IHS Aid Technology 4 ā Questions and Answers
Question 1: In a CROS (Contralateral Routing of Signal) system, where is the microphone placed and where is the signal delivered?
- Microphone on the better ear, signal to the poorer ear
- Microphone on the poorer ear, signal delivered to the better ear (Correct answer)
- Microphones on both ears, signal averaged between them
- Microphone behind the neck, signal delivered binaurally
Correct answer: Microphone on the poorer ear, signal delivered to the better ear
In a CROS system, a transmitter/microphone is worn on the non-functional ear and the audio signal is wirelessly routed to a receiver worn on the better ear.
Question 2: What is the primary advantage of a bone-anchored hearing aid (BAHA) over a conventional air-conduction aid for conductive hearing loss?
- It provides more high-frequency amplification
- It bypasses the damaged outer or middle ear by transmitting vibrations directly to the cochlea through bone (Correct answer)
- It eliminates the need for a sound processor
- It can be worn underwater without a protective case
Correct answer: It bypasses the damaged outer or middle ear by transmitting vibrations directly to the cochlea through bone
A BAHA uses direct bone conduction via an osseointegrated implant to deliver sound to the cochlea, bypassing a congenitally absent, malformed, or surgically altered outer/middle ear.
Question 3: Which hearing aid style places ALL componentsāincluding the microphone, processor, and receiverāinside the ear canal?
- Behind-the-ear (BTE)
- Receiver-in-canal (RIC)
- Completely-in-canal (CIC) (Correct answer)
- Body-worn aid
Correct answer: Completely-in-canal (CIC)
Completely-in-canal (CIC) aids have all components housed in a small shell that fits entirely within the ear canal, making them the least visible traditional style.
Question 4: What is 'datalogging' in modern hearing aids?
- Recording the patient's audiogram into the fitting software
- Storing information about the environments and listening situations the user encounters (Correct answer)
- Logging signal-to-noise ratios for regulatory reporting
- Tracking battery charge cycles for warranty purposes
Correct answer: Storing information about the environments and listening situations the user encounters
Datalogging records details such as hours of use, listening environments, volume control adjustments, and program usage, which clinicians use to guide counseling and fine-tuning.
Question 5: A hearing aid's 'attack time' in compression processing refers to:
- How quickly the gain increases when input level drops suddenly
- How quickly the gain decreases when input level rises above the compression threshold (Correct answer)
- The delay between sound input and digital output
- The time required for feedback cancellation to activate
Correct answer: How quickly the gain decreases when input level rises above the compression threshold
Attack time is the speed at which the compression circuit reduces gain in response to a sudden increase in input level above the compression threshold.
Question 6: FM (frequency modulation) assistive listening systems provide the greatest benefit in which challenging situation?
- Listening to music at home
- Communicating over a telephone
- Overcoming distance and room reverberation in classrooms or auditoriums (Correct answer)
- Using hearing aids while sleeping
Correct answer: Overcoming distance and room reverberation in classrooms or auditoriums
FM systems deliver the speaker's voice directly to the listener's ear via a wireless radio link, effectively eliminating the distance and reverberation problems of large rooms.
Question 7: Which of the following is a characteristic of Class D (digital switching) amplifier output stages used in hearing aids?
- They operate at 100% efficiency with no heat generation
- They are highly efficient, reducing battery drain compared to Class A/B amplifiers (Correct answer)
- They produce higher harmonic distortion than analog amplifiers
- They require larger batteries due to high current draw
Correct answer: They are highly efficient, reducing battery drain compared to Class A/B amplifiers
Class D amplifiers switch rapidly between power supply rails, achieving efficiencies of 80ā90%, which significantly extends battery life in hearing aids compared to linear amplifier classes.
IHS Aid Technology 4
In a CROS (Contralateral Routing of Signal) system, where is the microphone placed and where is the signal delivered?