Hearing Aid Technology & Electroacoustics Flashcards

What is wide dynamic range compression (WDRC) and what problem does it address in hearing aid fitting?

Answer: A compression strategy that applies gain across a wide range of input levels, making soft sounds audible while keeping loud sounds comfortable, to address the reduced dynamic range of sensorineural hearing loss

WDRC addresses the narrowed dynamic range of sensorineural hearing loss by applying high gain for soft inputs and progressively less gain for louder inputs, compressing the range of sounds into the patient's residual dynamic range.

What is the difference between attack time and release time in a hearing aid compressor?

Answer: Attack time is how quickly compression engages after a sudden loud sound; release time is how quickly gain returns to its pre-compression level after the loud sound stops

Attack time is the time constant for compression to activate (reducing gain) in response to a sudden increase in input level. Release time is the time constant for gain to return to its pre-compression value after the loud input ceases.

A hearing aid is described as having Bluetooth LE Audio. What does this enable?

Answer: Low-energy wireless audio streaming from smartphones and other devices directly to both ears simultaneously, with improved audio quality and reduced latency compared to classic Bluetooth

Bluetooth LE Audio (Low Energy Audio) enables direct, low-power stereo streaming from modern smartphones and audio sources to both hearing aids simultaneously with improved sound quality, latency, and battery efficiency.

What is harmonic distortion in a hearing aid, and at what level does it become clinically significant?

Answer: The generation of unwanted harmonic frequencies when a hearing aid is overdriven; total harmonic distortion (THD) above 5% is considered clinically significant per ANSI standards

Harmonic distortion occurs when non-linearity in the hearing aid circuit generates new frequency components not present in the input signal. ANSI S3.22 specifies that THD should not exceed 5% (measured at 500, 800, 1600 Hz) at 70 dB SPL input.

What is datalogging in a modern hearing aid and how does it inform the clinical fitting process?

Answer: Automatic tracking by the hearing aid's processor of hours of use, acoustic environment distributions, manual adjustments, and program usage; used at follow-up to guide fitting refinements

Datalogging captures objective data on how the patient actually uses the hearing aid in daily life—including hours worn, acoustic environment distribution, volume adjustments, and program selections—informing evidence-based follow-up adjustments.

What is the purpose of hearing aid fitting software such as Connexx, Genie, or Phonak Target?

Answer: To program the hearing aid's digital parameters by connecting the fitting computer to the hearing aid, downloading audiometric data, calculating initial prescriptive targets, and allowing fine-tuning of all acoustic settings

Hearing aid fitting software connects the clinician's computer to the hearing aid, imports audiometric data, calculates prescriptive gain targets, and allows comprehensive adjustment of all programmable hearing aid parameters.