Differentiating Cantonese-speaking preschool children with and without SLI using MLU and lexical diversity (D).
OBJECTIVE
In this study, the authors examined the diagnostic accuracy of a composite clinical assessment measure based on mean length of utterance (MLU), lexical diversity (D), and age (Klee, Stokes, Wong, Fletcher, & Gavin, 2004) in a second, independent sample of 4-year-old Cantonese-speaking children with and without specific language impairment (SLI).


METHODS
The composite measure was calculated from play-based, conversational language samples of 15 children with SLI and 14 children without SLI. Scores were dichotomized and compared to diagnostic outcomes using a reference standard based on clinical judgment supported by test scores.


RESULTS
Eleven of 15 children with SLI and 8 of 14 children with typical language skills were correctly classified by the dichotomized composite measure. The measure's sensitivity in this second sample was 73.3% (95% confidence interval [CI] 48%-89%); specificity was 57.1% (95% CI 33%-79%); positive likelihood ratio was 1.71 (95% CI 0.87-3.37); and negative likelihood ratio was 0.47 (95% CI 0.18-1.21).


CONCLUSIONS
The diagnostic accuracy of the composite measure was substantially lower than in the original study, suggesting that it is unlikely to be informative for clinical use in its present form. The value of replication studies is discussed.
Wong
Anita M-Y
AM
Division of Speech and Hearing Sciences, Faculty of Education, University of Hong Kong, Pokfulam, Hong Kong-SAR-China. amywong@hkusua.hku.hk
Klee
Thomas
T
Stokes
Stephanie F
SF
Fletcher
Paul
P
Leonard
Laurence B
LB
D000367:Age Factors; D002663:Child Language; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D007802:Language; D007806:Language Disorders / Q000175:diagnosis*; D016013:Likelihood Functions; D008297:Male; D010988:Play and Playthings; D012680:Sensitivity and Specificity; D013060:Speech; D013997:Time Factors; D014825:Vocabulary