Module 13: Wireless Accessories and ALDs Flashcards by Sam Gosse

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)

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What is wireless transmission?

1-way or 2-way transmission of data over short or long distances

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What is Radio Frequency (RF)?

-Low frequency electromagnetic wave propagated using an antenna
-RF can be built into HA

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What are the 2 types of wireless transmission?

-Near-Field Magnetic Induction (NFMI)
-Far-field transmission

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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)

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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

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Far-Field Transmission

-Higher frequency bands: 900 MHz, 2.4 GHz
-Longer transmission distance

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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)

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Bluetooth devices transfer auditory information back and forth using a ___ radio frequency

2.4 GHz

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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)

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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

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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

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New chip fabrication processes claim to have solved the ____ issue of Classic Bluetooth

Power consumption

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What does it mean that streamers are proprietary?

Streamer and HA have to be from the same HA manufacturer

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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

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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