Alicia Gawronski, 26, denied she assaulted or intimidated 81-year-old Gladys Buchanan on the evening of August 31 last year, but was found guilty of both offences following a two-day hearing in Wollongong Local Court.

The court heard police were called to Ms Buchanan's Station Street home about 10.45pm after a concerned neighbour reported hearing Gawronski "screaming" at her, part of which was filmed and recorded by the officers.

In the recording, played during a previous court hearing, Gawronski can be heard repeatedly berating Ms Buchanan, who has a "severe cognitive impairment", while directing her to be quiet and bend her knee as she bathed her

Ms Buchanan, can be heard whining, moaning and whimpering, before Gawronski puts a nappy on her in the lounge room.

"You're full of shit," Gawronski can be heard saying.

"You're a carry-on candy and you're full of shit. No one's going to believe someone who's full of shit and has dementia - remember that."

At one stage, Gawronski, who is Ms Buchanan's legal guardian and carer despite having no formal carer or nursing training, can be heard saying "do it again, I dare 'ya."

Giving evidence in court on Thursday, Gawronski said she had to use a closed fist to move Ms Buchanan's leg - which police claim constituted the assault - because she (Gawronski) had "razor sharp" acrylic nails and couldn't push the leg with her fingers.

Gawronski claimed she had to use "colourful" language to snap Ms Buchanan "back to reality" as she suffered from dementia.

Read more: Sons of Illawarra surfing legend convicted over Fairy Meadow pub brawl

The swear words, Gawronski said was language Ms Buchanan could understand as she was an "Aussie larrikin" you used "pub talk".

However, in finding Gawronski guilty of the offences, Magistrate Roger Clisdell said he was satisfied she had "reached the end of her tether and she was incapable of looking after Ms Buchanan".

"Gawronski took on a task which was well beyond her ability and indeed a high-dependence person like Ms Buchanan would certainly require more than one person to assist in her care given her frailty," he said.

"To say what was happening to Ms Buchanan was disturbing is to put it mildly.

"She was abused, threatened and I am satisfied as Ms Gawronski denies any of those things took place and that there was nothing out of the ordinary, that if she believes that, she is delusional.

"On the evidence the court has, she was no longer capable of caring for Ms Buchanan and at that stage she was mistreating her.

"I am satisfied she punched, in anger, a frail woman and intimidation is as clear as it could be on both those tapes."

Magistrate Clisdell found the evidence of the two police officers "reliable".

Police prosecutor Sergeant Sean Thackray said Gawronski "threatened" Ms Buchanan when the carer can be heard on the recording saying she would send her elderly patient to a nursing home.

Gawronski said this was Ms Buchanan's "worst fear" but she was trying to use the comment as an "incentive" rather than a threat.

Gawronski claimed Ms Buchanan was her "friend" for five years and she moved in and started caring for the elderly woman full time, unpaid, after she had been discharged from hospital in June.

The abuse happened almost two months after Gawronski became Ms Buchanan's legal guardian.

Gawronski repeatedly denied she assaulted Ms Buchanan during the night.

"We created our own little family. She was my adopted Nanna. I wouldn't hurt Gladys ever," she said.

She said she bruised or got cut every day as her skin was like "tissue paper".

Outside court, Ms Buchanan's neighbour Stephen Leebold said he was pleased with the guilty verdict.

He said it was "nauseating" to hear Ms Buchanan be abused for hours that day.

"It is despicable that someone could treat someone so harshly, and badly," Mr Leebold said.

"No one would treat a friend like that."

Gawronski will be sentenced on December 20 in Wollongong Local Court.