Auditory response detection method and apparatus
First Claim
1. Apparatus for generating data from which the likelihood of hearing impairment can be determined in a human subject who receives a selected auditory signal and whose response thereto is detected by an electroencephalographic transducer, comprising:
- (a) sampling means for sampling the polarity of the electroencephalographic signal at predetermined times after the time of application of the selected auditory signal which correspond to the positive and negative peaks of the waveform of the expected response component of the electroencephalographic signal, said sampling means providing a response output pulse when the polarity of the sampled signal matches the polarity of the expected response waveform at the predetermined time and also providing a trial output pulse at the time of each sample;
(b) synchronizing means responsive to the auditory signal for triggering the sampling means at the appropriate predetermined times;
(c) a response counter receiving the response output pulses from said sampling means and counting the pulses received by it and providing an output signal which is indicative of the total number of pulses counted; and
(d) a trial counter receiving the trial output pulses from said sampling means and counting the number of pulses received by it and providing an output signal indicative of the total number of pulses counted, whereby an operator can determine the ratio of the number of response pulses to the number of trial pulses over a selected period of time to provide a measure of the likelihood that a response is being evoked in a subject by the auditory signals.
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Accused Products
Abstract
Auditory tone burst signals are supplied to the ear of a human subject and the electroencephalographic responses are monitored, filtered, and provided to a sampler which samples the polarity of the EEG signal at predetermined times after the auditory signal has been applied. The existence of an expected response waveform of a definite shape and frequency in an individual who responds to the sounds causes a statistical shift of the ratio of sample polarities matching the expected polarity with respect to the total number of trials. The number of matched response polarities and the number of trials are counted and can be compared after the test is completed. A decision can be made as to whether a subject is responding by selecting a statistical confidence limit which allows the hypothesis that a subject is not responding to the auditory signal to be rejected if the ratio of responses to trials falls above the selected confidence limit.
60 Citations
22 Claims
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1. Apparatus for generating data from which the likelihood of hearing impairment can be determined in a human subject who receives a selected auditory signal and whose response thereto is detected by an electroencephalographic transducer, comprising:
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(a) sampling means for sampling the polarity of the electroencephalographic signal at predetermined times after the time of application of the selected auditory signal which correspond to the positive and negative peaks of the waveform of the expected response component of the electroencephalographic signal, said sampling means providing a response output pulse when the polarity of the sampled signal matches the polarity of the expected response waveform at the predetermined time and also providing a trial output pulse at the time of each sample; (b) synchronizing means responsive to the auditory signal for triggering the sampling means at the appropriate predetermined times; (c) a response counter receiving the response output pulses from said sampling means and counting the pulses received by it and providing an output signal which is indicative of the total number of pulses counted; and (d) a trial counter receiving the trial output pulses from said sampling means and counting the number of pulses received by it and providing an output signal indicative of the total number of pulses counted, whereby an operator can determine the ratio of the number of response pulses to the number of trial pulses over a selected period of time to provide a measure of the likelihood that a response is being evoked in a subject by the auditory signals. - View Dependent Claims (4, 6, 7, 9, 17, 18)
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2. Apparatus for generating data from which the likelihood of hearing impairment can be determined in a human subject who receives a selected auditory signal and whose response thereto is detected by an electroencephalographic transducer, comprising:
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(a) an auditory stimulus generator adapted to provide auditory signal pulses to the ear of the human subject at a known uniform frequency; (b) sampling means for sampling the polarity of the electroencephalographic signal at predetermined times after the time of application of the selected auditory signal which correspond to the positive and negative peaks of the wave form of the expected response component of the electroencephalographic signal, said sampling means providing a response output pulse when the polarity of the sampled signal matches the polarity of the expected response waveform at the predetermined time; (c) synchronizing means responsive to the auditory stimulus generator to trigger the sampling means at the predetermined times after the auditory signal; and (d) a response counter receiving the response output pulses from said sampling means and counting the pulses received by it over a selected period of time and providing an output signal which is indicative of the total number of pulses counted, whereby an operator can determine from the number of response pulses counted over the selected period of time and the number of pulses generated by the auditory stimulus generator during the selected period of time a measure of the likelihood that a response is being evoked in a subject by the auditory signals. - View Dependent Claims (16)
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3. Apparatus for generating data from which the likelihood of hearing impairment can be determined in a human subject who receives a selected auditory signal and whose response thereto is detected by an electroencephalographic transducer, comprising:
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(a) a handpass filter having a frequency pass hand containing the frequency of the component of the electroencephalographic signal expected as a response to the selected auditory signal in the subject being tested; (b) sampling means for sampling the polarity of the filtered electroencephalographic signal at predetermined times after the time of application of the selected auditory signal which correspond to the positive and negative peaks of the waveform of the expected response component, said sampling means providing a response output pulse when the polarity of the sampled signal matches the polarity of the expected response waveform at the predetermined time and also providing a trial output pulse at the time of each sample; (c) synchronizing means responsive to the auditory signal for triggering the sampling means at predetermined times after the auditory signal; (d) a response counter receiving the response output pulses from said sampling means and counting the pulses received by it and providing an output signal which is indicative of the total number of pulses counted; and (e) a trial counter receiving the trial output pulses from said sampling means and counting the number of pulses received by it and providing an output signal indicative of the total number of pulses counted, whereby an operator can determine the ratio of the number of response pulses to the number of trial pulses over a selected period of time to provide a measure of the likelihood that a response is being evoked in a subject by the auditory signals. - View Dependent Claims (5, 10, 11, 12, 13, 14, 15, 19)
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8. Apparatus for generating data from which the likelihood of hearing impairment can be determined in a human subject who receives a selected auditory signal and whose response thereto is detected by an electroencephalographic transducer, comprising:
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(a) an auditory stimulus generator adapted to provide auditory signal pulses to the ear of the human subject at a uniform frequency. (b) a bandpass filter having a frequency pass band containing the frequency of the component of the electroencephalographic signal expected as a response to the selected auditory signal in the subject being tested; (c) sampling means for sampling the polarity of the filtered electroencephalographic signal at predetermined times after the time of application of the selected auditory signal which correspond to the positive and negative peaks of the waveform of the expected response component, said sampling means providing a response output pulse when the polarity of the sampled signal matches the polarity of the expected response waveform at the predetermined time; (d) synchronizing means responsive to the auditory stimulus generator to trigger the sampling means at the predetermined times following the auditory signals; and (e) a response counter receiving the response output pulses from said sampling means and counting the pulses received by it over a selected period of time and providing an output signal which is indicative of the total number of pulses counted, whereby an operator can determine from the number of response pulses counted over the selected period of time and the number of auditory signal pulses over the selected period of time a measure of the likelihood that a response is being evoked in a subject by the auditory signals.
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20. A method of generating data which can be used to determine whether a human subject is capable of responding to auditory stimuli without requiring voluntary cooperation by the subject, comprising the steps of:
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(a) providing a series of auditory stimulus pulses to the ear of the subject during a test period; (b) detecting the electroencephalographic response of the subject to the stimulus pulses and providing an electrical signal corresponding thereto; (c) sampling the polarity of the electroencephalographic signal at predetermined times after the time of application of the auditory stimulus pulses to determine whether the polarity of the sampled signal matches the polarity of the waveform of the expected response component of the electroencephalographic signal at the time of the sample; (d) counting the total number of matches of the polarity of the electroencephalographic signal with the polarity of the expected waveform over the period of the test; (e) counting the total number of trials at which the electroencephalographic signal was sampled during the test.
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21. A method of generating data which can be used to determine whether a human subject is capable of responding to auditory stimuli without requiring voluntary cooperation by the subject, comprising the steps of:
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(a) providing a series of auditory stimulus pulses to the ear of the subject during a test period; (b) detecting the electroencephalographic response of the subject to the stimulus pulses and providing an electrical signal corresponding thereto; (c) filtering out frequency components of the electroencephalographic signal above and below a pass band of frequencies containing the frequency of the waveform of the expected response component of the electroencephalographic signal to improve the signal to noise ratio of the filtered signal; (d) sampling the polarity of the filtered electroencephalographic signal at predetermined times after the time of application of the auditory stimulus pulses to determine whether the polarity of the sampled signal matches the polarity of the waveform of the expected response component of the electroencephalographic signal at the time of the sample; (e) counting the total number of matches of the polarity of the electroencephalographic signal with the polarity of the expected waveform over the period of the test; (f) counting the total number of trials at which the electroencephalographic signal was sampled during the test. - View Dependent Claims (22)
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Specification