Development of lip closing function during taking food into the mouth in children with Down syndrome

Children with Down Syndrome (DS) show developmental retardation of gross motor function including acquisition of oral movements related to eating and swallowing. To characterize the process of development/acquisition of eating/swallowing function of children with DS, interlabial pressure (IP) during taking food into the mouth was assessed. This study included 99 children with DS (birth to 4 year-old), and 112 age-matched control children showing typical development. IP during taking food into the mouth was measured as an objective index of lip closing function. The system for measuring IP during taking food into the mouth consisted of a strain gauge-pressure sensor connected to a strain-measuring device, which sent data to a personal computer installed with electromagnetic oscillograph software to display pressure waveforms. The DS and typically developing children were grouped into each age group and the data were compared between matched-age groups. IP during taking food into the mouth, pressure-time (PT), variation coefficient (VC) of IP during taking food into the mouth and VC of PT were analyzed using the unpaired t-test. Analyses showed a significantly higher IP during taking food into the mouth in the DS population than in the typically developing children in the 2 and 3 year old (P = .042 and .049, respectively) groups. No significant difference was observed between the DS and typically developing groups with respect to PT, VC of IP during taking food into the mouth or VC of PT for any age group. Children with DS showed a process of acquisition of lip closing function during taking food into the mouth similar to the process found in typically developing children, even though children with DS experience developmental retardation in gross motor and cognitive functions.