G. Thoonen et al., TOWARDS A STANDARDIZED ASSESSMENT PROCEDURE FOR DEVELOPMENTAL APRAXIAOF SPEECH, European journal of disorders of communication, 32(1), 1997, pp. 37-60
This study addresses the assessment of developmental apraxia of speech
(DAS) in children. For this, 11 children with a clear diagnosis of DA
S were selected, based on documented speech history and perceptual eva
luation of speech. The children with DAS, as well as II normal-speakin
g children, produced singleton real word and nonsense word imitations
elicited in a standardised way. Phonetic transcriptions were analysed
and errors in consonants classified. The results showed, firstly, that
the children with DAS produced similar types of consonant errors as h
as been reported in the literature, which corroborates the method of e
licitation as a valid procedure to assess relevant speech symptoms of
DAS. Secondly, a large quantitative difference between children with D
AS and normal-speaking children was found, in that children with DAS p
roduced an overall higher rare of singleton consonant errors (substitu
tions, omissions, distortions) and cluster errors (cluster reductions)
than the normal-speaking children. For the DAS group, the substitutio
n-rate, particularly in real words (as opposed to nonsense words), was
significantly correlated with severity as rated by two speech and lan
guage pathologists. This suggests that substitution-rate yields an ade
quate measure of severity of DAS. Thirdly, a qualitative difference be
tween both subject groups emerged. Children with DAS did not benefit f
rom the lexical status of the utterance (real versus nonsense word) to
the same extent as normal-speaking children. Based on these findings
the nature of the underlying deficits in speech production in DAS is d
iscussed.