HEARING TESTING METHOD AND AUDIOMETER

• US 3,799,146 A
• Filed: 10/06/1971
• Issued: 03/26/1974
• Est. Priority Date: 10/06/1971
• Status: Expired due to Term

• Current Assignee: Erwin Roy John, Robert Laupheimer
• Original Assignee: Erwin Roy John, Robert Laupheimer
• Inventors: John, Erwin Roy, Laupheimer, Robert
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/187,003
• Time in Patent Office: 902 Days
• Field of Search: 128/2,2R,2Z,2.1B,2.1R 235/150.53 179/1N
• US Class Current: 600/544
• CPC Class Codes: A61B 5/121 evaluating hearing capacity
• CPC Class Codes: A61B 5/377 using evoked responses
• CPC Class Codes: A61B 5/38 Acoustic or auditory stimuli

Abstract

A hearing testing method permits the testing of infants and others who cannot respond and provides an accurate and rapid test for others. A group of pure tones at selected amplitudes and frequencies is played, through earphones, to a subject. Electrodes connected to the subject'"'"''"'"'s head detect the subject'"'"''"'"'s brainwaves which are evoked responses to those tones. The brain waves are amplified, averaged according to the tone frequencies, automatically analyzed on a statistical basis using the '"'"''"'"''"'"''"'"'t'"'"''"'"''"'"''"'"' test, and used to display a profile of the subject'"'"''"'"'s hearing ability.

Claims

1. An instrument for the testing of the hearing of a subject, including means to make audible to the subject a series of tones at selected frequencies and loudness levels;

a contact adapted to be worn by the subject to detect his brain waves;

an electroencephalograph amplifier having an input and output whose input is connected to said contact;

a signal detector having an input and an output and whose input is connected to said amplifier output, said signal detector comprising an absolute value circuit having its input connected to the input of said signal detector;

a polarity shifting circuit whose input is connected to the output of said absolute value circuit, an integrator whose input is connected to the output of said shifting circuit, and a comparator whose input is connected to said integrator and whose output is connected to the output of said signal detector;

a single-input multi-output switch whose input is connected to said signal detector output;

a plurality of memory section counters connected to said switch outputs;

a display device connected to said memory sections; and

a programmer connected to said tone means and to said switch to direct the evoked responses at each tone to one of the memory sections.

2. An instrument as in claim 1 wherein said tone means includes a variable frequency oscillator whose frequency is controlled by said programmer and a variable attenuator controlled by said programmer, said oscillator and said attenuator both being connected to said programmer.

3. An instrument as in claim 1 wherein sAid memory sections are up-down counters.

4. The method of testing the ability of a subject to hear tones, consisting of playing for the subject a recording of a musical composition which includes the tones selected to be tested at selected levels of loudness, obtaining and amplifying the brain waves of the subject during said playing, averaging the subject'"'"''"'"'s amplified brain waves with the brain wave response at each said tone being averaged with responses at the same tone and loudness, and displaying the subject'"'"''"'"'s averaged response at the said tones and loudness levels.

5. An instrument for the testing of the hearing of a subject, said instrument including means to make audible a series of tones at selected frequencies and at selected loudness levels;

a contact adapted to be worn by the subject to detect his brain waves;

an electroencephalograph amplifier having an input and an output whose input is connected to said contact;

a '"'"''"'"''"'"''"'"'t'"'"''"'"''"'"''"'"' test computer whose input is connected to the output of said amplifier, said computer having, connected in sequence, a first set of squaring circuits, an averaging circuit, a second set of squaring circuits, differential circuits, a first set of divider circuits, a summing circuit and a square root circuit and also having a differential circuit whose input is connected to the averaging circuit, a second dividing circuit whose input is connected to the outputs of the differential circuit and the square root circuit, and an absolute value circuit whose input is connected to said dividing circuit; and

display means connected in series with said computer to display the hearing test results.

6. The instrument of claim 5 and also including a programmer connected to and controlling said tone means and a significance detector whose input is connected to the output of said absolute value circuit, said programmer being connected to the output of said significance detector to receive control signals controlling its program.

7. The instrument of claim 6 wherein said tone means includes a variable frequency oscillator and a variable attenuator and wherein said programmer is connected to and controls said oscillator and said attenuator.

8. The instrument of claim 5 wherein said display device is an X-Y pen recorder adapted to produce a profile of the subject'"'"''"'"'s hearing.

9. The instrument of claim 5 and including a significance detector to set the '"'"''"'"''"'"''"'"'t'"'"''"'"''"'"''"'"' test standard value connected to said computer and said programmer, upon attainment of which standard '"'"''"'"''"'"''"'"'t'"'"''"'"''"'"''"'"' value a control signal is provided by said significance detector to said programmer.

10. An instrument as in claim 5 wherein the said averaging circuit of said '"'"''"'"''"'"''"'"'t'"'"''"'"''"'"''"'"' test computer is a four-channel average response computer.