The American musician, 82, joined British singer and campaigner Ashleigh Harley.
Brian Hyland has performed outside Downing Street to raise awareness for an NHS campaign.
The American musician, 82, joined British singer and campaigner Ashleigh Harley on Saturday, where they performed his hit Itsy Bity Teeny Weeny Yellow Polka Dot Bikini.
The pair played guitars and sung into a microphone set up outside the Prime Minister’s Office, where they were joined by others backing the campaign.
It aims to raise awareness of the number of young people who struggle to be diagnosed by the NHS and improve outcomes for patients facing delayed diagnosis of complex conditions.
Harley was 12 when she had her first seizure and started to become ill, but it took more than a decade before she was diagnosed, after her mother did her own research.
She previously told the Press Association: “I got seizures every day, which made school completely impossible because I was collapsing every day.
“I couldn’t see. I was getting paralysis quite badly, so I couldn’t use my hands. I couldn’t write down stuff. That was the first episode, that was when we realised something was wrong.
“We went down every single different route, and the doctors couldn’t figure out what it was. And there was the stipulation of, young people don’t get ill, therefore, you know, just go away and get on with it. It’ll be all right.”
However, Harley never recovered, and lost the ability to eat and speak and had to use a computer to communicate. She was eventually sent home from hospital to die.
She continued: “It actually was my mum who had to do all the research to figure out exactly what it was, figure out the sort of specialists we needed to talk to, and then as soon as she figured that out, then I was able to get treatment.”
Harley was eventually diagnosed with Ehlers-Danlos syndrome (EDS), a genetic condition that weakens connective tissue, which progressed into severe gastroparesis and refeeding syndrome, a life-threatening condition with a 15% survival rate.
She went on to say waiting for a diagnosis “ruined” her youth, which she had since discovered had been the experience of many other young people.
Harley has now founded a charity, Save Our Lives, to improve diagnostic protocols, and has released a cover of Itsy Bitsy Teenie Weenie Yellow Polkadot Bikini to raise funds.
The charity hopes to launch a new service adjacent to the NHS to speed up the diagnosis process and improve treatments for those suffering from delayed diagnosis.
Hyland previously told PA: “It touches me immensely because it’s such a tragic situation with children having their childhood taken away.”
