This sparked her campaign to ensure cyclists wore helmets so other families would not have to experience similar trauma.
Over six years, Oaten and her son visited hundreds of schools together, explaining what it was like for her to look after Aaron and educating the school kids they spoke to about the dangers of riding without a helmet.
The Palmerston North woman also helped to launch the Protect the Brains Trust, which lobbied across the country to make bike helmets compulsory.
Rob Storey, who was Minister of Transport between 1990 and 1993, said he would make the change if the trust could get 50% of New Zealand cyclists to wear a helmet voluntarily.
On January 1, 1994, the law was changed and cyclists had to wear a helmet or face a $35 fine. That fine has risen to $55 today.
Oaten became the inaugural winner of the Kidsafe Hero of the Past Award in 1998 and continued to care for her son until his death at the age of 37 in 2010.
Her obituary said she died peacefully on September 20 aged 83 and a private family memorial will be held for her later in the year.