Table 5.

Estimates of the prevalence of idiopathic MSD. Estimates of the prevalence of MSD in idiopathic SD are from the present study. Estimates of the prevalence of idiopathic SD are from studies in Australia, England, and the USA.

Present Study			Prevalence of idiopathic SD from three population-based samples of children in three countries				Estimates of the population prevalence of idiopathic MSD
SDCS MSD Classifications	Abbreviation	Prevalence Estimate in Idiopathic SD		Eadie et al. (2015)	Shriberg et al. (1999)	Wren et al. (2016)
			Age:	4 yrs	6 yrs	8 yrs	4–8 yrs
No Motor Speech Disorder	No MSD	82.2%	n:	1,494	1,328	7, 390	10,212
Speech Motor Delay	SMD	12.0%	Population-based estimates of
Childhood Dysarthria	CD	3.4%	the prevalence of idiopathic SD:	3.4%	3.8%	3.6%	3.4 – 3.8/100
Childhood Apraxia of Speech	CAS	2.4%	SMD	0.4%	0.5%	0.4%	4/1000
			CD	0.1%	0.1%	0.1%	1/1000
Childhood Dysarthria & Childhood Apraxia of Speech	CD & CAS	0.0%	CAS	0.1%	0.1%	0.1%	1/1000
			CD & CAS	0.0%	0.0%	0.0%	0/1000

Note: MSD = Motor Speech Disorder; SD = Speech Delay; SDCSS = Speech Disorders Classification System Summary.