The mother of a teenager who died at an NHS trust's care unit does not believe its "culture" has changed despite it admitting guilt over his death.
Connor Sparrowhawk, 18, died in the care of Southern Health NHS Foundation Trust at Slade House in Oxford in 2013.
The trust has since accepted it was "entirely preventable" and has pleaded guilty to breaching health and safety law.
But his mother, Dr Sara Ryan, said she did not think attitudes had changed.
"We have made a noise, and we have shone a light and managed to get to this stage, but I don't think it is something that has changed the culture of the trust at all," Dr Ryan said.
Mr Sparrowhawk, who had learning difficulties and autism, drowned in a bath after an epileptic seizure and an inquest concluded "serious failings" contributed to his death.
His drowning led to the discovery the trust only properly investigated 272 unexplained deaths of 722 in its care.
Dr Ryan has written a book called Justice for Laughing Boy in which she questions the way people with learning difficulties are treated.
She said the investigation into unexplained deaths showed how certain people die early and "no-one really cares".
Southern Health is due to be sentenced for breaching health and safety law in the case of Mr Sparrowhawk at Oxford Crown Court on 12 October
After the trust pleaded guilty at Banbury Magistrates' Court earlier this month, interim chief executive Julie Dawes said Connor's death had led to "significant changes and improvements".
She added she hoped all families and service users now experienced a "more compassionate approach" from the trust.
Southern Health said it did not want to comment on Dr Ryan's remarks.