Childhood apraxia of speech (CAS) is a neurological motor speech disorder affecting
spatiotemporal planning of speech movements. Speech characteristics of CAS are
still not well defined and the main aim of this thesis was to reveal them by analysing
acoustic and articulatory data obtained by ultrasound imaging. Ultrasound recording
provided temporal and articulatory measurement of duration of syllables and segments,
amount and rate of tongue movement over the syllables and observation of the patterns
of tongue movement. Data was provided by three teenagers with CAS and two control
groups, one of ten typically developing children and the other of ten adults. Results
showed that, as a group, speakers with CAS differed from the adults but not from
the typically developing children in syllable duration and in rate of tongue movement.
They did not differ from either of the control groups in amount of tongue movement.
Individually, speakers with CAS showed similar or even greater consistency on these
features than the control speakers but displayed different abilities to adapt them to
changes in the syllable structure. While all three adapted syllable duration and rate of
tongue movement in the adult-like way, only two showed mature adaptation of segment
durations and of the amount of tongue movement. Observing patterns of tongue
movement showed that speakers with CAS produce different patterns than speakers in
the control groups but are at the same time, like adults, very stable in their articulations.
Also, speakers with CAS may move their tongues less in the oral space than
speakers in the control groups. The differences between the control groups were similar
to those found in previous studies. The results provide support for the validity of
the methods used, new information about CAS and a promising direction for future
research in differential diagnostic and therapy procedures.sub_shsunpub361_ethesesunpu