Speech sound disorder at 4 years: prevalence, comorbidities, and predictors in a community cohort of children.
OBJECTIVE
The epidemiology of preschool speech sound disorder is poorly understood. Our aims were to determine: the prevalence of idiopathic speech sound disorder; the comorbidity of speech sound disorder with language and pre-literacy difficulties; and the factors contributing to speech outcome at 4 years.


METHODS
One thousand four hundred and ninety-four participants from an Australian longitudinal cohort completed speech, language, and pre-literacy assessments at 4 years. Prevalence of speech sound disorder (SSD) was defined by standard score performance of ≤79 on a speech assessment. Logistic regression examined predictors of SSD within four domains: child and family; parent-reported speech; cognitive-linguistic; and parent-reported motor skills.


RESULTS
At 4 years the prevalence of speech disorder in an Australian cohort was 3.4%. Comorbidity with SSD was 40.8% for language disorder and 20.8% for poor pre-literacy skills. Sex, maternal vocabulary, socio-economic status, and family history of speech and language difficulties predicted SSD, as did 2-year speech, language, and motor skills. Together these variables provided good discrimination of SSD (area under the curve=0.78).


CONCLUSIONS
This is the first epidemiological study to demonstrate prevalence of SSD at 4 years of age that was consistent with previous clinical studies. Early detection of SSD at 4 years should focus on family variables and speech, language, and motor skills measured at 2 years.
University of Melbourne, Melbourne, Vic., Australia.
Patricia
P
Eadie
University of Melbourne, Melbourne, Vic., Australia.|Murdoch Childrens Research Institute, Melbourne, Vic., Australia.
Angela
A
Morgan
NIHR CLAHRC South West Peninsula (PenCLAHRC), University of Exeter Medical School, Exeter, UK.
Obioha C
OC
Ukoumunne
Australian Catholic University, Melbourne, Vic., Australia.
Kyriaki
K
Ttofari Eecen
University of Melbourne, Melbourne, Vic., Australia.|Murdoch Childrens Research Institute, Melbourne, Vic., Australia.|Centre for Community Child Health, Royal Children's Hospital, Melbourne, Vic., Australia.
Melissa
M
Wake
University of Melbourne, Melbourne, Vic., Australia.|Murdoch Childrens Research Institute, Melbourne, Vic., Australia.
Sheena
S
Reilly
D001184:Articulation Disorders / Q000453:epidemiology*; D001315:Australia / Q000453:epidemiology; D002675:Child, Preschool; D015897:Comorbidity; D004410:Dyslexia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007805:Language Development Disorders / Q000453:epidemiology*; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D012307:Risk Factors