"When I first had aphasia [language impairment caused by stroke] I couldn't walk or talk," Ryan said.
"I couldn't speak to anybody, it was terrible. I couldn't communicate or make people understand. And I spent those first six years feeling that I couldn't do anything about it.
"I was feeling lost at first but I went every week and got better and better, learning how to communicate again," said the former business owner and recording artist.
"Before I started, I couldn't even talk but now I can speak pretty good."
Ryan said part of restoring her speech was through joining the group and watching how Matthews breathed.
"More often than not the stroke is in the left side of the brain, and the right side is where all the music and creative side is. So people have had a stroke and find they cannot speak, but they can sing."
Matthews said singing helped people who had experienced traumas such as strokes restore their speech.
"It has been shown to definitely help. That would certainly be the case with Margaret," he said.
"It's physiotherapy of the voice; singing as therapy.
"For people who have had a stroke, research shows they can regain the ability to talk by learning to sing words they are unable to speak. If the brain's language centres are damaged, neural plasticity - 'rewiring' the brain - may train the part of the brain responsible for singing to take over the speech functions."
Matthews said in the six years since the group was set up, "a very strong community" had formed, mutually supporting each other through their speech therapy.
"It's a very powerful thing."
He said many people with Parkinson's disease joined because their voice could become quieter and more monotonous.
Bay of Plenty District Health Board communications manager Diana Marriott said Ryan was "locked in silence", before the Brainwave Singers came along.
To celebrate the six-year anniversary of the choir a special song, Never Say Never Again, has been gifted by English singer/songwriter Charlie Stubbings to the choir. After hearing a recording of the choir singing his song for the first time, Stubbings was moved to write to Matthews.
"That song reaches a whole new level when you consider and understand the people who are singing it, it gains a powerful new meaning, a true message of hope and perseverance," wrote Stubbings. "It's the most moving thing I've heard in years."
The Vocal Chords, a choir made up by health professionals in the Bay, the DHB Kapa haka group and the cast from A Matter of Taste performed at the show alongside the Brainwaves at Sunday's show.