The reason why the amount of vocalisations often differ between hearing and deaf infants is that vocalisations are primarily motivated by their ability to hear their own babbling, the findings showed.
The researchers also found that cochlear implants can help infants with profound hearing loss to correct their hearing.
Cochlear implants are small electronic devices embedded into the bone behind the ear that replace some functions of the damaged inner ear.
“Hearing is a critical aspect of infants’ motivation to make early sounds,” said researcher Mary Fagan, an assistant professor at the University of Missouri in the US.
“This study shows babies are interested in speech-like sounds and that they increase their babbling when they can hear,” said Fagan.
Fagan studied the vocalisations of 27 hearing infants and 16 infants with profound hearing loss who were candidates for cochlear implants.
She found that infants with profound hearing loss vocalised significantly less than hearing infants.
However, when the infants with profound hearing loss received cochlear implants, the infants’ vocalisations increased to the same levels as their hearing peers within four months of receiving the implants.
“After the infants received their cochlear implants, the significant difference in overall vocalisation quantity was no longer evident,” Fagan said.
“These findings support the importance of early hearing screenings and early cochlear implantation,” Fagan noted.
The study was published in the Journal of Experimental Child Psychology.