What are Assistive Listening Devices (ALDs)?
Assistive Listening Devices (ALDs) help people with hearing impairments or speech disorders.
They can be used alongside hearing aids and come in a variety of types. Examples of ALDs include hearing loops, FM systems, infrared systems, personal amplifiers and other assistive technologies.
Use of ALDs enables individuals with hearing loss to improve their communication, participate better in social activities and manage daily tasks more confidently.
How ALDs Differ from Hearing Aids
Both hearing aids and assistive listening devices (ALDs) are designed to support those with hearing impairments, yet they possess distinct purposes and capabilities.
Primarily, hearing aids amplify overall sound perception, addressing individual hearing loss. These custom-fit devices, worn discreetly in or behind the ear, are tailored to the wearer’s specific hearing requirements.
Conversely, ALDs prioritise communication enhancement by isolating desired sounds – like speech or TV audio – from distracting background noise. ALDs may work alongside hearing aids or independently, based on the user’s needs. These devices excel in noisy environments, where those with hearing loss may struggle to discern speech or important signals. By employing ALDs, users bolster communication and hearing abilities across various settings, leading to improved overall well-being.
Types of Assistive Listening Devices Explored
Some of the most common types of ALDs include loop systems, FM systems, and infrared systems. Different ALDs offer various features and benefits, allowing individuals to choose the device that best suits their specific hearing needs and listening environments.
Hearing Loops and Their Functionality
Hearing loops, also known as audio induction loop systems, offer a direct and effective assistive listening solution for individuals with hearing loss. This technology leverages the telecoil (or T-coil) found within many hearing aids and cochlear implants, creating a wireless bridge between the user’s device and a desired sound source.
At its core, a hearing loop system consists of:
- Loop of Wire: Discreetly installed in a designated area (such as a room or auditorium) this wire carries an electrical signal representing the audio source (e.g., a speaker’s voice, television, etc.).
- Electromagnetic Field: The loop generates a magnetic field throughout the enclosed area.
- Telecoil Receiver: When a hearing aid is switched to the “T” setting, its telecoil acts like a miniature antenna, picking up the loop’s magnetic signal.
- Direct Audio: The telecoil converts the signal back into sound, delivering it directly to the user’s ears, bypassing the hearing aid’s microphone.
The key benefit of hearing loops lies in their ability to significantly reduce background noise. By delivering the desired audio directly to the hearing aid, competing sounds are minimized, resulting in dramatically improved speech clarity and overall listening experience.
Hearing loops are found in various public and private settings, making communication more accessible in spaces like:
- Places of worship, theaters, and auditoriums
- Conference rooms and classrooms
- Service counters and reception areas
- Homes (connected to sound systems or televisions)
For those with telecoil-compatible hearing devices, hearing loops offer a user-friendly and reliable way to enhance listening experiences across numerous environments.
FM Systems
FM systems (Frequency Modulation systems) are a type of ALD that overcomes the limitations that distance and background noise place on traditional hearing aids or cochlear implants.
At their core, FM systems consist of two main components:
- Transmitter & Microphone: Worn by the speaker (such as a teacher, presenter, or conversation partner) this captures their voice directly at the source and converts it into an FM radio signal.
- Receiver: Worn by the individual with hearing loss, the receiver is often integrated into their hearing aids or cochlear implants. It picks up the FM signal, amplifies it and delivers clear audio directly to the user’s ears.
The genius of FM systems lies in their ability to maintain a strong signal-to-noise ratio. Because the speaker’s voice is transmitted directly from the microphone, background noise is significantly reduced.
This is particularly beneficial in:
- Classrooms: Students can focus on the teacher’s voice, even amidst other students or classroom activities.
- Conferences and Lectures: Attendee’s can hear the presenter clearly, regardless of room size or audience noise.
- Social settings: Conversations in bustling restaurants or noisy gatherings become less frustrating.
Infrared Systems
Infrared (IR) systems offer another valuable tool for enhancing communication accessibility for those with hearing loss. Unlike FM systems, which utilise radio waves for transmission, IR systems rely on light waves to deliver sound.
Here’s a breakdown of how IR systems work:
- Transmitter: Located near the sound source (lecture hall podium, movie theatre screen), it converts audio signals into light waves invisible to the human eye.
- Receivers: Individuals with hearing loss wear these receivers, which pick up the infrared signals and convert them back into audible sound. Receivers can be headphones, neckloops that connect to hearing aids or standalone units with built-in speakers.
IR systems excel in controlled environments where ambient light can be managed. They offer several advantages:
- Clear Audio: In situations with minimal background noise, IR systems provide excellent sound quality due to the focused nature of the light transmission.
- Multiple Channels: Some systems offer multiple channels, allowing users to choose between the main audio source or an assistive listening channel, like audio description for visually impaired individuals.
- Portability: IR systems are often easier to set up and move compared to FM systems, making them suitable for temporary installations.
However, IR systems also have limitations. Their effectiveness can be hampered by:
- Line of Sight: The receiver needs a clear line of sight to the transmitter for optimal signal reception.
- Interference: Strong ambient light sources can disrupt the signal, making them less ideal for outdoor use.
Despite these limitations, Infrared systems remain a valuable option for improving communication accessibility in controlled environments like lecture halls, movie theaters, and conference rooms.
The Role of Telecoils in Assistive Listening
Telecoils, tiny wire coils within many hearing aids and cochlear implants, act as miniature wireless receivers crucial for assistive listening devices. These work in tandem with ALDs like hearing loops, FM systems, and infrared systems.
When activated, the telecoil lets the hearing aid or implant directly receive the signal sent by the ALD. This amplifies speech or clarifies sound, cutting through background noise for the listener.
Important Considerations
- Compatibility: Not every hearing device has a telecoil. Check for this feature when selecting hearing aids or cochlear implants.
- Activation: Make sure to activate the telecoil setting on your device to connect it with ALDs effectively.
For those with telecoil-equipped hearing aids or implants, activating the “T” setting unlocks the full potential of ALDs. It allows for direct, clear sound without the distraction of competing noises.
Technology Integration with Bluetooth
Modern technology has revolutionised the way people with hearing loss experience the world through assistive listening devices. Bluetooth connectivity allows ALDs to connect seamlessly with a whole range of devices, from smartphones and tablets to laptops and even computers. This includes integration with home television systems, where infrared devices can be used for easy listening. This eliminates the frustration of fiddling with connections and lets you focus on what matters most.
Additionally, user-friendly apps on your phone or tablet put you in control of your ALD settings, allowing you to personalise your listening experience and unlock a world of features that enhance your daily life.
Choosing the Right Assistive Listening Device
Finding the ideal assistive listening device requires careful thought. Factors like sound quality, how well it filters background noise, portability, and its compatibility with your existing hearing technology are all important.
Matching Needs to Features
The best ALD will depend on the severity of hearing loss. Different devices offer features tailored to specific needs:
- Mild Hearing Loss: Personal amplifiers can be helpful. These portable devices amplify sounds while reducing some background noise, making them useful for focused conversations or when other ALDs aren’t available.
- Severe Hearing Loss: Solutions like hearing loops, FM, or infrared systems may be necessary. These reliably transmit clearer sound, even in noisy environments, significantly improving speech understanding.
Additional Considerations:
- Environment: Where will the ALD be used most often – home, public spaces, etc.?
- Lifestyle: Does the user need a portable device, or is a room-specific system better?
- Budget: ALDs range in cost based on features and technology.
Closing Thoughts
Assistive listening devices can significantly enhance hearing capabilities and improve overall quality of life. Exploring the different types of ALDs available is highly recommended in order to choose a device that best suits your needs and preferences.
If you or a loved one are experiencing hearing difficulties and would like to talk to an audiologist about ALDs or hearing aids, why not schedule an appointment with us.