Does reduced movement of lip and
jaw contribute to difficulties understanding some children with CP?
According to Ignatius Nip from San Diego State University, yes. Nip explores
the development of speech from a kinematic perspective - that is the study of
motion - and in this case the movement of jaw and lips. In his latest
publication, he investigated how coordination between lips and jaw affect
speech production and intelligibility in children with CP. As part of this
study, he also intended to find out whether the complexity of an articulatory
movement - there is a difference between repeating sentences and repeating the
same syllable - plays a role as well.
To answer these questions Nip
invited 12 children with spastic CP and 12 typically-developing kids into his
lab. Reflective markers were put on the children’s faces to capture the
movements of upper lip and jaw, lower lip and jaw and upper, and lower lips when
repeating syllables and sentences. Temporal and spatial movement were measured,
that is the timing of the movements as well as how well the movements fit
together.
The study found that the children
with CP had difficulties coordinating the movements between upper and lower
lips. This is likely to affect sounds that are produced using both lips such as
[b]. The timing for moving upper lip and jaw was also affected. With regard to
the complexity of the speech movements the results showed that the coordination
of lips and jaw was more precise for the sentences than for the syllables. In
addition, there was a clear relation between effective movement coordination
and intelligibility. That is, the children who showed signs of dysarthria –
reflected in their intelligibility scores – were less successful in coordinating
their movements. Children
with CP and dysarthria do seem to move their lips and jaw differently than
their typically-developing peers. This difference in articulatory movement is
measurable and there is a chance that information on articulatory
performance can be used to help describe dysarthria problems in children with CP…provided relevant resources are in place...
Nip, I.S.B (2015). Interarticulator
coordination in children with and without cerebral palsy. Developmental Neurorehabilitation. Early online, 1-13.
