BATOD
The British Association of Teachers of the Deaf
Promoting Excellence in Deaf Education

AUDIOLOGY UPDATES AND AGONIES

The BATOD magazine articles will feature innovations and discussions of what is happening in real-world educational audiology and provide an opportunity for BATOD members to highlight issues that Teachers of the Deaf and their colleagues encounter in their workplace, or offer solutions.

If you can suggest a solution, or would like to pose a question for our BATOD members and experts, please contact Stevie Mayhook.

* Information provided by members of the Ewing Foundation.

Updates and Agonies topic list

Audiology Updates

Audiology agonies

BTEC Advanced Award for Audiology Technicians in Educational Settings

In July, the students studying for the BTEC Advanced Award for Audiology Technicians in Educational Settings at Mary Hare explored a range of personal amplification systems. There was a lot of interest in how to carry out routine checks on bone-anchored devices, and Ken Higgins demonstrated two methods.

The ‘bite bar’ supplied by the manufacturer enables a normally-hearing person to listen to a bone-anchored aid. The device is fitted to the abutment end of the bar; the tester then grips between their teeth and blocks their ears, allowing environmental sounds to be heard through bone conduction. This is a simple procedure, but obviously not practical in a setting where different members of a team may share equipment.

An alternative testing procedure uses the Baha/Ponto 22 listener kit (available from Connevans), comprising a special mount linked to the Crescendo 50 which allows the Baha/Ponto to be listened to via headphones. (For information, the Baha 32 ToD VIP listener kit also includes the FM accessories tester and an attenuated stetoclip).

Updates and agonies topic list

Using FM systems outside school

When discussing audiology policies with schools and services, we find that practice varies regarding pupils taking home their personal FM systems (radio aids). The potential benefits of using FM systems beyond the classroom are widely appreciated - and are addressed in the Quality Standards and Good Practice Guide published by NDCS - but practical concerns can prevent this becoming routine. Objections to systems leaving the school generally focus on cost of replacement if items are lost or damaged; doubts over families’ commitment or ability to use the systems effectively, or concerns about their reliability in returning equipment, fully charged, to school. In some areas, families are asked to insure the FM system or to pay a deposit before it is allowed to go home – although the NDCS Positioning Statement discourages such practice. (There may also be a problem insuring equipment that is the property of the school/LA, not the family, and there is no consistency in the way this is addressed.)

Other settings actively encourage families to incorporate the FM system into their everyday lives – accessing television and other technical/entertainment devices; engaging in conversations in a car or restaurant; participating in social clubs and activities etc. After all, clear communication is just as important in the evenings, at the weekend and during the holidays as it is in class! If deaf youngsters can experiment with using their systems in the wider world, they are more likely to recognise the benefits they may offer in college, the workplace and a variety of social settings and continue to use them once they leave school. This topic generates a lot of debate and demonstrates the need to have a clear audiology policy that recognises the importance of including families in planning and training sessions in order to ensure consistent good practice.

Updates and agonies topic list

Testing open fit hearing aids

The number of students being fitted with open fit hearing aids has been increasing, prompting a lot of queries about how to carry out routine tests on them. There are a few options available.

Using standard stetoclips for regular listening checks may not be practical when the audible gain is too low. However, Connevans Ltd has just produced a new gadget (Part No FMG750HA) to enable subjective listening of open fit aids, to be used in conjunction with their accessories tester and FM Genie microphone.

You can obtain comparative frequency response curves for open fit hearing aids in a testbox. Frye have a specific open fit coupler to enable testing of open fit hearing aids, so if you have a Frye testbox and pupils with open fit hearing aids then you should obtain one of these. If you don’t have the open fit coupler, it may be possible to fit the thin tube from the hearing aid into the tube from the 2cc coupler. You will need to remove the dome first so, if you use this method, make sure that you have an exact replacement dome available as the old dome must not be refitted once removed.

It is essential that open fit tubing (thin tubes) are cleaned regularly. As the diameter is much smaller than that of standard tubing they do become blocked much more easily. Users should be provided with cleaning sticks.

Updates and agonies topic list

Phonak Inspiro transmitter and Phonak MLxi receivers

A Year 9 boy uses Phonak Inspiro transmitter and Phonak MLxi receivers. The receivers are kept at school overnight in a small plastic box. The receivers worked fine on Monday, but on Tuesday both receivers were found to be not working. What is the possible cause for both to fail at the same time, and what test or checks could be made at school to try and resolve this issue?

You say:

I can think of three possible/likely reasons why both stop working at the same time:

  1. The hearing aid batteries are too flat to power the receivers; change the batteries
  2. The frequency on the Inspiro could have been changed, try standing next to the child and pressing the Sync button
  3. The microphone has been muted, check display/unmute.

The experts* say:

It would be unusual for both receivers to develop a genuine fault overnight: it is more likely that the transmitter is to blame (one item), which would have an effect on both receivers. However, my first thoughts are that this is probably an issue relating to the programming of the FM system or hearing instrument.

Carry out a systematic check to make sure the mic is not muted and that the plug at the rear is fully inserted (the backplate is easily removed by unscrewing the belt clip stud). I would test the transmitter using my scanning receiver set to the transmitter’s frequency, but a more practical option for a ToD would be to try a different transmitter on the same frequency.

A very useful piece of kit is the Connevans FM Accessories Tester. You can plug an ear level receiver into the top socket and listen directly to its output via earphones, eliminating all issues with the hearing aid: is it FM enabled? is the shoe faulty? etc. As the accessories tester provides power to the MLx, you can also use it to check the receiver with the ‘toaster’ and Successware: is the default frequency correct, or were the receivers originally made to work by ‘zapping’, or ‘syncing’ with the Inspiro? If all is well with the accessories tester, then the hearing aid or shoe must be the culprit, though again it is highly unlikely that both would fail at the same time, which brings us back to the transmitter.

A word from Phonak:

This may be battery-related.  People often forget that you should not wait for the low battery warning on the aid.  You need 1v to power an MLxi and the battery warning comes on at 0.8V, so the aid may work but as soon as you connect the FM it fails. Check this first, and also check that the aids are on the correct programme.  After that you need to look at basic mechanical things like bad audio shoes or dirty contacts.  Try checking them on another aid if possible or a tester.

Updates and agonies topic list

Nathos Micro aids

We have a child that has Nathos Micro aids. The audiology clinic says that the FM programme has been activated, but when we connect the FM system we cannot get it to work. We have tested the FM system independently and it definitely works. Please help.

You say:

I know this sound obvious, but we found that one of our children's aids had a tiny sticker over the contacts; it was really small and the same colour as its surrounding, so it was hard to see. If it’s there, remove it and FM should be fine. Also, if using ear level receivers, try replacing the battery in the hearing aid as it has to power the receiver as well.

The experts* say:

Did you remove the label from the contact on the hearing aid? Lots of people have been caught out by this and the shoes won't be able to make contact while it is in place. There is a tiny sticker covering the contacts which is often missed both by audiology departments and out in the field. It’s easily done as the contacts are inside the battery compartment and the sticker is very small: unless it has been pointed out to someone, they would be totally unaware. Carefully peel it away from the contacts and, as long as FM has been activated, the FM system should now work.

A word from Phonak:

It is likely that the cover has not been removed from the audio contacts.  Nathos Micro is popular with babies and small children, so we put some extra protection on the contacts. http://www.phonakpro.com/uk/b2b/en/products/fm/receivers/ml12i.html contains information and a video clip you may find helpful.

Updates and agonies topic list

Radio aid default frequencies

A radio aid seems to be broken, but it will sometimes work if I switch on the transmitter when I am next to the child. Does the system need to be replaced or is there a reason for this erratic behaviour?

You say:

It is likely that the transmitter and receiver are set to different default frequencies. If the child has plugged in the receiver AND it has powered up before the transmitter is turned on close by (within 200mm) then the receiver will change frequency to match and the system will work. This means that by chance sometimes it works but most of the time it doesn't.

Use the programming software to set the default frequencies to be the same.

The experts* say:

It sounds as though the default frequencies (channels) of the transmitter and receiver are not the same, so the transmitter is on and working but does not tie up with the receiver. However, if the transmitter is switched on when near to the receiver the receiver will synthesise to be the same as that of the transmitter and, bingo, it all works – until the hearing instrument or the receiver is switched off or disconnected, in which case the receiver will revert to its own default frequency. A quick check using the Phonak Successware would confirm what default frequency the receivers have been set to and the receiver or transmitter channels can then be changed to match appropriately.

* Information provided by members of the Ewing Foundation.

Updates and agonies topic list

If you can suggest a solution please contact Stevie Mayhook. and we will be able to share your answers