Patent Publication Number: US-2007118965-A1

Title: Medical electrode glove with partially insulating layer

Description:
BACKGROUND  
      The present invention generally relates to treating joints, such as a human hand and wrist.  
      The hand and wrist are affected by a number of diseases including several forms of arthritis, such as rheumatoid arthritis and osteoarthritis. Rheumatoid arthritis is a chronic, systemic inflammatory disease of unknown etiology characterized by the manner in which it involves the joints. The onset of the disease may be acute or insidious. Articular involvement is manifested clinically by pain, stiffness, loss of motion, deformity of joints, and the signs of inflammation. Rheumatoid arthritis affects many joints, most commonly the hands and wrists.  
      Osteoarthritis or osteoarthrosis is a degenerative joint disease, which commonly affects both axial and peripheral diarthrodial joints in humans. The effects of this increase steadily with age, so it is more common in the elderly. Osteoarthritis causes progressive deterioration and loss of articular cartilage from the surfaces of joints, and reactive changes at joint margins and in the underlying bone. Symptoms that are treatable include joint pain, stiffness, limitation of motion, and synovitis or joint inflammation. The treatments for rheumatoid arthritis and osteoarthritis of the hand and wrist are distinctly different, often individualized, and may include application of an electrical signal to the joints.  
      In U.S. Pat. No. 5,273,033 to Hoffman, which is specifically incorporated by reference herein, a device is shown that is said to decrease pain and improve joint function in patients with osteoarthritis of the knee.  
     SUMMARY  
      Embodiments are disclosed for a medical device that treats diseases of bones and joints, including the hand, wrist, and arm, such as rheumatoid arthritis and osteoarthritis. In one embodiment, the medical device includes a multi-layer glove system, an arm wrap, a signal generator, lead wires, and a garment. The multi-layer glove system serves as a treatment electrode. One of the layers electrically insulates a portion of the hand, allowing a different portion of the hand to make electrical contact with a conductive layer. The arm wrap serves as a return electrode. The signal generator produces a desired waveform, such as a spike shaped electrical signal, through the multi-layer glove system, at the treatment site. The garment has lead wires for connecting the multi-layer glove system and arm wrap to the signal generator. The garment keeps the lead wires in place and helps prevent the user from becoming tangled in the wires.  
      When a patient operates the medical device, a desired electrical signal is delivered to the joints of the hand and elbow. The system can reduce pain and increase the function of the treated joints. Other features and advantages will become apparent from the following detailed description, drawings, and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      For a more complete understanding of various embodiments of the present invention, reference is now made to the following descriptions taken in connection with the accompanying drawings in which:  
       FIG. 1  is a pictorial view of a medical device according to an embodiment of the inventions.  
       FIG. 2  is a side view of an arm wrap as worn.  
       FIGS. 3A-3C  are pictorial views of an insulating inner glove, a conductive glove, and a protective outer glove according to one embodiment.  
       FIG. 4A  is a pictorial view of the protective outer glove of  FIG. 3C , with a current-interrupting safety feature.  
       FIG. 4B  is an exploded, partial cross-sectional side view of the multi-layered glove system as worn.  
       FIG. 5  is a front plan view of a signal generator according to one embodiment.  
       FIG. 6  is a bottom plan view of the signal generator of  FIG. 5 .  
       FIG. 7  is an example of a voltage waveform illustrating characteristics of the electrical treatment signal under no load conditions as produced by an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  illustrates an embodiment of a medical device  10  that includes a multi-layer glove system (shown by  200 ,  300 , and  400 ), an arm wrap  101 , a signal generator  50 , a garment  103 , and at least one lead wire  104 . The user wears the glove system on the hand, arm wrap  101  around the upper arm, and garment  103  like a jacket. The garment has a pocket  105  for holding signal generator  50 . The signal generator, glove system, the patient&#39;s hand and wrist, the patient&#39;s arm, and the arm wrap form an electrical path. When used, signal generator  50  provides periodic electrical signals that pass to the glove system, up the patient&#39;s arm, through the arm wrap  101 , and back to the signal generator to try to alleviate the effects of bone and joint diseases.  
      In one embodiment, garment  103  is a jacket worn over a patient&#39;s clothing. Garment  103  may be made of a variety of materials, including traditional clothing fabric or a woven polymer fabric and can be designed for comfort. Garment  103  has at least one lead wire  104  sewn into the material of garment  103 , but could have two lead wires, one for treating the left side of the patient&#39;s body and one for treating the right side.  
      Lead wire  104  has a signal generator connection  106 , an arm wrap connection  107 , and a glove connection  108 . Signal generator connection  106  may be a keyed shape to ensure proper connection to the signal generator, also described below. Arm wrap connection  107  and glove connection  108  may be metal snaps, although other releasable connection mechanisms may be used. The connections may be color-coded to ensure connection to the proper component.  
      Lead wire  104  is attached to, or held within, garment  103  so that when garment  103  is worn, each connection is held for easy attachment to the desired components of medical device  10 . In addition, garment  103  helps to prevent the patient from becoming entangled in the lead wires. Signal generator connection  106  is held near pocket  105  for attachment to signal generator  50  in the pocket. Arm wrap connection  107  is held near a point about half way between the elbow and shoulder of the patient for attachment to arm band  101 . Garment  103  has a flap  109  to allow the patient easy access to arm wrap  101 . Glove connection  108  is held near the wrist for attachment to the multi-layer glove system. A like design would apply to a second lead wire (not shown) for use on the other side of the body.  
      Garment  103  may have snaps or other releasable connection mechanisms at the locations recited above. The snaps may be used to hold the various connections when not in use. For example, a snap  110  is located near the wrist of the patient and may hold glove connection  108  when the multi-layer glove system is not connected.  
       FIG. 2  illustrates a side view of arm wrap  101  worn on the patient&#39;s arm about half way between the elbow and the shoulder. Arm wrap  101  has a lead wire connection  111 , which connects to arm wrap connection  107  of lead wire  104  of  FIG. 1 . Arm wrap  101  has at least one electrically conductive surface, which is placed in contact with the skin of the upper arm. The electrically conductive surface may be made from silver plated nylon. Other electrically conductive surfaces, such as traditional transcutaneous electrical nerve stimulation electrode pads, may be used.  
       FIGS. 3A, 3B , and  3 C illustrate three separate components of the multi-layer glove system. All three components of the multi-layer glove system are worn simultaneously and in layers. Referring to  FIG. 3A , an electrically insulating inner glove  200  is worn on a hand of the patient. The finger-covering members of insulating inner glove  200  are shortened and open-ended. Thus, when insulating inner glove  200  is worn, the skin covering the interphalangeal joints (the “outer knuckles”) of the hand is exposed, but insulating material covers the palm and back portions of the hand and wrist, including the skin covering the metacarpophalangeal joints (the “inner knuckles”) of the fingers and thumb. For example, an exposed finger portion  201  protrudes from a shortened, open-ended finger-covering member  202 . Insulating inner glove  200  is made of an electrically insulating material, such as vinyl, neoprene, or polyurethane, and should be made comfortable to wear even over many hours.  
      Referring to  FIG. 3B , an electrically conductive glove  300  is worn on the hand of the patient, over the previously fit insulating inner glove  200  of  FIG. 3A . Conductive glove  300  makes electrical contact with the exposed finger portions that protrude from the shortened finger-covering members of insulating inner glove  200 . However, conductive glove  300  does not make electrical contact with the palm and back portions of the hand due to insulating inner glove  200 . A patient may massage conductive gel into the finger portions of conductive glove  300  to improve the electrical conductivity between the surface of the skin and conductive glove  300 . Conductive glove  300  is flexible so it can be worn. Conductive glove  300  could be made entirely of a conductive material, but would typically be made of a suitable combination of conductive and non-conductive materials, such as a silver plated nylon.  
      Referring to  FIG. 3C , a protective outer glove  400  is worn on the hand of the patient, over the previously fit conductive glove  300  and insulating inner glove  200 . Protective outer glove  400  completely covers conductive glove  300  to protect conductive glove  300  against damage and to insulate the outer surface of conductive glove  300 .  
      Referring back to  FIG. 3B , conductive glove  300  has a conductive hook-and-loop fastener  301  (such as a VELCRO brand hook-and-loop fastener) attached to the top, exterior wrist-area of conductive glove  300 . Conductive hook-and-loop fastener  301  is in electrical contact with conductive glove  300 , and is positioned to make contact with a complementary conductive hook-and-loop fastener of protective outer glove  400 . Other conductive releasable mechanisms may be used in place of the conductive hook-and-loop fasteners, but would typically allow easy connection and disconnection when desired, while being sufficiently well connected to not become undone with ordinary movement.  
      Protective outer glove  400  has a lead wire connection  401  positioned on the back of the glove, in the area covering the patient&#39;s wrist. Lead connection  401  releasably connects to the glove connection  108  of lead wire  104  (shown in  FIG. 1 ). Lead connection  401  may be a metal snap or some other releasable conductive mechanism that is easily removed manually when desired without tools. Lead connection  401  passes through the fabric of protective outer glove  400  and is in electrical contact with a conductive hook-and-loop fastener  402  (shown in  FIG. 4A ) mounted on the inside surface of protective outer glove  400 .  FIG. 4A  illustrates protective outer glove  400  with a portion of the fabric turned inside-out, exposing conductive hook-and-loop fastener  402 , as attached to the inner surface of the glove.  
       FIG. 4B  shows an exploded, partial cross-sectional right side view of the multi-layer glove system as worn by the patient on the right hand (the layers of the glove system are separated for viewing convenience). Conductive hook-and-loop fastener  402  is positioned to make electrical contact with conductive hook-and-loop faster  301  of conductive glove  300  when all three glove layers are worn. Insulating inner glove  200  is worn closest to the skin. Conductive glove  300  is worn over insulating inner glove  200 . Protective outer glove  400  is worn over both other gloves. Thus, an electrical connection is established between the finger portion  201  and lead wire  104  by way of conductive glove  300 , the complementary conductive hook-and-loop fasteners  301  and  402 , wire connection  401 , and glove connection  108 .  
      Protective outer glove  400  may be made from any fabric traditionally used to manufacture gloves. It may also have a coating on its inner surface to prevent the conductive gel used with conductive glove  300  from saturating the fabric of protective outer glove  400 . Protective outer glove  400  can be made, for example, from spandex fiber with an inner rubberized coating.  
      This embodiment of the multi-layer glove system has a number of useful features. Protective outer glove  400  prevents conductive glove  300  from making accidental electrical contact with areas of the patient&#39;s skin other than the finger portions as described above. The patient may handle objects or use his or her hands during treatment without interfering with the electrical signal. In addition, the inner surface coating contains the conductive gel to inhibit the gel from being deposited on other areas of the patient&#39;s skin, the patient&#39;s clothing, and objects that the patient may handle during treatment. Similarly, the inner surface coating also helps prevent the conductive gel from drying-out during treatment, thereby prolonging the effectiveness of the gel.  
      The complementary conductive hook-and-loop fasteners also perform a safety function. When the patient removes the protective outer glove, the electrical connection between the complementary conductive hook-and-loop fasteners is broken automatically and without additional action being required. Thus, the conductive glove is de-energized when the protective outer glove is removed. Should the patient accidentally leave the signal generator on before removing the glove system, this feature prevents the patient from accidentally completing the electrical circuit with an area of the skin other than the desired treatment area.  
      The glove system can isolate the finger portions as a treatment area. It is believed that isolating the finger portions as a treatment area is effective in treating symptoms associated with diseases of the joints, such as rheumatoid arthritis of the hand. It is theorized that isolation of the finger portions as a treatment area allow for superior ion conduction through the cartilage of the treated joints, thereby increasing the current through the joints. The increased current produces an increased electrical field in the cartilage, which is believed to mimic the electrical potentials found in healthy cartilage that cause the body to produce new cartilage.  
      Although the beneficial effects are thought to decrease as the distance from the treatment area increases, the glove system may be effective in treating aliments of the elbow. Use of the medical device disclosed herein is believed to reduce the patient&#39;s evaluation of pain and symptoms in the treated joints and increase the patient&#39;s evaluation of function in the treated joints. The ability of the glove system to isolate the fingertips may also have applications in traditional transcutaneous electrical nerve simulation therapy.  
      Turning to the electrical components and waveforms,  FIG. 5  is a front plan view of an embodiment of a signal generator  50 . Signal generator  50  may be a device such as the one described in U.S. Pat. No. 5,273,033 to Hoffman. Signal generator  50  may also be a traditional commercially available transcutaneous electrical nerve stimulator. Signal generator  50  is a battery powered electrical stimulator, which produces a specific, periodic, spike shaped electrical signal to the multi-layer glove system at the treatment site. Suitable sources of power include an alkaline battery or a Nickel Metal Hydride battery. Signal generator  50  has at least one treatment channel, which includes a complete electrical circuit when the signal generator output is connected to the arm wrap and multi-layer glove system described above.  
      Signal generator  50  has an LCD display  501 , which allows the patient to read information concerning the level of treatment, duration of treatment, battery status, signal generator status, and other information. Signal generator  50  has an On/Off button  502  which allows the patient to turn the unit on and off, a stimulation increase button  503  that may be pressed to increase the level of electrical stimulation produced by a treatment channel of signal generator  50 , and a stimulation decrease button  504  that may be pressed to change the level of electrical stimulation produced with suitable thresholds. Signal generator  50  may have multiple treatment channels, each having a set of stimulation increase and decrease buttons. The generator could have selectable alternative waveforms.  
      A function button  505  may be pressed to display the treatment time on LCD  501 . A battery button  506  may be pressed to display the battery charge level on LCD  501 .  
       FIG. 6  is a bottom plan view of the signal generator of  FIG. 5 . Signal generator has a lead wire connection  507 , which connects to signal generator connection  106  of lead wire  104  (shown in  FIG. 1 ). Lead wire connection  507  may be a keyed shape, complementary to the shape of signal generator connection  106 . This ensures proper connection to the signal generator and proper polarity between the treatment electrode and return electrode. In one embodiment, signal generator  50  has an additional treatment channel, in which case, an additional lead wire connection  508  is provided.  
       FIG. 8  is a voltage waveform illustrating the characteristics of an exemplary electrical treatment signal produced by the signal generator  50  under no load conditions. In one embodiment, the electrical treatment signal is a voltage-sourced, spike-shaped, monophasic, and asymmetrical DC signal. The frequency is fixed at 100±5 Hz. The voltage range is 0-12 volts at the peak. The voltage pulse width is 1.8 ms at the 10% point of peak and 0.64 ms at the 50% point of peak. The current output range is 0-24 mA at 500 ohms resistive load, with an average of 0.2 mA at 500 ohms resistive load. The current pulse width is 1.8 ms at the 10% point of peak and 0.64 ms at the 50% point of peak, both at 500 ohms resistive load. The maximum output charge is 20 μC into a load of 500 ohms. The voltage of the electrical treatment signal may be adjusted by the patient so the signal is subsensory to the patient. Treatment could be applied over many hours, and could be applied overnight. The selected waveform would typically not provide much heat to the treated area.  
      As will be realized, the inventions are capable of other and different embodiments and its several details may be capable of modifications in various respects, all without departing from the invention as set out in the appended claims. For example, the treatment signal produced by signal generator  50  may vary from the waveform described above, or the multi-layer glove system may be used with a current-sourced electrical signal generator, such as a traditional transcutaneous electrical nerve stimulator. Accordingly, the drawings and description are to be regarded as illustrative in nature and not in a restrictive or limiting sense with the scope of the application being indicated in the claims.