title: Characteristics of disfluency clusters over time in preschool children who stutter.
abstract: OBJECTIVE
  Disfluency clusters in preschool children were analyzed to determine whether they occurred at rates above chance, whether they changed over time, and whether they could differentiate children who would later persist in, or recover from, stuttering.
  
  
  METHODS
  Thirty-two children recruited near stuttering onset were grouped on the basis of their eventual course of stuttering and matched to 16 normally fluent children. Clusters were classified as stuttering-like disfluencies (SLD), other disfluencies (OD), or mixed (SLD and OD combined). Cluster frequency and length were calculated for all children and again after 6 months for those who stuttered.
  
  
  RESULTS
  Clusters occurred at rates greater than chance for both stuttering and normally fluent children. Children who stuttered had significantly more and longer clusters than did normally fluent children. Close to stuttering onset, clusters did not differentiate the course of stuttering. Cluster frequency and length decreased over time for children in the persistent and recovered groups. The proportion of disfluencies in clusters was significantly lower in the recovered group than it was in the persistent group after 6 months.
  
  
  CONCLUSIONS
  Clusters are an integral part of disfluent speech in preschool children in general. Although they do not serve as indicators of recovery or persistency at the onset of stuttering, they may have some prognostic value several months later.
authors.affiliation: Department of Communication Sciences and Disorders, Illinois State University, 204 Fairchild Hall, Normal, IL 61790-4720, USA. jsawyer@ilstu.edu
authors.forename: Jean
authors.initials: J
authors.lastname: Sawyer
authors.forename: Ehud
authors.initials: E
authors.lastname: Yairi
mesh_terms: D000704:Analysis of Variance; D016022:Case-Control Studies; D002675:Child, Preschool; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D007805:Language Development Disorders / Q000150:complications*; D008137:Longitudinal Studies; D008297:Male; D016555:Matched-Pair Analysis; D010700:Phonetics; D012016:Reference Values; D012720:Severity of Illness Index; D013060:Speech / Q000145:classification*; D013064:Speech Disorders / Q000145:classification* / Q000150:complications; D013068:Speech Production Measurement; D013342:Stuttering / Q000150:complications*; D014705:Verbal Behavior / Q000145:classification*