Research

This part of our website is dedicated to current findings in stuttering research. You may choose from a number of abstracts summarizing renouned research articles and professional discussions or you may want to take advantage of the links listed below that will connect you to a number of websites dedicated to the latest information on stuttering and its research.

General Research Findings:

  •  Incidence & Prevalence: 5% of preschool-age children will have stuttering episodes, but only ~1% of adults stutter (Yairi & Ambrose, 2005).
  •  Onset: Onsets are highest between child’s 2nd and 4th birthdays (Andrews, 1984), usually occurring between 30-36 months of age (Mansson, 2000; Yairi & Ambrose, 1992; Yaruss, LaSalle, & Conture, 1998).
    • Onsets are usually gradual, however about 1/3 of parents report abrupt onsets in their children (Yairi, 1983; Yairi & Ambrose, 1992).
    • Approximately 90-95% of the risk for stuttering is over by age 4 (Yairi & Ambrose, 2005).
    • Onsets after age 4 should be considered a separate subtype (Yairi & Ambrose, 2005).
  • Natural Recovery: Most often, the entire cycle of the disorder, from beginning to end, is completed in early childhood (Yairi & Ambrose, 2005).
    • Many preschoolers who begin to stutter will stop within the first year or two of onset without receiving any professional treatment (Andrews, 1984; Curlee & Yairi, 1997; Dickson, 1971; Glasner & Rosenthal, 1957; Yairi, Ambrose, Paden, & Throneburg, 1996).
    • Roughly 20-25% of preschooler who shows signs of stuttering will continue to stutter into adulthood (Andrews, 1984; Ramig, 1993; Yairi & Ambrose, 2005)
  • Gender Distribution: In early childhood, the male to female ratio is as low as 1:1 (Yairi, 1983) or 1.6:1 (Kloth, Janssen, Kraaimaat, & Brutten, 1995).
    • Males gradually come to outnumber females as time goes by, meaning girls are more likely to spontaneously recover (Felsenfeld, 1997; Yairi & Ambrose, 1990), and later male to female ratios in adulthood range from 3:1 to 5:1 (Bloodstein & Berstein Ratner, 2007).
  • Genetic Contribution: Up to 40% of children who stutter have parents or siblings who have stuttered, and up to 70% of children who stutter have an extended family history of stuttering (Bloodstein & Berstein Ratner, 2007; Yairi & Ambrose, 2005).
    • Howie (1983) found that 63% of monozygotic (identical) twins were concordant for stuttering, while only 19% of dizygotic (fraternal) twins both stuttered.
  • Phonological Disorders: Phonological impairment is the most common speech problem that coexists with stuttering in children (Conture, 2001; Throneburg, Yairi, & Paden, 1994).
    • Stuttering children near onset are slightly delayed in phonological development compared to fluent peers (Louko, Edwards, & Conture, 1999; Yairi & Ambrose, 2005).
    • The phonological delay associated with stuttering will likely be overcome within 1-2 years post-onset (Padden, Ambrose, & Yairi, 2002). 
    • Although the literature is unclear on whether the language skills of children who stutter are equivalent to their fluent peers (Andrews et al., 1983; Yairi, Watkins, Ambrose, & Paden, 2001), most experts agree that children who stutter, as a group, don’t exhibit gross language disorders (Bennett; 2006; Guitar; 2005; Yairi, Watkins, Ambrose, & Paden, 2001) 
  • Types of Disfluencies: part-word repetition (sound or syllable), whole-word repetition, phrase repetition (two or more words), sound prolongation, block (inaudible postural fixation), interjection (e.g., “um,” “uh,” “well,” “you know,”) (Fogle, 2008).
    • Other types of verbal behaviors include: revision (changing the content, intended message, or grammatical form of an utterance), abandoned utterance (“I’ll be there at… Where are we going?”), circumlocution (talking around a word or topic), hesitation or “waiting for fluency”( Ramig & Dodge, 1995; Bennett, 2006; Conture & Curlee, 2007) 

Compiled by Peter R. Ramig, Ph.D., CCC-SLP & Ryan Pollard, Doctoral Candidate

 Stuttering and the preschool child: 

Stuttering and the school-aged child:

Stuttering and adults:

For further information regarding current trends in stuttering treatment and research, please refer to the following links: