner, and M. A.Steindorf, “A wearable physiological sensor suite for unobtrusive mon-itoring of physiological and cognitive state,” in IEEE EMBC, Lyon,August 2007.

An introduction to future truly wearable medical devices - from application to ASIC

An introduction to future truly wearable medical devices--from application to ASIC.

An introduction to future truly wearable medical devices--from application to ASIC.

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