The victim of a one-punch assault outside a Civic nightclub has permanently lost his sense of smell, a court has heard.
The man almost died after he suffered a fractured skull and brain bleed when punched from behind last year.
His attacker, Mark Amosa, 26, was on Wednesday sentenced to almost two years behind bars.
The victim spent about a week in hospital, and now has lost his sense of smell, has impaired taste, and has an increased risk of developing dementia and Parkinson's Disease.
Amosa, from Victoria, pleaded guilty to recklessly inflicting grievous bodily harm and appeared in the ACT Supreme Court for sentence on Wednesday.
It is the second time Amosa has been convicted, with his first conviction a similar offence of violence and punching and stomping on a man in a Victorian nightclub in 2010.
The court heard the Canberra incident started when Amosa pushed a friend of the victim out of the Academy Nightclub about 4.15am on April 21.
The defendant exchanged words with the victim, who had then started to walk away when Amosa punched him from behind.
The victim fell to the ground and witnesses described hearing a "crack" when his head hit the footpath.
Amosa looked at the victim on the ground, before catching a taxi home with a friend.
Footage of the incident shows security did not attempt to detain the offender or help the victim.
Chief Justice Helen Murrell said: "So much for security" when the CCTV was played in court.
"Strangely, security didn't seem to have followed up to assist the victim," she said.
Amosa handed himself into police months later after a public appeal to identify him was seen by family.
Amosa, from the witness box, said his recollection of the assault had been blurry.
He admitted he had not read the entire victim impact statement because it had made him "feel funny".
The Crown described the attack as "cowardly" and "vicious" and argued Amosa had learnt little from his conviction for the 2010 assault.
The prosecutor questioned Amosa's remorse as he not only fled the scene but the jurisdiction.
"He showed no concern for the victim [and then] disappeared," the Crown said.
Defence lawyer, James Sabharwal, tendered character references which said his clients' behaviour had been out of character.
Mr Sabharwal told the court Amosa was a devoted Christian who was active in the Samoan community.
Chief Justice Murrell sentenced Amosa to three years and nine months jail, with a non-parole period of one year and 10 months.
He will be eligible for parole in December next year.
The judge said the assault had been an example of "alcohol fuelled, gratuitous violence" that the public had become sick of.
"[It] was a powerful and targeted blow that was directed at the head, the most vulnerable part of the body," the judge said.
But Chief Justice Murrell accepted Amosa had displayed remorse via his guilty plea and letter of apology to the victim.