title: A preliminary investigation of longitudinal changes in speech production over 18 months in young children with cerebral palsy.
abstract: OBJECTIVE
  This study examined longitudinal change in speech intelligibility, vowel space, and word duration over 18 months among children with cerebral palsy (CP) who varied in the severity of their speech motor involvement. The study also examined relationships among variables at each time point.
  
  
  METHODS
  Twenty-two children with CP participated in the study (mean age = 50 months at the first time point). Speech samples were collected at four time points that were 6 months apart. Children were separated into four severity groups based on intelligibility scores.
  
  
  RESULTS
  Change over time varied by severity. Children with CP who did not have speech motor involvement and children in the mild group showed gains in intelligibility, but no changes in vowel space area or word duration. Children in the moderate group showed no significant change, and children in the severe group showed increased vowel space and decreased word durations. Significant positive correlations between intelligibility and vowel space were noted at each time point for data pooled across all children.
  
  
  CONCLUSIONS
  Children showed different patterns of change over time in intelligibility, vowel space, and word duration based on their speech motor abilities. The relationship between intelligibility and vowel space across severity groups was constant, suggesting a robust relationship between these variables.
authors.affiliation: Department of Communicative Disorders and Waisman Center, University of Wisconsin-Madison, Madison, Wisc., USA.
authors.forename: Jimin
authors.initials: J
authors.lastname: Lee
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Hustad
mesh_terms: D001184:Articulation Disorders / Q000209:etiology* / Q000503:physiopathology; D001301:Audiometry, Pure-Tone; D002547:Cerebral Palsy / Q000503:physiopathology*; D002663:Child Language; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010700:Phonetics; D012720:Severity of Illness Index; D016037:Single-Blind Method; D013018:Sound Spectrography; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013068:Speech Production Measurement