Georges Delhomme

Flexible technologies and smart clothing for citizen medicine, home healthcare, and disease prevention

Improvement of the quality and efficiency of healthcare in medicine, both at home and in hospital, is becoming more and more important for patients and society at large. As many technologies (micro technologies, telecommunication, low-power design, new textiles, and flexible sensors) are now available, new user-friendly devices can be developed to enhance the comfort and security of the patient. As clothes and textiles are in direct contact with about 90% of the skin surface, smart sensors and smart clothes with noninvasive sensors are an attractive solution for home-based and ambulatory health monitoring. Moreover, wearable devices or smart homes with exosensors are also potential solutions. All these systems can provide a safe and comfortable environment for home healthcare, illness prevention, and citizen medicine.

Autonomic nervous system response patterns specificity to basic emotions

The aim of this study was to test the assumption that the autonomic nervous system responses to emotional stimuli are specific. A series of six slides was randomly presented to the subjects while six autonomic nervous system (ANS) parameters were recorded: skin conductance, skin potential, skin resistance, skin blood flow, skin temperature and instantaneous respiratory frequency. Each slide induced a basic emotion: happiness, surprise, anger, fear, sadness and disgust. Results have been first considered with reference to electrodermal responses (EDR) and secondly through thermo-vascular and respiratory variations. Classical as well as original indices were used to quantify autonomic responses. The six basic emotions were distinguished by Friedman variance analysis. Thus, ANS values corresponding to each emotion were compared two-by-two. EDR distinguished 13 emotion-pairs out of 15. 10 emotion-pairs were separated by skin resistance as well as skin conductance ohmic perturbation duration indices whereas conductance amplitude was only capable of distinguishing 7 emotion-pairs. Skin potential responses distinguished surprise and fear from sadness, and fear from disgust, according to their elementary pattern analysis in form and sign. Two-by-two comparisons of skin temperature, skin blood flow (estimated by the new non-oscillary duration index) and instantaneous respiratory frequency, enabled the distinction of 14 emotion-pairs out of 15. 9 emotion-pairs were distinguished by the non-oscillatory duration index values. Skin temperature was demonstrated to be different i.e. positive versus negative in response to anger and fear. The instantaneous respiratory frequency perturbation duration index was the only one capable of separating sadness from disgust. From the six ANS parameters study, different autonomic patterns were identified, each characterizing one of the six basic emotion used as inducing signals. No index alone, nor group of parameters (EDR and thermovascular for instance) were capable of distinguishing each emotion from another. However, electrodermal, thermo-vascular and respiratory responses taken as a whole, redundantly separated each emotion thus demonstrating the specificity of autonomic patterns.

Autonomic nervous system responses correlate with mental rehearsal in volleyball training

Abstract The aim of this study was to assess objectivèly the processes of mental rehearsing (imagery) by measuring variations of the autonomic nervous system (or ANS responses) during an open-ended complex motor skill in two actual experiments (volleyball) and during mental rehearsing taking place between them. Comparison between pre- and post-test (volleyball) scores related to imagining and non-imagining performances revealed significant improvement in the former (2=20.9, P<0.00001) while in the latter 2=27, P<0.9, NS. The ANS parameters (skin potential and resistance, skin temperature and heat clearance, instantaneous heart rate and respiratory frequency) were quantified by original techniques and indices. Results from a principal component analysis showed a strong correlation between the responses in actual tasks (pre- and post-test volleyball) and during mental imagery, since the same preferential variables appeared on the main axis in 87% of cases. Thus the same autonomic channels seemed to be used during the actual activity and during the mental imagery of this activity. So far as phasic results were concerned, the main finding was a differing development of skill between imagining and non-imagining volleyball players. No clear difference was seen between pre- and post-tests in non-imaginers, except an increase in the median of the duration of the response observed in heat clearance, m1 and m2 respectively [m1= 5.8 (SD 4.1) s, m2= 7.6 (SD 3.9) s, P<0.001]. Conversely, for other ANS parameters, a significant decrease was seen in the post-test responses compared to pre-test responses in the imagining group [for instance, the median of the duration of the resistance responses decreased from m1= 12.6 (SD 4.3) s, and m2= 7.8 (SD 4.5) s, P<0.0001 in imaginers, while no change was observed in non-imaginers: 9.6 (SD 6.0) s vs 9.5 (SD 6.1) s, NS] except in the duration of the heat clearance response where an␣increase was seen [m1= 7.3 (SD 5.0) s vs m2= 7.6 (SD␣3.1) s, NS]. Compared to the non-imagining group, the latter result may also have been associated with a response decrease in the imagining group. Thus mental rehearsing induced a specific pattern of autonomic response: decreased amplitude, shorter duration and negative skin potentials compared to the control group. As this pattern was associated with better performance in the tests it can be suggested that in the case of open-ended motor activity, mental rehearsing may help in the construction of schema which can be reproduced, without thinking, in actual practice. Thus a neural information process might develop in the central nervous system changing from a parallel into a serial treatment.

Wearable Medical Devices Using Textile and Flexible Technologies for Ambulatory Monitoring

Health smart clothes are in contact with almost all the surface of the skin offer large possibilities for the location of sensors for non invasive measurements. Head band, collar, tee-shirt, socks, shoes, belts for chest, arm, wrist, legs ... provide localization with specific purpose taking into account their proximity of an organ or a source of biosignal, and also its ergonomic possibility (user friendly) to fix a sensor, and the associated instrumentations (batteries, amplifiers, signal processing, telecom, alarm, display ...). Progress in science and technology offers, for the first time, intelligence, speed, miniaturization, sophistication and new materials at low cost. In this new landscape, microtechnologies, information technologies and telecommunications are a key factor. Microsensors:Microtechnologies offer the possibility of small size, but also intelligent, active device, working with low energy, wireless and non invasive or mini invasive. These sensors have to be thin, flexible and compatible with textile, or made using textile technologies, new fibers with specific properties: mechanical, electrical, optical... The field of applications is very large, e.g. continuous monitoring on elderly population, professional and military activities, athletes performance and condition, and people with disabilities. The research are oriented toward two complementary directions: Improving the relevancy of each sensor and increasing the number of sensors for having a more global synthetic and robust information

Thermal parameters measurement on fire fighter during intense fire exposition

To improve rescuer safety, coordination and efficiency, the European program ProeTEX aims at developing new equipment for the intervention staff. This equipment is based on micro and nanotechnologies and consisted of smart textile integrated sensor to monitor physiological parameters, environment of the rescuer but also acquisition module and communication module. Thermal parameters are of primer interest. Internal temperature, external temperature and heat flux are relevant parameters to prevent heat stroke in fire fighter when exposed to intense fire. These parameters are recorded during fire exposition and highlight, on one hand, that the outer garment of fire fighters’ equipment insulates the fire fighter from the external environment, and on the other hand, that the thermal monitoring is relevant.

Wearable Electronic Systems: Applications to Medical Diagnostics/Monitoring

The combination of an ageing population and the increase in chronic disease has greatly escalated health costs. It has been estimated that up to 75% of healthcare spending is on chronic disease management (mainly cardiovascular disease, cancer, diabetes and obesity) (World Health Organization 2010). It is now widely recognised that there is a need to radically change the present Healthcare systems, historically based on costly hospital-centred acute care, and make them more appropriate for the continuous home-based management of chronic diseases. The goals of the new approach are the improved management of the chronic disease through encouraging lifestyle changes and the effective early detection and treatment of any problem before it necessitates costly emergency intervention.

Muscular Nonshivering Thermogenesis in Cold-Acclimated Ducklings

In small terrestrial mammals, the existence of nonshivering thermogenesis (NST) is fully demonstrated in new-borns, cold-acclimated and hibernating species. The activation of the sympathetic catecholaminergic system by cold or by diet is largely documented. Norepinephrine is considered as the mediator of NST and brown adipose tissue as the major site of this NST.

Analysis Of Skin Potential Response Using A Novel Feature Code For The Study Of The Emotional Response

The skin electrodermal activity and the skin potential response (S.P.R.) are related to mental activity, emotional response and the level of arousal. A feature code for the study of the S.P.R. was designed from three positive and three negative elementary shapes. By this method, the S.P.R. can be broken up into its elementary shapes constituents. This method was used in correlation with skin blood and skin conductance for the study of the emotional response in marksmen (archery and pistol) during competition. Using this software, the operator has only to indicate the start and the end of the signal to be studied.

Cerebral temperature varies across circadian phases in humans

The 24-hour rhythm of core body temperature (CBT) is commonly used in humans as a tool to assess the oscillation of the central endogenous circadian pacemaker. The invasive nature of the rectal sensor used to collect CBT makes it difficult to use in ambulatory conditions. Here we validate the use of a newly developed brain temperature (BT) sensor against that of a standard rectal temperature sensor using a 72-hour ultra-rapid sleep-wake (URSW) cycle procedure. A significant circadian variation of both body temperature recordings was observed from which a phase and amplitude was reliably determined. These results indicate that BT can be refined as a non-invasive alternative to CBT measurements in the evaluation of circadian phase in field conditions.

Ambulatory monitoring of skin blood flow: the μHematron device

The study of skin blood flow (SBF) by measuring the thermal conductivity of living tissues is performed using a non-invasive Hematron sensor designed by A. Dittmar. This paper presents the design and realization of the instrumenta- tion (μHematron) associated with the Hematron probe. The miniaturization of the conditioning electronics was achieved using a Programmable System-on-Chip (PSoC™) component from Cypress Semiconductor Corporation. Validation of the μHematron device was done using analog reference condition- ing electronics. Experiments have been performed on a physi- cal model and under in-vivo conditions. Characteristics of the new instrument are promising, facilitating monitoring of skin blood flow under ambulatory conditions, thus enabling new monitoring applications 3 ). The new design of the associated electronics is based on a program- mable component, PSoC™ (2), with a view of reducing the number of external discrete components and thus minimiz- ing the hardware to facilitate ambulatory measurements by locating comfortably the total miniaturized system on the patients wrist. Skin blood flow is determined by measuring thermal conductivity which is directly related to the tissues thermal exchanges. These exchanges depend on the effective blood perfusion of the tissue and the thermal conductivity is con- sidered an indication of such tissue perfusion (3).