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There's a New Star in School: Making FM Work for Children with Listening Difficulties

There's a New Star in School: Making FM Work for Children with Listening Difficulties
Mary Humitz, AuD, CCC-A, FAAA
December 1, 2014
This article is sponsored by Oticon.

Editor’s Note: This text course is an edited transcript of a live webinar. Download supplemental course materials.

An Afternoon in the Classroom

All of you remember what it was like to be a student in a classroom.   I would like to ask you to imagine you are eight years old sitting in the back of the class.  This is your favorite spot because you are immediately out of the line-of-sight of the teacher and less likely to be called upon.  It is the afternoon, and you are learning a new lesson about volcanoes.  The teacher is presenting vocabulary that you have never heard before, like magma, crater, plate tectonics, and lava.  Two classmates are seated in front in you, and they are whispering about their plans after school.  You tend to shift your focus between the other kids and the teacher, but you are more distracted by these other children whispering.  The school grounds’ crew is working on the building just outside the window.  There is a fan overhead in the classroom adding some low-level noise.  All of this combined makes it hard to concentrate on the teacher.  So what do you do?  You zone out. The scenario I just described can make listening very difficult for any child.  There are noisy distractions both inside and outside of the room.  There is auditory competition from other students talking or whispering.  There are poor room acoustics, and you are a distance from the teacher who is presenting novel words that may or may not have meaning to you.  On top of that, it is the afternoon and fatigue is high. 

Students with normal hearing can struggle for full understanding of what the teacher is saying under these exact same conditions.  It should be obvious that students with listening difficulties would be struggling as well.  What can we do to help these children succeed?  We need to enhance their access to the auditory information. 


Today I will discuss the importance of acoustical accessibility in a classroom and/or other difficult listening situations, or situations with complex noise.  I will demonstrate how to assemble and fit the Amigo Star on the ear and integrate it with an FM transmitter.  Lastly, I will explain some of the practicalities of use of our Streamer Pro with a universal FM receiver option in the classroom.

Classroom Listening Conditions

Let me begin by talking about classroom listening conditions.  Children are in quiet learning environments for much of the day, and in noisier places at other times of the day.  During any activity, however, there can be significant fluctuations in noise levels.  In a recent study, Jeff Crukley and colleagues (2012) looked non-quiet listening situations in elementary and high schools.  He found was that there was great variation in signal-to-noise ratios (SNR) throughout the day.  He found that these results were similar for both elementary and high schools. 

We know that children are still in the process of acquiring speech and language, and they require a higher SNR than adults to achieve the same level of understanding (Bradley & Sato, 2008; Klatte, Lachmann, & Meis, 2010; Neuman, Wroblewski, Hajicek, & Rubinstein, 2010.)  Neuman and colleagues (2010) showed that adults require a +4 dB SNR to score 80% correct in word recognition.  Compare that to a child of age six.  In order to score the same 80% correct, this child needs a +11 dB SNR.  In other words, if you and I were in a classroom with children present, we are going to be able to understand more easily than the children. 

Why is that?  It is because the adult cognitive system is more developed than a child’s.  Our adult auditory systems can cope with listening and following in complex situations.  We have also developed speech and language with a richer linguistic diet.  We have more words in our repertoire.  Based on Crukley’s work (2012), there will be times over the school day where you will have poor SNRs in various environments, and depending on what age the child is, you need more or less of a SNR advantage. 

It is a complicated process to hear and integrate information from detection through central processing.  For children, having normal hearing is not always enough, because their auditory system is not as mature.  Children need to learn to integrate multiple acoustic sources at the same time.  Doing this effectively requires auditory and cognitive processes to be well integrated, which comes with age and maturation (Moore, 2012).  This matches the data indicating that children are not as good as adults at spatial separation tasks or timing information to locate the sound source.  Children have broader auditory filters, equating to poor frequency resolution, which, again, matures with age.  In general, young children are not as efficient as adults in decoding, processing, and encoding the information that they are receiving.  This improves with cognitive maturation. 

There are additional factors that compromise a child’s ability to listen in these complex environments, both inside and outside the classroom.  Research tells us that parts of the brain that control attention develop later and are more immature for younger brains (Hwang, Velanova, & Luna, 2010).  This maturation process can extend well into the teenage years and young adulthood even.  To be a good listener, especially in noise, children need a rich auditory diet (Flexer, 2011).  In some environments outside of the classroom, they may not be exposed to a rich auditory diet. 

Listening in complex environments can be compromised if the listener is unfamiliar with the language.  How many of you work with children where English is not their native language? 

If you are a child with unilateral or minimal hearing loss, it will be much harder for you to cope in complex auditory environments (Tabri, Abou Chacra, & Pring, 2011).  As many of you know, children with auditory processing deficits have a greater difficulty interpreting what is being said in complex acoustic conditions.  Greater effort is needed in a classroom that has a poor SNR.  Listening in complex situations is a cognitive process which can be much more difficult and require greater cognitive resources to follow along, especially when the teacher is presenting new vocabulary or auditory-only information. 

When children are permanently or temporarily compromised with respect to the factors I just mentioned, their ability to perform in noisy or distracting environments starts to break down.   What can be done to help children improve listening or to succeed in these challenging listening environments?  One option would be to fit an ear-level frequency modulated (FM) system to the child to help them listen more effectively in these classroom situations.  There is a fair amount of research showing that personal FM systems significantly improve the SNR to make it easier for children to listen in challenging situations. 

What is Amigo Star?

I am happy to introduce the Amigo Star.  Amigo Star is an ear-level FM receiver.  It is not a hearing instrument.  There is no environmental microphone on this instrument, and it receives its signal from an FM transmitter.  We see it being used primarily with school-age children in a binaural arrangement. 

There are many studies supporting the benefit of the use of FM systems for children with auditory deficits.  Research has shown that benefits from using ear-level FM can be seen in improved academic outcomes with auditory processing disorder (APD; Johnston, John, Kreisman, Hall, & Crandell, 2009), as well as possible improvements in social behavior.  Other studies support the benefits of the use of FM for non-native listeners (Tabri, et al., 2011), as well as children with reading delays (Purdy, Smart, Baily, & Sharma, 2009).

The Amigo Star works to overcome the negative effects of distance, noise, and reverberation, just like other FM systems.  The teacher wears an FM transmitter that broadcasts the signal to the ear-level receivers.  The Amigo Star is most often used by children ages 5 to 16, with a core group of ages 7 to 12, in the school setting.  We are seeing it being fitted on children both inside and outside of the classroom, and even on some of adults as well.  Interestingly, most users will be male.

Amigo Star Features

It is comfortable and easy to wear.  Audiologists and teachers report that it is easy to handle, fit and maintain.  Because of its light weight and Corda2 thin tube fitting, it is comfortable on the ear and inexpensive to maintain as the child grows.  It is also very reliable with a robust design.  The Amigo Star can be fitted from one child to the next in schools, year after year. 

I will discuss the key features in depth, but as a quick overview, the Star is equipped with a volume control, LED signal light, channel seek button and the option of a tamper-resistant battery door (Figure 1).  It has intelligent sleep and off modes.  The Amigo Star takes a 312 battery and carries the IP57 dust and water resistance rating.  Figure 1 shows a picture overview of the key features.  Any of the information I discuss can be found on our website ( 

Amigo Star key features

Figure 1.  Amigo Star key features.

Volume Control

In the early development of this product, one of the most requested features from our focus groups was volume control.  We added an analog wheel.  The wheel also functions as an off switch when the volume control is rolled down to one on the scale.  The range is 14 dB in 2 dB steps.  The volume control can be disabled for young children. 

Figure 2 shows the different volume control settings from one to four as a real-ear response.  The transmitter microphone is seated in the test box and the Amigo Star is on the child’s ear with a probe microphone down in the ear canal.  The targets are based on thresholds within the normal hearing range, 15 dB across the frequency range in this case. 

Real-ear responses for the volume control in various settings on the Amigo Star

Figure 2. Real-ear responses for the volume control in various settings on the Amigo Star.

The volume control set at one, for example, is the pink line in Figure 2.  If you inputted 15 dB thresholds, the targets you are trying to match are the pink plus signs.  You should be able to reach targets with the volume wheel set at two-and-a-half.  We developed this with DSL as our reference, and we consulted Leisha Eiten from Boystown on how to verify and set the Amigo Star with that 14 dB of gain.  The green line is the maximum power output (MPO), and you can see that the MPO never exceeds uncomfortable loudness levels (UCL).  Even if you had a child who wanted to use the device with a volume control higher than two-and-a-half, it will never be too loud. 

LED Light

Our hallmark LED can be seen on our hearing instruments and other FM receivers.  It provides the teacher with a quick and easy way to verify that the device is on and receiving information from a transmitter.  Additionally, when you are syncing or programming one of our T30 or T31 transmitters, it will give three quick blinks confirming that you have successfully synced or changed the channel on the transmitter and the receiver.  As with the volume wheel, the LED light can also be disabled. 

Corda2 Thin Tubes and Domes

We use Corda2 thin tubes on the Amigo Star, which provides a customizable, comfortable fit that is almost invisible on the ear.  Children like wearing it.  The tubes and domes are available in a number of different sizes so that you can fit almost any ear shape and size.  They are a cost-effective way to maintain the device for cleanliness and growth of the child.  The Corda2 thin tubes are easy for adults to attach and detach, and the domes are interchangeable. 

The Corda2 thin tube also acts as a high-pass/low-pass filter (Figure 3).  You can see the high-pass filter is below 750 Hz, and that is due to the open dome configuration.  We do not recommend the use of a closed mold with the Corda2 thin tube because it negates the open effect, especially with children who have normal hearing.  There is no environmental microphone on this instrument, and we do not recommend that you close off the ear canal.  Above 6000 Hz is a low-pass filter, and that is due to the natural attenuation of thin tubes.  We built in a low-pass filter that allows for compatibility with the Phonak transmitters, as well.

Effects of the Corda2 thin tube as high-pass and low-pass filters on the Amigo Star

Figure 3. Effects of the Corda2 thin tube as high-pass and low-pass filters on the Amigo Star.

When ordered, the Star comes with a starter tube kit.  You get four tubes, two for each ear.  They come in size 0 and 1 tube lengths, which are most common for children.  Those should fit most of your children’s ears.  Also included in the kit are medium and small domes.  We do have other sized domes and tubes that you can order for a nominal fee if you need them for children who do not fit the standard sizes.  They come in packages of 5 and 10.

Channel Seek Button

The Amigo Star also has a channel seek button located towards the bottom of the device.  It is analogous to pressing the button on your car stereo.  When pressed, the device will scan the environment and intelligently find the teacher’s transmitter.  This is a great feature for children who are moving from classroom to classroom throughout the day, encountering different transmitters or even different brands of transmitters.  You cannot point, shoot, and sync to our receivers from Phonak, but our receivers will scan the environment and lock into that transmitter.  It requires a pretty firm press, so do not worry that children will accidentally press it when they are placing it on their ear.  It can be disabled to prevent those inquisitive fingers from doing the wrong thing at the wrong time.  The channel seek button is also available on our other FM receivers.

Intelligent Sleep and Off Modes

To improve the instrument’s battery life, we have incorporated what is called intelligent sleep mode.  When there is no FM signal present, such as when the teacher turns off the transmitter because it is time to go to recess, the Amigo Star will go into sleep mode.  It will wake up every few seconds searching for the transmitter.  Once the transmitter is turned back on and an FM signal is received, the instrument will come out of sleep and into its normal mode. 

After 90 minutes of no FM signal, or at the end of the day when the child takes their Star off or the teacher turns off the transmitter, the instrument will reduce its power consumption and go to sleep.  It is not completely off, but the power consumption is minimal.  Even if the child never opens the battery door at night to completely turn it off, the battery will last a week.  With this intelligent sleep mode, you can put a fresh battery in on Monday morning and not replace the battery until the following Monday.  Children who are using the Amigo Star are not hearing impaired, so they may not be used to the routine of opening and closing the battery door.

There are a number of different ways to turn on the Star or take it out of sleep in the morning.  They can give a quick press to the channel seek button.  They can scroll the volume control up and down, or they could open and close the battery door.

Tough Construction

The Amigo Star was tested extensively.  It is very robust and carries our IP57 rating against dust and water, which our hearing devices have as well. 


The Star can be used with any transmitter.  We see it used most often with our Amigo T30 and T31 transmitters in the school.  It works beautifully with the T5 or T10 transmitters, too.  It is compatible with other manufacturers’ transmitters thanks to the channel seek button.


The Amigo can be programmed out in the field, which is a benefit for those working in schools.  All you need is our Amigo T30 or T31 transmitter with firmware of 9.6.0 or higher.  If you have a T30 or T31, it should show its firmware number on the screen at startup.  We can always walk you through that if you call customer service.  If you have an older model T30 or T31, we would be happy to update the firmware for you.  You do need to send us the transmitter, and we can send it right back.  Spring Break, holidays, or summer break are ideal times to send in the transmitters. 

Color Choices

The Star receiver comes in six colors (Figure 4).  Know that if you have a child who is actively involved in the decision-making of their Amigo Star, you have some color options.  We are finding that the Chroma Beige tends to be the most popular from a school inventory perspective. 

Color choices for the Amigo Star receiver

Figure 4. Color choices for the Amigo Star receiver.

Getting Started with Amigo Star

We have support materials for you to get started with Amigo Star.  Instructional videos are available from our website and from YouTube.  We also have instructional handouts.  I am going to show you a video clip of one of our instruction videos.  There is no audio on any of the videos.  This is because these are viewed around the world by a number of people speaking different languages.

Screenshot from video that demonstrates attaching the Corda2 thin tubes, inserting the battery door, and basic use of the system

This video demonstrates attaching the Corda2 thin tubes, inserting the battery door, and basic use of the system. As you can see, the system is very easy to use.  

FM Verification

Is verification still relevant with an ear-level FM receiver?  Absolutely.  It is the only way you know how much sound pressure level (SPL) the device is providing at the eardrum.  I would like to show you another video clip of the on-ear verification process.  We know that the output is influenced by ear canal volume, so smaller ear canals may give a louder SPL at the eardrum, and larger ear canals might be softer.  Verification is always recommended, even though this is not a hearing aid. 

Screenshot from video on FM Verification

We made this product with 14 dB gain and a low MPO.  A volume of two-and-a-half represents DSL targets for most children with normal or near-normal hearing thresholds.  Even if the child likes to turn the volume up higher, they are still going to be safe because they will never exceed 14 dB.  Keep in mind that this device is not designed for children with hearing loss; we have other products for children with hearing loss.  Furthermore, it is an open dome configuration and will not provide any amplification in the low frequencies.

Support Materials

Like I mentioned, there are good support materials with respect to the different transmitters that are used with the Star that can be accessed by support staff, teachers, and audiologists who work with teachers and school systems that are far away.  You could refer them to the instructional videos and walk them through it over the phone if needed. 

Streamer Pro with FM

I am going to change gears and talk to you now about another technology for FM application:  Streamer Pro.  We know audio connections have become an integral part of a young person’s everyday life.  The Oticon Streamer Pro offers a Bluetooth wireless connection between hearing instruments and devices such as smartphones, MP3 players, and gaming devices.  It also provides connection with FM.  As children get into their teen years, we know that the size of hearing instruments can be a major part of their acceptance and daily use of their hearing aids, but along with that can be the acceptance and use of their FM system. 

Children have said for years that they want smaller and cooler looking hearing instruments.  In past years, young people were not often able to wear smaller hearing instruments because it meant that they would not have FM accessibility.  However, it was a catch-22 when they started to reject their hearing aids because of size; FM went with it anyway.  If they were not wearing their hearing aids, they were not getting access to FM either.  Even children who had been good at wearing their hearing instruments and using FM daily started rejecting their amplification as they got older.  You and I know how important it is for them to continue wearing their hearing instruments both inside and outside a classroom, and we also know how important it is to their academic performance to have access to FM. 

The Streamer Pro can be thought of as another tool in your toolbox to help children who may be rejecting their FM because they are self-conscious.  The Streamer Pro ensures FM access without adding to the size of their hearing device.  By using the Euro pin socket at the bottom of the Streamer Pro, sound is received by the FM receiver and then is sent up to the hearing instruments.  FM is coming in at ear-level via Streamer Pro transmission. 

The Streamer Pro it is a gateway device between other devices and the hearing instruments.  It sits around the neck and communicates up to our hearing instruments through Bluetooth.  Bluetooth is not necessarily used with FM, however.  The FM receiver attaches at the bottom of the Streamer, and then the Streamer broadcasts to the hearing aids.  Only one FM receiver is needed to talk to both hearing instruments.  You get eight hours of battery life in the Streamer Pro when FM is used; it does not pull battery from the hearing instruments.  It can be used with any transmitter.

Young people really like this.  They can wear it around their neck and use it for many different applications outside of the classroom.  They talk on their phones.  They use it with their computers.  They use it with their music players.  Utilizing the Streamer in the classroom can be a solution when kids are not willing to wear the FM attached to their hearing aid or if the FM receiver is not compatible with a smaller hearing aid. 

Streamer Pro is backwards compatible with any Streamer-compatible Oticon hearing instruments (Figure 5).  Although not listed here, any Safari instruments that have already been fitted on children that are Streamer compatible are Streamer Pro compatible and can be used for FM purposes.  You might have a teenager or young college student who is now wearing an in-the ear (ITE) or a mini instrument and can receive the FM signal through the Streamer Pro.

Oticon hearing aids that are compatible with Oticon Streamer Pro

Figure 5. Oticon hearing aids that are compatible with Oticon Streamer Pro.  (Oticon Safari not shown.)


Further reading and resources for the Amigo Star can be found in Figure 6.

Further reading and resources for Amigo Star

Figure 6. Further reading and resources for Amigo Star.


Bradley, J. S., & Sato, H. (2008). The intelligibility of speech in elementary school classrooms. Journal of the Acoustical Society of America, 123(4), 2078-2086. doi: 10.1121/1.2839285.

Crukley, J., Scollie, S., Parsa, V. (2012). An exploration of non-quiet listening at school. Journal of Educational Audiology, 17, 23-35.

Flexer, C. (2011). Cochlear implants and neuroplasticity: linking auditory exposure and practice. Cochlear Implants International, 12 Suppl1(S19-S21). doi: 10.1179/146701011X13001035752255.

Hwang, K., Velanova, K., & Luna, B. (2010). Strengthening of top-down frontal cognitive control networks underlying the development of inhibitory control: a functional magnetic resonance imaging effective connectivity study. The Journal of Neuroscience, 30(46), 15535-15545. doi: 10.1523/JNEUROSCI.2825-10.2010.

Johnston, K. N., John, A. B., Kreisman, N. V., Hall, J. W., & Crandell, C. C. (2009). Multiple benefits of personal FM system use by children with Auditory Processing Disorder (APD). International Journal of Audiology, 48(6), 371-383. doi: 10.1080/14992020802687516.

Klatte, M., Lachmann, T., & Meis, M. (2010). Effects of noise and reverberation on speech perception and listening comprehension of children and adults in a classroom-like setting. Noise & Health, 12(49), 270-282. doi: 10.4103/1463-1741.70506.

Moore, D. R. (2012). Listening difficulties in children: bottom-up and top-down contributions. Journal of Communication Disorders, 45(6), 411-418. doi: 10.1016/j.jcomdis.2012.06.006.

Neuman, A. C., Wroblewski, M., Hajicek, J., & Rubinstein, A. (2010). Combined effects of noise and reverberation on speech recognition performance of normal-hearing children and adults. Ear and Hearing, 31(3), 336-344. doi: 10.1097/AUD.0b013e3181d3d514.

Purdy, S. C., Smart, J. L., Baily, M., & Sharma, M. (2009). Do children with reading delay benefit from the use of personal FM systems in the classroom? International Journal of Audiology, 48(12), 843-852. doi: 10.3109/14992020903140910.

Tabri, D., Abou Chacra, K. M., & Pring, T. (2011). Speech perception in noise by monolingual, bilingual and trilingual listeners. International Journal of Language and Communication Disorders, 46(4), 411-422. doi: 10.3109/13682822.2010.519372.

Cite this content as:

Humitz, M. (2014, December). There's a new Star in school: making FM work for children with listening difficulties. AudiologyOnline, Article 13084 Retrieved from:


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Mary Humitz, AuD, CCC-A, FAAA

Mary Humitz, MA, CCC-A, FAAA, is a Trainer and Support Audiologist in the Pediatric Department. Prior to joining Oticon, Mary served in a number of different capacities, including work as an educational audiologist and clinical audiologist, was a trainer for another hearing aid manufacturer, served as an adjunct professor at Eastern Michigan University, owned a private practice in Rochester Hills, MI, and was the Audiology Department Manager at a suburban Detroit Hospital. Mary did her undergraduate work at Michigan State University and completed her Master’s degree at Central Michigan University. She is currently completing her Doctorate of Audiology from Arizona School of Health Sciences at A.T. Stills University.

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