WASHINGTON (HealthDay News) -- The earlier deaf infants or toddlers receive a cochlear implant, the better their speech by the time they're three and a half years old, a U.S. study finds.

A cochlear implant senses sound and sends electrical signals to an internal component that stimulates the hearing nerves in the inner ear.

Researchers from the Washington University School of Medicine in St. Louis and from the Southwestern Medical School at the University of Texas in Dallas tested the spoken language skills of 76 children, all 42 months old, who had cochlear implants.

The results of the spoken language tests were compared to the length of time each child had had his or her cochlear implant.

The study found an association between longer implant time and richer vocabulary, longer, more complex sentences, and more frequent use of irregular words.

"Kids with residual hearing can get some help from hearing aids, but cochlear implants give a tremendous hearing advantage over hearing aids -- the implants provide more sound information," study co-author Johanna Grant Nicholas, a research associate professor of otolaryngology at the university's School of Medicine, said in a prepared statement.

"For example, high-frequency sounds are magnified more with cochlear implants, so kids can hear 's' sounds and 'ed' endings better. So, they tend to catch on to plurals and verb tenses faster," Nicholas said.

In this study, many of the children who received cochlear implants at the youngest ages had nearly the same spoken language skills as children with normal hearing, she noted.