"Although she is not paralysed, she doesn't want to use her hands," her mother explained. "She gets upset at being made to use them."
While she cannot press a button, she can still use a computer - by looking at it. Through eye-gaze software that tracks and responds to the movement of her eyes with an infrared beam, Gabriella has the means to communicate with the outside world.
"It's been great for us to have this," Mrs Bardon said. "It's made a huge difference to her."
Gabriella was first given access to the system last year by family charity Norwood, and since then she has made steady progress. At the further education college where she was learning life skills, staff were "blown away", Mrs Bardon said.
"They realised that she knows more than they thought she knew. It has been a real eye-opener for them. I thought it would take a couple of years to use it."
Throwing digital custard pies and playing other games has helped to familiarise Gabriella with the technology. "The goal is to move on and teach her symbols so that she can tell us what she wants," her mother said.
Gabriella is now learning to get to grips with a newly installed program that will enable her to give "yes" or "no" responses on screen to questions people ask her, plus a menu with a choice of two drinks.
Before, to understand what she wanted, people would have to interpret her expressions or follow where her eyes pointed.
In order to use the computer, Gabriella's mother has had to wheel her into the kitchen, where it is set up on a table. "It's a cumbersome system," Mrs Bardon said. "We have been looking for a smaller, portable system which can be attached to her wheelchair, so she can use it wherever she goes."
A top-of-the-range eye-gaze system costs in the region of £11,000 - but the family were turned down when they applied for a government grant.
Mrs Bardon admits it was "something of a disappointment. We have just bought a cheaper tablet alternative and with the help of Norwood have cobbled together a system for her."
Although it might not be as powerful as the more expensive model, Gabriella will be able to take advantage of the new device once it is mounted on her wheelchair.
"It's early days yet," Mrs Bardon said. "We're hopeful we're on the right road to allow her to communicate."
Through eye-gaze, other Norwood beneficiaries can now open the door of their room, turn on the television, or Skype family and friends.
Assistive technology, or AT, has come some way since Stephen Hawking's computer-generated voice enabled one of the world's greatest minds to speak.
Inside the Pears special resource unit at the Jewish Community Secondary School (JCoSS) in East Barnet is a replica flat with a bedroom, kitchen and lounge. It is where Norwood demonstrates the gadgetry to its staff and those from other organisations.
It is also where the charity carries out assessments of users to see if they can benefit from AT.
Norwood's AT manager Joanne Surridge explained: "An in-depth assessment can take two or three hours and can get quite intense. This is a more comfortable environment.
"Families may not know of the range of equipment that could support them and otherwise struggle. We are here to give them an insight into that equipment and how it could help them."
Their clients range from nursery-age children to 80-year-old residents of Ravenswood, the residential village run by Norwood in Berkshire.
AT support officer Jay Tuck said: "There are plenty of people with no independent movement at all. We have a man who is in his 70s who can now turn on a light or the telly in his room."
A wireless switch has been fitted to the pensioner's wheelchair behind his head, which he can activate by leaning backwards. He can also use it to choose music and video on a laptop.
Sophisticated censors are another type of technology enabling vulnerable people to be monitored during the night without carers having to enter their room to check on them.
A censor can detect if someone has fallen out of bed or wandered off, for example. In one case, a woman slipped and knocked her head but the alarm alerted staff, and an ambulance was swiftly on the scene.
"You can also set one on delay so they have time get up and go to the loo," said Mr Tuck. "But if they are not back in bed in 10 minutes, that will set off the alarm."
People who cannot manage to use a key can have the option of a fingerprint system. But Norwood was once faced with the one-in-a-million instance of a man who did not have fingerprints. To complicate matters, he also had memory problems, so an electronic fob might have been useless by itself if he could not remember what it was for. The charity had to find a symbol that would remind him to use his fob.
"We want to open people's eyes to what is available," said Ms Sturridge. "The main point is to understand who you are supporting and what they need. We try to match the app to the person.
"It enables them to take control over some elements of their lives and do something which previously they couldn't."
