Gabriella Cedillo, who was 24 years old at the time of her accident, was hit in the head by a cable while shooting the Michael Bay-directed film in September 2010.
The tow cable pulling her vehicle snapped under tension and smashed through the windscreen, NBC Chicago reports.
She was airlifted to hospital and underwent emergency surgery, but was left with irreversible brain damage.
Cedillo's lawyers allege that "a completely inadequate, superficial welt" was to blame for the cable having snapped, and that Paramount Pictures and Dreamworks Studios tried to avoid paying for Cedillo's medical bills or any compensation.
A lawyer for the family told RadarOnline: "She appears to be quite impaired with her ability to understand and appreciate everything.
"I'm not saying she's not coping... and considering where people thought she would be, she's fortunate.
"But she has the function of a small child right now."
Transformers star Shia LaBeouf was nearly blinded after being hit in the face by a prop on the film's set, and suffered a permanent hand injury in a vehicle collision.
Bay was reportedly close to cancelling the film owing to LaBeouf's injuries.
Watch Digital Spy's interviews with Transformers star Rosie Huntington-Whiteley and director Michael Bay below: