Polly Sanderson-Grasham said before the 2016 collision Terry Sanderson was a "fun-loving, gregarious" man, a "goer" and a "real positive influence", as well as an experienced skier.

But she told jurors her father's now "easily frustrated… gets agitated, angry" and "he's got a pretty short fuse".

She also said she didn't have a memory of him being an angry person before.

"I think he's just a little more cautious, not as confident - he's in a really negative place and that's hard for me as his daughter," she explained.

Retired optometrist Mr Sanderson, 76, is suing the Hollywood star for $300,000 (£244,000), claiming she was "out of control" and struck the fellow skier, causing him to suffer a brain injury, four broken ribs and other serious injuries.

Jurors heard the incident in Utah seven years ago "completely changed his life", with injuries likely to be "long-standing".

Paltrow, 50, is accused of leaving the scene without saying a word after the collision at the Deer Valley Resort on 26 February 2016.

The Shakespeare in Love star denies Mr Sanderson's claims and alleges it was he who crashed into her. Paltrow, who is also a lifestyle influencer, is counter-suing him for $1.

'Slap in the face'

On the third day of proceedings, Ms Sanderson-Grasham told the court in Park City, Utah, that at his granddaughter's graduation about three months after the crash, seeing the state of him was like "a slap in the face".

She said: "I felt like 'wow'. There was a moment when I almost expected drool to come out of his mouth.

"He wasn't engaged with anyone... that was my first slap in the face that something is terribly wrong."

He could now not "see the forest for the trees" and got stuck "in the minutiae" of things, according to Ms Sanderson-Grasham.

She later became emotional, telling the court: "I hope that he moves on. I hope that we're able to put this very strange chapter behind us.

"We have a lot of healing to do."

Missing GoPro footage

Paltrow's lawyer, Steve Owens, asked Ms Sanderson-Grasham about emails exchanged with her father on the day of the crash about GoPro footage which is missing.

Mr Owens asked her where the link went of what he called "the most important piece of evidence that could be presented at trial today".

Ms Sanderson-Grasham replied: "It looks like it's somewhere out there in the cybersphere."

The court then heard video testimony from Dr Richard Boehne who said the plaintiff's injuries had been caused by being struck from behind.

Dr Boehne said: "He was hit by someone from the side and from behind, bear in mind that person landed on him. People who fall don't get rib fractures... it takes something else."

Earlier, the court was told Mr Sanderson "pretty much" lost his love of life after the crash.

'It was affecting his personal life, his relationships'

Neuropsychologist Dr Alina Fong gave video evidence, saying when she first met Mr Sanderson in 2017, he presented "a myriad" of symptoms which indicated having suffered a concussion.

She said: "According to Terry's report, these were quite significantly affecting his life. It was affecting his personal life, his relationships.

"It affected him on so many levels, especially for someone who was used to loving life... by the time he came to me that was pretty much gone."

Her words echoed those of fellow neuropsychologist Dr Sam Goldstein, who on Wednesday said the 2016 incident caused an "acute rapid downturn" in Mr Sanderson's behaviour and functioning that had not stemmed from pre-existing medical issues.

Dr Fong challenged the opinions of other medical experts employed by Ms Paltrow's defence, adding: "This has completely changed his life physically, emotionally, biologically - and he has been affected in all those domains."

She said there was no evidence "whatsoever" that Mr Sanderson was "faking" his injuries and he had been "an ideal patient".

Read more:
Day one's evidence
Day two's evidence

On ski slopes, Utah law gives the skier who is downhill the right of way, and a central question in the case is who was farther down the run when the collision happened.

Both Paltrow and Mr Sanderson claim they were further downhill when the other rammed into them, causing their skis to intertwine and the pair to tumble.

The case is expected to last eight days.