An FM System for Speechreading

Mark Ross, Ph.D., Harry Levitt, Ph.D.

 

If one examines the history of special education, it seems that many of the most important developments were stimulated by the parents of the children who had special needs. This includes the founding of the major schools for the deaf in this country and all types of special education statutes and regulations. Now, we have another contribution to the world of special education by parents, this time a device that two parents have developed to help their hearing-impaired child in a regular classroom.

 

When it came time for Marie Lapalme and Luc Ducas to send their child to a regular school, they well understood that he was going to have problems. Raphael could do very well if he could both see and hear the teacher, but if he were to be deprived of one of these channels, his comprehension would suffer. Fortunately, these were not only committed parents, but computer engineers as well. As they brainstormed the various technical possibilities for their son, they came up with the simple notion (in retrospect) of expanding the capabilities of a classroom FM system so as to include visual as well as auditory cues. They named their new device the "Audisee".

 

In the Audisee, a miniature lightweight camera and microphone are mounted on a headset that can be worn conveniently by the teacher. The camera and microphone are positioned about eight inches from the face, slightly below the mouth. The device does not obstruct the normal visualization of the teacher’s lips. A wire leads to an FM transmitter worn at the waist. The image can be displayed on either a small 5-inch screen placed on the student’s desk or standard TV screen placed in front of the class. The system is compatible with current FM systems, so the teacher need wear only one transmitter for both sound and image.

 

Using this system, a child can consistently combine the audio and visual components of the teacher’s speech. Reception is not affected if the teacher turns to the blackboard or moves around the room, as would ordinarily be the case for children who depend partially or mainly upon speechreading. Another very useful feature of the system is that the visual image of the face is relatively large,  showing details of the lips mouth that are not normally visible in a classroom setting; i.e.; when the student is some distance from the teacher. The student is free to look at the screen or at the teacher, whichever is preferable at the time. Thus, audio-visual speech perception is consistently and continually optimized for the child. This not only facilitates notetaking, but also reduces the fatigue that occurs when children have to work doubly hard to receive a message. 

 

Several projects on the system have been conducted by Jean-Pierre Gagne from School of Speech-Pathology and Audiology at the University of Montreal in Canada. The focus in the first study was to determine if there is any improvement in speechreading ability with Audisee compared to the common classroom situation where the teacher and student are some distance apart. Videorecordings of test sentences were made of a speaker at three different distances (1.83, 3.66 and 7.32 meters). Videorecordings were also made simultaneously using the Audisee. Thus, there were two recordings, one from the Audisee and one directly from the speakers at the three different distances. Speechreading scores were obtained for the two sets of videorecordings. The results showed that, as expected, speechreading scores decreased as the distance between the speaker and the camera increased, particularly at the largest distance. The scores for the videorecordings obtained with the Audisee remained essentially the same for the three tests, since these recordings were obtained similarly in all three cases.

 

In the second study, twelve teacher-student teams in various schools tried the system for periods ranging from 8 to 31 weeks. The teachers recorded their observations during this time, while the experimenters made frequent in-class observations. At the conclusion of the trial, individual and group interviews were conducted. The results supported the concept of a wearable audiovisual FM system in that both teachers and students reported that the system facilitated overall speech perception.  One by-product of the project was the increased sensitivity of the classroom teachers regarding the value of visual cues for hearing-impaired students.  

 

The Audisee was designed for classroom use by a child who wears a hearing aid. It can be used, however, by any student who depends on speechreading cues for the reception of speech, including students who use a cochlear implant or even normal hearing students in a noisy or reverberant classroom. The possibility of including a variation of the Audisee concept in a classroom sound-field amplification system is intriguing and worth further investigation.

 

It is important to bear in mind that field experience with wearable audiovisual FM systems is still limited. As more of these devices are utilized in more and more schools, parents and professionals will be able to better judge its merits. It does appear to be an innovative and creative response to a child’s real need.

 
The philosopher Bertrand Russell was once asked for the secret of his success. He replied that it was important to choose one's parents wisely. In this regard, Raphael has made a very wise choice. (Further information on the Audisee can be obtained from luc.ducas@audisoft.net).