Researchers at Toronto's Hospital for Sick Children are questioning the safety of white noise machines used to help babies sleep.
Senior author Dr. Blake Papsin says several available models generate noise at levels that may be unsafe for young ears.
He says babies brains are looking for meaningful sounds to help with auditory development.
"The whole concept of replacing periodic, lovely, incredibly complex environmental sound for the young, developing, processing brain with a babbling brook... is foolish to me," he says.
Papsin, who heads the hospital's ear, nose and throat department, says if parents want to use these devices, they should use them for as short a period as possible and as far away from the baby as possible.
The study is published in the journal Pediatrics.