Method and apparatus for automated detection of suppression of TEOAE by contralateral acoustic stimulation
Inventors
Lodwig, Andre • Oswald, Johann • Janssen, Thomas
Assignees
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Publication Number
US-10743798-B2
Publication Date
2020-08-18
Expiration Date
Abstract
The invention is directed to a method of generating and measuring transiently evoked otoacoustic emissions (TEOAE) acoustic signals generated in the cochlea using a scheme of stimulating both inner ears simultaneously, left ear alone, and right ears alone with at least two different first and second averaging buffers per ear in a switching scheme with automated detection of contralateral suppression of TEOAE via statistical analysis of the differences of suppressed and unsuppressed responses.
Core Innovation
The invention provides an automated method to detect Transient-evoked Otoacoustic emissions (TEOAE) contralateral suppression. A patient is exposed to periodic sequences of sound stimuli that evoke TEOAE stimuli phase locked waveforms given off by left and right inner ears by periodically switching stimulus presentation. The switching provides first stimuli to both inner ears, a second stimulus to the left inner ear alone, and a third stimulus to the right inner ear alone.
The method sequentially records TEOAE stimuli phase locked waveforms for the left and right inner ears in the both-ears condition, and in the left-alone and right-alone conditions. For each inner ear, it averages waveforms into an unsuppressed buffer and a suppressed buffer based on which stimulus condition is provided during recording. It then calculates difference averaged TEOAE waveforms by subtracting the averaged suppressed waveform from the averaged unsuppressed waveform for each inner ear.
Morphological analysis is applied to the overall shape of each difference averaged TEOAE waveform to detect if TEOAE contralateral suppression is present or absent in the right inner ear, the left inner ear, or both. Detection is supported by morphological/statistical signal processing based on the waveform difference, including rules such as counting peaks that exceed an amplitude above an estimated standard deviation, and evaluating significance using estimated noise metrics rather than relying on small level differences.
An apparatus is also provided to automatically perform the method, including a sound generator, a recorder, left and right unsuppressed/suppressed buffers, and a computer configured to calculate the difference averaged TEOAE waveforms and apply morphological analysis. The apparatus further supports output and control features such as displaying PASS versus REFER and automatic stop criteria, as well as an extra tone to monitor probe stability.
Claims Coverage
The document includes two independent claims, one method claim and one apparatus claim. Each independent claim centers on periodic switching of left/right sound stimulation to obtain phase-locked TEOAE waveforms, averaging into suppressed and unsuppressed buffers, forming difference averaged waveforms, and applying morphological analysis to detect contralateral suppression across left, right, or both ears.
Periodic stimulus switching for ipsilateral/contralateral TEOAE phase locked waveforms
Expose a patient to periodic sequences of sound stimuli to generate TEOAE stimuli phase locked waveforms given off by left and right inner ears by periodically switching so as to provide first stimuli to both inner ears, a second stimulus to the left inner ear alone, and a third stimulus to the right inner ear alone.
Suppressed and unsuppressed per-ear averaging buffers from selected recording conditions
Sequentially record the TEOAE stimuli phase locked waveforms given off by the left and right inner ears, the left inner ear alone, and the right inner ear alone, wherein each inner ear has unsuppressed and suppressed buffers receiving and averaging recordings made in specific stimulus conditions so as to result in an averaged unsuppressed TEOAE waveform and an averaged suppressed TEOAE waveform.
Difference averaged TEOAE waveform computation by subtraction
Calculate a difference averaged TEOAE waveform for the left inner ear by subtracting the averaged left suppressed TEOAE waveform from the averaged left unsuppressed TEOAE waveform and calculate a difference averaged TEOAE waveform for the right inner ear by subtracting the averaged right suppressed TEOAE waveform from the averaged right unsuppressed TEOAE waveform.
Morphological analysis of the difference waveform to determine suppression present or absent
Apply morphological analysis to an overall shape of the difference averaged TEOAE waveform for each inner ear to detect if the TEOAE contralateral suppression is present or absent in the right inner ear, the left inner ear, or both right and left inner ears.
Across the independent claims, the inventive concept is realized by periodically switching sound stimuli across both-ears, left-alone, and right-alone conditions; recording and averaging TEOAE stimuli phase locked waveforms into left/right suppressed and unsuppressed buffers; computing per-ear difference averaged waveforms by subtraction; and using morphological analysis of the difference waveform shape to determine contralateral suppression as present or absent for right, left, or both ears.
Stated Advantages
Automatic detection of TEOAE contralateral suppression and identification of whether contralateral suppression is present or absent in the right inner ear, the left inner ear, or both.
Displaying a result as PASS or REFER when contralateral suppression is detected as present or absent.
Ability to use timing control such as recovery/settling periods and to optionally skip later unilateral stimulus/recording/averaging based on detection in one ear.
Monitoring probe stability using an extra tone.
Documented Applications
Automatic detection of Transient-evoked Otoacoustic emissions (TEOAE) contralateral suppression in a patient, including output labeling as PASS or REFER.
Determination of contralateral suppression status for the right inner ear, the left inner ear, or both right and left inner ears using morphological analysis of difference averaged TEOAE waveforms.
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