Phil Davison reports from Key Biscayne on the marine park where disabled children learn to talk
IN HIS home in Feltham, Middlesex, eight-year-old Joseph Stevenson cannot watch TV like other children. It is too noisy for his ultra-sensitive ears, the abrupt change of images too confusing. His parents, Jim and Sheila, have built an extension on to their home to allow them to watch TV, and they avoid using a normal refrigerator or electric kettle because of the noise.

Joseph is autistic, with a short attention span and a vocabulary of only 30 words spoken one at a time and rarely. Until two years ago, at the age of six, he had never uttered a word. Then, after swimming with dolphins in Florida, he surprised his parents by blurting out the word "In!" He wanted to get back in the water.

This week, Joseph was back in Florida with his parents, who hoped further "dolphin therapy" might not only add to his vocabulary but also increase his attention span, so that they can better communicate with him.

In a royal blue wetsuit and tightly-strapped into a lifebelt, Joseph looked a little uncomfortable as a baby dolphin called Ripley pushed him and Florida occupational therapist Natasha Bravo across the placid surface of a turquoise lagoon where the old TV series Flipper was first filmed.

Joseph kicked out and slapped the water but his mum assured me he was having a good time and that was just his way of interacting with Ripley. "He does that with dogs when he likes them," she said. "Autistic children rely on routine. Today, strangers are telling him what to do. In a couple of days, it will be part of his routine."

The Dolphin Human Therapy Centre here, behind the popular Seaquarium in a natural but filtered lagoon with a sand and rock bottom, treats children for assorted neurological problems, mainly cerebral palsy, Down's Syndrome and autism, by letting them interact with friendly, intelligent dolphins. Its founder, 53-year-old Glasgow-born neuropsychologist Dr Dave Nathanson, is proud of its successes but warns that the Centre cannot cure brain damage or perform miracles. Some of its past clients disagree.

"It is a miracle ... a dream come true ... a fairytale come true ... like seeing magic happening before your eyes," Tabitha Brice, of Weston- Super-Mare, said last month after her eight-year-old son, Nikki, pointed at the pool-sized lagoon and uttered his first-ever word - the same as Joseph's - "In". Nikki had always had the physical ability to speak, but had been starved of oxygen at birth and his vocal chords had never responded to the messages from his brain.

Not everyone agrees with Mrs Brice. "It sounds pretty hokey to me," says Dr Bernard Rimland of the Autism Research Institute in San Diego, California. "There is no scientific evidence at all that using dolphins is helpful. The reputable people in the field simply feel that the kids like the dolphins and it's a recreational thing."

Putting hope before such criticisms, families pay $6,200 for the recommended two-week therapy course - nine weekday sessions of 40 minutes each. At present exchange rates, that's around pounds 3,750, and does not include accommodation, air fares or any other costs. "I'm putting it all on credit cards," said Pauline Pearce, from Watford, whose eight-year-old son, Miles, who has Asperger Syndrome, a form of autism, was also dong therapy this week.

"He's very logical," said Mrs Pearce "but the social part is difficult. If Miles were in a native environment, like in the jungle, he'd probably be revered as the local witch doctor. But in or social environment, he's a misfit. He already speaks quite well, so I'm not expecting any dramatic change here."

One of Dr Nathanson's problems is the cost of dolphins, currently around $100,000 (pounds 60,000) for a baby. Here, he leases his eight dolphins from the Seaquarium. "You used to need a permit to let people swim with dolphins, but not any more. Now everyone's setting up swim-with-the-dolphins places and you can't buy dolphins for love nor money."

Over the past decade, Dr Nathanson's centre, formerly in the Florida Keys, has treated more than 800 children from 39 countries - from Australia and Azerbaijan to Kenya and Kuwait, but mostly from the US, Britain or Germany - and claims few, if any children go away without making progress. His staff claim 97 per cent success. "We routinely see kids speak here for the first time," says Dr Nathanson, who left Scotland at the age of three, spent his early career in New York and moved to Florida 25 years ago.

"There is no magic bullet. This is not a miracle. If a child comes here with Down's Syndrome or brain damage, we can't cure that. It's scientific therapy, with a lot of love and the involvement of the family.

"There are three things that increase a child's attention span - animals, music and water. We have two out of the three here."