Top Assistive Listening Devices and Systems for Hearing Loss
- Last Updated: Jun 2nd, 2018
- Posted by: admin
- Category: Research & Technology
There isn’t any doubt that hearing aid is an essential equipment for a person who is hard of hearing. But what if these aren’t enough?
Here comes in the picture, what we call Assistive Listening Devices (ALD), also known as Assistive Listening Systems. In some situations such as restaurants, huge classroom settings, or even places with poor acoustics, shortcomings of hearing aids are exposed; then comes in ALD. As such places have ambient noise and require some extra boost. ALDs are responsible to bring sound closer to the listener’s ear. This improves the speech-noise ratio, as well as separate the sound to be heard, from the unwanted background noise. This ultimately improves the user’s listening experience.
Generally, a hard of hearing person requires an increased volume of about 15 to 25 decibels to achieve normal hearing level. This is achieved by ALD without even disturbing others in the vicinity. In some situations, these devices can be used with hearing aids or cochlear implant and even separately if slight amplification is needed. There are many ALDs available in the market with certain advantages of their own in different situations. This is helpful in making hearing aid much more effective and also rounding out the hearing aid experience. Here, we are going to mention the most popular ALDs available in the market.
- Personal Amplifier
This ALD device is mostly used for one to one conversation. It consists of a box of the size of a cell phone with a mic and an attached listening cord. This can be attached to the clothing of person you are talking to, then plug it into the personal amplifier and hear clearly. This process cuts out the most of the background noise. This device is relatively inexpensive and costs around $200.
The downside of this device is that it cannot be useful in the situations when you are required to move around a lot, as it has a wired connection with the speaker. Situations such as concerts or theaters, which require mobility or hearing from a distance, will need a more flexible system. But this device can be useful in situations like watching TV, being outdoors, or traveling in a car. Some of the personal amplifiers come with directional microphones which can be angled towards the speaker or the source of the sound. In other ALDs, the amplified sound is picked up by the receiver that the listener is wearing either by a headset or earbuds.
- FM Systems
This ALD somehow overcomes the limitations of personal amplifiers as it allows mobility in addition to, hearing a more distant sound. FM System uses Radio Broadcast Technology which brings sound directly to the ear. This is a wireless device making its receiver portable which facilitates in hearing the speaker. The speaker has to wear a microphone transmitter, which allows listening up to 150 feet away. This ALD is suitable for classroom or outside setting as it allows mobility at will and still able to hear the distant sound clearly. But for this added flexibility, you have to pay the added amount, which costs up to $700 to $1,000 on an average.
This system can be used in the classroom setting where instructor wears a small microphone connected to a transmitter, the students have to wear the receiver tuned to a specific frequency or channel. Those having a built-in telecoil in their hearing aid or cochlear implant may also wear a wire around their neck (i.e. neckloop) or behind their aid or implant (silhouette inductor). This converts the signal into magnetic signals to be picked up directly by telecoil or t-coil. FM can transmit signal up to 300 feet.
As radio signals can penetrate walls, the listener in both rooms needs to listen to different channels to avoid receiving mixed signals. FM System can also be used on personal level, in the same way, it is operated on a larger system. This can help people with hearing loss to follow one to one conversations. Miniaturized receivers can be utilized in newer FM Systems that fit onto a hearing aid via a “boot”. This receiver is not available through the catalogue.
This device must be dispensed by hearing aid professional and it is more expensive as compared to traditional FM Systems. It uses a high frequency which makes it incompatible with other FM devices.
- Infrared Systems
In this system, light-based technology or infrared lights are used to transmit sound. Their working is similar to FM System. This high-tech system guarantees privacy while talking as lights cannot travel through walls. It will be very useful in situations like doctor’s office, court proceedings etc. They are often used in places of entertainment i.e. while watching TV or in theaters, and also where competing signals can be a problem.
Along with so many advantages comes a limitation i.e. the signal gets blocked if any object or person comes in between the listener and the emitter. However, this system can’t be used in an environment with too many light sources such as in sunlight or strongly lit room. Thus making this system suitable for some situations, and not as versatile as FM System. The transmitter converts the sound into a light signal which beams to the receiver worn by the listener. Then the receiver decodes this signal to sound. They are also designed to be used for television listening.
- Induction Loop Systems
Those having built-in telecoils in their hearing aids have an alternate option; an induction loop system. This system uses an electromagnetic field to carry sound to the user’s ear.
This loop system consists of four parts:
- A sound source, i.e. public address system, microphone, TV or telephone
- A thin loop of wire that encircles the room and branches out beneath carpeting
- Receiver, worn in the ear or as a headset
Hearing loops can also be connected to a public address system, TV, or any other audio source.
The system consists of an insulated wire. This wire can range from a small loop to (worn around the neck) to the loop that encircles entire room is connected to a power source, an amplifier, and a microphone. This system is inexpensive as well as versatile and is used for a single telecoil hearing aid user or a group. Since the user is not directly connected to the system, mobility is not an issue. Loop system can be used by even non-hearing aid users, with the headphone or receiver system.
An electromagnetic field is created by the amplified sound traveling through the loop. This field is picked up directly by the hearing loop receiver or t-coil, built-in miniature wireless receiver of hearing aid as well as cochlear implants. The listener must be wearing receiver and stay around the loop, to pick up the signal. As the sound is directly picked up by a receiver, it is very clear, free from the background noise associated with many listening environments. If a person doesn’t have a hearing aid with embedded telecoils, then not to worry, portable loop receivers are also available. These portable loops made it possible for people with hearing loss to improve their listening environment so that they can proceed with their daily activities.
- Sound Field System
This is a speaker system often used in schools that brings sound closer to the ears. This system is useful for people with a mild hearing loss as well as those who want to use hidden speakers. Some of these hidden speakers are wireless, resembling a lunch box or books. This sound system can be used for hearing by both hearing aid wearers as well as cochlear implants users, through the microphone. Use of sound field system is the concept of “electronic curb cut”. This is one of the most interesting features of this system.
Bluetooth technology is the latest innovation for the hearing aid wearers. But these are not yet available. Using this technology, two devices such as cell phones or computers and wireless hearing aid can be connected, with a compatible streamer to talk to each other. Though it’s range is limited, around 20 feet. But with no interference and secure connection of this convenient hands-free technology, one can overcome all its flaws. Using only one streamer can allow the user to switch back and forth among multiple devices i.e. phones, tablets, or iPods.
These assistive devices can be really helpful in your day to day life. Especially if you are a hearing aid wearer or cochlear implant user. This can certainly boost up your hearing experience. Based on the features and requirements, decide which of the above Assistive Listening Device is right for you and your lifestyle.