Module 13: Wireless Accessories and ALDs Flashcards
What are some uses for wireless technology in hearing aids?
-Hearing aid to hearing aid
-Hearing aid to hearing aid specific proprietary accessory (remote control, streaming device)
-Hearing aid to ALD (loop systems, infrared systems)
-Hearing aid to smart phone (audio, phone call, app functionality)
What is wireless transmission?
1-way or 2-way transmission of data over short or long distances
What is Radio Frequency (RF)?
-Low frequency electromagnetic wave propagated using an antenna
-RF can be built into HA
What are the 2 types of wireless transmission?
-Near-Field Magnetic Induction (NFMI)
-Far-field transmission
Near-Field Magnetic Induction (NFMI)
-Lower frequency band: 3 to 15 MHz
-Short transmission distance (1 meter ideally)
-Can pass around/through objects (e.g., human head)
-Typically no interference from other devices due to its short transmission range
-Small antenna – NFMI can fit in small hearing aids (some models may not have this technology)
NFMI Applications
-Hearing aid to hearing aid processing (e.g., synchronization of volume control, programs, polar plots)
-Binaural telephone reception
-Remote control for hearing aids
-Communication between neck-worn streamer and hearing aids
Far-Field Transmission
-Higher frequency bands: 900 MHz, 2.4 GHz
-Longer transmission distance
3 Stages of Bluetooth
-Discovery: 2 devices are set to Bluetooth findable mode so they can find each other
-Pairing: the devices exchange coordinates so they can communicate securely every time they are within range of each other (done once but can lose connection)
-Connecting: the paired devices transfer auditory information back and forth (2.4 GHz radio frequency)
Bluetooth devices transfer auditory information back and forth using a ___ radio frequency
2.4 GHz
Advantages of Classic Bluetooth
-Wireless transfer of information over a secure connection
-Reduced interference with other wireless devices operating in the 2.4 GHz band through frequency “hopping” between channels
-Several Bluetooth devices can be paired with a HA streamer or to hearing aids directly (smart phone, iPad, tablet, etc)
Limitations of Classic Bluetooth for HAs
-Bluetooth has a delay (30-150 ms)
·May be tolerable when streaming music or phone, but can be problematic when streaming from the TV or face-to-face communication
-Classic bluetooth has high power consumption
Bluetooth Low Energy (BLE)
-Simplified version of classic bluetooth designed for low power consumption
-Shorter delay than classic bluetooth
-Operates in 2.4 GHz band (same as classic)
-Cannot stream audio signals
New chip fabrication processes claim to have solved the ____ issue of Classic Bluetooth
Power consumption
What does it mean that streamers are proprietary?
Streamer and HA have to be from the same HA manufacturer
Streamer features
-Can be paired to multiple bluetooth devices (cell phone, iPad, laptop, etc)
-Antenna may be worn around the neck
-Some streamers also serve as a remote control
Remote mic technologies tackle problems of ___ (3 things)
Distance, noise, and reverberation
Features of remote mics
-Cost friendly
-Good applications for adults
-Not universal (HA and mic from same manufacturer)
Features of FM/DM systems
-Expensive
-More versatile than remote mics
-School applications
-Universal
With reverberation, energy of vowels is ___ and ___ which may mask the following consonants
Prolonged, repeated
What reverberation time is generally desirable for persons with hearing loss?
< .4 sec
Remote mics/FM/DM systems improve S/N ratio by approximately ___ dB
6-20 dB
T/F: remote mics/FM/DM systems may be beneficial to those with auditory processing deficits
True
Remote microphones can work via a ___, while others send the signal directly to the HA
Streamer
FM/DM system components
-Transmitter with mic picks up a speaker voice and transmits it to the listener wearing a receiver either attached or integrated into hearing aids
-In classic FM, transmitter and receiver were “tuned” to the same channel (similar to a radio station)
Transmitter mics
-Different kinds (e.g., body worn transmitter with external mic, mic built into transmitter, conference/table mic, pen mic, etc)
-May be omni or directional
Important tips for speakers wearing transmitter mics
-Wear mic as close to mouth as possible for best S/N
-Do not wear mic under clothing
Who may be an ideal candidate for FM/DM?
-Poor speech understanding in noise
-Auditory processing disorders
-Patients who express they need more assistance when trying to hear over distance
-Patients who express they need more assistance than hearing aids alone in challenging listening environments
-Not necessarily dependant on hearing loss alone as per the audiogram!
Classification of Assistive Listening Devices (ALDs)
-To overcome the problem of listening in adverse conditions (listening devices, television devices, telecommunication devices)
-To alert the person with hearing loss of important environmental sounds (alerting or signalling devices)
PockeTalker
-Sound amplifying device
-Set of headphones, a microphone, and amplifier to adjust volume
-Doesn’t replace hearing aids because the wire provides limited distance and it is not prescriptive
Loop systems
-Wire around a room, connected to a mic-amplifier system, generates magnetic energy
-Magnetic energy is picked up by a HA telecoil
-Can loop a room, char, or neck
-Commonly used in places of worship; some drive-thru venues
Advantages & disadvantages of loop systems
-Low cost (compared to other technologies)
-Stronger response if HA user is close to loop
-Can be accessible by many users
-Interference
TV connectivity options
-Proprietary (HA & TV link from same manufacturer)
-Some send TV signal to streamer, then to HA
-Some send TV signal directly to HA
What is a CaptiView?
System borrowed from movie theatres that provides closed captions
Alerting devices alert those with hearing loss to important environmental sounds through cues that are ___, ___, or ___
Auditory, visual, tactile
T/F: the majority of residential smoke detectors emit a 85 dBA alarm at ~3200 Hz
False: ~3100 Hz
Residential smoke detectors have found to wake up what percentage of people with mild to severe hearing loss & severe to profound hearing loss?
-Mild to severe HL: 57%
-Severe to profound: 0%
520 Hz alarm woke up ___ % of people with mild to moderately-severe HL
100
Examples of Alerting Devices
-Amplified, lower frequency, or visual display (light flashing) of: telephone ringer, doorbell, door knocks, alarm clocks
-Bed or pillow shaker
