More than one in 10 children had a stutter by age four in a new Australian study, but those kids scored just as high or higher than their peers on assessments of language, thinking skills and temperament.
"Stuttering onset is relatively common but parents can be reassured that developmental stuttering is not associated with poorer outcome in the preschool years at least," Sheena Reilly, the study's lead author from the Murdoch Childrens Research Institute in Parkville, said.
The researchers said the frequency of stuttering among their preschoolers - about 11 percent - was higher than in previous studies, perhaps because they started following the children very early in life.
Commonly accepted estimates put the rate of stuttering at about 5 percent of children and 1 percent of adults, Reilly told Reuters Health in an email.
Her group's study included just over 1,600 children from Melbourne, Australia. Mothers filled out regular questionnaires starting when babies were eight months old and kids were assessed on a range of language and behavior scales at age four.
Reilly and her colleagues asked parents to call the study group if their child started showing signs of stuttering. Diagnoses were confirmed by a speech pathologist, who then visited the homes of children with a stutter every month to check on their progress.
By age four, 181 of the study children had been diagnosed with a stutter. Follow-up visits for the 142 who were consistently assessed after diagnosis showed just nine no longer had their stutter one year later.
Stuttering children scored 5.5 points higher than their non-stuttering peers on language tests and 2.6 points higher on a test of non-verbal intelligence, where 100 is an average score.
Parents also rated four-year-olds with and without a stutter similarly on behavior and temperament scales, according to findings published Monday in Pediatrics.
The researchers said it's possible stuttering could somehow improve language skills, or that stuttering could result from very fast language development among some kids.
"This is a period in which a child's motor speech system is challenged to keep pace with the phenomenal rate of language acquisition," they wrote.
Corrin Richels, a speech-language pathologist who has studied stuttering at Old Dominion University in Norfolk, Virginia, said it wasn't all that surprising preschoolers who stuttered didn't tend to be worse off in other ways.
She said most of the anxiety and other problems that have been tied to stuttering are seen among teenagers and adults.
"The adverse outcomes come from being a person who stutters over a long period of time," Richels, who wasn't involved in the new study, told Reuters Health.
The researchers said parents of children who stutter are typically advised to wait a year before seeking treatment - which can be both time-intensive and expensive - to see if the stutter goes away on its own, unless the child becomes distressed or stops talking.
Richels said the new findings support that approach.
"The good thing is, we can now counsel families whose children have just begun to stutter that it is okay to wait," she said.
"After a year, if the stuttering is consistently getting worse, if the child is starting to show concern, if the child is getting teased at all - all of those things say it's time to intervene."