Adjustable Headband Carrying Electrodes For Electrically Stimulating The Facial And Mandibular Nerves

Abstract

Electrodes capable of conforming to irregular surfaces include a cup-shaped housing having an open end, a pad of electrically conductive coiled metallic wire in the housing, a felt of porous material over the metallic wire pad, and a mounting ring contacting the wire pad and felt around their circumference to hold the pad and felt in place in the housing. Three electrodes, two input electrodes and a dispersal electrode, of the type described are attached through electrically conductive support members to an adjustable headband. The two input electrodes are pivotally attached to the headband. Lead wires from the output of a pulse generator connect with the electrodes. The lead wires to the input electrodes are run along the surface of the headband and covered with an insulating material.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an adjustable headband carrying unique electrodes for electrically stimulating the facial and mandibular nerves of a human.

2. Prior Art Relating to the Disclosure

Various means of making electrical contact by means of electrodes placed in contact with the skin of an individual are known. Most frequently electrodes are taped to the desired areas of the skin so that they will remain in continuous contact. Taping of multiple electrodes to various areas, however, is disadvantageous and time consuming and does not provide the necessary pressure contact. The present invention is primarily useful in electrically stimulating the muscle complex that work synergistically to close the human mandible. Such a method is useful to dentists in fitting dentures, in correcting occlusional difficulties of patients, in reduction of swelling or discoloration after surgical operations or accidental injury, and in treatment of various nerve and/or muscle disorders associated with the facial muscles. As the device is used clinically it is desirable to have a way for quickly and accurately connecting electrodes firmly and with adequate pressure contact in the right positions on the patients's face without causing the patient any discomfort or inconvenience. The problem in obtaining the requisite firm pressure adaptation of the electrodes to the skin has been the irregular contours of the input area. Variation of compressibility of the tissues compounds the problem. In some areas, such as the zygomatic arch, bone closely underlies the skin and soft tissue while in other areas, such as the mandibular notch, there is an absence of bony support. In general the thickness and compressibility of the tissues of the input area varies considerably. Flat metal electrodes do not conform to variation in contours and compressibility. There are two requirements for an adequate input electrode (1) adaption of variation in contour and compressibility; and (2) conductivity.

SUMMARY OF THE INVENTION

This invention relates to unique electrodes used in electrical stimulation of the facial and mandibular muscles and an apparatus for carrying the electrodes. Each of the electrodes comprises a housing of dielectric material in which is mounted a pad of compressible, resilient, flexible, electrically conductive, preferably coiled, metallic wire over which a pad of porous, flexible, moisture retentive material is placed. The pad of metallic wire and porous material are held in place in the housing by a mounting ring extending around the circumference of both the metallic wire and porous pad, the ring having side walls frictionally engaging the housing. Each electrode is attached to one end of separate electrode support members. The two input electrodes are pivotally attached to an adjustable headband opposite one another and the third electrode, designated a dispersal electrode, attached to the headband between the input electrodes. Conductive means leading from a pulse generating apparatus are electrically connected to each of the electrodes. The support members of the input electrodes are attached to the headband forward of each ear of the patient when the headband is in place. The common or dispersal electrode, placed between the two input electrodes, is preferably contoured to contact the nape of the neck. The overall apparatus is compact, can be positioned in place rapidly and accurately without discomfort or inconvenience to the patient, and can be removed readily.

It is a primary object of this invention to provide electrodes for electrically stimulating nerves and muscles through the skin.

It is a further object of this invention to provide an adjustable headband carrying the electrodes connected to a pulse generating means.

It is a further object of this invention to provide an adjustable headband providing a stable platform from which electrodes are extended.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the electrodes of this invention attached to an adjustable headband adapted to encircle the patient's head, the electrodes electrically connected to a pulse generating apparatus;

FIG. 2 is a side elevational view of the headband and electrode assembly of FIG. 1 in place on a patient's head;

FIG. 3 is a sectional view along line 3--3 of FIG. 2 showing details of one of the electrodes and its mode of connection to the adjustable headband and to conductive elements from the pulse generating apparatus; and

FIG. 4 is a sectional view along section line 4--4 of FIG. 3 showing further details of one of the electrodes.

DETAILED DESCRIPTION OF THE INVENTION

The overall apparatus of this invention, including the electrodes and adjustable headband, is primarily useful in electrical stimulation of the motor nerves controlling the masticatory and facial muscles with resultant involuntary closure of the human mandible. The method of producing a muscularly balanced closure of the human mandible through electrical stimulation of the masicatory and facial muscles is described in detail in applicant's copending application Ser. No. 855,480 filed Sept. 5, 1969, now U.S. Pat. No. 3,593,422. This copending application is hereby incorporated by reference. Described in the copending application is a method of involuntarily closing the human mandible for various clinical objectives by electrically stimulating the motor roots of the mandibular and facial nerves on both sides of the face, stimulation of the nerves resulting in coordinated contraction of the masticatory and facial muscles controlling opening and closing of the mandible. In practicing the method described in the aforementioned application for various clinical objectives, it is essential that the input electrodes placed on each side of the face be in continuous pressure contact with the skin. If the electrodes placed on each side of the face are not maintained in pressure contact with the skin the current flow through the skin varies, giving rise to unequal stimulation of the muscles on each side of the face. This is unacceptable in the method described in applicant's copending application. Additionally, light contact of the electrodes with the shin of the patient results in discomfort to the patient. The design of the electrodes of this invention enables continuous pressure contact at all times. Further the design of the overall assembly is such that it can be quickly positioned and adjusted to fit different individual needs. The headband on which the electrodes are mounted is adjustable so that the circumference thereof can be increased or decreased to fit a particular patient's head. The headband itself forms no part of the instant invention as it is fully described in U.S. Pat. No. 3,325,824. Each of the electrodes, i.e. the two input electrodes and the common dispersal electrode, are attached to the headband by means of electrically conductive support members. The support members for the two input electrodes are pivotally attached to the headband so that they can be swung in and out of position when the headband is placed on the patient's head or removed therefrom.

FIG. 1 shows the adjustable headband to which the two input electrodes and common dispersal electrode are attached. The headband 1 comprises a flat, flexible strip of plastic or other suitable material 2. The two ends of the strip, which have elongated slots therein, are telescoped into opposite ends of sleeve 3. A rotatable knob 4 connected to a toothed pinion meshes with gear racks formed in the slots. Rotation of knob 4 increases or decreases the circumference of the headband depending on the direction of rotation. The electrodes, two input electrodes 5 and 6, and a common dispersal electrode 7, are attached to the headband 1 by means of support members 8, 9 and 10. The input electrodes are positioned on the headband so that when it is positioned in place on the patient's head the points of attachment will lie just forward of the ears of the patient, as shown in FIG. 2. The common dispersal electrode is preferably positioned so it will contact the nape of the neck as shown in FIG. 2. Lead wires are electrically connected to each of the electrodes and to a pulse generating apparatus, generally shown as reference numeral 11.

To keep the lead wires from the pulse generating apparatus to the input and dispersal electrodes from hindering the work of the dentist, they are extended from the pulse generator to the rear of the headband. The wires to the input electrodes extend along the circumference of the headband on both sides thereof to the points of attachment of the input electrode support members to the headband. A strip of reinforcing material such as glass fiber is preferably extended part-way along the head band in the area where the input electrode support members are attached to prevent the headband from twisting when the input electrodes are placed in operating position. A cross section of the headband and one of the input electrodes is shown in FIGS. 3 and 4. This cross section is representative of the electrode construction and means of attachment of the headband of the other input electrode and common dispersal electrode except that the dispersal electrode is preferably not pivotally attached to the headband. As shown lead wire 12 extends along channel 13 to its point of electrical connection to bolt 14 which extends outwardly through the headband. Channel 13 is formed along the inner circumference of the flat strip 2 of headband 1 by two parallel strips 15 of matted synthetic filaments. Over the channel is placed a strip 16 of synthetic material which adheres to the matted felt when pressed into place, but which can be removed therefrom. The combination of matted filaments and plastic strip is a commercially available material sold under the trademark "Velcro." Over the "Velcro" strip is preferably bonded a vinyl strip 17 having an adhesive backing. The strip can be removed and replaced after each use. The purpose of the strip is principally for sanitation reasons.

Support members 8 and 9 for the input electrodes 5 and 6 are bent to the configuration shown in FIG. 3 so that when they are attached to the headband and to the input electrodes the face of the input electrodes will press firmly against the face of the patient just in front of the ear. Support member 10 for the dispersal electrode 7 is of a different configuration. It is bent so that it will press the dispersal electrode 7 firmly against the nape of the neck of the patient. Support electrodes 8, 9 and 10 are made of an electrically conductive material, preferably spring steel. The upper and lower portions of the support members electrically connect the respective lead wires from the pulse generator to their respective electrodes. The middle portion of the support members is coated with a dielectric material 18, such as an insulating plastic. Over the bolts 14, extending outwardly through the headband are placed washers 19 of a suitable dielectric material. A spring washer 20 of electrically conductive material is then placed over the dielectric washers followed by the support member. The entire assembly is held in place by nuts 21. The manner in which the support members are attached to the headband allows them to be swiveled in either direction about bolts 14. The dispersal electrode is preferably fixed to the headband in the position shown in FIGS. 1 and 2 as head movement of the patient may cause loss of electrical contact if the electrode is pivotally mounted.

The lower ends of support members 8 and 9 are preferably slotted with a vertical slot 22 as shown in FIG. 2 to allow vertical adjustment of the input electrodes for correct positioning.

As mentioned previously the electrodes, and particularly the input electrodes, must continuously and intimately contact the skin of the patient to establish good electrical contact. To accomplish this the electrodes must be capable of conforming to irregular surfaces. No two individuals have a facial configuration that is exactly the same. The electrodes must be able to conform to the facial structure just forward of the ears of all patients without difficulty. One of the input electrodes is shown in cross section in FIG. 3. The design of the remaining electrodes is the same. The preferred electrode of this invention is an aggregate of metallic wire which is springy and adaptive. The wire strands are preferably coiled into an elongated spring which is folded and packed into an electrode housing to provide a springy mass. The mass of springy coiled wire adapts to, and equalizes pressure against, irregular yielding surfaces as the coils move against each other within the container. An alternate electrode configuration which can be employed is a thin flexible wire screen overlying an adaptive pad of elastomeric foam material. The wire screen curves around or in the foam to receive the electricity at the base of the electrode housing. It covers the foam where it is in contact with the skin.

The electrodes comprise a housing 23 of a suitable dielectric material, such as a molded plastic material, the housing having side walls 24, a bottom wall 25, and an open end. The input and dispersal electrodes may be of any suitable configuration, although the input electrodes are shown as being semicircular while the common dispersal electrode is rectangular in shape. The electrodes 5, 6 and 7 are secured to support members 8, 9 and 10 by any suitable retaining means. As shown in FIGS. 3 and 4 a bolt 26 extends through and contacts support member 8 and further extends through the bottom wall of electrode 5. An electrically conductive disc 27 is secured to the inner end of the bolt. The disc may be of any suitable configuration.

The housing of each of the electrodes is filled with a pad of electrically conductive material 28 which is compressible, resilient and flexible. The pad should extend above the side walls of the housing a short distance. Over the pad of electrically conductive material is placed a thin felt of porous, moisture-retentive material 29 such as a cellulosic sponge. The porous material and pad of electrically conductive material are held in the housing by a mounting ring 30 of dielectric material adapted to contact the pad of electrically conductive material and porous pad around their circumference to hold them in place in the housing. Side walls 31 of the mounting ring are adapted to frictionally engage the side walls 24 of the housing. By not rigidly securing the mounting ring 30 to the housing the mounting ring is free to move to conform to irregular surfaces on the face of an individual patient.

A plastic liner 32 may be placed around the side walls 24 of the housing of each electrode, the plastic liner extending a short distance above the side walls of the housing to help retain the pad of electrically conductive material in place when the mounting ring is removed. The liner also facilitates positioning of the mounting ring over the side walls of the housing.

OPERATION

To use the assembly of this invention the adjustable headband 1 is extended to easily fit over the patient's head. Each of the electrodes is saturated with an electrolyte solution. Any of the common electrolyte solutions may be used. Preferably, a soap solution is used, the soap solution being electrically conductive. The input electrodes 5 and 6 are swung forward around their pivot points so that the support members to which they are attached are substantially parallel with the headband 1. The dispersal electrode 7 is preferably locked into the position shown in FIG. 1 The headband is then placed over the patient's head and tightened around the head by rotation of knob 4. The input electrodes are then swung into the position shown in FIG. 2. If necessary the individual input electrodes are adjusted vertically so that the electrode contacts the mandibular notch region of the patient. Once the headband and electrodes are in place the pulsing apparatus is energized. Once treatment is completed the input electrodes are swung forward, the headband expanded, and removed.

The electrode assembly described is compact and easy to use, is comfortable to the patient and has a relatively long service life.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An assembly for electrically stimulating facial muscles with a pulsing electrical current comprising;

a single non-conductive flexible band adapted to be secured around the head of the patient, said band being adjustable in length,

a pair of input electrodes pivotally attached to the head band by means of electrically conductive support means said electrodes being movable along the length of the support means and adapted to be placed in contact with the patient's skin forward of his ears,

a common dispersal electrode attached to a conductive support means, said support means secured to the band intermediate the input electrode supports and adapted to contact the skin of the patient at the nape of the neck,

insulated electrically conductive means adapted to be connected to the output of a pulse generator and connected to each of the input electrodes,

insulated electrically conductive means adapted to be connected to a pulse generating means and connected to the dispersal electrode, whereby the stimulating current is administered through the input electrodes and received by the dispersal electrode,

the electrodes each comprising a housing of dielectric material having a bottom wall, side walls and an open end, a pad of compressible, resilient, flexible electrically conductive metallic wire mounted within and substantially filling the housing, said pad being connected to the conductive mounting means by a blot secured to the mounting means passing through the housing, the bolt including a conductive disk mounted thereon which is imbedded in the wire pad and a thin moisture retentive piece of material covering the skin contacting surface of the pad.

2. An assembly as in claim 1 wherein the compressible pad extends beyond the side walls of the housing.

3. An assembly as in claim 1 wherein the means for connecting the electrodes to a source of pulsing current includes separate strands of conductive wire along the surface of the headband.

4. An assembly as in claim 3 wherein the strands are covered by removable material.