PALPATION METHODS
United States Patent 3742935
A method for simultaneous palpation by a plurality of individuals in which the physical displacement of a sensor may be amplified and simultaneously reproduced at a plurality of remote locations. The physical displacement signal from a transducer in pressural engagement with the patient's skin is amplified and utilized to drive a palpation platform which is tactually engaged by the physician to aid in the diagnosis. Additional palpation platforms may be slaved to the physician' s unit and the slave units utilized for instruction purposes. The palpation platform may include a speaker cone substantially filled with a solid material and covered by a material approximating human skin. The method may take the form of a physician's diagnostic aid, or as a medical teaching aid. Use, including self-instruction, of the equipment for speech therapy is also disclosed.
US Patent References:
Tactual interpretation of vibrations
Jones - October 1929 - 1733605
/2058796.html
Hogle - October 1936 - 2058796
Loud-speaker
Henrich et al. - September 1942 - 2297218
Person alerting device
Powlison - January 1952 - 2582277
Apparatus for use in stethoscopy
Howell - November 1963 - 3110770
Tactual interpretation of vibrations
Jones - October 1929 - 1733605
/2058796.html
Hogle - October 1936 - 2058796
Loud-speaker
Henrich et al. - September 1942 - 2297218
Person alerting device
Powlison - January 1952 - 2582277
Apparatus for use in stethoscopy
Howell - November 1963 - 3110770
Inventors:
Baessler, Lee R. (Manhattan Beach, CA)
Gerard, James G. (La Palma, CA)
Glassner, Harvey F. (Los Angeles, CA)
Waters, James T. (Bethesda, MD)
Gerard, James G. (La Palma, CA)
Glassner, Harvey F. (Los Angeles, CA)
Waters, James T. (Bethesda, MD)
Application Number:
05/108720
Publication Date:
07/03/1973
Filing Date:
01/22/1971
View Patent Images:
Export Citation:
Assignee:
Humetrics Corporation (Los Angeles, CA)
Primary Class:
Other Classes:
434/275
International Classes:
A61B7/00; A61B5/10; A61B5/02
Field of Search:
128/2.5P,2.5S,2.5R,2K,2S,2Z 340/407,384 179/121C,181F,17E,1ST,1B 181/31B 35/35A,35C
US Patent References:
| 3187832 | Loudspeaker assembly | June 1965 | Broadley | |
| 3247324 | Acoustic and electronic stethoscope | April 1966 | Cefaly et al. | |
| 3283181 | Electromechanical transducer | November 1966 | Johanson | |
| 3285364 | Loudspeaker construction | November 1966 | Cohen | |
| 3378639 | Instruction apparatus for classrooms | April 1968 | Dufendach et al. | |
| 3453749 | TEACHING BY SOUND APPLICATION | July 1969 | Snedeker, Jr. |
Primary Examiner:
Howell, Kyle L.
Parent Case Data:
RELATED APPLICATIONS
This application is a continuation-in-part application of application Ser. No. 862,653 entitled "Palpation Method and Apparatus," filed Oct. 1, 1969, now abandoned and assigned to the assignee of the present invention.
Claims:
We claim
1. A method of teaching speech to students with hearing defects including the steps of:
2. The method of claim 1 wherein the signal is generated responsively to a recording.
3. The method of claim 1 wherein the signal is generated responsively to a transducer in pressural engagement with the throat of an instructor.
4. The method of claim 1 including the further steps of generating a second signal related in amplitude and frequency to the speech of the student;
5. A method of examining the physical displacement of a patient's skin due to subcutaneous cardiovascular displacement comprising the steps of:
6. The method of claim 5 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
7. A method of teaching the art of palpation to a student comprising the steps of:
8. The method of claim 7 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
9. The method of claim 7 including the step of simultaneously modifying the degree of amplification of the generated electrical signal applied to each of the palpation platforms.
10. A method of examining the physical displacement of a patient's skin comprising the steps of:
11. The method of claim 10 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
12. The method of claim 10 including the steps of applying the amplified signal to a plurality of additional palpation platforms and tactually sensing the physical displacement of the additional palpation platforms.
13. The method of claim 12 including the step of simultaneously controlling the degree of amplification of the signal applied to all of the additional palpation platforms.
14. A method of examining subcutaneous cardiovascular displacement comprising the steps of:
15. The method of claim 14 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
16. The method of claim 14 wherein the signal generated is electrical and is related in amplitude to subcutaneous cardiovascular displacement.
1. A method of teaching speech to students with hearing defects including the steps of:
2. The method of claim 1 wherein the signal is generated responsively to a recording.
3. The method of claim 1 wherein the signal is generated responsively to a transducer in pressural engagement with the throat of an instructor.
4. The method of claim 1 including the further steps of generating a second signal related in amplitude and frequency to the speech of the student;
5. A method of examining the physical displacement of a patient's skin due to subcutaneous cardiovascular displacement comprising the steps of:
6. The method of claim 5 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
7. A method of teaching the art of palpation to a student comprising the steps of:
8. The method of claim 7 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
9. The method of claim 7 including the step of simultaneously modifying the degree of amplification of the generated electrical signal applied to each of the palpation platforms.
10. A method of examining the physical displacement of a patient's skin comprising the steps of:
11. The method of claim 10 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
12. The method of claim 10 including the steps of applying the amplified signal to a plurality of additional palpation platforms and tactually sensing the physical displacement of the additional palpation platforms.
13. The method of claim 12 including the step of simultaneously controlling the degree of amplification of the signal applied to all of the additional palpation platforms.
14. A method of examining subcutaneous cardiovascular displacement comprising the steps of:
15. The method of claim 14 wherein the amplification of the generated signal includes the amplification of frequency components in the range between about 0.05 Hz and about 35 Hz.
16. The method of claim 14 wherein the signal generated is electrical and is related in amplitude to subcutaneous cardiovascular displacement.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to the art of palpation and more specifically to the method for diagnostic and instructional aid in the art.
Palpation is the application of the hand or fingers to the surface of the body as a means of physically diagnosing the state of the structures beneath the skin. The act of palpation is of great significance, for example, in the determination of the integrity of the cardiovascular system. In such an examination, the pressure phenomenon of blood vessels and vibration or thrills of the precordium, when properly interpreted via palpation, is a significant aid to the physician in his diagnosis.
It is, of course, a physical impossibility for a group of physicians to simultaneously physically examine a specific point on a given patient e.g., neck pulsations and chest vibrations. Since the palpations are by their very nature transitory, it is difficult to determine whether or not the diagnosis of different doctors is based on the same physical stimuli.
This problem of identifying the stimuli upon which a diagnosis is based is particularly acute in teaching the art of palpation to medical students during hospital rounds or at teaching or consultation sessions. While medical students are generally instructed in the art of palpation at these bedside teaching sessions, the instructor may experience difficulty in determining whether or not the student is palpating the desired location on the patient and whether or not the student is palpating with the required finger pressure. In addition, some pulsations are of short duration and small amplitude, thereby increasing the difficulty in determining whether or not the student is, in fact, receiving the physical stimuli.
A further problem in the recognition of pulsations of short duration and/or small amplitude exists in the instruction of patients with hearing defects. It is a practice, for example, in teaching the deaf to speak, for the student to place the fingers of one hand on the throat or cheek of the instructor and the fingers of the other hand in the corresponding location on his own body. The student then attempts to reproduce the tactile sensations produced by the instructor in voicing certain sounds.
It is, accordingly, an object of the present invention to provide a novel palpation method.
It is another object of the present invention to obviate the aforementioned diagnostic difficulties and to provide a method by which a plurality of physicians may simultaneously palpate a given area of the patient.
It is another object of the present invention to provide a novel method by which short duration and small amplitude pressure phenomenon and vibrations may be amplified to increase the facility of detection and evaluation by a physician.
It is still another object of the present invention to provide a novel method by which an instructor may properly position a detector on the patient and monitor the physical stimuli simultaneously received by a plurality of students.
A further object of the present invention is to provide a novel method for teaching speech to people with defective hearing and/or speech impediments.
A still further object of the present invention is to provide a novel method by which a number of persons with defective hearing may simultaneously be taught by a single instructor.
Yet a further object of the present invention is to provide a novel method for self-instruction in speech therapy.
These and other objects and advantages of the present invention will be readily apparent to one skilled in the art to hich the invention pertains from a perusal of the appended claims and the following detailed description when read in conjunction with the appended drawings.
THE DRAWINGS
Reference may now be had to the drawings in which:
FIG. 1 is a block diagram of the present invention as adapted for monitoring the cardiovascular palpation of a patient;
FIG. 2 is a schematic circuit diagram of the block diagram of FIG. 1;
FIG. 3 is a view in elevation of the master unit of FIG. 1 partially broken away to illustrate the construction of the movable palpation platform;
FIG. 4 is a pictorial view of the present invention as adapted for teaching speech; and,
FIG. 5 is a block diagram of the present invention as a self-teaching device.
THE DETAILED DESCRIPTION
Referring now to FIG. 1 of the drawings, a transducer 10 is shown in pressural engagement with the skin 12 of a patient. The transducer may be directly connected through an amplifier 14 to a master unit or palpation platform 16. The master unit 16 may contain controls for the amplifier 14 whereby the response of the master unit to the cardiovascular or other displacement sensed by the transducer 10 may be adjusted. The amplifier 14 may also be connected to a plurality of slave units 18 through suitable power amplifiers (not shown).
In operation as a device for monitoring the cardiovascular displacements beneath the skin 12 of the patient, the arterial or venus pulses or motions of the heart are sensed by the transducer 10 and then amplified to drive the palpation platform of the master unit 16. The palpation platform, of course, may be a mechanical replica of the surface of the body and the movement thereof reflects the cardiovascular displacement sensed by the transducer 10. Adjustment of the amplifier 14 in a conventional manner will also control the amplitude of the signals applied to the slave units 18 and thus the response of the palpation platforms contained therein to the cardiovascular displacement of the patient sensed by the transducer 10.
In this manner, an instructor may personally place the transducer 10 on the skin of the patient, thereby obviating the difficulty as to ascertaining whether or not the student is palpating the desired location of the patient with the required finger pressure. Once the master unit has been adjusted by the instructor for maximum performance, a plurality of students may simultaneously observe the cardiovascular displacement sensed by the transducer 10 by pressural engagement with the palpation platform of the slave units 18.
A circuit of the block diagram of FIG. 1 is shown schematically in FIG. 2 wherein the transducer of FIG. 1 comprises a pulsewave microphone 20. The microphone 20 may be conventional in construction and operation and may be, for example, of the type manufactured by Hewlett-Packard as part of a pulsewave Kit No. 21051-D. The reference microphone has a 3 db frequency response from 0.03 to 40 hertz and a sensitivity of 25 mV per mm of water. Other types of transducers may be utilized and may vary in sensitivity and configuration as desired to accommodate the physical area of the subject from which the palpations are to be sensed.
The output signal from the microphone 20 is fed through a coupling capacitor 22 to one input terminal 24 of an operational amplifier 26. The input terminal 24 is separated from ground potential by a resistor 28 as is the second input terminal 30 by a resistor 32. The output terminal 34 of the amplifier 26 is also separated from ground potential by a resistor 36 and is connected to the second input terminal 30 thereof by way of a capacitor 38 and a resistor 40 in parallel. The input terminal 30 is also connected through a resistor 40 in parallel. The input terminal 30 is also connected through a resistor 42 to the slide wire contact of a potentiometer comprising resistors 44, 46 and 48 to provide a voltage offset adjustment for the operational amplifier 26.
The output signal of the amplifier 26 thus appears across the resistor 36 which may also be provided with a slide wire contact or variable pick-off for service as a gain control potentiometer. The signal thus picked off the resistor 36 is fed through a coupling capacitor 50 and a resistor 52 to one input terminal 54 of a second operational amplifier 56 whose other input terminal 58 is connected to ground by way of an offset current compensating resistor 60.
The output signal from the amplifier 56 is directly connected to one input terminal 62 of a third operational amplifier 64 whose other input terminal 66 is open-circuited. The output terminal 68 of the amplifier 64 may be directly connected to the input terminal 54 of the amplifier 56 by way of a resistor 70 and capacitor 72 in parallel circuit. The input terminal 54 may also be connected through a resistor 74 to the slide wire or variable contact of a potentiometer comprising resistors 76, 78 and 80 to provide a voltage offset adjustment.
The output terminal 68 of the amplifier 64 may be directly connected to the speaker coil 82 of the high fidelity, low frequency response speaker which comprises the palpation platform of the master unit 16 of the block diagram of FIG. 1. The speaker desirably has a very good low frequency response from direct current to 100 Hz and may, by way of example, be Monarch Model SP-50X having a frequency response from d.c. to over 10 KHz, although any DC displacement transducer may be suitable.
In operation, the signal derived from the microphone 20 on pressural engagement with the skin of the patient is coupled through the capacitor 22 to the operational amplifier 26, and the output signal therefrom is fed back to the other input terminal 30 thereof and is coupled to the input terminal 54 of the amplifier 56 which acts, in conjunction with amplifier 64, as a single operational amplifier. The output signal of the operational amplifier comprising amplifiers 56 and 64 is fed back through capacitor 72 and resistor 70 to the input terminal 54 of the amplifier 56.
The adjustment of the sliding contact of the potentiometer resistor 46 enables a voltage offset adjustment for the operational amplifier which might occur due to a mismatch in the transistors in the operational amplifier. A zero-volt steady-state is, of course, desired.
As earlier stated, the potentiometer 36 provides a gain adjustment at the input of the operational amplifier which comprises the amplifiers 56 and 64, and the output signal from terminal 68 is fed directly to the speaker coil of the palpation platform of the master unit 16 of FIG. 1.
By way of example the various circuit components of the circuit of FIG. 2 utilized in conjunction with plus 12 and minus 12 volt power supplies are as follows:
Operational Amplifier 26 ZEL 134 Operational Amplifier 56 ZEL 1 Operational Amplifier 64 Philbrick 2001 Capacitor 22 5 microfarads Capacitor 38 0.047 microfarads Capacitor 50 10 microfarads Capacitor 72 100 picofarads Resistor 28 4.7 M ohms Resistor 32 2.2 K ohms Resistor 36 25 K ohms Resistor 40 24 K ohms Resistors 42, 44, 48, 76 and 80 47 K ohms Resistor 46 25 K ohms Resistor 52 2.2 M ohms Resistor 60 1.8 M ohms Resistors 70 & 74 10 M ohms Resistor 78 25 K ohms
A preferred embodiment of the palpation platform of the master unit 16 of FIG. 1 is illustrated in FIG. 3 wherein a styrofoam block 84 is cemented to the speaker cone 86 for movement therewith. The speaker 88 is desirably mounted with respect to the enclosure 90 such that the plane of the exposed surface of the styrofoam filled cone is parallel to the plane of the enclosure. The exposed styrofoam and the surrounding enclosure may be covered by material having the color and texture of human flesh. A vinyl has been found suitable for this purpose although other materials may be satisfactory. The speaker may be horizontally or vertically orientated as desired for a particular adaptation
Referring now to FIG. 4, the present invention also has great utility in teaching speech to persons having hearing defects. As schematically illustrated, a transducer such as a conventional throat microphone 100 may be secured in an appropriate manner to the throat of an instructor. The output signal from the microphone 100 is amplified in an amplifier 102 such as that illustrated in FIG. 2 and the amplified signal utilized to drive a plurality of palpation platforms 104. The palpation platform may be of the type illustrated, for example, in FIG. 3.
In operation, a student 108 with a hearing defect may place the fingers 110 of one hand on the surface 106 of the palpation platform 104 to sense the physical displacement of the instructor's throat as a specific sound is made. The fingers 112 of the other hand of the student 108 may be placed in a position on his own throat corresponding to the position of the microphone 100 on the throat of the instructor. The student is thus able to sequentially sense and thus compare the physical displacement of the instructor's throat when speaking and the physical displacement of his own throat in attempting to reproduce the sound.
In the self-teaching embodiment illustrated in FIG. 5, the instructor of FIG. 4 has been replaced by a suitable source 114 of the desired speech responsive signals. The source or simulator 114 may be, for example, of the magnetic tape or wire type. The output signal from the simulator 114 is amplified in an amplifier 116 and applied to a palpation platform 118 and to a visual display 120.
Also applied to the visual display 120 is the output signal from a throat microphone or other suitable transducer 122 attached to the throat, or cheek, as appropriate, of the student. The output signal from the transducer 122 may also be applied to a second palpation platform 124.
The display 120 may be any suitable conventional display for illustrating the two electrical signals for visual comparison purposes. The Model EI 100 from Masden Electronics at 2432 Grand Concourse, New York, N.Y. 10458 is exemplary of this type of display.
In operation, the signal from the simulator 114 may be simultaneously viewed and tactilely sensed by the student through the fingers of one hand. In attempting to reproduce the sound, the student can simultaneously view and tactilely sense the electrical signal from the microphone 122 positioned on his throat through the fingers of his other hand. The student may thus effect both a tactile and a visual comparison of the desired sound and his attempted reproduction thereof.
ADVANTAGES AND SCOPE OF THE INVENTION
While preferred embodiments have been illustrated and described in the foregoing specification, the substitution of components may readily be accomplished by one skilled in the art to which the invention pertains. For example, the electrical signals may be replaced by fluid pressure signals. The transducer may be varied in configuration and in method of operation, e.g., electromagnetic, electrostatic, pneumatic, hydrostatic, sonic, etc., depending on the configuration of the body surface and the part of the body to be sensed.
As a classroom or clinical instruction aid, several units may be slaved to a single transducer and a specific sound or cardiovascular movement simultaneously displayed to a plurality of students. By means of a master unit, the instructor may adjust the placement and sensitivity of the transducer to maximize identification.
As a self-teaching aid, a selected signal may be continuously reproduced for identification and is of great value to both medical students and speech students with hearing defects.
As a diagnostic aid, the increased sensitivity which results from amplification may be utilized to detect and identify palpations which may otherwise be overlooked.
It is, therefore, intended that the scope of the present invention be limited, not by the specific embodiments disclosed, but solely by the language of the appended claims when accorded a full range of equivalents.
The present invention relates to the art of palpation and more specifically to the method for diagnostic and instructional aid in the art.
Palpation is the application of the hand or fingers to the surface of the body as a means of physically diagnosing the state of the structures beneath the skin. The act of palpation is of great significance, for example, in the determination of the integrity of the cardiovascular system. In such an examination, the pressure phenomenon of blood vessels and vibration or thrills of the precordium, when properly interpreted via palpation, is a significant aid to the physician in his diagnosis.
It is, of course, a physical impossibility for a group of physicians to simultaneously physically examine a specific point on a given patient e.g., neck pulsations and chest vibrations. Since the palpations are by their very nature transitory, it is difficult to determine whether or not the diagnosis of different doctors is based on the same physical stimuli.
This problem of identifying the stimuli upon which a diagnosis is based is particularly acute in teaching the art of palpation to medical students during hospital rounds or at teaching or consultation sessions. While medical students are generally instructed in the art of palpation at these bedside teaching sessions, the instructor may experience difficulty in determining whether or not the student is palpating the desired location on the patient and whether or not the student is palpating with the required finger pressure. In addition, some pulsations are of short duration and small amplitude, thereby increasing the difficulty in determining whether or not the student is, in fact, receiving the physical stimuli.
A further problem in the recognition of pulsations of short duration and/or small amplitude exists in the instruction of patients with hearing defects. It is a practice, for example, in teaching the deaf to speak, for the student to place the fingers of one hand on the throat or cheek of the instructor and the fingers of the other hand in the corresponding location on his own body. The student then attempts to reproduce the tactile sensations produced by the instructor in voicing certain sounds.
It is, accordingly, an object of the present invention to provide a novel palpation method.
It is another object of the present invention to obviate the aforementioned diagnostic difficulties and to provide a method by which a plurality of physicians may simultaneously palpate a given area of the patient.
It is another object of the present invention to provide a novel method by which short duration and small amplitude pressure phenomenon and vibrations may be amplified to increase the facility of detection and evaluation by a physician.
It is still another object of the present invention to provide a novel method by which an instructor may properly position a detector on the patient and monitor the physical stimuli simultaneously received by a plurality of students.
A further object of the present invention is to provide a novel method for teaching speech to people with defective hearing and/or speech impediments.
A still further object of the present invention is to provide a novel method by which a number of persons with defective hearing may simultaneously be taught by a single instructor.
Yet a further object of the present invention is to provide a novel method for self-instruction in speech therapy.
These and other objects and advantages of the present invention will be readily apparent to one skilled in the art to hich the invention pertains from a perusal of the appended claims and the following detailed description when read in conjunction with the appended drawings.
THE DRAWINGS
Reference may now be had to the drawings in which:
FIG. 1 is a block diagram of the present invention as adapted for monitoring the cardiovascular palpation of a patient;
FIG. 2 is a schematic circuit diagram of the block diagram of FIG. 1;
FIG. 3 is a view in elevation of the master unit of FIG. 1 partially broken away to illustrate the construction of the movable palpation platform;
FIG. 4 is a pictorial view of the present invention as adapted for teaching speech; and,
FIG. 5 is a block diagram of the present invention as a self-teaching device.
THE DETAILED DESCRIPTION
Referring now to FIG. 1 of the drawings, a transducer 10 is shown in pressural engagement with the skin 12 of a patient. The transducer may be directly connected through an amplifier 14 to a master unit or palpation platform 16. The master unit 16 may contain controls for the amplifier 14 whereby the response of the master unit to the cardiovascular or other displacement sensed by the transducer 10 may be adjusted. The amplifier 14 may also be connected to a plurality of slave units 18 through suitable power amplifiers (not shown).
In operation as a device for monitoring the cardiovascular displacements beneath the skin 12 of the patient, the arterial or venus pulses or motions of the heart are sensed by the transducer 10 and then amplified to drive the palpation platform of the master unit 16. The palpation platform, of course, may be a mechanical replica of the surface of the body and the movement thereof reflects the cardiovascular displacement sensed by the transducer 10. Adjustment of the amplifier 14 in a conventional manner will also control the amplitude of the signals applied to the slave units 18 and thus the response of the palpation platforms contained therein to the cardiovascular displacement of the patient sensed by the transducer 10.
In this manner, an instructor may personally place the transducer 10 on the skin of the patient, thereby obviating the difficulty as to ascertaining whether or not the student is palpating the desired location of the patient with the required finger pressure. Once the master unit has been adjusted by the instructor for maximum performance, a plurality of students may simultaneously observe the cardiovascular displacement sensed by the transducer 10 by pressural engagement with the palpation platform of the slave units 18.
A circuit of the block diagram of FIG. 1 is shown schematically in FIG. 2 wherein the transducer of FIG. 1 comprises a pulsewave microphone 20. The microphone 20 may be conventional in construction and operation and may be, for example, of the type manufactured by Hewlett-Packard as part of a pulsewave Kit No. 21051-D. The reference microphone has a 3 db frequency response from 0.03 to 40 hertz and a sensitivity of 25 mV per mm of water. Other types of transducers may be utilized and may vary in sensitivity and configuration as desired to accommodate the physical area of the subject from which the palpations are to be sensed.
The output signal from the microphone 20 is fed through a coupling capacitor 22 to one input terminal 24 of an operational amplifier 26. The input terminal 24 is separated from ground potential by a resistor 28 as is the second input terminal 30 by a resistor 32. The output terminal 34 of the amplifier 26 is also separated from ground potential by a resistor 36 and is connected to the second input terminal 30 thereof by way of a capacitor 38 and a resistor 40 in parallel. The input terminal 30 is also connected through a resistor 40 in parallel. The input terminal 30 is also connected through a resistor 42 to the slide wire contact of a potentiometer comprising resistors 44, 46 and 48 to provide a voltage offset adjustment for the operational amplifier 26.
The output signal of the amplifier 26 thus appears across the resistor 36 which may also be provided with a slide wire contact or variable pick-off for service as a gain control potentiometer. The signal thus picked off the resistor 36 is fed through a coupling capacitor 50 and a resistor 52 to one input terminal 54 of a second operational amplifier 56 whose other input terminal 58 is connected to ground by way of an offset current compensating resistor 60.
The output signal from the amplifier 56 is directly connected to one input terminal 62 of a third operational amplifier 64 whose other input terminal 66 is open-circuited. The output terminal 68 of the amplifier 64 may be directly connected to the input terminal 54 of the amplifier 56 by way of a resistor 70 and capacitor 72 in parallel circuit. The input terminal 54 may also be connected through a resistor 74 to the slide wire or variable contact of a potentiometer comprising resistors 76, 78 and 80 to provide a voltage offset adjustment.
The output terminal 68 of the amplifier 64 may be directly connected to the speaker coil 82 of the high fidelity, low frequency response speaker which comprises the palpation platform of the master unit 16 of the block diagram of FIG. 1. The speaker desirably has a very good low frequency response from direct current to 100 Hz and may, by way of example, be Monarch Model SP-50X having a frequency response from d.c. to over 10 KHz, although any DC displacement transducer may be suitable.
In operation, the signal derived from the microphone 20 on pressural engagement with the skin of the patient is coupled through the capacitor 22 to the operational amplifier 26, and the output signal therefrom is fed back to the other input terminal 30 thereof and is coupled to the input terminal 54 of the amplifier 56 which acts, in conjunction with amplifier 64, as a single operational amplifier. The output signal of the operational amplifier comprising amplifiers 56 and 64 is fed back through capacitor 72 and resistor 70 to the input terminal 54 of the amplifier 56.
The adjustment of the sliding contact of the potentiometer resistor 46 enables a voltage offset adjustment for the operational amplifier which might occur due to a mismatch in the transistors in the operational amplifier. A zero-volt steady-state is, of course, desired.
As earlier stated, the potentiometer 36 provides a gain adjustment at the input of the operational amplifier which comprises the amplifiers 56 and 64, and the output signal from terminal 68 is fed directly to the speaker coil of the palpation platform of the master unit 16 of FIG. 1.
By way of example the various circuit components of the circuit of FIG. 2 utilized in conjunction with plus 12 and minus 12 volt power supplies are as follows:
Operational Amplifier 26 ZEL 134 Operational Amplifier 56 ZEL 1 Operational Amplifier 64 Philbrick 2001 Capacitor 22 5 microfarads Capacitor 38 0.047 microfarads Capacitor 50 10 microfarads Capacitor 72 100 picofarads Resistor 28 4.7 M ohms Resistor 32 2.2 K ohms Resistor 36 25 K ohms Resistor 40 24 K ohms Resistors 42, 44, 48, 76 and 80 47 K ohms Resistor 46 25 K ohms Resistor 52 2.2 M ohms Resistor 60 1.8 M ohms Resistors 70 & 74 10 M ohms Resistor 78 25 K ohms
A preferred embodiment of the palpation platform of the master unit 16 of FIG. 1 is illustrated in FIG. 3 wherein a styrofoam block 84 is cemented to the speaker cone 86 for movement therewith. The speaker 88 is desirably mounted with respect to the enclosure 90 such that the plane of the exposed surface of the styrofoam filled cone is parallel to the plane of the enclosure. The exposed styrofoam and the surrounding enclosure may be covered by material having the color and texture of human flesh. A vinyl has been found suitable for this purpose although other materials may be satisfactory. The speaker may be horizontally or vertically orientated as desired for a particular adaptation
Referring now to FIG. 4, the present invention also has great utility in teaching speech to persons having hearing defects. As schematically illustrated, a transducer such as a conventional throat microphone 100 may be secured in an appropriate manner to the throat of an instructor. The output signal from the microphone 100 is amplified in an amplifier 102 such as that illustrated in FIG. 2 and the amplified signal utilized to drive a plurality of palpation platforms 104. The palpation platform may be of the type illustrated, for example, in FIG. 3.
In operation, a student 108 with a hearing defect may place the fingers 110 of one hand on the surface 106 of the palpation platform 104 to sense the physical displacement of the instructor's throat as a specific sound is made. The fingers 112 of the other hand of the student 108 may be placed in a position on his own throat corresponding to the position of the microphone 100 on the throat of the instructor. The student is thus able to sequentially sense and thus compare the physical displacement of the instructor's throat when speaking and the physical displacement of his own throat in attempting to reproduce the sound.
In the self-teaching embodiment illustrated in FIG. 5, the instructor of FIG. 4 has been replaced by a suitable source 114 of the desired speech responsive signals. The source or simulator 114 may be, for example, of the magnetic tape or wire type. The output signal from the simulator 114 is amplified in an amplifier 116 and applied to a palpation platform 118 and to a visual display 120.
Also applied to the visual display 120 is the output signal from a throat microphone or other suitable transducer 122 attached to the throat, or cheek, as appropriate, of the student. The output signal from the transducer 122 may also be applied to a second palpation platform 124.
The display 120 may be any suitable conventional display for illustrating the two electrical signals for visual comparison purposes. The Model EI 100 from Masden Electronics at 2432 Grand Concourse, New York, N.Y. 10458 is exemplary of this type of display.
In operation, the signal from the simulator 114 may be simultaneously viewed and tactilely sensed by the student through the fingers of one hand. In attempting to reproduce the sound, the student can simultaneously view and tactilely sense the electrical signal from the microphone 122 positioned on his throat through the fingers of his other hand. The student may thus effect both a tactile and a visual comparison of the desired sound and his attempted reproduction thereof.
ADVANTAGES AND SCOPE OF THE INVENTION
While preferred embodiments have been illustrated and described in the foregoing specification, the substitution of components may readily be accomplished by one skilled in the art to which the invention pertains. For example, the electrical signals may be replaced by fluid pressure signals. The transducer may be varied in configuration and in method of operation, e.g., electromagnetic, electrostatic, pneumatic, hydrostatic, sonic, etc., depending on the configuration of the body surface and the part of the body to be sensed.
As a classroom or clinical instruction aid, several units may be slaved to a single transducer and a specific sound or cardiovascular movement simultaneously displayed to a plurality of students. By means of a master unit, the instructor may adjust the placement and sensitivity of the transducer to maximize identification.
As a self-teaching aid, a selected signal may be continuously reproduced for identification and is of great value to both medical students and speech students with hearing defects.
As a diagnostic aid, the increased sensitivity which results from amplification may be utilized to detect and identify palpations which may otherwise be overlooked.
It is, therefore, intended that the scope of the present invention be limited, not by the specific embodiments disclosed, but solely by the language of the appended claims when accorded a full range of equivalents.