Electro-acupuncture device with stimulation electrode assembly

#The methods and devices described below relate to the field of electro-acupuncture and non-invasive stimulation of nerves.

#We have developed an electro-acupuncture device which has proven effective for the control of nausea and vomiting. The device, marketed under the trademark Relief-Band®, is worn on the wrist like a wristwatch, with a watch-like housing which is positioned on the underside of the wrist. The housing has two electrodes on the inside face (the face in contact with the wrist when secured to the wrist), a battery and circuitry inside the housing, and control buttons on the outer face. A patient suffering from nausea or vomiting (from seasickness, morning sickness, chemotherapy, or anesthesia) can strap the device onto their wrist and turn it on. When turned on, the device emits an electrical stimulation pulse over the P6 acupuncture point (corresponding to the superficial course of the meridian nerve through the wrist). Within several minutes, most patients experience a substantial relief of nausea. The device uses non-invasive nerve stimulation whereby electricity is passed through two electrodes to stimulate nerves located on the ventral side of the wrist (this anatomical position is sometimes referred to as the palmar side of the wrist). The treatment provided by the device is sometimes referred to as electro-acupuncture, which is a form of acupuncture, and the ventral site of application is referred to in the acupuncture art as the P6 point, pericardium 6 point, or master point of the pericardium meridian (sometimes referred to as the vascular meridian). A primary object of the invention is to provide a non-chemical, non-invasive, painless and inexpensive method of alleviating nausea. It is also portable, self-contained and convenient to the patient. Electrical pulse repetition rate of approximately 70 pulses per second and a pulse width of 80 microseconds has been found to provide effective relief of nausea in a patient. Our currently preferred electrical pulse pattern comprises about 350 microsecond pulse width at about 31 pulses per second at power levels of about 10-35 milli-amps peak pulse height. Thus a wide range of pulse patterns may be used in non-invasive nerve stimulation devices. The device is described in Bertolucci, Nausea Control Device, U.S. Pat. 4,981,146 (Jan. 1, 1991).

#Previously, we have provided devices in several models, each providing a different strength of stimulation deemed appropriate for particular patients and indications. We have also marketed a version of the device which included circuitry and operator controls which allowed the patient to select from a wide range of power setting and stimulation patterns. Currently, we are marketing over-the-counter devices and prescription devices. Both the over-the-counter device and the prescription are provided in embodiments in which the device is disposable (the batteries cannot be replaced after depletion) and in which the device is reusable, (the batteries may be replaced indefinitely). In each of these versions, we have provided complete circuitry, power supply, and electrodes in each device manufactured. Thus, for each version of the device, different circuitry had to be provided. The devices and methods described below provide for easier manufacturing of a line of devices with different characteristics. In each of our electro-acupuncture products, the stimulation and effect are greatly enhanced if the patient applies a gel to the skin before strapping the device onto the wrist. This gel serves as an impedance matching layer between the electrodes and the skin, greatly enhancing the effect of the device and lowering the power requirements for the device. As a replacement for the gel, we have developed a gel coating for the electrodes. This coating comprises a hydrogel film which adheres to the electrodes and can be applied to the electrodes during manufacture. Providing the gel during manufacture enhances effectiveness of the device since it eliminates the possibility that some users will omit the application of gel, either through forgetfulness or ignorance of need to use it. A current limitation on the installed hydrogel film is its short lifespan. The films that are currently available last only a few days. While this is acceptable for some temporary indications and applications, such as seasickness, it is undesirable for chronic applications such as morning sickness and chemotherapy induced nausea. Our solution is to provide the device in modular form, with the watch-like housing manufactured in one unit and the electrodes manufactured as an attachable or insertable part which can be readily replaced by the patient.

#FIG. 1 the device in use on the wrist of the patient.

#FIG. 2 is a view of the bottom of the device showing the placement of the electrode assembly on the bottom of the housing.

#FIG. 3 is a view of the bottom of the device showing the snap fittings used to secure the electrode assembly on the bottom of the housing.

#FIG. 1 illustrates the device in use on the wrist of the patient. The non-invasive nerve stimulation device 1 is secured with a strap 2 to the ventral side of the wrist 3 such that the pair of electrodes 4 were disposed over the median nerve 5 (indicated by the phantom line) and in contact with the skin in the vicinity of the P6 acupuncture point. The electrodes are on the underside of the housing 6, the required battery and control electronics are housed within the housing, and input mechanisms (push buttons, dials, and the like) are located on the outer face of the housing. For electro-acupuncture applications on the wrist, two electrodes 4 are provided, and these two electrodes are place on the assembly so that, when applied to the wrist, the electrodes are disposed over the P6 point and oriented so that the long axis of each is perpendicular to the median nerve while the pair is oriented along the length of the median nerve.

#As shown in FIG. 2, the nerve stimulation device is formed in two parts, including the housing 6 and an electrode assembly 7. The electrode assembly is releasably attachable to the housing so that it may be easily yet securely attached and removed by a user. The underside of the housing 6 is fitted with a receiving aperture 8 for receiving the electrode assembly. Several releasable fasteners are provided in the form of simple snap sockets 9, which are preferably comprised of electrically conductive material so that they may also be used to electrically connect the pulse generation circuitry within the housing to the electrodes on the electrode assembly. The sockets receive snap studs shown in FIG. 3. The electrode assembly includes the electrodes 4 on the bottom of the assembly, opposite the bottom of the housing. The snap stud bases 10 can be seen from the underside of the electrode assembly, and these support the studs shown in FIG. 3. Each electrode is covered by an impedance matching film 11. The film is comprised of a hydrogel with suitable impedance, adhesive properties, and material strength and softness. The hydrogel is applied during manufacture and covered with a protective sheet of plastic which is removed by the user after attaching the electrode assembly to the housing. (Impedance matching can also be accomplished with separately applied gel).

#FIG. 3 shows the top of the electrode assembly 7 in position opposite the bottom of the housing 6, illustrating that electrode assembly includes one or more protrusions 12 on the upper side of the assembly which are keyed to the shape of the sockets on the underside of the housing. These protrusions may be the studs of a typical fabric snap fastener, and are preferably comprised of electrically conductive material so that they may also be used to electrically connect the pulse generation circuitry within the housing to the electrodes on the electrode assembly. While four snap connectors are illustrated, more or less may be used depending on the number of connections required for a particular circuit. Any male/female connector or multi-pin connector may be used in place of the snaps illustrated. Also, additional connectors may be used to establish the connections illustrated in the following schematics while using the snaps or other fasteners merely for attaching the electrode assembly to the housing.