Patent Publication Number: US-8522916-B2

Title: Occlusion effect mitigation and sound isolation device for orifice inserted systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/492,164, filed Jun. 26, 2009 which claims the benefit of U.S. provisional patent application No. 61/076,122 filed on 26 Jun. 2008. The disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to devices that can be inserted into orifices and sealed, and more particularly although not exclusively related to earpieces with expandable systems. 
     BACKGROUND OF THE INVENTION 
     The occlusion effect is generally described as the sensation of increased loudness (sound pressure level), especially in the low frequencies, that a person experiences to self-generated sounds (vocalization, chewing, swallowing, walking, and the like), when the ears are covered (occluded). Note that this resonance amplification can occur in tubes that have a sealed volume and have acoustic leakage into the volume. The occlusion effect has been identified as a major obstacle to successful hearing aid use and shallow (within the first ½ of the channel) inserted earpieces. The theories of why the occlusion effect forms and what it is are numerous and diverse and to date no single explanation has been totally accepted. 
       FIG. 3  illustrates typical occlusion effect levels as a function of frequency for various in-ear devices. 
     There are several theories of the occlusion effect. They include outflow theory (Mach, 1863): occlusion of the ear canal results in an increase in middle ear impedance, and hence to a decrease in energy lost from the inner ear via the ossiculaer chain. Resonance theory (Huizing, 1923): increased perception of sound is brought about by the walls of this artificially closed cavity acting as resonators. Masking theory (Pohlman, 1930; Hallpike, 1930): occlusion of the ear canal eliminates masking influence of ambient noise. Inertial/osseotympanic theory (von Bekesy, 1932): the occlusion effect results from sound pressure increase in the auditory canal with occlusion. Inertia of the mandible to the skull sets up pressure variations in EAM. Impedance theory (Huizing, 1960): occlusion alters the impedance of the column of air in the canal (increasing it), resulting in improved coupling of the air in the canal to the middle ear. 
       FIG. 4  illustrates several occlusion effect studies and their values at various frequencies for earphones, while  FIG. 5  illustrates several occlusion effect studies for earmolds. Roughly the occlusion effect is in the range of 13-25 dB between 250-500 Hz. Roughly from Killion, Wilber, and Gudmundsen (1988) a shallow insertion has an occlusion effect of about 13 to 21 dB, while a deep insertion has an occlusion effect of about 20 dB for a tapered tip, and about −9 to 4 dB for a bony contact ear inserted device. Related art solutions involve acoustic vents between the sealed region (now unsealed) and the outside environment of about 3 mm in diameter, however venting has limitations as well, for example ringing. Another solution is deep insertion with contact in the bony section of the ear canal. 
     Thus for shallowly inserted systems (e.g., &lt;½ the ear canal length), the occlusion effect can be an issue (e.g., &gt;5 dB). 
     SUMMARY OF THE INVENTION 
     At least one exemplary embodiment is directed to an occlusion effect mitigation device comprising: an insertion element; and an expandable element operatively attached to the insertion element, where the expandable element is configured to expand against a portion of the walls of a flexible channel forming a sealed chamber in the channel, where the expansion reduces the occlusion effect in the sealed chamber. 
     At least one exemplary embodiment is directed to a sound isolation device comprising: an expandable element; and an insertion element, where the expandable element is operatively attached to the insertion element, where the expandable element includes an expanding medium, where the pressure of the expanding medium is varied to vary sound isolation across the expandable element. 
     At least one exemplary embodiment is directed to a method of sound isolation comprising: expanding an element to a first pressure where the expanded element varies the sound isolation across the element as the pressure exerted by the expanding element is varied. 
     At least one exemplary embodiment is directed to a method of occlusion effect reduction comprising: inserting an insertion element into a flexible channel; and expanding an expanding element, where upon insertion of the insertion element and expansion of the expanding element a sealed chamber is formed, where when the expanding element presses against a portion of a wall of the flexible channel, the occlusion effect in the sealed chamber is reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  illustrates an ear canal as a non-limiting example of an orifice that can be sealed forming a resonance chamber; 
         FIG. 2  illustrates occlusion effect values of at least one exemplary embodiment when the device is sealed at various sound isolation values; 
         FIGS. 3-5  illustrates various values of the occlusion effect according to several scientific studies; 
         FIG. 6  illustrates sound isolation values (e.g., acoustic energy absorption and reflection) for an inflatable system according to at least one exemplary embodiment; 
         FIG. 7  illustrates an inflatable device in accordance with at least one exemplary embodiment; 
         FIGS. 8-13 , and  15  illustrate at least one method of inflating an inflatable device in accordance with at least one exemplary embodiment; and 
         FIGS. 14A ,  14 B, and  14 C illustrate various non-limiting examples of electrode configurations in accordance with at least one exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION 
     The following description of exemplary embodiment(s) is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. 
     At least several exemplary embodiments are directed to or can be operatively used on various wired or wireless earpiece devices (e.g., earbuds, headphones, ear terminal, hearing aids, behind the ear devices, or other acoustic devices as known by one of ordinary skill in the art, and equivalents). 
     Processes, techniques, apparatus, and materials as known by one of ordinary skill in the art may not be discussed in detail but are intended to be part of the enabling description where appropriate. For example material fabrication may not be disclosed, nor attachment procedures (e.g., adhesive attaching of separate ridge structures), but such, as known by one of ordinary skill in such arts is intended to be included in the discussion herein when necessary. 
     Notice that similar reference numerals and letters refer to similar items in the following figures, and thus once an item is defined in one figure, it may not be discussed or further defined in the following figures. 
       FIG. 1  illustrates a sealed (occluded) ear canal  50 , with a sealed volume  30 . Voice can leak  80  into the sealed volume  30  from various source paths  80 A,  80 B, and  80 C. Source paths  80 A and  80 B represent sound conducted from bones  10  adjacent to ear canal  50 . Source path  80 C represents sounds  90 ,  95  to ear canal  50  from areas of the inner ear. In one explanation, the leaked acoustic energy results in an amplification (e.g., by resonance) at certain frequencies within the sealed volume, resulting in the occlusion effect. If the ear canal (a non-limiting example of an orifice) was unsealed then no resonance could build and hence there would be no occlusion effect. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions of the relevant exemplary embodiments. For example exemplary embodiments do not require the formation of a sealed chamber in the channel, exemplary embodiments can increase the sound isolation across the sealed section of the channel. 
       FIG. 1  illustrates at least one exemplary embodiment. An earpiece  100  can include an insertion element  75  operatively connected to a sealing section. The sealing section can include an expandable element  70  (e.g., expanding polymers, inflatable systems, mechanically expanded systems, balloons of various shapes, sizes and materials, for example constant volume balloons (low elasticity &lt;=50% elongation under pressure or stress) and variable volume (high elastic &gt;50% elongation under pressure or stress) balloons). Many materials can be used for the expandable element  70 . For example if the interior medium is air then the material (e.g., membrane) for the expandable element can be chosen so that the pressurized air (e.g., 0.1 bar gauge to 2 bar gauge) leaks through the membrane in a chosen period of time (e.g., 5% pressure decrease in 8 hours). Additionally other fluids (e.g., air, water, oil, glycerin) can be used as the interior medium. A pumping mechanism can be used to pressurize the interior medium. For example a manual pump, electrical pumps, and chemical pumps (e.g., electrolysis). Sealed volume  30  is formed between expandable element  70  and tympanic membrane  40 . Expandable element  70  may seal ear canal  50  from sound in ambient environment  20  external to ear canal  50 . 
       FIG. 2  is a graph of the occlusion effect as a function of sound isolation in accordance with an exemplary earpiece of the present invention. The example illustrates occlusion effect values when an exemplary earpiece is sealed at various sound isolation values.  FIG. 2  shows that the occlusion effect is reduced as sound isolation is increased. Conversely, the occlusion effect increases as the sound isolation decreases. 
       FIG. 6  illustrates sound isolation (attenuation+reflection) results as a function of inflation plotted in semi-log scale. Note that the inflation can be varied to obtain a variation in the attenuation and/or acoustic reflection. Additionally the inflation medium (interior medium) can be either a liquid (e.g., water, baby oil, mineral oil), a gas (e.g., H2O vapor, H2, O2 gas), or a combination of both. Thus in accordance with at least one exemplary embodiment sound isolation can be increased as the pressure is increased above a particular seal pressure value. However if the expandable element is a stressed membrane, then there can be an elongation percentage where the acoustic transmission through the membrane is higher than at larger or lower elongation percentage. For example if the stressed membrane is stretched to 50% elongation in one dimension the acoustic transmission can be lower than unstretched or 150% elongation stretched (stressed) membranes. The seal pressure value is the pressure at which the inflatable system (an example of an expandable element) has conformed to the inside of the orifice (e.g., whether regular or irregular) such that a drop between the sound pressure level on one side of the inflatable system is different from the sound pressure level on the opposite side of the inflatable system by a drop value in a short period of time. For example when a sudden (e.g., 1 second) drop (e.g., 3 dB) occurs at a particular seal pressure level (e.g., 2 bar). For example if a balloon is used where the medium is air, an internal pressure of 1.2 bar absolute (0.2 bar gauge) can result in a sound isolation of 20+ dB across the balloon. For permeability consideration, for example suppose one wishes inflation to last for 8 hours with less than 5% internal loss of pressure, the permeability will have to be much better than silicon, for example Teflon. For variable volume balloons (such as silicon balloons) various high elongation materials (some over 1000%) can have the requisite permeability. 
       FIG. 7  illustrates an inflatable system  300  comprising an insertion element (e.g.,  320 , multi-lumen tube) and an expandable element (e.g.,  330 , urethane balloon, nylon balloon). The expandable element can be filled with an expanding medium (e.g., gas, liquid, electroactive polymer or gel) fed via a supply tube (e.g.,  340 ). The device illustrated in  FIG. 7  illustrates a flange  310  (e.g., made of plastic, foam, rubber) designed to stop at a designated position in the orifice (e.g., at the opening of the orifice), and an instrument package (e.g.,  350 ) can include additional devices and equipment to support expansion control (e.g., power supply and leads, gas and/or fluid generation systems). 
       FIG. 8  illustrates at least one exemplary embodiment for pressure generation and control, designated generally as system  400 . The non-limiting example illustrated includes a balloon (e.g.,  430 ), at least one pressure control valve (e.g.,  420 A,  420 B); electrodes  410 , a porous plug (e.g.  440 , micro pore plastics that allow gas to pass but block fluid motion), and optionally a membrane (e.g.,  415 , Nafion™) that absorbs the electrolysis medium (e.g., H2O with NaCl dissolved at 0.001 mole/liter) allowing a current to pass between the electrodes as if the electrodes were essentially in free electrolysis material, and at the same time preventing the electrodes from touching. The membrane facilitates close placement of the electrodes increasing the electric field and hence the current. As illustrated the seal pressure value is as discussed above, the operating pressure is some value greater than the seal pressure value (e.g., 20% greater) at which an expandable element operates for a given condition.  FIG. 8  illustrates an electrolysis system where the gas generated passes through a porous plug into a chamber that has control valves. The control valves are designed to allow a certain gauge pressure value to be reached inside the chamber (e.g., 0.25 bar, 0.5 bar gauge) while allowing gas from the outside of the chamber to enter if the gauge pressure value drops below a value (e.g., −0.5 bar gauge), where the gauge pressure in this instance is calculated as the pressure inside the chamber minus the pressure outside the chamber. A non-limiting example of sealing time is 12 seconds for a balloon volume of 1000 mm^3 using &lt;12 volts and less than 300 milliamps. 
     An example of electrolysis conversion efficiency is conversion at 75% efficient, roughly 4.0 J/per inflation, or roughly 0.0002823 grams H2O for roughly 0.2823 mm^3 H2O. 
       FIG. 9  is another exemplary embodiment of a pressure generation and management system  500  in accordance with at least one exemplary embodiment. In this exemplary embodiment the gas formation is controlled by controlling the size of the electric field (e.g., by relative placement of the electrodes (e.g., platinum cylinders)). As the gas is generated fluid must be displaced and a partially filled balloon  530  can start to fill. Near the gas formation region a porous plug  540  can be used to let the gas generated pass and a valve  520  (e.g., duckbill, for example from VERNAY™ or a MINIVALVE™), or other types of valves, such as flapper valves, umbrella valves, spring and ball valves, and any other valves that have low leak rates (loss of less than 5% internal pressure in 8-16 hours), can be used to control the amount of pressure generated. Note that the fluid moves  550  by being displaced by controlling where the bubble formation  560  occurs (e.g., by placing the electrodes closer at the first desired bubble formation point). 
       FIG. 10  illustrates another pressure generation and management system  600 , which includes a manual depression bladder (e.g.,  680 ). When depressed  670  the gas and/or fluid in the volume defined by the depression bladder (e.g.,  680 ) can be encouraged (e.g., by correctly placed one-way valves (e.g.,  620 B,  620 C)) to move the evacuated gas and/or fluid along a tube to further inflate or pressurize an expandable element (e.g.,  630  Balloon). Another valve (e.g.,  620 A) can control the largest value of the pressure. 
       FIG. 11  illustrates another non-limiting example of a pressure generation and management system  700 . System  700  includes electrolysis medium  735  and electrodes  710  for generating a gas via electrolysis. In the illustrated system  700  an elastic bladder (e.g.,  765 ) provides a bladder force  775  that can aid in forcing any formed gas through the porous plug  740 . The gas can be moved along a tube to fill balloon  730  with expanding medium  717 . Valves  720  can control the pressure of expanding medium  717  to balloon  730 . 
       FIG. 12  illustrates yet another exemplary embodiment of a pressure generation and management system  800 . In the system illustrated as gas is formed (via electrolysis medium  835  and electrodes  810 ), water is displaced expanding the elastic bladder  865  with expansion force  845 . The expanding elastic bladder (e.g., compliant urethane) produces bladder force  875 , displacing a medium (e.g.,  837 ) in a chamber, where the displaced medium can further inflate an expanding element (e.g., Balloon  830 ) via expanding medium  817 . Similar to system  500  ( FIG. 9 ), system  800  includes porous plug  840  and valve  820 B for controlling passage of the generated gas. System  800  may also include valves  820  for controlling the pressure to balloon  830 . 
       FIG. 13  illustrates yet another pressure generation and management system  900  according to at least one exemplary embodiment. System  900 , similar to system  800  ( FIG. 12 ), includes electrolysis medium  935 , electrodes  910 , and elastic bladder  965  which has a bladder force  975 . As in  FIG. 12  the gas is forced through the porous plug (e.g.,  940 ), however in the configuration illustrated a smaller chamber is constructed with its own inflation bladder (e.g.,  985 ) and the pressure control system (e.g., valves  920 A and  920 B) are operatively connected to the smaller chamber. Inflation bladder  985  produces expanding force  945 , which displaces a medium (e.g.,  937 ). Displaced medium  937  can inflate balloon  930 , via expanding medium  917 . 
     Although not mentioned to this point, the electrodes can vary in shape and relative size. For example the electrode producing more gas (e.g., the electrode associated with H formation in water) can be made large in surface area facilitating a greater formation area. Additionally the electrodes can be separated by an electrolysis medium absorber (e.g., Nafion™,  1020 ).  FIGS. 14A through 14C  illustrate several non-limiting arrangements of electrodes  1010 . Note that the electrode material can vary, for example, the electrode may include a conductive material that will not oxidize in the electrolysis medium (e.g., stainless steel, platinum, gold). In  FIG. 14C , electrolysis system  1000 C includes spacer  1020  that allows current to flow between electrodes at a level similar to the current without the spacer but separates the electrodes so there is no shorting (e.g., Nafion™). This configuration can also keep air in but not water. 
       FIG. 15  illustrates at least one pressure generation and management system  1100  in accordance with at least one exemplary embodiment. In this system the electrodes  1110  are surrounded by a water soluble (porous) membrane  1191  (e.g., Nafion™), so that when gas is produced water is forced through the membrane  1191  while gas is still trapped inside the enclosed membrane chamber. An opening connected to a porous plug  1140  can allow the gas trapped to escape, and the pressure can be controlled by placing valves  1120 A,  1120 B after the porous plug  1140 . Note that the electrodes  1110  can be positioned relative to each other to control the gas formation  1155  in electrolysis medium  1135 . Displaced medium  1136  may be used to inflate balloon  1130 . 
     Note that several configurations illustrate gas as the expanding and/or displaced medium. Note that other exemplary embodiments can use the same configuration for liquids. For example the displaced medium (e.g.,  937 ) in  FIG. 13  could be a fluid (gas or liquid). 
     At least one exemplary embodiment is directed to a device (e.g., an occlusion effect mitigation device, a sound isolation device, an earpiece) comprising: an insertion element (e.g., catheter, catheter with multiple interior channels, tube, body of an earpiece (thus possible irregular)); and an expandable element (e.g., stressed membrane, balloon, electroactive membrane, stressed foam or a combination of these) operatively attached to the insertion element, where the expandable element is configured to expand against a portion of the walls of a channel (e.g., an ear canal, nose, pipe) where the device is configured to seal the channel when expanded (e.g., inflated). Upon sealing the device can reduce sound transmission and/or the occlusion effect in any sealed chamber. Note that the catheter can have at least one interior channel and the interior channel can transmit acoustic energy. In at least one exemplary embodiment the expandable element is a balloon, with an expanding medium inside the balloon, where the expanding medium is at an operating pressure. The balloon can be variable volume (e.g., made of a material with an linear elongation &gt;50% at operating pressure) or a constant volume balloon (e.g., a balloon made to a certain shape where upon inflation at an operating pressure does not expand more than 100% by volume from its shape volume). Note that the balloon shape can vary and be irregular or regular, for example disk shaped, conical, and/or spherical. Note that the operating pressure can be between 0.15 and 1 bar gauge pressure. Also note that the fluid can be ambient air. 
     Thus, the description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the exemplary embodiments of the present invention. Such variations are not to be regarded as a departure from the spirit and scope of the present invention.