A performance curve for assessing change in Percentage of Consonants Correct Revised (PCC-R).
OBJECTIVE
Interpreting the rapidly changing speech skills of young children recovering from neurological injury is difficult because developmental expectations are generally available only at relatively lengthy intervals (e.g., 6 or 12 months). In this research note, the authors describe the process of generating a Percentage of Consonants Correct-Revised (PCC-R; L. D. Shriberg, D. Austin, B. A. Lewis, J. L. McSweeny, & D. L. Wilson, 1997a) performance curve and illustrate some of its applications for assessing change in performance over time.


METHODS
The authors compiled mean PCC-R scores from 16 samples of typically developing children (18-172 months) and used curve fitting to test more than 11,000 statistical models of monthly growth in PCC-R. They selected a parsimonious and developmentally plausible model with R(2) = .9839 (p < .0005) and used it to generate the PCC-R, standard deviation, and standard error expected at each monthly age.


RESULTS
The PCC-R performance curve distinguished among 65 children (37-57 months of age) diagnosed independently with normal or disordered speech with a high degree of success. More important, the PCC-R performance curve can be used to identify the points at which children (18-172 months) recovering from neurological injury achieve normal-range consonant production.


CONCLUSIONS
The curve-fitting approach holds promise as a means of interpreting temporal variations in speech production at a finer grain than existing normative data currently allow.
Campbell
Thomas F
TF
Callier Center for Communication Disorders, University of Texas at Dallas, 1966 Inwood Road, Dallas, TX 75235, USA. thomas.f.campbell@utdallas.edu
Dollaghan
Christine
C
Janosky
Janine E
JE
Adelson
P David
PD
D000293:Adolescent; D001930:Brain Injuries / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010700:Phonetics; D015203:Reproducibility of Results; D013060:Speech; D013062:Speech Articulation Tests / Q000379:methods* / Q000592:standards*; D013064:Speech Disorders / Q000175:diagnosis* / Q000209:etiology*