Patch technology health

Duke University's CovIdentify. California Insititute of Technology's E-Skin. PrecisionCool Headband. Amazfit X Fitness Watch. Polar Grit X Multisport Watch. Care Smart Accessibility Watch. Samsung Blood Pressure Monitoring. More than 88 million US adults have prediabetes which increases the risk for type 2 diabetes, heart disease, and stroke. But early intervention and lifestyle changes can help prevent more threatening cases down the road.

This is why the Australian startup, Nutromics, is developing a smart patch device to help manage the risk for the disease. This allows for noninvasive and painless assessment of dietary biomarkers. The patch then sends the information to an app which allows users to see how their bodies respond to certain foods.

By giving dietary modifications, it helps users reduce their risk for lifestyle-related diseases. V-Go is a hour, patch-like wearable that delivers insulin.

A trial shows that adults with type 2 diabetes can safely achieve good blood sugar control by using regular human insulin RHI in the wearable. It found that this is just as effective and safe as the more modern rapid-acting insulin RAI. This suggests a more affordable option than the newer insulin.

RHI takes longer to reach the bloodstream and has a longer duration of action when injected by an insulin pen or syringe.

This can influence blood sugar control. Adults with diabetes can currently use V-Go with RAI to deliver insulin steadily over 24 hours and on-demand at mealtime. Continuous infusion of insulin for 24 hours with this device showed minimal differences of action between RHI and RAI. The results support that adults with diabetes can safely and effectively use RHI if delivered by V-Go.

The technology could provide an alternative for invasive blood tests for diabetes. It uses chip technology to track glucose levels through blood vessels behind the eyelid.

It can also dispense medicine to treat diabetic retinopathy, a common condition from damaged blood vessels in the eye. More research is necessary to determine if this can serve as a next-generation device to advance the treatment of diabetes. This could even pave the way for treating certain eye diseases. A University of Houston professor is developing a smartwatch to improve remote learning.

The signal processing and control algorithms deliver information on three types of brain states:. These come from signals including sweat response, respiration, cardiac function, and temperature. The possible applications for this technology stretch beyond the classroom. Another useful application of this algorithm could be for the elderly who are home alone and possibly depressed. The algorithm can detect this in a smart home setting.

Once detected, it can change the frequency or color of light in the home, or even start playing background music to lighten their mood. The inventing professor is testing the smart light and music system capabilities in her lab to develop this possibility. Apollo is a wearable technology developed by neuroscientists and physicians.

The watch-like device worn on the wrist or ankle uses gentle vibrations to help the body respond to stress. It uses inaudible sound waves for changing mindfulness and mood through the sense of touch. Early users of this tool were doctors and patients, athletes, and those dealing with chronic stress. But Apollo Neuroscience aims to use this as a holistic alternative to mental health treatments that use prescription drugs.

Apollo has a coordinated data-monitoring app for iOS or Android phones. It has seven different modes so users can reach different goals by relaxing the body, clearing the mind, and restoring natural balance. Some users say it feels like wearing an ocean wave with the vibrations which help them mediate between calmness and energized states.

Stanford Medicine researchers are working with Fitbit and Scripps Research to develop a tool that predicts illness. The effort will detect early signs of viral infection through data from wearables. This constant monitoring is particularly important in children with pulmonary diseases [ 13 , 15 ]. This vital parameter is normally calculated from the acquired respiratory waveform that reflects the chest volume variation during the inspiration and expiration. Thoracic expansion joined with muscle signs allow to calculate the respirator effort, indicating different physiological states.

The analysis of these data in sport, mainly in competitive athletes can help in the achievement of a better respiratory performance [ 13 , 15 , 23 ]. Nowadays to obtain the respiratory function there are three primary methods: elastomeric plethysmography EP , impedance plethysmography IP and respiratory inductive plethysmography RIP. EP technique converts current variation of piezo-electric sensors in voltage using an elastic belt. Guo et al. IP uses impedance changes of the body surface due to the expansion and contraction during breathing.

This technology was used in the development of a uniform vest to be used in soldiers [ 4 ]. RIP technology principle is based on a loop wire with current that generates a magnetic field normal to the loop orientation. Chest volume variations change the area enclosed by the loop, creating an opposing proportional current [ 29 ].

Beside these three primary methods, other technologies are being used to get respiratory waveform: accelerometers [ 30 ]; extracted from the ECG signal [ 31 ]; derived from pulse oximetry [ 32 ] polymer-based transducers sensors [ 33 ]; optical fibers [ 34 ]; etc. Al-Khalidi in [ 35 ] has made a deep review about the methods used to measure respiration rate. Many other methods that are not suitable to be implemented in WHDs are referred on his review such as using infrared cameras or acoustic methods.

More recently, RR was acquired using a polymer named Polypower. This dielectric active polymer DEAP is being commercially produced as Polypower and changes its electrical attenuation when stretched in one direction.

Before this type of polymers, the stretchable strain sensors were mainly based on fluid metals, such as mercury or gallium—indium, which was a dangerous material in case of a metal leak due to a possible packaging damage. The polymer based stretchable strain sensors allows to acquire electrical changes without the use of these dangerous fluid metals. Tognarelli et al.

Blood oxygen saturation SpO2 is an extremely valuable vital parameter and easy to measure using photoplethysmography PPG technology and pulse oximetry principles. The PPG method enables to acquire blood vessel variation waveform, and when measured using two wavelengths normally nm and nm it is possible to estimate blood oxygen saturation. This is due to the haemoglobin absorbance spectrum change when it bounds with oxygen.

One of the problems in blood oxygen saturation measurement is when the patient is anemic [ 13 , 38 , 39 ]. Besides medical use, pulse oximetry ambulatory monitoring has a particular interest in the evaluation of aerobic efficiency of a person undertaking a routine exercise.

A study about the oxygenation of capillary bed from muscles can lead to a maximization of the athlete performance. Limb and brain oxygenation information is also important in military and space applications where gravity changes may affect the delivery of oxygen to these parts of the body leading to blackouts.

There are several non-invasive technologies to measure blood oxygen saturation that can be applied to wearable devices, but PPG stands out being very popular in medical environment [ 38 ]. Finger is the most used place to acquire blood oxygen saturation levels and is the most commonly used in clinic conditions. Ring PPG sensors are under development due to its more wearing-comfortability and easily adaptation. Mobile connections leads these sensors to a much more independent and wearable device [ 40 ].

PPG sensors in forehead are used to measure brain oxygenation and have already been developed as described in the literature [ 41 ]. A surface chest PPG reflectance prototype device was developed by Puke et al. Recent developments made by Chen et al.

Concerning textile technology, several approaches have been developed to try to implement PPG sensors in this area. One approach is the integration of flexible plastic strips in weft direction containing two LEDs strips and two photodiode strips, with copper wires in the textile to conduct the signal in the textile fiber [ 43 ].

Another approach is to use optical fibers embroidered into textile. Krehel et al. It is not measured in a normal procedure of a clinical environment, but is important in diabetic global population. Diabetes disease causes several physiological disorders cerebral vascular disturbance, retinopathy and nephropathy. To prevent it, diabetic individuals control blood glucose concentration measuring BG levels and inject insulin when needed to maintain the standard values.

The most used method to evaluate BG concentration is collecting a blood sample by pricking the finger with a lancet. There has been a lot of effort to prevent finger pricking and as a result several devices have been developed and are already in the market that have the purpose to continuous measure BG levels still using invasive methods. Some examples are the Medtronic Continuous Glucose Monitoring CGM device capable to measure BG levels using an adhesive patch with a needle, sending the data wirelessly into a wearable insulin pump to release insulin into the human body [ 45 ]; Dexcom, Inc.

Dexcom become the first company to obtain FDA pre-market approval for their mobile application to support continuous monitoring. To try to prevent the human body invasion in BG measurements, non-invasive techniques have been developed to improve continuous self-monitoring and increasing efficacy in diabetes management during daily activities [ 16 , 48 ]. In it was discontinued due to skin burning effect.

Other non-invasive techniques have been developed since then, such as: bioimpedance spectroscopy, a non-viable technique to continuous monitoring due to its poor reliability and acquisition requirements, where the user must rest 60 min before the measurements [ 50 ]; electromagnetic sensing with the disadvantage of being strongly affected by the temperature [ 50 ]; fluorescence technology [ 48 ]; mid- and near infrared spectroscopy are both possible technologies but presents several barriers, like weak penetration and reading correlation respectively; Measurement of BG through the eye, technology already used by Google to developed a prototype that has been taken to the FDA for early independent clinical trials [ 16 ]; Ultrasound has high sensitivity but with some interference from biological compounds [ 50 ].

In some of these devices there are also temperature sensors, skin perspiration sensors and actigraphy sensors to predict energy expenditure, helping in the estimation of insulin that a subjects needs to administrate. There are still several challenges and barriers in this area, leading to a constant effort from many research groups to develop new technologies to get a stable, reliable, conveniently and economic continuous monitoring wearable device [ 49 , 50 , 51 ].

One of these difficulties is the delay of time between the concentration of blood glucose between the actual blood glucose and the one measured in the interstitial fluid, which may lead to a less reliable estimation of insulin dosage. To contour this issue new algorithms are being developed to estimate the future blood glucose levels with a time window of around 30 min [ 52 ].

Skin perspiration is not a clinical parameter but a physiological sign used to analyze human reaction to several situations.

Life situations can cause neurological reactions from the autonomic nervous system ANS stimulating an increase of skin sweating. This moisture changes the electrical conductance of the skin, allowing measuring the quantity of sweat produced by sweat glands, named as galvanic skin response GSR. As ANS is responsible to control other physiological parameters like heart rate, respiration and blood pressure, GSR has been used alongside the acquisitions of some of these signals.

For example, skin perspiration and heart rate variability can be used to classify mental states, helping in the distinction, as also in the detection of mental stress [ 53 , 54 ]. In sports, skin perspiration continuous monitoring is considered an important physiologic sign with enormous applications in this area and human behavior.

It opens a new field of research in the clinical settings, such as in dehydration area, but it should not be interpret without knowing the physical activity context [ 15 , 54 ]. From skin perspiration, it is possible to obtain information about the physiological condition of the subject due to the several ions and molecules that constitutes it. For this reason, it is an excellent bio-fluid for non-invasive chemical sense to identify pathological disorders through ions levels, with a possible high benefit in clinical environment.

Sodium, ammonium, calcium and lactate levels are indicators of electrolyte imbalance but also of cystic fibrosis, osteoporosis, bone mineral loss and physical stress. For example, physical stress can be used in psycho-physiological evaluation of militaries undergoing intense training [ 15 , 55 ].

Epidermal-based have a conformal contact between the electrodes surface and the biofluid, like elastomeric stamps to print electrodes directly on human epidermis for continuous monitoring.

Kim et al. It is small, flexible and the surface is made of a dry polymer foam electrode to maintain a stable contact with the skin. A different technology is also under development—a technology based on microfluidic sweat analysis. Liu et al. Very recently, Koh et al. Blood oxygen saturation measurement by pulse oximetry is a widely used method to access arterial oxygenation but it is not a good method for human ventilation assessment.

Capnography is a non-invasive and cost effective method to evaluate human ventilation, indicating the carbon monoxide levels present in the respiration cycle, being very useful to avoid clinical problems and ensure patient safety [ 12 , 58 ]. Capnography continuously measures the inhaled and exhaled partial pressure of carbon dioxide PCO 2 in the respiratory gases, from where an estimation of the CO 2 partial pressure in the arterial blood can be made.

This measurement is made through air capturing just below the nose, where it goes to capnography device to perform CO 2 gas quantification, obtaining a characteristic waveform from which it is also possible to obtain the respiration rate [ 58 , 59 ]. For more than 25 years, capnography has had a widely use in clinical practice as integral part of anaesthesia care in operating rooms, allowing anaesthesiologists to evaluate the consciousness level of the patient during the sedation process, but when patients are moved to the intensive care unit ICU , they are not continuously monitored with capnography.

A recent study shows a high correlation of morbidity and mortality with the underuse of capnography in ICUs [ 58 ]. Several reasons have been enumerated by Shankar [ 58 ] from Harvard Medical School to explain why capnography should be considered a routine monitor, highlighting that this method can be used as a guide to metabolic rate, or as an essential adjunct to monitor the integrity of airway, cardiac output and ventilation.

Capnography is mainly used outside the clinical environment to monitor sleep apnea syndrome. Normally this disorder is diagnosed and monitored using polysomnography or cardio-respiratory polygraphy can also include capnography monitoring, but not as a single parameter , both high costs methods and dependent on the access to a specialized sleep laboratory.

An investigation published in by Dziewas et al. Capnography is becoming a prevalent vital sign on portable devices and is helping first responders make life-saving decisions. In a near future, it is expected that capnography become widely used outside clinical environments.

To ensure this, manufactures should make an effort to produce reliable, cost effective and portable capnography units with quick calibration procedures [ 58 ]. Although it is less suitable to monitor patients during anaesthesia proceedings and it does not assess respiration rate, it has progressively shown good performance to monitor home ventilated subject as described in the study of Orlikowski et al. This method has been developed since late s and it depends on the capillary blood flow increment by increasing the tissue temperature caused by a heating element in the electrode, assessing PCO 2 using electrochemical electrode or oximetry principles.

This method has revealed some issues related with calibration, elevated temperatures and associated burns. Body temperature BT is the outcome of the balance between heat production and heat loss in the body, being its measurement vital to avoid many elements defunctionalization due to high temperatures e. BT divides in two measures: core temperature CT and skin temperature.

Skin temperature is affected by blood circulation and is also related with HR and metabolic rate [ 65 , 66 , 67 ]. External factors such as air circulation, ambient temperature and humidity also play an important role in this body temperature regulation mechanism [ 65 , 66 ].

Different wearable systems have been developed to measure both temperatures, such as skin-like arrays of precision temperature sensors or wearable adhesive devices to continuously measure temperature [ 68 , 69 , 70 ]. A very recent example is a re-usable wireless epidermal temperature sensor [ 71 ]—a battery-less RFID thermometer that is showing to be a promising device to estimate CT. Measuring CT through non-invasive methods, such as heart rate and skin temperature acquisition still remains a challenge.

This is mainly due to the external factors that can affect physiological signs, making it difficult to have a direct correlation between these variables that only depends of the human physiologic thermoregulation mechanisms [ 66 ]. Looney et al. The gold standard for CT measurement nowadays is still the rectal temperature, and while other techniques like the telemetric pill allow for better usability, they face technical issues that influence the CT measurements.

The evaluation of human body movements has several applications in medical rehabilitation, posture evaluation and sport performance. Motion analysis is widely used in actigraphy, a monitoring method to evaluate human rest and activity cycles that enables to provide an insight of daily activities routine. In medical rehabilitation, it is important to monitor mobility, in specific therapeutic exercises in order to evaluate movements and help in exercise techniques improvement, maximizing patients recover [ 16 ].

A WHD, with the proper sensors, can provide guidance and feedback to the patient and generate warnings based on the patient physiological conditions. Pulmonary rehabilitation can also be included in this type of monitoring, helping patient to complete a physical activity rehabilitation program. Posture is also an important factor that has a particular interest in patients submitted to hip surgery. Muscle activity can be acquired and associated to motor functional tasks.

Motion evaluation and muscle activity used in sport activities allows accessing physiological signals, body kinematics and fatigue during exercise leading to athlete performance improvement. A recent example is reported by Maglott et al.

To measure body movements, several sensors can be embedded in textile WHDs or in the portable units, such as inertial sensors accelerometers, magnetometers and gyroscopes , electromyography electrodes, shoes force sensors [ 76 ] and even stimulators [ 2 ].

To obtain location and distance data, a GPS can be also added to the device. Complex body movement patterns can be measured, combining these sensors along with WHDs fabric, assessing to a higher amount of human body movements. The best way to access reliable data of human movements is using tight clothes. To contour this and try to obtain viable data using normal clothes, some research is being made to try to remove movement artifacts, enabling to use inertial sensors in casual clothes [ 77 ].

The increase of implantable cardiac devices is leading to a development of long-term surveillance, to improve patient safety and care. These devices are mainly implantable pacemakers, cardioverter defibrillators and cardiac resynchronization therapy systems. A remote monitoring of these devices will minimize the need of caregivers in several situations, allowing an early detection of adverse events and prompt corrective measure, accessing to up-to-date information stored in the devices memory.

The incorporation of new communication technologies will provide a daily, remote, wireless, patient independent ambulatory monitoring of medical and technical data. A study with this type of system was conducted in a large population during four years concluding that, if the system was intelligently used, it was capable to improve care and increase safety of these patients [ 78 ]. Ambiance parameters are the environmental parameters in each subject surroundings and have a high relevance in several human body monitoring areas.

The most used sensors are temperature, light, humidity and sound level. The continuous monitoring of air pollutants is also important due to its association with cardiac and pulmonary diseases. Outdoor daily activities should also be continuously monitored with ambiance sensors to analyze ambiance characteristics that the human body is subjected during sport activities or simply rehabilitation exercises, being temperature and humidity important to evaluate dehydration [ 16 ].

With ambiance sensors it is possible to estimate the occupancy activity of subjects, easily estimating metabolic rate, mainly in indoors environments due to the non-contribution of external factors. According to a study made by Jin et al. Ambiance parameters such as ambient light, sound and temperature are also important to study and evaluate sleep quality and quantity. For example a sound sensor joined with an actigraphy sensor is an important tool to study sleep disturbances suffered by people living near airports [ 80 ].

Since the last decade, an aging population and the emergence of chronic diseases lead to a bigger interest in wearable physiological measurements devices. The effort in these developments is resulting in small wearable devices, with the benefits of a lower cost and higher mobility while the data is being collected [ 5 ].

Based on our literature review we have designed an abstract generic WHD architecture Figure 3 where we included the features from several wearable devices already developed both researched prototypes and commercial products. Generic architecture of wearable health devices system [ 3 , 10 , 81 , 82 , 83 ]. The generic architecture presented is divided in four modules: A Body Area Network, which can have different approaches, as we will see ahead; B Data Logger or Portable Unit whit all the electronic; C Data Analysis, an offline method to see the recorded data; D and Real Time Monitoring that enables to visualize live data [ 81 , 82 ].

These three terminologies can be used in different types of wearable devices according to its architecture. In the image, the terminology BAN is used because it is related only with the sensors placed around the human body. The interconnection of these sensors creates a network of sensors BAN , which are sent to a processing unit like a portable unit. If each node from the connecting network has a sensor or medical device with a sensing unit, containing more than just the sensor, we should refer it as a BSN rather than a BAN [ 10 , 12 ].

On the most general level, WSNs usually involve large numbers of low-cost, low-power and tiny sensor nodes, with each node having a predefined set of components sensors, microcontroller, memory and radio transceiver [ 12 ], among others granting that each node has sensing, computing, storage and communication capabilities [ 8 ].

Connecting all sensors by means of a network presents clear advantages, as it enables centralization of data in a single portable unit, gathering information from different sensors and sending it to external networks for remote processing. Furthermore, it enhances control, synchronization, scheduling and programming of the whole system, which allows the system to adapt according to present body condition and external environment. These advantages culminate in an optimization of the resources usage [ 10 ].

Wireless communication is a key asset and mandatory to enable systems to go mobile and ubiquitous. The portable unit PU , also denominated as user interface box or datalogger unit, is where all the information is gathered, containing the outputs and inputs of the WHDs. The main inputs are the vital signs from sensors, but it can also receive data from other connected portable devices. The communication between sensors and the PU is normally made through wires, resulting in a simpler and cheaper WHD.

Some variations in this communication technique have been emerging, such as in smart clothes, where the interconnections wires are embedded and woven into the fabrics.

This is a much more favorable approach in WHDs, avoiding loose wires around the body leading to a higher comfort and movement liberty. There is an innovative approach where the communication is made through biological channels, where the human body is used as a transmitter using electrostatic fields [ 5 ].

Signal processing can be made in the PU or in other device after the data transmission to it. This processing extracts features to evaluate the subject health, allowing the detection of an anomaly, the prediction of a disease or in the diagnose support. The raw-data collected by the PU can be transmitted using a wireless protocol or stored in a SD memory card.

As Figure 3 shows, PU can also receive data from online monitoring devices and store it in a local memory. This two-way communication allow other devices to stablish a wirelessly connection to a main device, which stores the data of several sensors. This system can also be helpful to label the timing of important events using external devices [ 5 , 10 , 81 , 84 ]. Bluetooth is a short-range radiofrequency based connectivity between portables and fixed devices requiring low-power consumption and with a low-cost.

It is ideal for WHDs and widely implemented in commercial devices like smartphones and laptops. The new Bluetooth technology version 4. Wi-Fi protocol lower layers were adopted, allowing higher data throughput for low-power requirements applications, not as low as the Bluetooth technology but can also be a good connection protocol to use in WHDs, mainly when a higher distance of communication is needed.

ZigBee is another technology used for low power and low data rate communication protected by the use of the Advanced Encryption Standard. This feature makes ZigBee ideal to medical applications because it can consume less energy than Bluetooth versions earlier than 4.

LoRa technology is a long distance coverage, low cost and low power consumption wireless protocol. According to Jeevan Kharel et al. It has the disadvantage of low data rate, but a huge advantage of scalability and customization of several parameters such as frequency channel, transmission power and data rate. This enables to reduce the power consumption and adapt it according to the transmission specifications [ 85 ].

Table 2 summarizes some of the main features of these wireless protocols. Wireless Protocols main features [ 9 , 85 ]. Mobile telecommunications technologies can also be used to transmit real-time data using GPRS, a standard mobile data service in the global mobile communication.

In the construction of a wearable device the communication protocol is very important in order to minimize the energy consumption [ 86 ].

A possible way to help battery longer lifetime is reducing the amount of data transmitted. With a data selection, it is possible to send it only when it is relevant, or save it in internal memory. At these cases a later offline data analysis can be performed. Data storing can be perform using SD memory card or internal digital memory slot, transmitting then data through a USB connection between the WHD and another device, where data from the SD card can be read.

Another method to minimize the energy consumption is to incorporate compression techniques in the transmission protocol.

Beside the reduction in the energy consumption this method help when network bandwidth limitations exists, or even when the storing space is reduced and a data compression is needed [ 87 ]. A higher need of monitoring patients during long periods in the hospital led to real-time requirements.

With WHDs it is possible to perform clinical monitoring outside a medical environment, alerting the patient in case of any physiological problem or just to monitor himself and be updated of his vital signs during daily activities [ 10 ]. In a medical environment WHDs allows the patients monitoring inside the boundaries of a specific area, normally a Hospital, where the patients can move while their vital information is being wirelessly transmitted to a remote monitoring center.

Some devices can also send the patient location inside clinical environments. All these features allow the patient to move without any machines with him instead of being laid in the Hospital bed.

These live systems can also be configured with a set of alarms for each patient helping in the detection of some required anomaly. The vital signs can also be recorded in Medical Information Systems to be later analyzed by a medical professionals [ 81 , 88 ]. This feature allows the patient to have a normal life while being monitored, with his vital signs continuously or intermittently transmitted to a remote monitoring center, with health support and, if needed, inform the patient of his medical status.

The ambiance data acquisition is also important to know the conditions which people are exposed. For example, if an elderly person is subjected to an excessive cold or hot weather that can cause lung infection, dehydration or other diseases, an appropriate action might be taken to prevent a dangerous situation [ 15 , 81 ]. For last, vital signs can also be transmitted via Bluetooth to portable devices or personal computers to visualize and analyze the health status of an individual.

This type of real-time monitoring can be used in sport activities to analyze the athlete vital signs during exercise, or in a simple daily run.

Another example is the use of these devices in the health status monitoring of firefighters and combatants in field using mobile technologies, such as GPRS [ 81 , 84 ]. All data from vital signs can be stored in a portable unit micro-SD memory card for example , for future use in medical analysis or just as personal record. The data can be stored at the same time that a real-time monitoring is occurring. The main aim of such monitoring is to record vital data for clinic diagnosis and prediction by a medical professionals.

For example, sleep issues such as apnea, can be analyzed through saved data from the patient: a home sleep monitoring allows to monitor sleep in a familiar environment resulting in reliable data acquisition [ 11 , 84 ].

Wearable health devices are becoming important ambulatory monitoring systems helping in medical prediction, anomaly detection and diagnosis.

One of the problems is the limited number of measured physiological parameters. Many WHDs are developed with the aim to acquire only one physiological sign measurement, adapting its design and use to that only parameter. This fact results in several WHDs able to monitor a certain amount of vital parameters, but with monitoring limitations.

Wristwatches, also known as smartwatches, are under development for a few years and are denominated as accessories for the human being.

More recently, a new smartwatches generation is emerging with wireless and mobile communication, able to provide more than 24 h of vital monitoring [ 90 ]. Their comfortable design, similar to a normal watch, allows to worn it constantly. These are being developed as activity and fitness trackers, monitoring physical activity like burned calories and distance travelled, heart rate, and, more recently, sleep monitoring, like PEAK TM Figure 4 - 4 which was the first smartwatch able to track sleeping cycles [ 91 , 92 ].

Moov Figure 4 - 7 is a recent bracelet wearable to monitor movement. It can be used in different parts of the body according to the sport practiced, like swimming that is used in the wrist or in the leg in case of running activities [ 93 ]. Examples of some wearable health devices.

Google eye lens Figure 4 - 2 is a type of WHD that can represent the future of wearables, where they are going from macro size to micro and, in the future, will go nanoscale to be introduced in the body [ 16 ]. Another type of accessory device is emerging, an ear device that is able to acquire several physiological parameters like oxygen saturation level and heart rate. These type of devices, connected to the ear Figure 4 - 1 , are considered viable sensors due to its composition of mainly cartilage, removing muscle interfering, and has arteries near the surface.

Valencell, a major supplier of sensing technology argues that ear signal is times clearer than at the wrist. There are a very low number of these devices, and it can represent a new trend line of wearables [ 97 ]. A big group of wearable devices are related with heart activity. To continuously monitor this parameter there are three main types of wearable devices: chest straps Figure 4 - 5 ; adhesive patches Figure 4 - 3 ; and t-shirt Figure 4 - 6 with embedded electronics.

The first two are more capable to acquire several vital signs, but are not so comfortable and easy to wear as a simple part of clothing, like a t-shirt. When electronic technology meets garment the smart clothes denomination appears, being one of the best bets to acquire a higher amount of physiological signals since it covers a higher body area.

The incorporation of electronic based technology in garments lead to the concept of smart textiles. These can be applied to several areas from fashion dresses with lights to medicine vital signs monitoring. A scientific effort is being made to evolve these smart fabrics into textiles capable to integrate unique properties that are normally performed by usual electronic systems, and can be divided in two categories: metal yarns incorporating conductive fibres or in electro-conductive yarns containing polymeric or carbon-coated threads.

In terms of the development of smart textiles to be incorporated in WHDs, the main focus is on the textile electrodes also called textrodes to acquire the signals from the human body as it was already referred in some vital signs acquisition methods.

It is possible nowadays to develop smart textile WHDs systems for a high number of applications for lifestyle and sport monitoring.

A dream to use Two simple patches will replace cumbersome sensors, and patients will rest easier being monitored at home or in a medical setting suggested by their doctor. Count on us Put your trust in testing results that match the accuracy of conventional in-lab sleep clinics at a fraction of the cost. We're hiring!