| dc.description.abstract | Children with Autism Spectrum Disorder (ASD) often experience delayed speech
development. Current research shows that ASD is associated with atypical vocal quality. An
early sign of ASD is difficulty recognizing and using speech prosody, which is how a speaker
manipulates changes in pitch, loudness, and duration to emphasize what is important. Pitch is the
perceptual representation of fundamental frequency (f0), or the physical speed by which the
vocal folds vibrate (cycles per second). Manipulating f0 is a developmental skill that
neurotypical children learn in infancy. Children with ASD struggle with this skill. This study
examined whether quantifiable differences in pitch exist among three groups of children: (1)
children diagnosed with ASD, (2) children with developmental delay (DD) but not ASD, and (3)
neurotypical children. Children from each group were audio-recorded individually in a
naturalistic setting. For each child, the f0 of each utterance was first identified, and then analyzed
quantitatively (e.g., mean, range, and other descriptive statistics) and visually (i.e., the f0 pitch
contour or shape). The values were then compared across the three groups. Children with ASD
tended to have higher f0 means and medians than the other groups. However, results did not
support a hypothesis that children with ASD showed less manipulation of f0, only that their
utterances were primarily non-word productions. Fundamental frequency is a critical acoustic
vocal parameter and is important in understanding speech development. Identifying differences
in f0 between children with ASD and without ASD can help expand the knowledge base of
Autism diagnostic teams and early interventionists. This knowledge will enable professionals
and caregivers to develop more efficient strategies for supporting communicative development in
children with ASD. | |
