Appearing in Dubbo District Court yesterday, Stanley Robin Doolan, 20, was sentenced to 12 years' imprisonment with a non-parole period of nine years after pleading guilty to one count of aggravated break and enter and commit a serious indictable offence and one count of aggravated sexual assault.

The offences can attract a maximum penalty of up to 20 years.

Mr Doolan was arrested on November 12 2002 five days after the incident, which saw the elderly woman, who cannot be named for legal reasons, attacked in her home in the early hours of the morning.

The court heard the woman and her daughter went to bed in their Whylandra Street home on the night of November 6, with the victim waking up at 1am to find Mr Doolan in her bedroom.

Judge Sir Robert Woods noted the callousness of the crime, which saw Mr Doolan pull the victim's clothes off before vaginally and anally sexually assaulting her.

During the course of the assault, which lasted for more than an hour, Mr Doolan pushed a pillow over the victim's face to muffle her cries.

The victim was left on the floor after the attack and due to osteoporosis was unable to move until 6am, when she woke her daughter, who then took her to hospital.

Judge Roberts said the crime was of the most serious type.

"That it took place in the sanctity of the victim's home is enough to produce a long-lasting fear for general security," he said.

"The public was horrified at this crime and wonder how a human being could behave so towards another human being ..."

The court heard the victim was initially unable to return to her home of 50 years after the assault and eventually felt compelled to sell the house and find somewhere else to live.

"It is impossible to calculate the damage done to the victim and to calculate the penalty when the victim is affected for the rest of her life," Judge Woods said.

"Such a callous assault on an elderly person, who is entitled to respect - it is hard to find any mitigating factors.

"This was a deliberate break and enter for the purpose of sexual assault, there was nothing stolen from the home."

The court heard Mr Doolan had been drinking with friends on the night of the incident and claimed he did not remember committing the offences, although Judge Woods said he doubted the veracity of that claim.

"This was a horrendous crime - the prisoner has not had a life of social deprivation, there were no mitigating circumstances, it was a deliberate break and enter to find sex," he said.

Judge Woods noted Mr Doolan, a father of four, had come from a "close-knit and stable family" and he had begun drinking at the age of 17, after his father's death.

"Youth cannot be a mitigating factor, clearly he has lived as an adult, with four children of his own - the only mitigating factor is the plea of guilty, which has reduced the trauma of going through events again during a trial for the victim," he said.