Prolonged Exposure to Noise Machines Causes Hearing Loss in Infants: Study

White noise machines that curb background noise and disturbances by producing soothing sounds to help infants fall asleep can potentially damage their hearing, according to a study.

Researchers tested the effects of maximum noise levels of 65 sounds and 14 different  white noise machines that were kept at varying distances- 30, 100 and 200 centimeters away from the crib. The noise levels in all machines exceeded the recommended noise limit of 50 dBA or weighted decibels per hour

It was found that regular exposure to white noise while sleeping during night hours can affect hearing, speech and language development abilities in infants.

 Dr Blake Papsin, study author and chief otolaryngologist at the Hospital for sick children in Tornonto said, "Used too loud or too close or too long, these machines can exceed safety standards and potentially damage the hearing of the infant. And those sound limits may be too liberal for infants whose ears differ from adults," reports NBC News.

The authors noted that the ears of infants are relatively sensitive compared to adults and high-frequency sounds are amplified in their small ear canals causing hearing loss. Dr Papsin said, " The infant's ear has little straighter tube. It is a little wider open, and it amplifies the higher frequencies."

This study advises parents to limit exposure of young children and infants to high volume sounds created by machines and set them on volumes that are very low.  Safety control bodies like the Canadian Centre for Occupational Health and Safety and the  U.S. National Institute for Occupational Safety and Health recommend an exposure of not more than 85 dBA for eight hours for adults in work places.

 Prior studies have pointed out numerous health effects like noise-induced hearing loss, blood pressure damages to nervous system and cardiovascular disease in adults that were associated to prolonged exposure to noise at high intensity and frequency. Using animal models, the researchers proved its dangerous impacts on the developing cochlea. Findings from a Chinese study also attributed congenital defects to noise exposure during the first trimester of pregnancy.  

The research titled 'Infant Sleep Machines and Hazardous Sound Pressure Levels' is published in the journal Pediatrics.