The system responsible for the fluctuating sound is called a Soundbeam, and the man who devised this way of using it is Phil Ellis, professor of performance arts at the University of Sunderland. The key component of the system is a small ultrasound transmitter and receiver mounted on a stand behind Dionne. This device directs a beam of ultrasound at the back of her head, then detects the reflections from it. Each time she moves the reflections change, and these changes are used to modulate the output of an electronic sound synthesiser.
Phil Ellis trained in classical music, taught in a comprehensive school, then moved into higher education to work on electro-acoustic music. He became interested in children with special needs 10 years ago while working in Warwick University's education department. "For a lot of these young people it's the only time in their lives they're in control of anything. Normally they may have no self-control, little self-awareness and no self-help skills at all. Everything has to be done for them. Some have no communication skills. They may be blind or hearing impaired or have epilepsy or cerebral palsy."
Although he speaks of what he does as sound "therapy", Phil Ellis admits he only uses the word for want of something more appropriate. "The essence of the approach I've developed is very much non-interventionist." The children are doing it for themselves.
Some children, for example, are plagued by involuntary movements. Once they have learned to associate these movements with changes to the sounds they are hearing, they have an incentive to control the movements.
In a related project Phil Ellis uses sensors attached directly to the body; even tiny movements of the child's muscles affect what is coming through the speakers. "I remember one boy who'd had months of physiotherapy but wouldn't move at all. The first time we put a sensor on his arm he started to move it. After about two months he was using his arm in day-to-day living."
Emotional development is another aspect. Phil Ellis talks of "reaching" pupils, of establishing relationships with them, of seeing them smile for the first time. "Just magic," he says. Cognitive improvement is less dramatic, but he claims to detect signs of greater concentration and engagement. "Time and again you find children who might be able to concentrate on something for just 10 or 15 seconds. They come to sound therapy and after that they're regularly engaged for 10 or 15 minutes."
Class teacher Jackie Magee sees changes in Dionne when she comes back from a session. "She's calmer, less likely to hyperventilate, more aware of what's happening. Like the other children she seems to get a better sense of herself."
The aim is to help able pupils to develop their potential. With the variety of disorders and disabilities at a school such as Davenport, this covers a wide range. Sceptics might wonder whether the benefits of the Soundbeam are as specific as Phil Ellis believes: whether the more general effect of the extra attention paid to the children might not be just as important. He offers two arguments. First, some of the children have already failed to respond to any other form of help; second, most of what goes on is an interaction between the child and the sound, not between the child and the therapist or teacher.
Young people using the Soundbeam normally have weekly sessions lasting from five to 30 minutes. The cost of the set-up is around pound;2,700 but the training required is minimal. "One of my aims is to make it possible for anyone to operate this system," says Phil Ellis.
* Soundbeam, e-mail: firstname.lastname@example.org Geoff Watts presents Radio 4's science programme 'Leading Edge'