HAC Assistive Listening Device Technology 3 — Questions and Answers
Question 1: Which assistive device is specifically designed to alert a person with profound hearing loss to a doorbell ringing?
- Personal FM system
- Visual alerting device (Correct answer)
- Amplified telephone
- Cochlear implant sound processor
Correct answer: Visual alerting device
Visual alerting devices flash lights or use vibration to notify individuals with severe to profound hearing loss of environmental sounds like doorbells.
Question 2: In a digital RF assistive listening system, what is the key advantage of using encrypted transmission?
- Improved signal range
- Prevention of eavesdropping on private conversations (Correct answer)
- Higher audio fidelity
- Reduced battery drain in the receiver
Correct answer: Prevention of eavesdropping on private conversations
Encrypted RF transmission ensures that only authorized receivers can decode the audio signal, protecting user privacy.
Question 3: Under ADA guidelines, what is the minimum percentage of fixed seating in assembly areas that must be served by an assistive listening system?
- 10%
- 25%
- 4% (minimum 2 seats) (Correct answer)
- 50%
Correct answer: 4% (minimum 2 seats)
ADA Standards require that 4% of total fixed seats (minimum of 2) in assembly areas be served by assistive listening systems.
Question 4: A patient with a cochlear implant processor equipped with a telecoil wishes to use a hearing loop. What must the audiologist verify?
- That the loop frequency matches the FM band
- That the processor's telecoil program is activated and the loop field strength is adequate (Correct answer)
- That the loop uses digital rather than analog modulation
- That the patient has bilateral cochlear implants
Correct answer: That the processor's telecoil program is activated and the loop field strength is adequate
The telecoil program must be enabled on the processor, and loop field strength must meet IEC 60118-4 standards for reliable pickup.
Question 5: What is the function of a silhouette inductor in an ALD system?
- It amplifies the FM signal before transmission
- It inductively couples an FM receiver to a behind-the-ear hearing aid's telecoil (Correct answer)
- It converts infrared signals to audio output
- It acts as a directional microphone for the transmitter
Correct answer: It inductively couples an FM receiver to a behind-the-ear hearing aid's telecoil
A silhouette inductor is a flat inductive coupler worn beside the hearing aid that transfers the FM receiver's audio signal to the hearing aid's telecoil.
Question 6: Which standard defines the minimum magnetic field strength for hearing loop installations?
- ANSI S3.22
- IEC 60118-4 (Correct answer)
- FCC Part 68
- ISO 9001
Correct answer: IEC 60118-4
IEC 60118-4 specifies that hearing loop systems should produce a minimum field strength of 100 mA/m (−20 dBrel) for reliable telecoil reception.
Question 7: A patient reports their FM hearing loop receiver produces a high-pitched whistle when held near their hearing aid microphone. This is most likely caused by:
- A weak transmitter signal
- Acoustic feedback between the receiver's speaker and the hearing aid microphone (Correct answer)
- Incompatible FM frequencies
- A defective telecoil in the hearing aid
Correct answer: Acoustic feedback between the receiver's speaker and the hearing aid microphone
Acoustic feedback occurs when amplified sound from the receiver's speaker re-enters the hearing aid's microphone and is re-amplified in a loop.
HAC Assistive Listening Device Technology 3
Which assistive device is specifically designed to alert a person with profound hearing loss to a doorbell ringing?