IHS Aid Technology 3 — Questions and Answers
Question 1: What is the function of a telecoil (T-coil) in a hearing aid?
- It boosts bass frequencies during music listening
- It picks up electromagnetic signals from compatible loop systems or telephones (Correct answer)
- It wirelessly charges the hearing aid battery
- It detects and suppresses wind noise
Correct answer: It picks up electromagnetic signals from compatible loop systems or telephones
A telecoil is an inductive pickup coil that converts electromagnetic energy from hearing loops or telephone handsets into audio signals, bypassing the microphone.
Question 2: Which of the following best describes 'frequency lowering' technology in hearing aids?
- Reducing overall amplification at low frequencies
- Transposing or compressing inaudible high-frequency sounds into a lower, audible range (Correct answer)
- Lowering the sampling rate of the digital processor
- Decreasing the signal delay through the hearing aid
Correct answer: Transposing or compressing inaudible high-frequency sounds into a lower, audible range
Frequency lowering moves high-frequency speech cues (such as /s/ and /sh/) into a frequency region where the patient has better residual hearing.
Question 3: The ANSI/ASA S3.22 standard is used to measure and report:
- Audiometric booth acoustic specifications
- Electroacoustic characteristics of hearing aids (Correct answer)
- Calibration standards for audiometers
- Real-ear measurement probe tube dimensions
Correct answer: Electroacoustic characteristics of hearing aids
ANSI/ASA S3.22 specifies the test methods and electroacoustic measurements—such as OSPL90, full-on gain, and THD—used to characterize hearing aid performance.
Question 4: What does 'WDRC' stand for in hearing aid signal processing?
- Wide Dynamic Range Compression (Correct answer)
- Wireless Digital Radio Communication
- Wideband Directional Receiver Circuit
- White-noise Distortion Reduction Control
Correct answer: Wide Dynamic Range Compression
Wide Dynamic Range Compression (WDRC) applies different amounts of gain across a range of input levels so that soft sounds are audible and loud sounds remain comfortable.
Question 5: A patient reports that their hearing aid sounds 'too tinny' and lacks bass. The most appropriate electroacoustic adjustment would be to:
- Increase high-frequency gain above 3000 Hz
- Boost low-frequency gain and check for an overly large vent (Correct answer)
- Switch the aid from omnidirectional to directional mode
- Reduce the attack time of the compression circuit
Correct answer: Boost low-frequency gain and check for an overly large vent
A tinny sound typically indicates insufficient low-frequency amplification or excessive venting that allows low-frequency energy to escape; boosting lows and evaluating vent size addresses this.
Question 6: Which type of battery is used in most rechargeable hearing aids on the market today?
- Zinc-air (size 312)
- Nickel-metal hydride (NiMH)
- Lithium-ion (Li-ion) (Correct answer)
- Alkaline AA
Correct answer: Lithium-ion (Li-ion)
Lithium-ion batteries dominate the rechargeable hearing aid market due to their high energy density, stable voltage curve, and long cycle life.
Question 7: What is the purpose of real-ear-to-coupler difference (RECD) measurements?
- To verify the audiometer is calibrated to HL norms
- To translate coupler-based prescriptions to the individual patient's ear acoustics (Correct answer)
- To determine the maximum power output of the hearing aid
- To measure the signal-to-noise ratio at the hearing aid microphone
Correct answer: To translate coupler-based prescriptions to the individual patient's ear acoustics
RECD accounts for the acoustic differences between a standard 2-cc coupler and the individual's residual ear canal volume, allowing more accurate prescriptive fitting—especially for children.
IHS Aid Technology 3
What is the function of a telecoil (T-coil) in a hearing aid?