Patent Application
20090326418
This invention relates to medical devices and more particularly to such devices for applying a microphone to a body surface.
Body sounds are routinely used by physicians in the diagnosis of various disorders. A physician may place a stethoscope on a person's chest or back and monitor the person's breathing or heart sounds in order to detect adventitious (i.e. abnormal or unexpected) body sounds. The identification and classification of these adventitious sounds often provide important information about physiological abnormalities.
It is also known to affix a microphone to the body in order to record body sounds. The recorded sound signals may be amplified and filtered before being listened to by the physician. The recorded signals may also be analyzed by signal processing techniques.
It is also known to affix a plurality of microphones over a body surface in order to obtain a plurality of sound signals simultaneously from the body surface. Applicant's U.S. Pat. No. 6,887,208 discloses a system in which a plurality of microphones are affixed to a person's back or chest for recording respiratory tract sounds. This patent teaches embedding the microphones in a matrix that may be in the form of a vest or garment securely worn by the person during signal acquisition. Different sized or shaped matrixes may be used for differently sized individuals, for different sexes, ages, etc.
U.S. Pat. No. 6,394,967 discloses a system in which a plurality of microphones are affixed to a person's back or chest for recording respiratory tract sound. This patent teaches affixing the microphones to the body surface using tape or straps to prevent dislocation or movement during the data acquisition process.
Kompis et al. (Chest 120:4, 2001, 1309-1321) discloses affixing eight or sixteen microphones to an individual's chest for obtaining respiratory tract signals, but the method of attachment is not disclosed.
U.S. Pat. No. 4,777,961 discloses affixing a microphone to a body surface by means of suction. A microphone embedded in the wall of a dome shaped stethoscope head is formed from an elastic flexible material. The stethoscope head is squeezed by fingertip pressure as it is applied to the body surface. When the fingertip pressure is removed, the head expands slightly so as to create a partial vacuum in its interior so as to keep the head affixed to the body surface. The membrane of the microphone, however, is not pressed against the body surface.
U.S. Pat. No. 4,736,749 discloses a holder for a signal pick-up device, such as a microphone or electrode that is fixed to the body surface by vacuum. The holder has a chamber that is evacuated by an external source of negative pressure. When the chamber is evacuated, the holder is held firmly to the skin and the signal-pick up device is pressed to the skin inside the chamber.
U.S. Pat. No. 6,790,183 discloses embedding a plurality of microphones within a single structure referred to as a “cassette”. The cassette includes a core preferably made from foam, for supporting the microphones. Recesses formed in the foam core receive the microphones so that the microphones are flush with the upper surface of the core. The cassette is positioned on a hospital bed between the mattress and a patient and the patient lies on the cassette with the microphones positioned at a location of interest to for the recording of body sounds.
U.S. Pat. No. 7,011,087 discloses a mat that is placed beneath a lying patient. The mat contains measuring means to measure airway vibrations of the patient.
In its first aspect, the present invention provides a microphone matrix for recording body sounds. The microphone matrix of the invention comprises a housing having a surface with a plurality of recesses. A microphone assembly is suspended in each recess by means of one or more elastic elements. The elastic elements position the microphone assembly in a position in which at least a portion of the microphone assembly protrudes beyond the surface of the housing. When a force is applied to the microphone assembly towards the housing, the microphone assembly moves against the elasticity of the elastic elements towards the interior of the housing. Thus, when a body surface, such as a person's back is applied to the matrix, the microphone assemblies are pressed onto the body surface to create good acoustic coupling between the body surface and the microphone assembly.
The housing and the elastic elements are preferably formed from an acoustically dampening material. A spacer in each microphone assembly is preferably formed from an acoustically conducting material. Thus vibrations received in the spacer are conducted to the microphone while vibrations in the housing or the projection are essentially not conducted to the microphone. Cross-talk between the microphones is also reduced.
In one embodiment of the invention, the microphone matrix comprises a plurality of microphone units joined together by a flexible frame. In another embodiment, the microphone matrix has a housing contoured to receive a body portion from which body sounds are to be recorded. For example, the surface may be contoured so as to receive the back and neck region of the body when respiratory sounds are to be detected. A microphone is suspended in each of a plurality of recesses in the surface by means of two or more elastic elements, as explained above.
In its second aspect, the invention provides a system for recording and/or analyzing body sound signals. The system of the invention includes one or more microphone matrices of the invention. Each microphone in the matrix produces an analog voltage signal indicative of pressure waves arriving at that microphone. In use, the matrix is placed on a surface such as an examination table or hospital bed. Since the microphones in the microphone matrix are elastically biased to protrude beyond the upper surface of the matrix housing, with a body surface applied to the surface of the housing, at least some of the weight of the individual is transferred to the microphones. In this way, the microphones are firmly applied to the body surface without the need of an attachment system, such as straps, tape, or vacuum. Respiratory tract sounds, or other body sounds at the body surface are detected by the microphones. The system of the invention also includes signal processing circuiting for processing signals obtained by the microphones, as required in any application. For example, the electronic circuitry for processing acoustic signals obtained from two or more microphones, as disclosed in U.S. Pat. No. 6,394,967 to Murphy, Kompis et al. supra, and in Applicant's U.S. Pat. No. 6,887,208 may be used in the system of the invention.
In its third aspect, the invention provides a method for recording body sounds. In accordance with this aspect of the invention, a body surface is applied to a microphone matrix of the invention and sounds detected by the microphones are recorded and/or analyzed.
This, in its first aspect, the invention provides a microphone matrix for recording body sounds, comprising:
In its second aspect, the invention provides a method for recording body sounds comprising:
In its third aspect, the invention provides a system for analyzing body sounds comprising:
The invention also provides a microphone assembly for use in the microphone matrix of the invention.
In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
The hinge in the projection 6 formed by the groove 14 and is biased in a straight position, as shown in
The housing 2 and the projection 6 are formed from an acoustically dampening material. The spacer 22 is formed from an acoustically conducting material. Thus vibrations received in the dome portion 24 of the spacer 22 are conducted to the microphone 20. Vibrations received in the housing 2 or the projection 6 are essentially not conducted to the microphone 20. Thus, vibrations originating in the body part 28 are received in the dome portion 24 and conducted to the microphone 20.
The frame 42 is provided with one or more recesses 48. A microphone 42 is disposed in each of the recesses 50. A microphone 44, for example, the microphone 44a is suspended in its respective recess 48a by means of two or more elastic cords 52, so that the microphone 44a is not in direct contact with the frame 42. By not placing the microphones 42 in direct contact with the frame 42, any extraneous vibrations in the frame 42 are essentially not picked up by the microphones 2.
Each of the microphones 44 is provided with a spacer 43 made from an acoustically conducting material. The microphones 44 are disposed in the recesses 48 so that the spacer 43 of each microphone protrudes above the upper surface 46 of the frame 42, as shown in
As explained above, the microphones in the microphone matrix 61 are elastically biased to protrude above the upper surface of the matrix housing. Thus, with the back of the individual 64 properly positioned on the upper surface of the housing of the microphone matrix 61, at least some of the weight of the individual 64 is transferred to the upper surface of the support housing. In this way, the microphones are firmly applied to the individual's back without the need of an attachment system, such as straps, tape, or vacuum. Since the spacer of the microphone assembly is preferably made from an acoustically conducting material, respiratory tract sounds, or other body sounds originating in the thorax are detected by the microphones in the matrix 61. Extraneous vibrations originating outside the body such as vibrations due to movement of the individual or vibrations conducted through the surface 62, for example, due to the movement of other people or due to the operation of equipment in the vicinity of the surface 62, are essentially not detected by the microphones in the matrix since the microphone assemblies are connected to the housing or frame by a material that is not acoustically conducting.
The ability to apply the microphone matrix of the invention to a body region without the need for any fastening devices such as straps or vacuum, allows the microphone matrix to be applied to a body over a prolonged period of time. The system of the invention may thus be used for continuously monitoring and recording body sounds over a substantially unlimited period of time. In particular, the system may be used to continuously monitor body sounds such as reparatory tract sounds or cardiac sounds in an individual in an intensive care unit.
A cable 68 is connected to signal processing circuiting 70 for processing signals obtained by the microphones 44, as required in any application. The wires in the cable 68 provide each microphone 44 with a voltage that may be used for activating a preamplifier in the microphone, and also serve for transmitting a voltage signal to recording or analyzing circuitry when wires connected to a microphone are connected at another end to recording or analyzing circuitry, as described below. If the microphones 44 are wireless, the electronic circuitry 70 includes a receiver for receiving signals from the microphone transmitters.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IL2007/000985 | 8/7/2007 | WO | 00 | 6/30/2009 |
| Number | Date | Country | |
|---|---|---|---|
| 60835892 | Aug 2006 | US |
