Untersuchung zur Kernsymptomatik bei Kindern mit einer kindlichen Sprechapraxie im Alter von 4-7 Jahren

Childhood Apraxia of Speech (CAS) is a speech sound disorder, whose etiology, definition and diagnostic criteria have been the subject of great controversy. The unsettled causality between the component of speech motor and linguistic aspects leads to difficulties in differential diagnosis of children with CAS and children with Phonological Disorders (PD) by overlapping symptoms. Aim of the current study was an investigation of core features of CAS and their distinction from children with PD by means of acoustic and perceptual analyses of vowel and consonant errors. This thesis explores the question of whether different kinds of vowel errors and different quantities of vowel errors are obvious between the two speech sound disorders. 8 children with CAS, 10 children with PD and 10 control speakers aged between 4;0 – 7;6 years participated and were compared by their vowel and consonant errors. Differential diagnosis of the children with CAS and PD were validated by 15 raters. For analyzing vowel and consonant errors 115 words, 64 pseudo words and 105 syllables were elicited by picture naming and repeating after auditory presentation and digital recorded. Words and syllables were controlled by frequency and complexity and were analyzed perceptually and acoustically. The perceptual analysis of vowel productions from all children was done with the use of ratings. The ratings were performed by professional speech-language pathologists with the help of a web interface. For the results ANOVA and t-Test for group comparison were computed with SPSS 16.0. The acoustic analysis comprises the investigation of the curves (as function frequency over time) of the formants F1 and F2 of all vowel productions. Therefore all words and syllables were extracted with the programme PRAAT. Afterwards horizontal position (frequency), slope and curving of F1 and F2 was computed with Matlab and compared between all groups of children (ANOVA, t-Test). The results of acoustic analysis showed significant differences between all groups regarding vowel errors. Hence a difference between both groups of speech sound disorders could be identified by vowel productions in pseudo words. The group with CAS as well the group with PD showed error patterns concerning slope of F1 and F2 (CAS) and both slope and curving of F2 (PD). Results of perceptual analysis confirm significant differences between all groups regarding vowel and consonant errors. Even in perceptual analysis significant differences between CAS and PD could be found for vowels in pseudo words. CAS–children showed different vowel and consonant errors in pseudo words and this implies to assume particularly deficits in speech motor planning and programming