Liam Champken, diagnosed as profoundly deaf as a baby, woke up when the packet popped. Mum Jennie was told her son could not hear because his cochlea was irreparably damaged.
Mum Jennie, a support worker from Gloucestershire, was told the 14-month-old had only reacted to the smell but tests later showed his hearing was restored.
The mum-of-two said: "When you get told certain things, your whole world completely collapses. ''I opened a bag of crisps and he woke up. I said to the doctor that I thought he could hear, ''But she said Liam would have smelled them because the sense of smell can be heightened if there are hearing problems.
Liam has now overcome a long list of health problems to become an impressive athlete. Although Liam hears within normal limits, he still suffers minor problems with his ears, which have been damaged by grommets and are set to undergo operations.