The present invention relates to the treatment of disorders, such as Bell's palsy, wherein a subject has a denervated muscle, and in particular to a method and apparatus for stimulating the denervated muscle in response to a the contraction of a corresponding functional muscle of the subject.
Approximately 140,000 patients per year are affected by a deficit of the seventh cranial nerve, the nerve that provides signals for the muscles of facial expression for one side (left or right) of the face (as described elsewhere herein, those muscles are referred to as being “denervated”). About half of these are due to Bell's palsy, an idiopathic condition probably related to a herpes infection. Most of the Bell's patients will recover fairly good function within about 6-12 months. About 15%, however, will recover only partially and be left with significant weakness of blinking. The other 70,000 palsies are secondary to head trauma, tumors, surgical trauma and other causes. These latter patients are much less likely to recover, and much more likely to suffer permanent damage to the eye.
The current treatments for this disorder are crude and disfiguring, at best: sewing the eyelids together, connecting other nerves to the facial nerve, implanting gold weights into the upper eyelid, and others. None of these treatments, however, gives dynamic restoration of blink. Blinking, both the involuntary blinks which occur about 10-20 times per minute, and the voluntary blinks occurring when asked to close one's eyes, is critically important for protection of the eye. It functions to lubricate the ocular surface and sweep away foreign material and bacteria. Even lubrication maintains the integrity of the ocular surface, protecting it from bacterial invasion, and provides a smooth refractive surface for clear vision. Breakdown in any part of this system immediately places the eye at risk of pain, infection, and decreased vision.
In addition, a number of other disorders exist that involve unilateral paralysis of some sort, such as in the above-described Bell's palsy disorder, wherein a subject has a denervated muscle and a corresponding functional muscle. Such disorders include, without limitation, swallowing disorders, vocal cord paralysis, facial nerve dysfunction in the rest of the face (e.g., which prevents a normal smile and/or allows for saliva leakage from the paralyzed corner of the mouth), bladder dysfunction, and paralysis of half of the diaphragm (the largest muscle responsible for breathing).
There is thus a need for a method and apparatus for automatically stimulating denervated muscles in a subject that may be used to treat the above described disorders that does not include the drawbacks of the known treatment methods described above.
In one embodiment, an apparatus is provided for stimulating a denervated muscle of a subject that has a functional muscle corresponding to the denervated muscle. The apparatus includes a sensing device located on or implanted within the body of the subject and operatively associated with the functional muscle. The sensing device includes at least one sensor for sensing a parameter, such as a voltage, current or movement, associated with the functional muscle and generating a sensor signal based thereon, and (ii) control circuitry for receiving the sensor signal, determining whether the functional muscle has contracted based on the sensor signal, and causing a first RF transmitter included in the sensing device to transmit a first RF signal if it is determined that the functional muscle has contracted. The apparatus further includes a control unit located separately from the sensing device (e.g., in a device worn by the subject, such as a pair of eyeglasses) that has an RF receiver, a controller and a second RF transmitter. The RF receiver receives the first RF signal and provides a signal based on the first RF signal to the controller. In response to receipt of the signal based on the first RF signal, the controller causes the second RF transmitter to transmit a second RF signal. The apparatus also includes a stimulating device located on or implanted within the body of the subject that has stimulating circuitry operatively associated with the denervated muscle. When the stimulating device receives the second RF signal, the stimulating circuitry provides a stimulus to the denervated muscle to cause the denervated muscle to contract.
In another embodiment, an apparatus is provided for stimulating a denervated muscle of a subject that has a functional muscle corresponding to the denervated muscle. The apparatus in this embodiment includes a sensing device located on or implanted within the body of the subject and operatively associated with the functional muscle. The sensing device includes (i) at least one sensor for sensing a parameter (such as a voltage, a current or movement) associated with the functional muscle and generating a sensor signal based thereon, and (ii) an RF transmitter for transmitting a first RF signal based on the sensor signal. The apparatus further includes a control unit located separately from the sensing device that has an RF receiver, a controller and a second RF transmitter. The RF receiver receives the first RF signal and provides a signal based on the first RF signal to the controller. The controller determines whether the functional muscle has contracted based on the signal based on the first RF signal and causes the second RF transmitter to transmit a second RF signal if the controller determines that the functional muscle has contracted. The apparatus also includes a stimulating device located on or implanted within the body of the subject that has stimulating circuitry operatively associated with the denervated muscle. When the stimulating device receives the second RF signal, the stimulating circuitry provides a stimulus to the denervated muscle to cause the denervated muscle to contract.
In either embodiment, multiple similar sensing devices and/or stimulating devices may be provided. In addition, a number of different powering methodologies may be employed. For example, power may be provided to the control unit, the sensing device or devices and the stimulating device or devices by a power storage device, such as a battery, provided therewith. Alternatively, the sensing device or devices and/or the stimulating device or devices may be powered by near-field inductive coupling with the control unit. As a further alternative, the stimulating device or devices may be powered by harvesting energy from the second RF signal that is transmitted to it/them and converting the harvested energy to DC. As still a further alternative, the sensing device or devices and/or the stimulating device or devices may be powered by harvesting energy from RF energy transmitted by a far-filed source, such as an AM radio station, and converting the harvested energy to DC.
In another embodiment, when the control circuitry of the sensing device of the apparatus determines that the functional muscle has contracted, it causes a signal to be transmitted by an antenna electrode through the subject's bodily tissue by volume conduction as described in U.S. Pat. No. 6,847,844, the disclosure of which is incorporated by reference herein. That signal is received by a similar antenna electrode provided in the stimulating device provided as part of the apparatus. Upon receipt of the signal, the stimulating device provides a stimulus to the denervated muscle to cause it to contract.
Also provided is a method of stimulating a subject having a denervated muscle and a corresponding functional muscle, wherein the functional muscle and the denervated muscle are responsible for producing actions on first and second portions, respectively, of the subject's body. The method includes determining whether the functional muscle has contracted, generating a contraction signal if it is determined that the functional muscle has contracted, and causing the denervated muscle to contract following the generation of the contraction signal.
In one particular embodiment, the method includes generating a first RF signal at a first location on or within the body of the subject and operatively associated with the functional muscle, wherein the first RF signal is based on a parameter measured in association with the functional muscle. In this embodiment, the determining step includes receiving the first RF signal at a second location and determining whether the first RF signal indicates that the functional muscle has contracted. The contraction signal in this embodiment is a second RF signal and the step of generating the contraction signal comprises generating the second RF signal only if it is determined that the first RF signal indicates that the functional muscle has contracted. The causing step in this embodiment includes receiving the second RF signal at a third location and causing the denervated muscle to contract in response to receipt of the second RF signal by providing a stimulus to the denervated muscle.
In another particular embodiment, the contraction signal is a first RF signal generated at a first location on or within the body of the subject and operatively associated with the functional muscle, wherein the causing step includes receiving the first RF signal at a second location, generating a second RF signal at the second location in response to receipt of the first RF signal, receiving the second RF signal at a third location and causing the denervated muscle to contract in response to receipt of the second RF signal by providing a stimulus to the denervated muscle.
A number of unilateral paralysis disorders may be treated with the apparatus and method described herein, including, without limitation, the following: a blinking disorder where the subject has a functional orbicularis muscle and a denervated orbicularis muscle caused by, for example, Bell's palsy; a swallowing disorder where the subject has a functional pharyngeal muscle and a denervated pharyngeal muscle; a disorder affecting the operation of the vocal cords of said subject where the functional muscle is responsible for controlling a first one or more of the vocal cords and the denervated muscle is responsible for controlling a second one or more of the vocal cords; a bladder control disorder where the functional muscle is responsible for controlling a first part of the a subject's bladder and the denervated muscle is responsible for controlling a second part of the bladder; a facial paralysis disorder where the functional muscle is responsible for moving a first part of the face of the subject and the denervated muscle is responsible for moving a second part of the face of the subject; a diaphragm paralysis disorder that adversely affects inspiratory and expiratory forces where the functional muscle includes a first portion of the diaphragm of the subject and the denervated muscle includes a second portion of the diaphragm of the subject; or any other disorder that affects a function that requires coordinated movement on both sides of the body (e.g., where the first action on the first side of the body is similar or identical to the second action on the other (opposite) side of the body).
It is an object of the present invention to provide a method and apparatus for automatically stimulating denervated muscles in a subject.
It is a further object of the present invention to provide a method and apparatus for automatically stimulating denervated muscles in a subject using an RF link with a corresponding or associated functional muscle.
It is still a further object of the present invention to provide a method and apparatus for automatically stimulating denervated muscles in a subject using volume conduction within the body of the subject as described in U.S. Pat. No. 6,847,844, the disclosure of which is incorporated by reference herein.
It is still a further object of the present invention to provide a method and apparatus for automatically stimulating denervated muscles in a subject using implantable sensing and stimulating devices.
It is still a further object of the present invention to provide a method and apparatus for automatically stimulating denervated muscles in a subject using implantable sensing devices that are powered by a near-field technique such as near field inductive coupling.
It is still a further object of the present invention to provide a method and an apparatus for treating subjects having unilateral paralysis.
It is still a further object of the present invention to a method and an apparatus for treating subjects having facial paralysis, including the inability to blink an eye.
It is still a further object of the present invention to a method and an apparatus for treating subjects having vocal cord paralysis.
It is still a further object of the present invention to a method and an apparatus for treating subjects having diaphragmatic paralysis.
It is still a further object of the present invention to a method and an apparatus for treating subjects having bladder dysfunction.
It is still a further object of the present invention to a method and an apparatus for treating subjects having pharyngeal muscle paralysis.
Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain the principles of the invention. As shown throughout the drawings, like reference numerals designate like or corresponding parts.
As used herein, the term “muscle” shall refer to a single muscle or portion thereof or a group of two or more muscles or portions of muscle tissue, such as a group of two or more muscles working cooperatively to cause a certain activity.
As used herein, the term “contract” or “contracted” shall refer one or a combination of the initiation of the contraction of a muscle or the actual contraction of a muscle to a particular degree, including full contraction and less than full contraction.
As used herein, the term “denervated” shall mean that a muscle is either partially or fully deprived of a nerve supply such that the ability of the muscle to contract normally is partially or fully impaired.
As used herein, the term “eyeglasses” shall include a device or instrument that includes corrective or non-corrective lenses or no lenses at all.
As used herein, the term “worn” shall mean carried on the person of an individual.
As used herein, the term “subject” shall refer to any member of the animal kingdom, including, but not limited to, human beings.
Referring to
The control unit 10 includes a controller 25, which may be a microcontroller, a microprocessor, or some other type of suitable processor, including custom designed control/logic circuitry. The controller 25 is operatively coupled to an RF receiver 30 capable of receiving and preferably decoding (i.e., converting to DC logic signals) RF signals transmitted through the air, and an RF transmitter 35 capable of transmitting RF signal through the air. The RF receiver 30 and the RF transmitter 35 may be separate components, or may be combined into a single suitable RF transceiver device, many of which are known and commercially available.
The control unit 10 further includes a power supply 40 including a battery 45 for providing power to the controller 25, the RF receiver 30 and the RF transmitter 35. In addition, the battery 45 is operatively coupled to an adjustable oscillator 50 and which in turn is operatively coupled to a primary winding 55 for providing power to the sensing device 15 (or devices 15 if more than one is included) through near field inductive coupling. The definition of the near-field is generally accepted as a region that is in proximity to an antenna or another radiating structure where the electric and magnetic fields do not have a plane-wave characteristic but vary greatly from one point to another. Furthermore, the near-field can be subdivided into two regions which are named the reactive near field and the radiating near field. The reactive near-field is closest to the radiating antenna and contains almost all of the stored energy, whereas the radiating near-field is where the radiation field is dominant over the reactive field but does not possess plane-wave characteristics and is complicated in structure. This is in contrast to the far-field, which is generally defined as the region where the electromagnetic field has a plane-wave characteristic, i.e. it has a uniform distribution of the electric and magnetic field strength in planes transverse to the direction of propagation. As used herein, the terms near-field and far-field shall have the meaning provided above.
Referring to
Furthermore, because of losses that occur in the inductive coupling, it is preferred to increase the voltage of the induced AC signal in order to provide a supply voltage of an appropriate level to the control circuitry 65. In addition, because a DC signal is employed to power the control circuitry 65, the induced AC signal is also converted to DC. Thus, the induced AC signal is provided to the voltage boosting and rectifying circuit 75, which increases the voltage of and rectifies the received AC signal. In one particular embodiment, the voltage boosting and rectifying circuit 75 is a one or more stage charge pump, sometimes referred to as a “voltage multiplier.” The DC signal that is output by the voltage boosting and rectifying circuit 75 is provided to the voltage regulator 80, which in turn provides a regulated DC voltage signal to the control circuitry 65. The voltage regulator 80 is primarily provided to resist spikes in the DC voltage signal provided to the control circuitry 65 and to resist DC voltage signals that may overdrive the control circuitry 65.
The sensor device 15 includes a sensor 85 for sensing certain activity which indicates that the functional muscle with which the sensing device 15 is associated has contracted (preferably in a manner sufficient to cause the action in question (e.g., blink) to occur). The sensor 85 is operatively coupled to the control circuitry 65 of the sensing device 15 and provides a signal thereto. The control circuitry 65 may be a processor, such as a microcontroller or microprocessor, or a custom designed logic/control circuit. Based on the signal, the control circuitry 65 makes a determination as to whether the functional muscle has contracted. As seen in
In one embodiment, the sensor 85 is a voltage sensor, such as a potential transformer or any other type of suitable known or hereafter developed voltage measuring device, that is operatively associated with (e.g., in contact with) the functional muscle and that is adapted to detect voltages that are generated in connection with the contraction of the functional muscle. The sensor 85 in this embodiment provides a detection signal to the control circuitry 65 which indicates the voltage level, if any, that is being sensed by the sensor 85. According to an aspect of this embodiment of the invention, the control circuitry 65 then determines whether the detection signal indicates that a voltage having at least a predetermined voltage level has been generated, wherein the predetermined voltage level is used as an indicator of muscle contraction. In other words, if the sensor 85 detects a voltage that is greater than some predetermined level (that is the minimum that will be considered be indicative of a contraction taking place), then the control circuitry 65 will conclude that the functional muscle has contracted and generate a signal accordingly.
In an alternative embodiment, the sensor 85 is a current sensor, such as a current transformer or any other type of suitable known or hereafter developed current measuring device, that is operatively associated with (e.g., in contact with) the functional muscle and that is adapted to detect currents that are generated in connection with the contraction of the functional muscle. Similar to the voltage sensing embodiment described above, the control circuitry 65 receives a signal from the current sensor and determines whether the signal indicates that a current having at least a predetermined level has been generated, wherein the predetermined level is used as an indicator of muscle contraction.
In still another embodiment, the sensor 85 is a motion sensor, such as an accelerometer, that is operatively associated with (e.g., in contact with) the portion of the body that is controlled by the functional muscle and that is adapted to detect movement of that body portion that is associated with the contraction of the functional muscle. The sensor 85 in this embodiment provides a detection signal to the control circuitry 65 which indicates the extent of the movement, if any, that is being sensed by the sensor 85. According to an aspect of this embodiment of the invention, the control circuitry 65 then determines whether the detection signal indicates a level of movement considered to be associated with a muscle contraction.
As seen in
The preferred energy harvesting circuit 100 is shown in
In operation, when the sensing device 15 determines that the functional muscle has contracted as described elsewhere herein, the RF transmitter 90, under the control of the control circuitry 65, generates and transmits a first RF signal. The first RF signal is received by the RF receiver 30 of the control unit 10, which in turn sends a signal to the controller 25 of the control unit 10. In response thereto, the controller 25 causes the RF transmitter 35 to generate and transmit a second RF signal. The second RF signal is received by the stimulating device 20, and in particular by the antenna 105 of the energy harvesting circuit 100. In response thereto, the energy harvesting circuit 100 generates a DC signal which is provided to the stimulation circuitry 95. The stimulation circuitry 95 then provides a stimulus, as described elsewhere herein, to the denervated muscle that causes the denervated muscle to contract.
According to an alternate embodiment, instead of the control circuitry 65 determining whether the parameters sensed by the sensor 85 are indicative of the contraction of the functional muscle as described above, that determination may be made by the controller 25 of the control unit 10. In particular, in this embodiment, the signals generated by the sensor 85 are converted to RF and are transmitted to the RF receiver 30 by the RF transmitter 90. The RF receiver 30 in turn provides the signal (converted back into a DC data signal) to the controller 25. Based on the received signal (i.e., the data collected by the sensor 85), the controller 25 makes a determination as to whether the functional muscle has contracted. If it is determined that the functional muscle has contracted, the controller then causes the second RF signal described above to be transmitted by the RF transmitter 35, which in turn causes the stimulus to be generated for causing the denervated muscle to contract. This embodiment may or may not omit the control circuitry 65. In addition, in this embodiment, the controller 25 may be provided with neural net software to learn the appropriate strengths of signals (e.g., voltage or current levels or extent of movement) which indicate a contraction in the functional muscle and adapt (i.e., decide when to cause the denervated muscle to contract) accordingly.
As noted elsewhere herein, the apparatus 5, 5′, or 5″ may be used to treat a blinking disorder and may be implemented in a fashion wherein the control unit 10 is formed as part of a pair of eyeglasses, such as eyeglasses 140 shown in
Still a further alternate embodiment of an apparatus 155 for stimulating a subject that has a disorder wherein the subject has a denervated muscle and a corresponding functional muscle is shown in
While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, deletions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as limited by the foregoing description but is only limited by the scope of the appended claims.
This application claims the benefit of U.S. Provisional Application No. 60/773,943, entitled “Method and Apparatus for Stimulating a Denervated Muscle,” which was filed on Feb. 16, 2006, the disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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60773943 | Feb 2006 | US |