Method and apparatus for analyzing and visualizing the performance of frequency lowering hearing aids
Inventors
Assignees
United States, Defense, Secretary of • US Department of Defense
Publication Number
US-9807519-B2
Publication Date
2017-10-31
Expiration Date
2034-08-11
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Abstract
A method of analyzing performance of frequency lowering hearing aids. The method includes generating a sequentially of noise signals and transmitting acoustical sounds from a sound output device in response to the sequence of noise signals. A sound input device records the acoustical sounds and saves as a first device data. The sound input device with a frequency lowering hearing aid records the acoustical sounds and save as a second device data. The second device data is compared to the first device data and, in response to the comparison, at least one function of the frequency lowering hearing aid is optionally adjusted.
Core Innovation
The problem addressed relates to the deficiency of current acoustic verification systems, such as real ear measurement systems, which cannot suitably verify the performance of hearing aids that incorporate non-linear frequency shifting algorithms. Conventional systems cannot effectively evaluate or visualize the effect frequency lowering has on the signal produced by such hearing aids, creating challenges for audiologists and hearing professionals to assess and adjust these devices accurately. This gap creates a need for a simple, efficient, and intuitive method to assess hearing devices with these advanced algorithms.
Claims Coverage
The patent claims include one independent claim focused on a method of analyzing frequency lowering hearing aids, detailing various inventive features regarding signal generation, data recording, comparison, and visualization.
Method of analyzing frequency lowering hearing aids using sequential noise signals and data comparison
The method comprises generating a sequence of successive one-third octave band noise signals covering a frequency range, transmitting acoustical sounds in response to these noise signals, recording acoustical sounds with a sound input device as a first data set and again with the hearing aid as a second data set, and comparing these data using an arrow-based visualization that plots center frequencies and output levels, connecting first and second data points with arrows.
Arrow-based visualization method for performance comparison
The comparison includes generating a single graphical display that plots center frequencies and output levels of first device data and extends arrows from these points to corresponding values in the second device data, facilitating intuitive visualization of changes induced by the hearing aid.
Calibration and signal modulation techniques
The method further includes calibrating the sound output device, sound input device, and hearing aid, modulating noise signals with random variations within speech perception frequencies (about 4 Hz to 16 Hz), and parametrically varying successive noise signal bands within each frequency octave by offsetting sound pressure levels.
Signal processing steps to identify center frequency and verify data validity
Identification of center frequency involves windowing data (using a Hanning window), transforming to frequency domain data, smoothing by convolving a rectangular window, and selecting maxima. Validity of identified frequencies is verified by estimating envelopes of recorded sounds, applying low-pass filters, calculating coherence between envelopes, and discarding data with coherence below about 0.5.
The independent claim defines a method that integrates the generation and transmission of noise signals, data recording with and without a frequency lowering hearing aid, a detailed signal processing approach to identify key characteristics, and a unique arrow-based visualization method for displaying differences, thereby addressing the challenges of evaluating frequency lowering hearing aids comprehensively.
Stated Advantages
Provides a simple, efficient, and intuitive method for analyzing the operational state of frequency lowering hearing aids, overcoming deficiencies of conventional methods.
Enables visualization of frequency shifts and output level changes simultaneously across a wide range of input frequencies and amplitudes in a single graphical display.
Offers improved insight into signal fidelity and distortion by evaluating coherence between input and frequency-shifted output signals, which conventional systems cannot assess.
Allows detection and visualization of processing delays across frequency bands, facilitating diagnosis of issues that impact speech intelligibility.
Supports more complete and intuitive analysis of hearing devices with or without frequency shifting capabilities compared to traditional verification systems.
Documented Applications
Analysis and verification of frequency lowering hearing aids performance to aid audiologists and hearing professionals.
Visualization and assessment of non-linear frequency shifting algorithms in hearing aid devices.
Use in clinical environments by audiologists, clinicians, and technicians for fitting and adjusting hearing aids incorporating frequency lowering technology.
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