Many boys caught up in the Northern Territory's juvenile justice system suffer a "disease of disadvantage" that has crippled almost every aspect of their lives, the Northern Territory's royal commission into youth detention and protection has heard.
Jody Barney, who works as a deaf indigenous community consultant, told the inquiry she has spoken to several young Aboriginal people with hearing impairments who have had their faces covered by spit hoods and bound behind bars.
"Taking away another sense from a person who already has a limited sense is frightening. And that fear stays forever... long after their sentence," she said.
Footage of boys being tear gassed, shackled and put in spit hoods at Don Dale Youth Detention Centre was aired on national television in July, sparking the royal commission
Psychologist Damien Howard told the inquiry a chronic housing shortage is creating an "epidemic" of hearing loss in indigenous children that leads to learning difficulties, family breakdown and criminal involvement.
"It's very much a disease of disadvantage," Dr Howard told Darwin's Supreme Court.
Crowded housing overwhelms a child's capacity to maintain hygiene, allows infections to pass quickly, and increases exposure to cigarette smoke and loud noises, while the poverty limits nutrition.
On average, non-Aboriginal kids experience middle ear disease for three months of their childhood while indigenous children can get fluctuating hearing loss for more than two years.
This can result in a permanent condition, which Dr Howard says is a "smoking gun" leading to over-representation in the criminal justice system.
A 2011 study found that 94 per cent of inmates in Darwin and Alice Springs prisons suffered significant hearing loss, a figure Dr Howard says would be similar in youth detention centres.
He advocates more culturally-based communication training in schools, courts, law enforcement and corrections.
Ms Barney has worked with 15 young offenders with hearing impairments who said Don Dale was their "worst nightmare."
Some detainees had their hearing aids taken off them or didn't have access to batteries, while there were no visual alarms for fire safety.
"This young boy was flogged, beaten, pinned up to the wall," she said.
"He went from a cheeky young fella to a young man who has been released, isolated, doesn't leave his home, has suicidal thoughts."
Muriel Bamblett, who co-wrote the 2010 Growing them Strong, Together report on the NT's child protection system, also gave evidence on Thursday.
She said she had discovered a "tsunami of need" in Aboriginal communities where 20-30 people lived under the same roof and kids slept on the floor.
"It's conditions no child should live in," she said.
Ms Bamblett described housing as the single highest priority for a child's social and emotional wellbeing and said the NT should offer priority homes for Aboriginal families in crisis and kids leaving foster care.
Ms Bamblett wants a complete overhaul of the "imploding" NT child protection system, calling it a "vehicle for trauma rather than protection."
She called for a separate Aboriginal children's commissioner, and a dedicated Aboriginal child care agency.
Compounding all of this is the prevalence of foetal alcohol spectrum disorder in indigenous children, which carries immense lifelong financial and social costs, paediatrician John Boulton says.
Both are highly linked with depression, suicide, drug addiction, mental illness and antisocial criminal behaviour, he said.
