Wearing a black hat to hide a month-old scar zig-zagging along the side of her shaved head, Madam Jazz Wong watched in tears as her orchestra mates took the stage without her for a cello concert in January last year.

The 53-year-old - who picked up the instrument three years ago - had devoted most of 2014 to practise, raring to perform with her son, cello instructor Hughes Chong.

It was not to be. A stroke in October 2014 put her in a coma. Doctors warned Mr Chong that his mother's chances of recovery were slim.

But two years on, Madam Wong is well on her way to recovery, spending the bulk of her waking hours on the cello. Her first concert since the stroke is looming - she will perform with her son's amateur cello orchestra this Saturday - and she is making up for lost time.

Mr Chong, 28, says with a laugh: "Sometimes, it will be almost midnight and I'll be like 'Huh, what's that ghostly sound?' And it's my mother practising quietly.

"Missing the concert last year was a huge blow to her. So this year, I think she's been the most hardworking among all of us because she wants to be part of the concert so badly."

The Cellography Concert 2016 will see the orchestra he founded in 2014 playing popular hits such as Taylor Swift's Blank Space and Ed Sheeran's Thinking Out Loud. The pieces were rearranged by Mr Chong, a Nanyang Academy of Fine Arts graduate who majored in the cello and studied composition.

Madam Wong says: "I just don't want to be a burden. So I'm doing my best to play well with the orchestra. I want to play the cello with my son."

Music was her son's bridge to her as she lay in a coma in the intensive care unit (ICU) at the National University Hospital. Mr Chong would shuttle back and forth between the hospital and the cello classes he taught around the island, playing Madam Wong recordings of her favourite songs in the hopes of getting a reaction from her.

"I'd go to Yishun for one class, back to the hospital to play her one song and talk to her, down to Punggol, then back to the hospital," he recalls.

"One of the songs I played was her favourite: Summertime by George Gershwin. Every time I play it for her, she cries. So when she was in a coma, I'd put it on and just sit there in the ICU, crying along to the song."

Each time he saw her fingers twitch, the glimmer of hope he was nursing would grow.

After two weeks in a coma, Madam Wong woke up. But her memory had taken a hit. The widow could not recognise Mr Chong's brother - the older of her two sons - and drew a blank when asked for her name and address.

Moyamoya disease, a disorder caused by blocked arteries to the brain, was diagnosed as the cause of her stroke.

In December, Madam Wong went for surgery that would leave her with the palm-sized scar running along the right side of her head.

She was later moved to a rehabilitation centre in Senja.

There, she had her first encounter with the cello after her stroke.

"I'd always sneak in the cello and play it for her. One day I handed it to her and she wasn't sure what it was. But when I put it in her hands, she was able to set it up and sit in the correct posture," says Mr Chong.

"It showed me how the human brain can bounce back from anything."

When Madam Wong was discharged, she wanted to pick up where she left off with the cello - but 2015 would be a long year of recovery. She could not remember how to read the scores and her movements were impaired.

"It was very painful for her. She cried every single time she practised," says Mr Chong to his mother's laughter.

"A lot of people would have given up. But she, despite crying, despite saying many times 'I don't want to play any more', didn't. She'd play the cello, struggle, cry, leave, then come back with another song and go 'I want to try this now.' This entire experience taught me about my mother's never-say-die spirit."

She has since regained her memory and can read scores.

For Madam Wong, it revealed a new side of her younger son. Her husband died five years ago and her only other child lives and works in China.

She says of Mr Chong: "He's grown up. He can take care of himself, he can take care of me. I'm not worried about him any more."

Madam Wong started learning the cello in 2013, partly because she loved its rich sound and partly as a challenge to herself.

"If my son can play it, maybe I also can," the housewife says of her decision to learn her first musical instrument at age 50.

Mr Chong started his cello orchestra to band cello-lovers, whatever the skill level, together. It now has about 45 members, from students to working professionals, including lawyers and doctors.

The orchestra may be small, but it has big ambitions. For its first all- cello concert last year, it played to a crowd of 400. This year, it will perform at the Drama Centre Theatre, which seats about 600.

Mr Chong says: "Next year, we'll aim for 1,000 and, eventually, no matter how many years it's going to take, we want to move to the Esplanade Concert Hall. We shouldn't think of just performing small concerts for friends and families forever."

He adds: "We're going to get better, we're going to get bigger.

"And, hopefully, people who start off thinking 'Yucks, the cello is so weird and boring, sounds like a herd of buffalos' can walk away understanding the range of sounds the cello can produce and how versatile it can be."