Measurements of pressure distribution by the tongue of infants on an artificial nipple

Abstract

Infants can feed themselves immediately after birth by using the primitive human sucking reflex. Infants place their tongues on and around the nipple to apply pressure and extract milk with peristaltic-like movements of the tongue. Measurements of tongue movement are very important to elucidate the maturation of sucking behavior to obtain nourishment. It is necessary to directly measure pressure on the nipple at various sites to describe tongue movement. In this study, an artificial nipple with several small pressure sensors was developed, and the pressure distribution exerted by the tongue on the artificial nipple was measured. The small pressure sensors, 10 mm in length, 3 mm in width, and 4 mm in height, have a cantilever structure and include a strain gauge. Pressure was measured by the strain on the stainless steel cantilever caused by contact of the tongue with a pressure transducer block. The artificial nipple for pressure measurement was in the form of a resin plate with two sensors located longitudinally and covered by an artificial silicon nipple, which allowed measurement of pressures at the tip and root of the nipple. Pressure signals were amplified, converted (A/D) at the sampling rate of 100 Hz and quantization resolution of 12 bits, and were input to a personal computer via a USB connection. This system measured pressure distribution on the artificial nipple by the tongue of an infant of 34 weeks gestation. Results showed that the largest pressures at the tip and root of the nipple were 358 kPa and 266 kPa, respectively, and pulsation at 1.7 Hz was confirmed at the two sites.