Lip closing pressure in disabled children: a comparison with normal children.

Lip functions play an important role in the oral stages of feeding. Lip closing is an important early motor act in food acquisition and is essential for controlling chewing and swallowing. To date, there have been few papers on the developmental aspects of lip closing strength when taking in food, especially with regard to disabled children. This investigation was designed to produce an ordinal scale of midline lip pressure measurements for a cross-sectional, age-grouped population of normal children. Developmental changes in lip pressure were then compared with those of two populations of disabled children. Pressure measurements were obtained with a strain gauge transducer that was embedded in a spoon during normal feeding. The study population consisted of 104 normal children ranging in age from 5 months to 5 years, 11 children who showed developmental delay (mean 4.5 years), and 10 children with cerebral palsy (mean 5.0 years). Lip pressure was found to increase steadily from 5 months to 3 years and to increase slightly from 3 to 5 years in the normal population. The developmentally delayed group and the cerebral palsied group produced lip pressures and coefficients of variation below those of the normal 1 to 2-year-old group.