Intelligent Garment for Nerve Stimulation

Abstract

During the treatment of different diseases relating to pains and disorders of the body, electrical stimulation on the afflicted area is beneficial, and even the more for stimulation of the nervous system. This transcutaneous electrical nerve stimulation (TENS) therapy has been applied through conductive silica gel hydropads in the affected area where front end of body nerves is stimulated by the electrical current (Imboden et al in Current rheumatology diagnosis and treatment. Lange Medical Books McGraw-Hill, NY, 2007 [1]). The present TENS products consisting conductive silica gel hydromaterial help to decrease the skin resistance, but are normally supplied in two to four pieces and do not readily target the back of the body. Their stickiness can create discomfort. They are unlaunderable, and repeated use is unhygienic. With the fast advancement of technology, intelligent garments are becoming one of the important innovations in the textile industry, particularly in the areas of intelligent medical and athletic textiles (Tsang in design and development of electrically conducting textile sensors for smart textiles and apparel. The Hong Kong Polytechnic University, Hong Kong, (2006), Langenhove in smart textiles for medicine and health care: materials, systems, and applications. Woodhead Pub Ltd, Cambridge, (2007), Bradley in techno fashion. Oxford, NY, (2002), Lee in Fashioning the future: tomorrow’s wardrobe. Thames & Hudson, London, (2005) [2, 3, 4, 5]). TENS is frequently being used in the treatment of different painful conditions. Many investigations have shown the effectiveness of TENS on different pain conditions, provided patients use them continuously in the correct way. It stimulates the large afferent fibers that can decrease the transmission of pain signals through the small nonreceptive afferent fibers, consequently inhibiting pain discrimination and perception (Chiu et al in Clin Rehabil 19:850–860, (2005) [6]). Moreover, studies have shown that patients given TENS therapy with acupuncture point stimulation yield better results (Chiu et al in Clin Rehabil 19:850–860, (2005), Wang et al in Taiwan J Phy Med Rehabil 34:235–240, (2006), Wang et al in Chinese Med J 116:1864–1868, (2003) [6, 7, 8]). Figure 7.1 shows the commercial products of available electrodes. They are commonly used, but their property is not suitable for use in intelligent garment. In the medical treatment products used at present, electrodes are mostly made of silica gel hydropads that can be absorbed to skin, which can be repeatedly used for several tens of times. This type of electrode performs very well. But, their demerits are apparent: They are susceptible to fragmentation, nonwashable, and uncomfortable because of their stickiness. Placing conductive ointment between the conductor and skin to reduce the resistance is a possible solution to the problem. But this is rarely practiced because of its uncomfortable feeling and spreading to neighboring places. Fabric electrodes are being used often in smart clothing needing a good contact to skin, such as acquiring breath, temperature, and electrocardiogram signal. A simple way to achieve good contact is to increase the contact area and pressure. But, the bulky electrode is less flexible and high contact pressure would cause discomfort. Hence, a water filler is commonly used to increase the moisture and conductivity of skin, compromising convenience. Attempt has been made to develop a wearable TENS garment with incorporated Chinese acupuncture therapy for long-term continuous treatment and establish a novel therapeutic technique for health care. The design of TENS garment is discussed, followed designs of textile electrode and TENS signal generator, using two experimental setups to evaluate the newly proposed intelligent clothing prototype incorporating textile electrodes and conductive yarns.