Chewing cycles in 4- and 5-year-old Down's syndrome children: a comparison of eating efficacy with normals.

Chewing movements of Down's syndrome children were measured and compared with those of normal preschool children. Twenty-six Down's syndrome children were monitored: 14 were 4 (8 males, 6 females) and 12 were 5 years old (6 males, 6 females). Chewing movements were measured by time (in seconds), number of cycles, and a time/cycle ratio. A chewing cycle was defined as an upward and downward movement of the chin. The time/cycle ratio is the total time, from the moment food was placed in the mouth until the final swallow occurred, divided by the number of cycles counted for the same period. The children's ages and gender did not affect time, cycles, or the time/cycle ratio. However, the measures were strongly affected by the type of food eaten. Children with Down's syndrome chew at a rate comparable to that of normal children. However, the duration of chewing is significantly prolonged per bite of food. This may be attributed to these children's lack of chewing vigor or their inability, at the ages studied, to chew solid foods. Time/cycle ratios are an excellent index to document such differences. How much sensory differences or deficits contribute to these findings is not known.