Deaf/Hearing Loss Equipment
David Walliams using a radio aid
Assistive Listening Equipment
Hearing aids and cochlear implant processors are essential pieces of equipment as they help deaf children by enabling them to hear the sounds of speech more clearly. However, they can also amplify unwanted background noise in addition to the essential speech sounds. For optimum listening, the speaker should be about one metre from the hearing aid user.
Ways to Improve Listening Conditions in Classroom for Pupils with Hearing Impairment
There are three main problems when listening through a hearing aid:
- Background noise
- Reverberation or echoes
Classrooms with good acoustic properties make listening so much easier for all pupils but especially those with hearing difficulties and hearing aids. Sensory Consortium Service staff can look at the classrooms and give advice on ways to improve the listening environment. Here are a few ways that modifications can be made:
- Putting carpets on the floor or fitting rubber feet on tables and chairs
- Installing double-glazing to cut down on noise from outside
- Putting pin boards on the walls to 'soften' hard surfaces
- Putting blinds or curtains at the windows
For pupils with hearing aids, the teacher's voice should be ideally 15-20dB above the background noise of the room, as it enters the child's ear. This is called the signal to noise ratio.
Soundfield systems can enhance the listening experience of all pupils in the class, and are usually supplied by the school. These can be permanently fixed speakers in ceiling or on the walls, or can be portable and moved into another classroom when required. The teacher uses a microphone, and the sound is distributed evenly around the room, through the speakers. In order to work well, the room must have reasonable acoustic properties.
For an individual child with hearing aids or a cochlear implant, the best way of overcoming the problems of distance, and improving the signal to noise ratio is to use a radio aid system. This comprises a microphone and transmitter worn by the teacher, and a receiver worn by the child, attached to their hearing aid or processor.
The microphone, worn close to the teacher’s mouth, picks up the teacher’s voice, and the sound is then transmitted to the child’s receiver. This enables the teacher’s voice to be received directly into the hearing aid or processor, wherever they are in the room, giving a more consistent and much improved signal to noise ratio.
Radio aids also help to reduce the effect of background noise, as the signal from the teacher’s voice is louder and stronger.
There are many different systems available commercially. The majority of radio aid systems currently used by the SCS are Roger technology, the latest digital standard from Phonak. The Sensory Consortium Service can loan radio aid systems to pupils in schools, set them up, and train staff and pupils in their use and maintenance.
The Qualified Teacher for the Deaf and the Educational Audiologist, following discussion with the parents and class teacher, decide whether or not a radio aid system is appropriate. The SCS uses a radio aid request form, which the visiting teachers fill in, giving details about the child's needs and situation. Acting on their advice, the Educational Audiologist then decides on the best system to use, and will issue as soon as one is available and/or funding allows.
Please see our videos page for further information on equipment.