Monitoring systems for monitoring of physiological parameters of a living being are well known in prior art. For example, PCT/IL2010/000774, the disclosure of which is included herein by reference in its entirety, discloses a health monitoring system that continuously checks the wellbeing of a person (or any other living being) that, typically, is considered healthy (or with a known set of diseases), covering a significant range of health hazards that may cause a significant life style change/limitation, and provides an alert as early as possible—all this, with no significant limitation to the normal life style of the person bearing the system.
There exist other systems for monitoring heart rate, respiration and bio impedance, which can be used at home. Other systems, e.g. electroencephalographic (EEG) systems, electrocardiographic (ECG) or electromyographic (EMG) systems, are mainly adapted for clinical use, and typically use gel electrodes. The electrodes require a good skin contact to the monitored person. To make such electrodes more user friendly and easy to use, e.g. in a home environment, textile electrodes have been suggested. Such electrodes can be integrated into garments, for example, an undershirt.
Unlike conventional gel electrodes, which are directly applied to the living being's skin, using a conductive gel, textile electrodes are dry contact sensors adapted for use in measuring ECG signals and other vital signals such (EEG), electroencephalogram (EOG), electrooculogram and other medical measurements on the skin without any skin preparation, such as needed with wet electrodes, for example, shaving hairy skin.
Attempts have been made to tailor textile electrodes into a garment, in order to monitor health related physiological parameters of living beings. However such systems either record the signals for future, off-line analysis, or attempt to provide a health diagnosis. The off-line analysis may often prove to be too-late, and the health diagnosis is usually not accurate enough to trigger a definite intervention or instruction to the user.
The term “continuous monitoring”, as used herein with conjunction with a health monitoring system, refers to a health monitoring system, facilitated to monitor a living being substantially continuous, day and night, when the monitored living being is awake or asleep, and active in substantially all common activities of such living being.
The term “seamless”, as used herein with conjunction with a wearable device, refers to a device that when worn by an average person, wherein the device puts no significant limitation to the normal life style of that person and preferably not seen by anybody when used and not disturbingly felt by the user while wearing it. Furthermore, no activity is required from the monitored person in order for the system to provide a personal-alert when needed. It should be noted that people that pursue non-common life style, such as soldiers in combat zone or in combat training zone, or firefighters in training and action, or athletes in training or competition may utilize non-seamless devices. As the “seamless” characteristics refers also to the user's behavior, the wearable component is preferably an item that is normally worn (e.g., underwear) and not some additional item to be worn just for getting the alert.
The terms “underwear” or “garment”, as used herein with conjunction with wearable clothing items, refers to seamless wearable clothing items that preferably, can be tightly worn adjacently to the body of a monitored living being, typically adjacently to the skin, including undershirts, sport shirts, brassiere, underpants, special hospital shirt, socks and the like. Typically, the terms “underwear” or “garment” refer to a clothing item that is worn adjacently to the external surface of the user's body, under external clothing or as the only clothing, in such way that the fact that there are sensors embedded therein, is not seen by any other person in regular daily behavior. An underwear item may also include a clothing item that is not underwear per se, but still is in direct and preferably tight contact with the skin, such as a T-shirt, sleeveless or sleeved shirts, sport-bra, tights, dancing-wear, and pants. The sensors, in such a case, can be embedded in such a way that are still unseen by external people to comply with the “seamless” requirement.
The terms “course” and “line segment”, are used herein as related terms. The tubular form of the garment is knitted on a knitting machine, such as a Santoni knitting machine, where the tubular form is knitted in a spiral having substantially horizontal lines. A single spiral loop/circle us referred to herein as a course and a portion of a course is referred to as line segment.
The term “tightly” means that specific portions of the garment where there are electrodes or other sensors that require certain pressure on the body to obtain a satisfactory signal, are designed to be as tight as needed. However, all the other parts of the garment may be not as tight. Optionally, there is a provision to facilitate tightening or releasing certain portions of the garment, by built-in straps or other tightening means, so that the need for more or less tightness does not require the replacement of the whole garment.
The phrase “clinical level ECG”, as used herein with conjunction with ECG measurements, refers to the professionally acceptable number of leads, sensitivity and specificity needed for a definite conclusion by most cardiology physicians to suspect a risky cardiac problem (for example, arrhythmia, myocardial ischemia, heart failure) that require immediate further investigation or intervention. Currently, it is at least a 12-leads ECG and preferably 15-lead ECG, coupled with a motion/posture compensation element, and a real-time processor with adequate algorithms.
Because ECG is a powerful and noninvasive tool that can provide high temporal resolution to directly reflect the dynamics of the heart activities, it has been widely used for medical diagnoses and CVD research. Conventional wet Ag/AgCl electrodes are generally and most frequently used to measure ECG signals. The conventional wet electrode characteristics have been widely studied and discussed in detail, including their applications. Indeed, ECG signal quality is excellent with a proper skin preparation (e.g. shaving hairy skin) and conductive gel usage.
However, skin preparation and the use of conductive gels are always required when using conventional wet electrodes, which is not user friendly and, typically, is therefore in clinical use only. These processes are employed to reduce skin-sensor interface impedance. In terms of the convenience of the ECG signal measurement process, these procedures usually create trouble for users, especially in daily life applications for long-term monitoring. In particular, the use of conductive gels inevitably leaves residues on the chest. The gel may also leak out of the wet ECG electrodes, causing a short circuit between two electrodes in close proximity when too much gel is applied or the wet electrode is pushed down too hard on the chest. Moreover, the above-mentioned preparation procedures for wet electrodes also have some significant drawbacks, such as being time-consuming, uncomfortable, and painful for participants because the skin preparation usually involves outer skin layer abrasion.
Repeated skin preparations and gel applications may also induce allergic reactions or infections. The ECG signal quality may degrade over extensive time periods as the skin regenerates and/or the conductive gel dries. Some issues also arise when measuring location that is covered with hair. This procedure leads to insufficient skin-electrode contact area, especially for continues long-term studies. Dry textile electrodes may be used to acquire ECG signals without any skin preparation or the use of conductive gel.
There is therefore a need and it would be advantageous to have dry knitted electrodes coupled to operate with a system that facilitates measuring health related physiological parameters of a living being, such as clinical level electrocardiogram (ECG) and enables real-time analyze the sensed data, while the living being is at rest or in motion. Furthermore, textile electrodes may provide comfort of use, facilitating continuously and seamlessly monitor a person, providing physiological parameters of that person.