Neuromuscular control of masticatory muscles in people with intellectual disability, middle-aged adults and older adults.
Adults with ID chew worse than typical seniors—check feeding safety and add oral-motor drills.
01Research in Context
What this study did
Cruz-Montecinos et al. (2024) watched how adults with intellectual disability chew. They compared them to two groups: middle-aged and older adults without ID.
Tiny sensors on the jaw tracked muscle timing and force. The team looked for jerky or mistimed bites.
What they found
More than half of the adults with ID showed messy chewing control. Their bite timing was off and muscles fired wrong.
Even healthy older adults chewed smoother than the ID group. Poor control raises choking risk.
How this fits with other research
Plant et al. (2007) also saw odd motor signs in aging ID adults. They found slow, uneven eye blinks tied to stereotypy. Both studies flag hidden neuromotor trouble.
Cameron et al. (1996) showed adults with Prader-Willi syndrome scored high on irritability. C et al. now add motor deficits to the list of adult-ID challenges.
Fyfe et al. (2007) proved stereotypy can be cut with a punishment cue. That offers hope: if chewing is motor-based, similar cues might help at meals.
Why it matters
You may see clients pocket food, cough, or refuse tough textures. These could be signs of weak chewing control, not just behavior. Ask for a speech-language swallow screen and add oral-motor warm-ups to your program. Simple bite-and-hold practice or chewy tubes before meals can build safer, stronger feeding.
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02At a glance
03Original abstract
BACKGROUND: Motor control issues are common for people with intellectual disabilities (PWID), resulting in difficulties with basic activities of daily living, including eating. Mastication, which is crucial for digestion and overall health, is poorly understood in this population. PWID shows frailty similar to older people, highlighting the importance of comparing masticatory motor control with older adults. This study compared the neuromuscular control of the masticatory muscles in middle-aged, PWID and older adults. METHODS: A cross-sectional analytical design was used. During the mastication task of a carrot piece (2 cm in diameter and weighing 0.5 g), surface electromyography was used to record muscle activity patterns from the right and left masseter and temporalis muscles. Principal component analysis (PCA) was used to assess neuromuscular control. A z-score normalisation of the first component's variance from PCA to identify those individuals with altered neuromuscular control. A mixed ANOVA was performed to assess the interaction between principal components, groups and body composition. RESULTS: Thirty PWIDs (aged 35-55 years), middle-aged adults and 32 older adults were recruited. PWID and older adults showed decreased neuromuscular control of the masticatory muscles compared to middle-aged control adults (P < 0.05). PWID had the highest proportion of individuals with altered neuromuscular control of the masticatory muscle (53%) compared to older adults (19%) and middle-aged adults (0%) (P < 0.05). CONCLUSIONS: Our results indicate that PWID and older adults have reduced neuromuscular control compared to middle-aged adults. Notably, a significant proportion of the PWID showed altered masticatory muscle control compared to older adults. Further research is needed to explore the potential benefits of masticatory muscle training for PWID.
Journal of intellectual disability research : JIDR, 2024 · doi:10.1111/jir.13089