Abstract:
A soft-solid ear piece is formed to fit the typical human ear canal and will self form to fill the ear cavity by having an internal structure, endoskeleton, or bladder to expand to precisely fit the ear piece securely and comfortably in the ear canal. This self forming ear piece will enable ready-ware and custom molded hearing aids, hearing protectors, audio ear pieces, cell phone ear pieces and assistive listening devices to fit comfortably, securely, and free of acoustic feedback in the external ear canal. It creates an acoustic seal to optimally reduce peripheral leakage and intermodulation distortion delivering excellent acoustic performance while keeping environmental sounds blocked out.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Priority of U.S. Provisional Patent Application Ser. No. 60/575,533, filed May 28, 2004, incorporated herein by reference, is hereby claimed. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable  
       REFERENCE TO A “MICROFICHE APPENDIX” 
       [0003]     Not applicable  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     The present invention relates to hearing devices. More particularly, the present invention relates to in-the-canal hearing devices, wherein a metallic frame expands responsive to body temperature when inserted into the ear canal to ensure a good fit.  
         [0006]     2. General Background of the Invention  
         [0007]     The hearing industry has desired a one size fits most ear piece to efficiently serve the hearing impaired for many years. Industrial audiologists have also advocated a one-size-fits-most to serve in the hearing protection and communication needs in industry, sport shooting, and military applications. This device has eluded engineers and researchers because the human ear canal is dynamic in nature and is anatomically variant between subjects (indeed, variant from ear to ear).  
         [0008]     Each ear canal shape is unique in size, in the directional bend into the head, in geometrical shape (i.e., circular vs. elliptical cross section), and in sensitivity to contact pressure (in the form of a plugged up feeling, in sensations pain, or in reactions of coughing or sneezing). These anatomical variations are a fit problem in combination with dynamic action of the ear canal caused by the rolling, medial to lateral motion of the temperomandibular joint (TMJ) during the opening closing ones mouth. Research has demonstrated that dynamic action of the anterior-posterior plane of the ear canal will vary by about three to five millimeters during talking, chewing, or laughing. These factors, along with the fact that the ear canal slopes upward along the medial plane, deleteriously affect efforts to maintain an acoustic seal in the external ear canal in normal, daily operation of a hearing device.  
         [0009]     The challenge to one-size-fits-most is heightened by the secretions of cerumen, oils, and moisture impeding electronic performance and life cycle. The chemical make up of cerumen alone is as individual as the ear in which the end product will reside. Cerumen may vary in acidity, as well as in the content of lipids, proteins, cholesterols, and waxy esters. The content latter component will, in fact, determine whether a wearer&#39;s cerumen is “wet” or “dry” in nature, each of which presents a different problem for hearing instrument longevity.  
         [0010]     From a psycho-acoustic perspective the location and pressure of the acoustic seal is very important. Poor placement will cause a sense of occlusion or stuffiness in the ear. The occlusion effect is the result of soft-tissue-conducted sounds that create an internal sound level greater than 10-12 dB above the ambient (or “out-side” of the head) sound levels. When this occurs, wearers report their own voice sounds funny, hollow, or as if their heads are in barrels. This is commonly caused by too tight an acoustic seal on soft tissue between the aperture medially to the first directional bend of the external ear canal. Occlusion effect is further heightened by varied peripheral or “slit leakage” and poor or no venting. The slit leakage facilitates annoying low frequency resonation and distorts the mid-frequency sounds. Conversely, these problems are best managed with good venting and uniform acoustic seal.  
         [0011]     When the acoustic seal is created properly at a point in the ear canal where there is a balance of cartilaginous and bony material, there is less slit leakage, sound is natural, and acoustic feedback is avoided. By adding a well designed vent system to allow excess low frequency sound energy to roll-off, and undesireably high ear canal air pressure to be released, the hearing device is optimized in all applications. The over-all performance of the device can then yield better sound quality and “distinctness of sounds.” 
         [0012]     With the goal of high fidelity amplification in both custom and non-custom hearing instruments, entailing a 20-20,000 Hz frequency response, a dynamic, secure, yet comfortable acoustic seal is paramount.  
         [0013]     All previous efforts to achieve this type of fit have revolved around the concept of building up the exterior of the hearing instrument, making a “tighter” fit. This approach, unfortunately, was the only avenue available with those instruments composed of rigid, non-compliant acrylic.  
         [0014]     The traditional shell molded from an individual&#39;s unique ear impression has not yielded a truly typical form that anatomically fits a significant percentage of any external ear category. It is further limited by a dated acrylic design which is the most commonly used shell technology. This technology was adopted from dental industry in the 1960&#39;s. It has a Shore Hardness factor of 90 Durometer. Little design change has been introduced since its development. Production and curing techniques have improved, however, through laser modeling and 3-D imaging. Since the ear is a dynamic acoustic environment and is ill-served by a rigid material like acrylic. The material however has a reasonable life cycle in the environment of the ear. Hard Durometer devices rock in the ear with jaw motion (TMJ), as opposed to flexing and accommodating the dynamic action of the ear.  
         [0015]     Attempts with soft hollow shell technology have failed based on several key issues: Most soft material shrinks, discolors (usually unsightly yellow or brown), hardens after a few months.  
         [0016]     Silicone based materials, which are preferred to be used in the body, are incompatible for bonding to the typical electronic faceplate. Soft/hollow materials tend to collapse upon insertion and deform over time loosing their ability to create an acoustic seal.  
         [0017]     Foam technology typically requires multiple sizes to achieve a fit. They are uncomfortable, stuffy, and should not be reused as cellular foam becomes a breeding ground for bacteria.  
         [0018]     The following U.S. patents are each hereby incorporated herein by reference:  
         [0019]     U.S. Pat. No. 6,478,656 Method and apparatus for expanding soft tissue with shape memory alloys; This patent describes the application of a body worn bra where by the soft tissue of the skin forming the breast is expanded by incorporating an adhesive and an appliance with a shape memory alloy.  
         [0020]     U.S. Pat. No. 6,135,235 discloses a self-cleaning cerumen guard for a hearing device.  
         [0021]     U.S. Pat. No. 5,999,859 discloses a apparatus and method for perimodiolar cochlear implant with retro-positioning.  
         [0022]     U.S. Pat. No. 5,977,689 discloses a biocompatible, implantable hearing aid microactuator.  
         [0023]     U.S. Pat. No. 5,800,500 discloses a cochlear implant with shape memory material and method for implanting the same.  
         [0024]     U.S. Pat. No. 5,772,575 discloses an implantable hearing aid.  
         [0025]     U.S. Pat. No. 5,630,839 discloses a multi-electrode cochlear implant and method of manufacturing the same.  
         [0026]     U.S. Pat. No. 4,762,135 discloses a cochlea implant.  
         [0027]     U.S. Pat. No. 3,865,998 discloses an ear seal. This patent states that the typical cross section of the external ear canal is best approximated by a super ellipse which is defined by the equation.
 
( x/a ) n +( y/b ) n =1 where n=2.4. 
 
         [0028]     The hypothesis is that an ear seal could be created using a soft material with an outer periphery defined by the super elliptic shape. The patent does not address the bigger issues associated with the longitudinal axes formed by extending a line through the medial-lateral plane or the dynamic nature of the TMJ. The latter issue was neglected because the device was very short by today&#39;s standards for insertion. The patent also did not consider the surface pressure necessary to create the acoustic seal it desired to deliver. In essence it was a tapered flanged silicone plug of super ellipse cross section.  
         [0029]     Nitinol wire is used in a variety of medical and nonmedical device applications including guide wires, catheters, stents, filters, orthodontic appliances, eyeglass frames, cellular phone antennae and fishing tackle, to name a few.  
         [0030]     Because shape memory and super elasticity are very temperature dependent, the fully annealed austenitic peak temperature is used to classify Nitinol to set the transformation temperature at which the Nitinol material has completely transformed to its memory shape or below which, exhibits malleable, ductile characteristics.  
         [0031]     Of the many mechanical properties unique to Nitinol, two critical characteristics exhibited in the austenitic phase are the loading plateau and the unloading plateau, usually diagrammed on a stress/strain curve. The loading plateau is the stress level at which material produces an almost constant stress level over a relatively large range of strain, up to about 8%. Stainless steel conversely, does not exhibit this property of constant stress after 0.3% of strain. Other information relating to Nitinol can be found at www.nitinol.com.  
       BRIEF SUMMARY OF THE INVENTION  
       [0032]     The present invention provides a unique self-forming device to the individual external ear canal employing a metallic frame, preferably of the Nitinol family of alloys. The current preferred Nitinol is comprised of near equiatomic percentages of nickel and titanium, such as Memry Corporation tube stock BB-196X230.  
         [0033]     Nitinol exhibits a thermoelastic transformation. This transformation is responsible for either shape memory or super elasticity being exhibited by the alloy on the respective side of the target temperature. Following deformation below the transformation range, the property called “shape memory” allows recovery of a predetermined shape upon heating above the transformation range. Super elasticity is the non linear recoverable deformation behavior at temperatures above the austenitic finish (Af) temperature, which arises from the stress-induced martensitic transformation on loading and the reversion of transformation upon unloading. Coronary stents utilize this technology as a recovery mechanism once deformed and inserted through a catheter. The Nitinol alloy is strong and resilient. The strain recovered with shape memory or super elasticity typically provides nearly ten times the elastic spring back of other alloys such as stainless steel. Additionally, Nitinol has excellent biocompatibility properties.  
         [0034]     The austenitic and martensitic characteristics of a Nitinol endoskeleton, in concert with a soft-solid silicone body, acts to create an easily inserted ready-wear ear device which will self form to the shape of the external ear canal, establishing a precise wall pressure. Simply stated, a small soft device with the endoskeleton grows once inserted into the ear canal. It may transform by heat, electrical current, or other means. As it grows (i.e. recovers from deformation to the pre-molded shape) to sufficient size, the ear worn device resides in equilibrium, comfortably and securely in the ear. The endoskeleton can be shaped similar to a human rib cage. This anatomical choice allows the device to expand like the chest cavity breathing. The particular design more closely follows that of an eel or snake rib cage. This makes the instrument self-seeking during insertion as it snakes through the directional bends of the ear canal.  
         [0035]     The present invention provides a hearing device or hearing aid or hearing protector with a Nitinol endoskeleton in a soft silicone body that will enhance the fitting of pediatric and young children, who have been relegated to wearing behind-the-ear appliances that are routinely taped to the heads of the young wearers. In the past, parents have objected to this practice, but are typically faced with no alternatives. Small in-the-ear hearing devices can, with this invention, be manufactured with an endoskeleton, extending the proper fit of the device by several months. This enables the commercialization of a new generation hearing device uniquely suited for children. Today, children outgrow acrylic devices. They are often outgrown too quickly to be cost effective.  
         [0036]     Advanced self-forming endoskeleton technology will eventually achieve a customer satisfaction ratings of 80-90%. Advances in shell technology incorporating soft-solid bodies with endoskeletons manufactured from memory-metal technology will make it possible to mass-produce instruments that will provide a secure, comfortable fit rivaling custom-fit instruments. This will result in better over-all sound performance and cost reductions based on mass production techniques. Significant savings will be realized at all levels of the current hearing aid delivery system. The need to make ear impressions will be greatly reduced, eliminating the need to send those impressions into a laboratory. In those cases where ear impressions are necessary, the application of shape memory technology will yield a more predictable fit in the custom-molded embodiment.  
         [0037]     Post-fitting care will be greatly improved in that a replacement or loaner device is readily available to the patient. This alone will reduce office visits for the patient and eliminate overnight delivery cost necessary to meet patient expectations on an important medical, audio, or communications device.  
         [0038]     To the end this shape memory technology will lead to impression-less hearing aids for the vast majority of the hearing impaired market. Ready wear fittings will achieve levels of fit, comfort, security, and performance that will rival or exceed custom devices. These improvements will affect all devices intended to be inserted into the ear for sound delivery and voice pickup.  
         [0039]     Voice pickup technology, through the use of subminiature electret microphones a piezoelectric accelerometers (similar to the Endevco Model 22 PICOMIN™), or a MEMS accelerometers, facilitates communication through hard wired or wireless platforms such as Blue Tooth or Zigbee. In turn, the acoustic system delivers incoming signals to the ear drum. For voice pickup the accelerometer is positioned between the external ear canal wall and the outer side of the stent in such a way as to create radial pressure between the ear canal and the accelerometer. This design could achieve hands free communication in many applications.  
         [0040]     The design of a self-forming device is achieved by expanding the soft-solid device in a way that contact with the external ear canal wall is achieved by reaching equilibrium. Each surface point on the external ear canal wall, adjacent to the skeletal structure, will have forces on the canal wall where, F(a)=F(b)=F(c)=F(n). The shape of the extruded wire may be, for example, round or rectangular or of an I-beam cross-section. The cross-sectional shape and the cross sectional area of the members forming the endoskeleton, such as a stent or truss system, govern the amount of force that the endoskeleton will exert on the silicone embedding it. This force, by design, is equal to the elasticity of the surrounding silicone plus the required surface pressure necessary to bring the external surface of the device into contact with the wall of the external ear canal. This will establish an acoustic seal of known pressure. This, in turn, will accommodate a variety of ear canal shapes within the known range of deflection. This self regulating force will enable custom-molded devices to fit optimally and will enable ready-wear devices to accomplish one-size-fits-most in real world terms. The forces generated by the endoskeleton will be perpendicular to the ear canal wall, eliminating any shearing action on the skin.  
         [0041]     The mechanics of the current device are driven by temperature change from room temperature to ear canal temperature. In another embodiment, the transformation is driven by an electrical current through the endoskeleton. This could be necessary in applications where room temperature is greater than ear canal temperature. Activation temperatures are metallurgically set. The following are exemplary endoskeleton material parameters for the memory metal (Nitinol, from Fort Wayne Metals Research Corporation):  
         [0042]     1. Passive metal excited by temperature change: 
        i. EAC temperature @ 35° C.±1° C.     ii. T=10° C.±1° C. or 32° C.±3° C.        
 
         [0045]     2. Active metal excited by an electrical current. 
        i. Electrical current will heat the Nitinol, causing transformation.        
 
         [0047]     3. Attribute of Nitinol: 
         Will not interfere with hardware of wireless communication.        
 
         [0049]     The endoskeleton extruded design can be a simple spring. The intended use is to pull on the proximal end of the device, there by reducing its cross sectional area and increasing its longitudinal dimension. Once inserted, the device returns the device to a diameter sealing the ear canal with uniform pressure. The Nitinol is molded as a star in its austenitic. The intended use is to compress the proximal end of the device on the endoskeleton, thereby reducing its cross sectional area. As the user inserts the device, its memory shape returns the device to a diameter sealing the ear canal with uniform pressure. A gradient wedge coil can be formed from extruded wire, molded into a coil with the thicker end to be placed near lateral end. A truss system can include members of cross-sectional shapes selected to optimize the deflection and force transferred to the ultimate excursion of the silicone device. The truss system shape is selected to accommodate a typical ear canal shape. Sinusoidal shapes of various cross-sectional sizes can be connected together to generate vector forces of precise angular change delivering optimum excursion of the endoskeleton. These designs are generally micro-machined from tubing, laser cut, and micro blasted to a polished finish.  
         [0050]     The endoskeleton would ideally be of a shape to optimize acoustic seal, placed in the device to minimize the occlusion effect. The acoustic seal would be uniform on the canal wall three millimeters past the second directional bend. In power hearing device applications, the seal could be continuous from the aperture to three millimeters past the first directional bend.  
         [0051]     The endoskeleton would also serve to further protect the delicate electronics. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0052]     For a further understanding of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:  
         [0053]      FIG. 1  is a sectional view of the external ear canal of a wearer, wherein the out-of-ear embodiment of the in-the-ear device is in the malleable Martensite state which is deformed by bias spring to its smaller size, the device being easily inserted through the bends of the wearer&#39;s ear canal;  
         [0054]      FIG. 2  is a perspective view of the preferred embodiment of the apparatus of the present invention shown positioned in the external ear canal thereby being exposed to body heat causing transformation from the Martensite phase to the Austenite Start (As) that starts recovery from the deformed shape to its annealed shape;  
         [0055]      FIG. 3  is a perspective view of the preferred embodiment of the apparatus of the present invention shown in the recovered Austenite Finish (Af) state that transmits a radial force through the silicone body to the external ear canal wall yielding a comfortable, secure acoustic seal, free from acoustic feedback;  
         [0056]      FIG. 4  is a perspective view of the preferred embodiment of the apparatus of the present invention showing the Nitinol stent portion that is in its molded state in the Austenite finish thus demonstrates the expanded size as shown in the device of  FIG. 3 ;  
         [0057]      FIG. 5  is an end view of the stent, taken along lines  5 - 5  of  FIG. 4 , wherein dimension (Dim.) A is in the major axis and dimension (Dim.) B is the minor axis;  
         [0058]      FIG. 6  is a side view of the preferred embodiment of the apparatus of the present invention showing a Nitinol stent that is in its compressed or deformed state in the Martensite phase, the small size as in the device of  FIG. 1 ;  
         [0059]      FIG. 7  is a side sectioned view of the preferred embodiment of the apparatus of the present invention showing a Nitinol skeleton as a spring;  
         [0060]      FIG. 8  is a side, sectioned view of the preferred embodiment of the apparatus of the present invention showing the Nitinol stent in the Austenite finish, wherein the expanded size creates pressure on an accelerometer, establishing a vibratory pathway from the ear canal wall so that the accelerometer picks up vibratory voice signals from the wearer to be transmitted to a communication device by a hard wire or a wireless system;  
         [0061]      FIG. 9  is a perspective view of the preferred embodiment of the apparatus of the present invention showing a Nitinol stent characterized by rotating horseshoe cross sections that are in the molded state at the Austenite finish, (the expanded size when in the device of  FIG. 3 ); and  
         [0062]      FIGS. 10-14A  are perspective views of the preferred embodiments of the apparatus of the present invention showing various Nitinol stent designs that are in its molded state in the Austenite finish (the expanded size when in the device illustrated in  FIG. 3 ). 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0063]      FIGS. 1-3  show generally the preferred embodiment of the apparatus of the present invention, designated generally by the numeral  10 . Hearing device  10  has an internal stent or frame  17  that expands to its pre-molded state at human body temperature. In  FIGS. 1-3  the practical application of apparatus  10  is an in the ear worn hearing aid, an active hearing protector, or a combination hearing protector hearing device, a passive hearing protector, a communication device, or a combination communication hearing and hearing protector device, or any combination sub-miniaturized into a single unit. As used herein, the term “hearing aid” is broadly construed to cover any of the above devices. Dim. C (arrow  27 ) of  FIG. 1  is the smallest diameter of the device  10  in the malleable Martensite phase. The Nitinol preferably used to construct stent  17  will preferably reside in this state at typical room temperature below 30° C. The same malleable state may exist in the absence of a power signal for electrically driven stents. Illustrated by Dim. D (arrow  28 ) of  FIG. 3  is the pre-molded diameter of the stent  17  for temperatures at or above 35° C. or when activated by an electrical signal for the active stents. Once completely inserted into a patient&#39;s ear canal  15  and expanded in the external ear canal  15 , the device  10  achieves a precise peripheral seal with ear canal  15  wall  16  as shown in  FIG. 3 .  
         [0064]     The hearing aid device  10  of  FIG. 1  is characterized by a preferably flexible body  11  of soft silicone or other soft material compatible with ear canal  15  tissue. Hearing aid components  13  are also contained in body  11  and can include the battery compartment  18 , the battery contacts and wire connections. Other hearing aid components  13  can include for example a microphone, a receiver, a transceiver, an electromagnetic coil, or a circuitry transceiver electromagnetic coil. Vent tube  29 , extends through hearing aid  10  including body  11  and faceplate  12 .  
         [0065]     The pena  19 , external ear canal wall  16  and ear canal cavity  15  define the typical human ear. The outside environment (depicted by the numeral  20  in  FIGS. 1-3 ) is room temperature for the preferred embodiment. Body heat shown in  FIGS. 1, 2  and  3  transforms the stent from its smaller or deformed size ( FIG. 1 ) to its original pre-molded shape memory size ( FIG. 3 ). The flexible (e.g. silicone) body  11  may act as a bias spring to return the stent  17  to a deformed state when the device  10  has been removed from the ear and exposed to room temperature. Re-insertion of the device  10  into the ear canal  15  returns the device  10  to its original design shape. This property enables ready wear devices to self form to many individual ear canal  15  shapes without the logistics of an ear impression from which to custom mold the device form for that individual ear canal.  
         [0066]      FIGS. 4-6  illustrate the Nitinol stent or frame  17  that can be micro-machined from a cylindrical tube, its preferred outer diameter (OD)  FIG. 5  Dim. A ( 24 ) is 5-10 mm and Dim. B ( 25 ) is 3-9 mm viewed by  6 . In  FIGS. 4-6 , stent  17  includes straight sections  21  connected with curved sections or bends  22 . Angle  23  formed by two adjacent straight sections  21  can be between about 15 and 45 degrees. The overall longitudinal length  26  is preferred to be between about 4-8 mm. The cross sectional member depicted in  FIG. 6  can be square, round, or rectangular. In the preferred embodiment the thickness is 0.0235 inches each. The cross section may vary in shape and size depending on application and redial force requirements. The geometric angles forming the stent are defined are dependent on redial force requirements and additionally physical dimensions.  
         [0067]      FIG. 7  illustrates a passive hearing protector or “ear plug” designated generally by the numeral  30 . The faceplate  31  covering the proximal end of the device is typically plastic bonded to body  32 . The silicone body  32  contains a conical or coil spring shape Nitinol spring  33 . The device  30  is at room temperature  20  and is in the Martensite phase which is highly malleable. This embodiment would be elongated prior to insertion which reduces the cross sectional area for insertion. At body temperature the coil  33  will retract to its pre-molded austenite shape. In this simplest preferred embodiment illustrated in  FIG. 7  in the invention utilizes a coil of similar shape to a spring in an inexpensive ink pen. This circular coil  33  can be extruded in memory metal. The coil  33  can then be shaped into a star configuration in the Martensite phase. This star shaped coil is then molded in a soft-solid silicone body  32  with its electronic components if an active device. The coil  33 , or endoskeleton, is placed in the ear worn device  30 , such that its longitudinal axis is parallel to the longitudinal axis of the external ear canal or more specifically to the medial-lateral axis of the ear canal. No electronic components are placed between the endoskeleton the external ear canal wall.  
         [0068]     In more complex applications, such as the case of hearing devices shown in  FIG. 1 , the hearing aid components such as a receiver or transducer is housed inside the endoskeleton. In the case of electromagnetic devices, the electromagnetic coil is suspended from a micro machined hinge and gear assembly from the inside diameter of the stent. In both cases, at ear temperature shape memory alloy stent expands outward into its original Austenite shape, causing the soft-solid body of the ear device to move outward into full contact with the ear canal wall of the external ear canal precisely and securely positioning the transducers.  
         [0069]      FIG. 8  shows a combination hearing protection and communication device, designated generally by the numeral  34 . This complex hearing amplification device  34  provides both a hearing protection device and a communication device housed in a soft body  35 . Two transducers are used in concert with a two channel RF transceiver. The acoustic transducer  36  delivers sound from the hearing amplification circuitry  37  delivering processed out side environmental sound and from the two channel transceiver  38  to the ear drum. The stent  17  positions the acoustic transducer  36  aming it at the ear drum  39 . The receiver is usually placed lateral to the stent with a port tube  40  extending through the inside of the stent  17  for acoustic sound transmission. The accelerometer  41  is positioned between the out side diameter of the stent  17  and the ear canal wall  16 , so that once the stent  17  expands the accelerometer  41  is mechanically engaged to the external ear canal  15  wall  16  allowing it to pick up the wearers voice signals via bone conduction and transmit the voice signals to the transceiver  38 . An ultra low power two channel RF transceiver, such as the Gennum Corporation GA3272, optimizes wireless digital audio communication to compatible wireless sensor networks. This apparatus  34  would achieve hearing amplification and hearing protection if desired, as well as enabling voice transmission from the wearer to a communication device (e.g. telephone  42 ) channeling phone signals back to the ear drum by way of the hearing amplification circuitry  37  via the transceiver  38 . The apparatus  34  of  FIG. 8  would further serve to protect the hearing of the wearer by an acoustic seal and a limiting circuit in the hearing amplification circuit  37 .  
         [0070]     In another embodiment of the invention, a stent or skeleton  17 A is formed by a series of ribs shown in  FIG. 9  is formed by a connected spine, similar to a human rib cage. This horseshoe shaped cross sectional structure is extruded in memory metal. The individual horseshoe shaped elements  43  are connected together by a spine  44  enabling the configuration to act like a plumbing snake during compression i.e. insertion. The spine  44  also maintains the relative spacing of the individual horseshoe shaped elements  43 . This ribbed skeleton  17 A is then molded in a soft body  12  with its electronic components  13 . The skeleton  17 A is located medially between the receiver and the proximal end of the soft device. This ear worn device&#39;s longitudinal axis is parallel to the longitudinal axis of the external ear canal  15  or more specifically to the medial-lateral axis of the ear canal  15 . No electronic components are placed between the endoskeleton and the external ear canal wall. During expansion, pressure is developed on the anterior and posterior surfaces of the ear canal wall. The superior and inferior surfaces are maintained so that at ear temperature, said skeleton expands outward into its original horseshoe shape, causing the soft-solid body of the ear device to move outward into full contact with the ear canal wall of the external ear canal.  
         [0071]     In  FIGS. 10-14A  various shapes and actions of the stent (designated respectively as  17 B,  17 C,  17 D,  17 E,  17 F) are shown that would anchor devices for numerous applications in different locations of the external ear canal  15 . Any of the preferred geometric configurations of the endoskeleton can be designed and validated through the use of Finite Element Analysis (FEA) modeling. Finite element models are created by breaking the design into numerous discrete members. The models simulate the functionality and mechanical properties covering boundary conditions and the effects on elements such as fields of displacement, strains, stresses, temperatures, state variables, etc. Further, FEA will identify any design are process problems in the earliest time frame.  
         [0072]     The following is a list of parts and materials suitable for use in the present invention.  
       PARTS LIST  
       [0073]    
       
         
               
               
             
           
               
                   
               
               
                   
               
               
                 Part Number 
                 Description 
               
               
                   
               
             
             
               
                 10 
                 hearing aid 
               
               
                 11 
                 flexible body 
               
               
                 12 
                 faceplate 
               
               
                 13 
                 hearing aid component 
               
               
                 14 
                 ear 
               
               
                 15 
                 ear canal 
               
               
                 16 
                 surface 
               
               
                 17 
                 nitinol stent 
               
               
                 18 
                 battery 
               
               
                 19 
                 pena 
               
               
                 20 
                 outside environment 
               
               
                 21 
                 straight section 
               
               
                 22 
                 curved section 
               
               
                 23 
                 angle 
               
               
                 24 
                 dimension “A” 
               
               
                 25 
                 dimension “B” 
               
               
                 26 
                 length 
               
               
                 27 
                 arrow 
               
               
                 28 
                 arrow 
               
               
                 29 
                 vent tube 
               
               
                 30 
                 hearing protector 
               
               
                 31 
                 faceplate 
               
               
                 32 
                 soft, solid body 
               
               
                 33 
                 coil spring stent 
               
               
                 34 
                 hearing protection and communication device 
               
               
                 35 
                 body 
               
               
                 36 
                 acoustic transducer 
               
               
                 37 
                 circuitry 
               
               
                 38 
                 two channel transceiver receiver 
               
               
                 39 
                 ear drum 
               
               
                 40 
                 tube 
               
               
                 41 
                 accelerometer 
               
               
                 42 
                 mobile telephone 
               
               
                 43 
                 horseshoe shaped element 
               
               
                 44 
                 spine 
               
               
                   
               
             
          
         
       
     
         [0074]     All of the above designs eliminate the need for component suspension since they are embedded in soft solid silicone throughout. Vent and sound bores are created by molding leaving a bore without wall space requirements.  
         [0075]     All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.  
         [0076]     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.