WO2013166127A1

WO2013166127A1 - Ear odor sensor

Info

Publication number: WO2013166127A1
Application number: PCT/US2013/039035
Authority: WO
Inventors: Richard Lee Fink
Original assignee: Applied Nanotech Holdings Inc
Current assignee: Applied Nanotech Holdings Inc
Priority date: 2012-05-01
Filing date: 2013-05-01
Publication date: 2013-11-07
Anticipated expiration: 2014-11-01

Description

EAR ODOR SENSOR

This application claims priority to IKS. Provisional Patent Application Serial No. 61 640,760, which is hereby incorporated by reference herein. This application s also related to U.S. Published Application No. 2013/0066349, which is hereby incorporated by reference herein.

Background and Summary

Volatile organic compounds ("VOCs") have been used for maintaining health and monitoring or diagnosing disease states in plants, animals and humans. In humans, the first studies were made by profiling the metabolites that are present in body fluids. Modem instrumental techniques have demonstrated that hundreds of VOCs are detected from human body fluids (see, M. Philips et a^'L "Variation in volatile organic compounds in the breath of norma), humans,'" Journal Chromatography B Biomedical Sciences and Applications 1999, 729, pages 75-88, which is hereby incorporated by reference herein).

Odors are produced in several areas of the human body, such as the scalp, mouth, axillae (arm pits), groin, and feet. Some of the VOCs are produced by enodogenous metabolic processes in and on the human body. Other VOCs are produced from external sources, such as from the air during breathing, from digested food, and from use of personal care products. Breath samples in particular may contain a large amount of VOCs that come front external sources, since the mouth s used for both breathing and eating.

Body odor may also be used for monitoring VOCs, but it too may be highly loaded with

VOCs from external sources, since most of the skin is washed with soaps that contain fragrances and clothes that are washed with detergents that also contain fragrances. Personal care products used on the skin will also add t the VOC signature for many odor samples taken from the skin. One area of the body that typically does not get exposure to personal care products and detergents is the human ear.

Ear odor has been used to identify ear infections (e.g., the ear emanates a sour smell), but it may be useful for detecting and monitoring a wide variety of disease states and useful for health management. It is not used for eating and breathing, and is often not exposed to personal care products to the degree that other parts of the body are. Earwax, the substance that coats the ear canal, is also genetically linked to an individual. Whether a person has "dry" or "wet" earwax is determined by the make-up of the ATP-binding cassette CI I gene (see, Yoshiura K.,

I Kinoshita A,, Ishkla T. et al (2006), "A S SfP In (he ABCX! I gene is the determinant of human earwax type," Nature Genetics 38 (3); 324-30. doi: 10.1038/n l 733; see also. A, Martin et at,, *'A Functional ABCC I I Allele Is Essential in the Biochemical Formation of Human Axillary Odor," Society for Investigative Dermatology, 2009, do?: l. J O38/]kt20 9,254_< which are hereb Incorporated by reference herein).

Monitoring ear odor may be much simpler than monitoring breath or body fluids. Also, the level of humidity of gas samples taken from the ear is much less than from breath, which is typically saturated with humidity.

Brief Description of the Drawings

FIGS. 1 A- I B illustrate a foam ear plug configured in accordance with embodiments of the present invention.

FIG. 2 Illustrates a gas-absorbing capsule.

F G, 3 illustrates a block diagram of a trap - GC - DMS system.

FIG. 4 illustrates air sampled by pumping through, a trap,

FIG. 5 illustrates the trap of FIG. 4 releasing the sample, into the GC column by heating and the sample flows through the column.

FIG. 6 illustrates the GC column heated allowing the sample components to separate while flowing through the column and into the DMS filter where the sample is analyzed; the system may be cleaned with filters in an air .recirculation system.

FIGS. 7A -7B illustrates a MS ion filter used to separate different, analytes in a gas sample.

FIGS . 8A-8B show an example of an ionization source coupled to a DMS analyzer, FIG. 9 illustrates an example of an ear cleaning tool.

FIG. 10 illustrates an example of a behind the ear ¾TE^M) hearing aid instrument.

FIG. 1 1 illustrates an embodiment of the present invention implementing a BTE hearing aid instrument

FIG, 12 illustrates a diagram of the analysis of gasses collected from an ear, such as for medical analysis.

FIG. 13 illustrates a hearing aid configured in accordance with embodiments of the present invention. Dei a i 1 ed Descri p tion

Embodiments of the present invention are described herein with respect to a human ear, but may be applicable for utilization with an animal ear,

An embodiment for monitoring ear odor comprises wearing an odor absorbing ear plug at night and then taking the ear plug out in the morning and submitting it for analysis. An embodiment for monitoring ear odor comprises wearing s odor absorber ear plug and then taking the ear ping out for analysis, The ear plug may be worn at night or other convenient parts of the day. This could be a daily effort or weekly or monthly.

FIGS. 1 A-I B illustrate a typical foam ear ping that has been modified in accordance with embodiments of the present invention. The foam ear plug has a foam outer part 10 and a gas-absorbing capsule 20 inserted at the end that is inserted into the ear.

FIG, 2 illustrates further details of the gas-absorbing capsule 20, which may comprise a gas-impermeable layer 21. a membrane 22 on one end of the gas-absorbing capsule 20, which allows gasses to pass from an ear cavit into the interior of the gas-absorbing capsule 20. and a gas absorber material 23, which is contained in the interior of the gas-absorbing capsule 20. Another embodiment ma ot contain the membrane 22, as it may not be needed .

Examples of this gas absorbing material 23 are (but not limi ed to): graphite, graphitic materials, Tenax (a type of polymer fiber), glass fiber wool, metal wool, and glass or ceramic beads. Combinations or mixtures of these materials may also be used.

Examples of a gas-impermeable layer material are: glass (e.g., soda lime, borosiiieate, or other types), ceramics (e.g., alumina or other types), low-outgasing polymer materials such as teflon or polyimide, or metal (e.g., copper, aluminum, or other types). Materials that can withstand elevated temperatures and not degrade or outgas may be utilized. Materials that have no or very little inherent VOC signatures may also be utilized.

The gas membrane material 22 may be a polymer filter material, cloth filter material, a glass frit material, porous glass, metal or ceramic, or metal screen or mesh.

The gas-absorbing capsule may have a cap 24 on the membrane end that prevents gasses ^•from accumulating in the gas-absorbing capsule 20, for example when the capsule is stored or not in use. This cap 24 may be made out of an inherently low VOC signature material. The cap 24 may be removed before the ear plug 10 containing the capsule 20 is inserted into the ear to collect VOCs from the ear cavity. A process of collecting the VOC signature from an ear cavity using the gas absorbi ng ear plug 10 may be performed as follows. The cap 24, if implemented is removed from the gas- absorbing capsulelO, then the ear plug 10 is placed into the ear cavity with the membrane end 22 of the capsule, facing inside the ear canal, much like sound absorbing ear plugs arc worn. Thenar plug 10 is maintained in the ear cavity for a period of time (e.g., from 1 second to several hours), but overnight use may also be allowed. The ear plug 10 is then removed from the ear, and the the cap 24 may be placed back on to store the gas-absorbing capsule 20 for analysis of the absorbed gas signature at a later time. The gas-absorbing capsule 20 is then coupled to a gas analysis machine for characterizing the gas content of the ear (as further described with respect to FIGS. 3-8B) after the ear plug with the gas-absorbing capsule 20 is removed, if analysis is performed soon after removing the ear plug 10 from the ear, the cap 24 may not need to b placed on the capsule 20. The cap 24 is removed for analysis of the gas-absorbing capsule.

The gas signature is measured by releasing the absorbed gases from the gas absorbing material 23. The gas-absorbing capsule can be removed from the foam outer pari and placed in an instrument to release the gases that are trapped in the gas absorbing material 23 and the gases are analyzed in the instrument, The gases may be released by heating the capsule to temperatures ranging from .! Q0°C to 600°C, depending on what absorber material is used and what gases need to be analyzed. Means of doing this is known in the prior art.

Another embodiment is that the gas absorbing material 23 is removed from the capsule and the gas absorbing material 23 is placed in the gas analysis machine for measurement.

The analysis may be made by a local instrument (such as in. the home or a I the bedside), or an ear plug 10 .may be stored in a sealed vial for later analysis at a central facility. The ear plug 10 may be similar to the varieties used to cancel noise from loud equipment or used on plane flights. The time for wearing the ear plug may be as short as a few minutes or less, depending on the concentration of th odor that is needed for detection.

Referring to FIG. 9, another embodiment is to use the end of a "q-ttp" or other ear cleaning tool as a means of collecting an odor signature from the ear. This could be pan of the regular ear-cleaning regiment (e.g.. daily, weekly, etc.) or as needed, basis. This form of analysis is analogous to what is done at airport check points in which a swab is used to wip baggage and clothing for detecting explosives or narcotics residue. FIG. 9 shows an example of an ear cleaning, tool 30 configured for use in embodiments of the present invention. The ends 35 of the tool are sized such that it will clean the ear canal. The swab material ends 35 ma be made of fiber, foam, woven, or spun material, that can be used to swab the ear canal. The swab material 35 may then be placed in a gas analyzer such that the gas sample cat* be measured, similar as described for the gas absorber ear plugs.

Another embodiment for monitoring ear odor comprises taking a direct odor sample from the ear by retrieving air directly from the ear canal and. submitting it to VOC odor analyzer. This has an. added advantage in that humidity in. the ear will likely be close to that of the air in the local, environment. The VOC odor analyzer in this embodiment may be used, by an individual on a regular but intermittent basis (e.g., once a morning) or it may be worn by the individual on a continuous basis, such as part of a hearing aid instrument. Thus, the hear aid instrument itself can serve two purposes, one is to amplif sound into the ear and the other is to monitor VOC concentrations as a means of health management. This may be incorporated int hearing aids that are mounted, behind the ear ("BTE"), in the ear CITE"), in the ear canal, or as part of a Cochlear implant in which the unit that sits on. the ear stimulates the hearing implant and also can be used for monitoring ear odor.

PIG. 10 illustrates an example of a BTE hearing aid instrument. The tube 6.1 going into the ear 63 may also be collecting gases from the ear that are then analyzed, and measured by an electronic nose or gas sensor inside the hearing aid instrument part 62 that is located behind the ear 63.

Larger machines that cannot be mounted on the ear .may be mounted in. a pocket or worn. on a belt or other mounting procedure, and a tube is used to transfer gas samples from the ear to the gas analyzer that is mounted on the person. FIG. 1 .1 illustrates such an embodiment where the odor gas sensor 81 may be part of the hearing aid 63 or it may be an. instrument that is significantly larger but small enough to be held in the hand or worn in a pocket or placed, at. bedside. The hand-held part may be only the data analyzer 86, but .may also be a packaged combination of electronic odor sensor 81 combined with the data analyzer 86,

Embodiments of the present invention thus may incorporate a gas absorbing capsule- integrated into a hearing aid device such that gases are collected on an absorbing material in such a way that it does not interfere with the ^'function of the hearing aid. For a behind the ear hearing aid, the gas absorbing capsule may not be in the eat canal but in the hearing aid unit located behind the ear and gas is collected from the ear through the tube 82 that connects the behind the ea unit 81 to the ear canal For an in. the ear hearing aid, the gas absorbing capsule may be .integrated, with the in the ear unit. An example of this embodiment is shown in FIG. 1 , which illustrate a cross-section of a hearing aid that contains a ventilation channel 5 that is adjustable. See U.S. Patent No, 6.549.635, which is hereby incorporated by reference herein. The gas absorbing capsule 20 can be placed in the ventilation channel 5 of the hearing aid. For embodiments of the present invention, it is not required that the ventilation channel 5 have adjustable flow. An embodiment would be to have a gas permeable membrane 22 on both ends of the capsule 20 to allo w gas to pass through the ventilation channel 5. Another embodiment would be to have only the gas absorber material 23 in the ventilation channel 5. This i possible if the gas absorber material is a plug of material that does not require -an outer shell.

Another embodiment would be to have more than one ventilation channel n a hearing aid with at least one of the ventilation channels containing the gas absorbing capsule 20 or gas absorbing material 23.

Another embodiment would be to have a gas sensor placed in the ventilation channel 5. similar to how the gas absorbing capsule 20 is placed in the^■ventilation channel 5 of FIG, 13.

The result of the gas analysis may be presented to the patient or person whose ear odor Is being sampled, or it may be communicated to a central facility that i remote from the patient, or to a clinic or doctor who ma wish to monitor the person or patient. The results may be a survey of the odors present in the ear and their relative or absolute concentrations (odor signature), or it may be a measure of a small subset of odors that .may be important to one or more disease states (e.g., sueh as one that monitors glucose levels in the blood for controlling diabetes), or for monitoring drug metabolism in which case one may monitor drug levels directly o indirectly through metabolites of the drug indicating a reaction of the drug in the body. The odor signature or changes in the odor signature may be part of a medical diagnosis, or may be used as an indicator of change in the health state.

FIG. 12 illustrates a system for the analysis of gasses collected from, an ear in accordance with embodiments of the present invention. Odor samples are collected from the ear 63 by the electronic odor sensor 81, such as described with, respect to FIGS. 1-2 and 9-1 L Tube 82, pumps (not shown), valves (not shown) or other devices (not shown) that help move the odors from the ear 63 to the electronic odor sensor 81 may be used. Data from the electronic odor sensor 81 may be analyzed against a set of analysis iniormaiion 84 by a data analysis tool 86. The data analysis tool 86 may be physically integrated into the electronic odor sensor 8.1 in a single package. The set of analysis information 84 may include information from previous measurements and the medical information output 88 may be an indication of increasing or decreasing values as a function of time. The set of analysis information 84 may also include a set of previously determined gas concentration levels thai may indicate a health state or a non- healthy state of the patient. The medical information output 88 may he information that is sent to a central location for analysis or to a medical practitioner for analysis and consideration or it may be used to trigger an alarm (e.g., sound alarm, visual light alarm, vibration alarm, or combinations of these) that prompts action or response by one or more individuals. The medical information output 88 may be communicated by any number of means, through wired and/or wireless processes. The foregoing may be performed in a manner as similarly described in U.S. Published Patent Application No. 2007/0167832, which is hereby incorporated, by reference herein.

A hearing aid may also be used to monitor other human vital signs such as heart pulse rate, brain wave activity, and blood pressure. It may also be used to monitor the position of the head (whether a person is standing up or lying down) or where the person is at (which room of tSie house is the person). This may be useful for remote monitoring of elderly living alone or for individuals suffering from dementia.

The gas analyzer that is used for monitoring or sampling ear odor ma be one of many currently used for gas analysis, including but not limited to semiconducting oxide compound ga sensors, both o-type (e.g., SnQ_¾ TiCh, ZnQ, or combinations of these and other compounds) and p-type; micro-resonant oscillator gas sensors, such as the Applied Nanoteeh Holdings, Inc. methane (MS-!O) or hydrogen sensor (see, U.S. Published Patent Application No. 2010/0107735, which is hereby incorporated by reference herein); photo-acoustic sensors (see, U.S. Published Patent Application No, 2008/01210 IB, which is hereby incorporated by reference herein); light absorption sensors; electrochemical, sensors, including enzyme-based sensors (see, U.S. Patent. No. 7,399,400, which is hereby incorporated by reference herein); resistive type sensors, including chemresistive-type sensors; and trace chemical, sensors, which include ion mobility approaches, gas ehroniatograph approaches, micro-channel gas ehroniatograph approaches, microfluidics and mass spectrometer approaches, or combinations thereof

Ion mobility approaches may be one of several varieties, including time-of-flight ion mobility, differential Ion mobility, or F IMS, aspirator-type ion mobility, or combinations thereof. The ionization source that is used for creating ions is one or more of these trace chemical sensors, which may be based on radioact i ve isotopes or may be based on one of several non-radioactive gas analyzer approaches, including the approaches described in U.S. Patent

Application Serial ^'Numbers 61/583,288, 61/587,352, and 12/284,323, which are hereby incorporated by reference herein.

FIG. 3 illustrates a simpli fied block diagra of an electronic odor sensor 301 for sensing

VOCs that are collected as described with respect to FIGS. 1.-2 and 9- 12, in the system 301- 302, a gas chromaiograph ("GC") 304 may be coupled with a differential son mobility spectrometer ("DMS") 305, the combination also referred to as GC/DMS. Input gas 300 comes into the electronic odor sensor 301 through a port. In a configuration of the electronic odor sensor 30.1 , the input gas 300 is passed through a trap 303 that concentrates the ^'VOC analyf.es in the. gas. Then the concentrated gas is passed through a GC column 304, The GC column 304 is then eluted into the DMS 305. The DMS 305 is pari of a family of ion mobility spectrometers that is related to High-Field Asymmetric Waveform. Ion. Mobility Spectrometry ("FAIMS") (see, e.g., Roger Guevremont, "High-Field Asymmetric Waveform Ion Mobility Spectrometry," Canadian. J. of Anal. Sciences and Spectroscopy, Vol. 49(3), pp. 105-1 13, 2004, which is hereby incorporated by reference herein). Examples of tools that ma be used to monitor VOCs are gas chromatographs, gas chromatographs coupled to mass spectrometers, and gas chromatography coupled to ion mobility spectrometers. In some cases, the mass spectrometer and/or the ion mobility spectrometer ma be used independent of a gas ckromatograph, In some cases, the mass spectrometer may be coupled with an ion mobility spectrometer. In some cases, a gas chromaiograph may be coupled to both an ion mobility spectrometer and a mass spectrometer, either in series or in parallel.

FIGS, 4-6 illustrate an operation of the electronic odor sensor 301 in more detail, A first step is trap loading. The left side of the diagram in FIG. 4 shows the system drawing in the gas 300 into the sample port as shown by arrow 4 1. The gas 300 is pumped through the trap 303 where the analytes in the gas 30 are concentrated during several seconds of collection. A pump 402 may be used to help transport the gas 300 through the trap 303. Gas thai passe through the trap 303 may then be exhausted through a port 403.

Another embodiment i that the ga absorbing capsule ^'20 is used to replace the trap 303. Another embodiment is that the gas absorbing capsule 20 or the gas absorbing material

23 is used as part of the trap 303. Referring to FIG. 5, a next step involves releasing the analytes that are concentrated in the trap 303 into the GC column 304. This ma be performed by closin the flow of gas 300 shown by arrow 401 through the trap 303 from the sampling port and opening the valve to the gas in the recirculating loop as depicted by arrow 501. A three-way valve 502 may be activated to begi flow 501. A check valve 503 may be used to keep this gas flow from escaping from the sample port. Other alternative configurations may be used. When gas flow 501 starts to flow through the trap 303, the trap 303 may be heated to release the analytes into the GC column 304. Analytes are carried throug the GC column 304 at a low flow rate (see arrow 501. over the GC column 304). ^'The GC column 304 may separate components of the analytes while maybe adding a time dimension to the data, which enhances an ability to identify the chemicals of interest.

Referring to FIG. 6, the analytes are eluted from the GC column 304 into the main recirculation flow of the DMS part of the electronic odor sensor 301 (see arrows 601-602 near pressure transducer 603). This is where the ionization and analysis of the sample occurs. The trap 303 ma go through a cooling cycle at this time. Depending on the analyte(s) and the configuration of the electronic odor sensor 301 (e.g., type and length of GC column, etc.), the analytes may take approximately 1.0—1200 seconds to elute from the GC 304, but only spend a small fraction of a second passing through the DMS 305 because of the higher flow rate through the DMS and smaller distance travelled (e.g., 1-2 cm). Flow rates through the GC column. may be 1-5 seem (standard cubic centimeter per minute), and flow rates through the DMS may range from 100-1000 seem. The length of the GC column may be 0.01-20 meters. A shorter length GC column, made up of arrays of capillary tubes in parallel may be uti lized.

The VOC analyte molecules are ionized as they enter the DMS 305. One technique used to create gas ions is to place a radioactive source materia! 701 (either beta emitter or alpha emitter) next to the gas flow 601 and 602. Alternatively, an ion generator tha does not utilize radioactive sources may be utilized (see FIGS. 8A-8B).

The gas sample is separated by the DMS filter 305 to further improve the analyte identification. By carefully calibrating the tool for the chemicals of interest, the analyte concentrations to. the gas sample are known. Once the analytes and their concentrations have been identified, the data is further analyzed for the desired purpose, hi another analysis method, the .identification, details may be compared to a previously determined database of compounds and concentration ratios see with known disease conditions to determine disease status. Alternative analyses of compounds identified may be performed by pattern, recognition method such as principal component mapping, k-nearest neighbor classification, o neural network recognition. The anaSyte identification step may be alternatively bypassed and the system simply map disease conditions to the signal output of the DMS filter. This has an advantage of not requiring detailed calibration of the tool for specific chemical identifications, bat produces no intermediate information for verification of the biochemical identity of the targeted disease condition.

The DMS is essentially an ion filter operating in a gas environment The gas environment may be filtered and dried (de-humidified) air at near atmospheric pressure. Other gasses ma be used such as high parity nitrogen, argon or other noble gasses, A principle of operation of the DMS is illustrated in FIGS. 7A--7B, and as disclosed in U.S. Published Patent Application Nos. 2012/0160997 and 2010/0127167, whic are both hereby incorporated by reference herein.

As stated previously, DMS is one of a family of Ion Mobility Spectrometry ("IMS") tools that has several advantages compared to standard time-of-flight IM approaches. Mainly it provides a richer set of data and improves on the chemical selectivity while maintaining sensitivity. Gas chromatography coupled with differential mobility spectrometry (G ^'DMS) has a number of advantages,

• GC DMS has the sensitivity and fidelity to detect and measure a wide variety of compounds a very low concentration levels (ppb is common).

• GC/DMS can. be significantly miniaturized because it does not require a vacuum to operate.

• GC/DMS can be made low-cost compared to GC/mass spectrometry.

• GC/DMS tools typically require radioactive gas ion sources but disclosed herein is a non-radioactive gas ionization source that will significantly decrease the cost of ownership and administrative burden.

A physical principle of DMS is based upon the relationship of an. ion's velocity in gas being proportional to an applied electric field strength, or

where k !i ) is the ion mobility. ki(E) depends on the carrier gas pressure, composition and temperature as well, but those variables can be fixed by design. The DMS takes advantage of the non-constant and non-Hnear electric field dependence of the ion mobility. Referring to FIGS. 7A--7B, a scheme that a DMS employs places an asymmetric RF electric field in the ion drift regio 702, The electric field may be generated by voltages placed on electrodes 703 and 704 that contain the gas flow in the ion drift region 702 illustrated in the cross-section, view FIG, 7A. These electrodes may be 2-10 mm wide and 10-30 mm long in the direction of the air flow 705. The gap between the electrodes may be 0.1-1.0 mm. Two other non-conducting walls (not shown) may complete the form of the channel of the drift region 702. An electric waveform may be created by placing voltages on the electrodes 703 and 704, The waveform cycle may alternate between a high field, short pulse duration and a lower field, longer pulse dtrration of the opposite polari ty such that the total integrated area of a cycle is zero. The non-linear mobility results in ions having a net nonzero drift velocity in the y direction so they eventually strike the RF electrodes. The superposition of a weak DC electric field in the y direction cancels the RF induced net drift and. the ions then pass through the filter, where they are collected onto electrodes 706 {e.g., DC biased positive) and 707 (e.g., DC biased negative), and the ion current becomes the detected signal (e.g., as measured by high sensitive current meters 708 and 709). By sweeping the weak DC electric Held successive ion components pass through the ion filter and are selectively measured. Concepts of exemplary DMS are described in detail in. Kolakowski Β,ΙνΙ,, Meste Z„ "Review of applications of high- field asymmetric waveform ion mobility spectrometry (FAIMS) and differential mobility spectrometry (DMS)," Analyst 132 (9), pp. 842-64, September 2007; I. A, Buryakov, E. V, Kryiov, E.G. Nazarov, U.Kh. Rasulev, "A new method of separation of multi-atomic ions b mobility at atmospheric pressure using a Mgh-trequency amplitude- asymmetric strong electric field," International Journal of Mass Spectrometry and km. Process, Vol. 128, pp. 143- 148, 1993; and E. Krylov, E.G. Nazarov, R.A. Miller, B Tadjikov, and G.A, Eiceman, "Field Dependence of Mobilities for Gas-Phase-Protoiiated Monomers and Proton- Bound Dimers of Ketones Planar PPAIMS " I Phys Cliern. A 2002, Vol. 106, pp. 5437-5444, which are all incorporated, by reference herein.

Another electronic odor sensor embodiment is ion Mobility Spectrometry ("IMS"). IMS is similar to DMS with a difference. IMS essentially uses a time-of-fiight ('TGF") measurement to measure how fast a given ion is able to move through a -uniform, electric Held at a given pressure/atmosphere. D S does not rely on. a TOP, but instead uses the differences in mobility of different ions to detect only the ion as it passes through an ion filter.

Another electronic odor sensor embodiment is gas chroma ogniph mass spectrometry ("GC/MS"). GC MS systems are sensitive and capable of identifying the constituents of a large number of unique combinations of VOCs signatures to diagnose many different types of diseases. However, a drawback to this technology is in the lengthy operating times, cost, and size. In addition, GC/MS systems require vacuum pumps, which may limit miniamrization and increase power consumption. In contrast, DMS technology has advantages for portable applications and can -achieve the required sensitivity.

Another electronic odor sensor embodiment is a quartz raierobatance ("QBM"). Thi technology relies on the change in resonant frequency of a microniachined quartz beam when the molecules of a desired analyte adsorb onto it, thus changing the resonant mass. These beams are patterned with special coatings, such as metalloporphyrin complexes to selectively capture molecules of interest. To detect multiple analytes simultaneously, arrays of these sensors are used, making it more difficult to fabricate as well as implement for odor analysis, as this requires complex analysis algorithms, QMB technologies have some advantages for certain applications, but the sensitivities are insufficient compared to IMS, DMS, or GC/MS technologies, which may be necessar for many applications. The limit of detection for Q.BM is in the parts per million range and more recently into the hundreds of parts per billion range,

Another electronic odor sensor embodiment is colorimetric sensors. These sensors may be two-dimensional arrays of chemically active "spots." Each spot is sensitive to one type of chemical, which is made sensitive by impregnating a disposable cartridge with a chemically sensitive compound that changes color when bound to the analyte to be detected. The chemically sensitive compounds may be meialloporphyr is as well as other materials. The gas is flowed across the sensor, and the changes in color are detected by an optical scanner or camera system, which analyzes and quantifies the detection. These sensors have achieved only moderate success due to the lack of sensitivity and the limited number of spots on the sensor.

Another electronic odor sensor embodiment is conducting polymers. Conductive polymer-based ga sensors are a relatively mature technology and are based on the change in conductance of an organic polymer in the presence of selected ana!ytes. These conductive polymers may be pattern d in thin layers over electrodes, which are connected to electronics that sense a change in resistance of the material whe exposed to the desired analyte, Seensive Technologies Limited, a company in the United Kingdom started in 1995, has been developing a sensor platform referred to as the Bloodhound, which they claim can detect down to parts per million and parts per billion levels. The Bloodhound and similar electronic odor sensor approaches have more difficulty separating out specific anaiytes, since the sensors i the array are not uniquely sensitive to those compounds and will be confounded by cross-sensitivity to other anaiytes.

An alternative odor sensor embodiment is surface- acoustic wave ("SAW") analysis in which compounds are adsorbed onto a thermally controlled piezoelectric crystal. By altering the temperature of the crystal, or by applying a chemically absorptive coating, various compounds can. be .made to condense or adsorb on the surface of the crystal, thereby providing specificity, in order to simultaneously detect multiple anaiytes, the crystal is either swept across an. appropriate range of temperatures, which is slow, or is duplicated at .multiple temperatures, which increases the complexity and cost of the analyzer. The chemically absorptive coating approach limits single devices to detecting only compounds attracted b the coating, and specificity is controlled by the chemistry of the coating-compound interaction.

Claims

WHAT IS CLAIMED IS:

1. A system for identifying an odor produced within an ear cavity comprising:

an ear odor absorbing device suitable for collecting a gas emanating from the ear cavity, the gas containing a volatile organic compound, produced within the ear cavity; an electronic odor sensor suitable for sensing the volatile organic compound emanating from the ear odor absorbing device; and

means for coupling the ear odor absorbing device to the electronic odor sensor in a manner suitable for enabling the electronic odor sensor to sense the volatile organic compound emanating from the ear odor absorbing device.

2. The system as recited in claim I, further comprising electronics configured for

identifying the volatile organic compound sensed by the electronic odor sensor,

3. The system as recited in claim Ϊ , wherein the ear odor absorbing device comprises a gas absorbing material encased in a ca sule, which is integrated with a foam ear plug suitable for insertion into the ear cavity.

4. The system as recited in claim L wherein the ear odor absorbing device comprises a hearing aid modified so that it is suitable for collecting the gas emanating from the ear cavity while the hearing aid is worn by a user.

5. The system as recited in claim 1 , wherein the electronic odor sensor comprises a gas chromatograph coupled to a differential ion mobility spectrometer.

6. The system as recited in claim 5, wherein the electronic odor sensor further compri ses an ionizer,

7. The system as recited in claim 6, wherein the ionizer comprises a radioactive ion source,

8. The system as recited in claim 6, wherein the ionizer comprises a non-radioactive ion source.

9. The system as recited in claim 1 , wherein the ear odor absorbing device comprises an ear cleaning tool with gas absorbing material on an end of the ear cleaning tool siiitabie for absorbing the gas when the ear cleaning tool is inserted into the ear cavity.

10, A system for identifying an odor produced within an ear cavity comprising: a gas sampling system suitable for collecting a gas emanating from the ear cavity, the gas containing a volatile organic compound produced within the ear cavity;

an electronic odor sensor suitable for sensing the volatile organic compound emanating from the ear gas sampling system; and

means for coupling the ear odor sampling system, to the electronic odor sensor in a manner suitable for enabling the electronic odor sensor to sense the volatile organic compound emanating from the ear.

1 L The system as recited in claim 10, wherein the gas sampling system comprises a hearing aid suitable for collecting the gas emanating from ihe ear cavit while the hearing aid is worn by a user.

12. The system as recited in claim 10, further comprising electronics configured for

identifying the volatile organic compound sensed, by the electronic odor sensor.

13. The system as recited in claim 1 , wherein the ear odor sensor comprises a gas absorbing material encased in a capsule, which is integrated with a foam ear plug suitable tor insertion into the ear cavity.

14. The system as recited in claim 10, wherein the ear odor sensor comprises a hearing aid modified so that it is suitable for collecting the gas emanating from the ear cavity while the hearing aid is worn by a user.

15. The system as recited in claim 10, wherein the electronic odor sensor comprises a gas chromatograph coupled to a differential ion mobility spectrometer.

16. The system as recited in claim 15, wherein the electronic odor sensor further comprises an ionizer.

1 1. The system as recited in claim 16_:, wherein the ionizer comprises, a radioactive ion

source.

18. The system as recited in claim 16, wherein the ionizer comprises a non-radioactive ion source.

19. The system as recited, in claim 10, wherein the ear odor absorbing device comprises an ear cleaning too! with gas absorbing material on an end of the ear cleaning tool suitable for absorbing the gas when the ear cleaning tool is inserted into the ear cavity,