PLANS to implant a tiny hearing device in profoundly deaf children have been stalled for a year because Hong Kong parents do not want to be the first to undergo the procedure. The Hong Kong Society for the Deaf which is funding the project has been searching for five children to receive the device - known as the cochlea implant - since last year. It has been implanted in several adults in Hong Kong but not in children, although it is used in youngsters in other countries, including Japan, Australia, the United States and Taiwan. Although several parents have said they are willing for their children to undergo the procedure - which would enable them to hear sounds for the first time in their life - they do not want to be the first to receive the surgical implant. Hong Kong University audiologist Dennis Au Kiu-kwok, who is working on the project, said the society, which would foot the cost of $180,000 for each cochlea implant, was very surprised by the parents' reluctance. ''But we can't force people to do the operation,'' he said. ''It's just ignorance of what's happening overseas. They feel it is a new surgical means.'' Mr Au said the families were afraid of being used as ''guinea pigs'' despite being reassured that the device is well-established elsewhere. The US Food and Drug Administration gave the go-ahead for the cochlea implant to be used in children a couple of years ago in all hospitals. It has been approved for adults since 1989, Mr Au said. ''Its effectiveness has been confirmed so it is no more a research project, it is a clinical procedure.'' The cochlea implant is a tiny electrical device implanted directly into the ear where it mimics the behaviour of the hair cells which pass electrical impulses to the auditory nerve, which the brain then translates as sounds. Damage to these hair cells - or lack of them - results in deafness. ''It gives the pattern of speech sounds,'' Mr Au said. ''It just bypasses the hair cells.'' The sounds heard through the cochlea implant are not exactly the same as those heard by people with full hearing. Mr Au said they sounded ''a little bit mechanical, like sound from the radio''. But for profoundly deaf people, who cannot be helped by conventional hearing aids, the cochlea implant is their only chance of ever entering the world of sound. In addition to the implant patients must wear a receiver to pick up sounds and a speech processor, which is the size of a hearing aid. The device can be implanted in children as young as two years old. After the surgery, they must receive extensive speech training, which can last years. Mr Au said the sooner children could receive the implant the better their social and educational development would be. ''Profoundly deaf children are quite isolated,'' he said. ''They can't communicate, they can't join in social activities. ''Their speech and language might be delayed and even their thinking or cognitive processes because these depend on speech and language.''