Speech-associated labiomandibular movement in Mandarin-speaking children with quadriplegic cerebral palsy: a kinematic study.
Kids with spastic quad CP can’t sync lip and jaw in time—so probe and train timing first.
01Research in Context
What this study did
Hong et al. (2011) watched the lips and jaws of Mandarin-speaking kids with spastic quadriplegic CP while they talked.
Tiny reflective dots were glued to each child’s face. Infrared cameras tracked how the dots moved.
The team asked: do the lip and jaw move in tight sync, or do they drift apart?
What they found
The CP group’s lip and jaw were badly out of time. Their movements were also more wobbly from one word to the next.
Speech sounded slurred because the two articulators arrived at different moments.
How this fits with other research
Franich et al. (2021) saw the same timing mess in English-speaking kids with ASD. Speech and even finger-drumming were off-beat. Together the papers say “loose internal clock” can live in CP or ASD.
Tassé et al. (2013) found shaky ankle torque in older CP students. Wei-Hsien now shows the same variability up in the mouth, so the whole motor system in CP seems to wobble.
Johnston et al. (2017) looked from the listener side: ASD teens need lip-sync within 100 ms or they lose the message. Wei-Hsien proves the speaker side can easily miss that tiny window.
Why it matters
If a client’s speech sounds mushy, check timing, not just position. Use a metronome app or hand-tap cue so lip and jaw land together. Start with slow syllables, then speed up only when the pair stays locked. Better timing may lift clarity without extra artic drills.
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02At a glance
03Original abstract
The purpose of this study was to investigate the speech-associated labiomandibular movement during articulation production in Mandarin-speaking children with spastic quadriplegic (SQ) cerebral palsy (CP). Twelve children with SQ CP (aged 7-11 years) and 12 age-matched healthy children as controls were enrolled for the study. All children underwent analysis of percentage of consonants correct (PCC) and kinematic analysis of speech tasks using the Vicon Motion 370 system. Kinematic parameters included utterance duration, displacement and velocity of the lip and jaw, coefficient of variation (CV) of lip utterance duration, and spatial and temporal coupling of labiomandibular movement of speech produced in mono-syllable (MS) and poly-syllable (PS) tasks. Children with CP showed lower temporal coupling (MS, p = 0.015; PS, p = 0.007), but not spatial coupling, of labiomandibular movement than healthy children. Children with CP had greater CVs (MS, p = 0.003; PS, p = 0.010) and the peak opening displacement and velocity of lower lip and jaw (p < 0.05) and lower PCC (p < 0.001) than healthy children. Children with SQ CP displayed labiomandibular coupling movement impairment, especially in the aspect of temporal coupling. These children also had high temporal oromotor variability and needed to make more effort to coordinate the labiomandibular movement for speech production.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.06.016