Design and testing of an instrumented infant feeding bottle

Existing methods to assess infant nutritive sucking patterns are often limited to modified bottle apparatuses used solely in the clinic, and time-consuming analyses of videotaped meals by trained observers who count the number of sucks during a meal. To address the need for a method to efficiently assess meal and sucking patterns of infants across different settings, we developed an unobtrusive Instrumented Bottle (IB) based on a commercially available bottle. Sensors are located in a detachable bottom and include a digital 14-bit pressure sensor that measures pressure inside of the bottle (range +/- 10cm H20), a 3-axis accelerometer that measures orientation of the bottle, and a 5 megapixel camera that takes images of the infant face at preset intervals. In-vitro testing of the IB included bench testing where sucking patterns were generated by a commercially available breast pump, over a range of sucking frequencies and strengths offered by the pump. The mean relative error in suck count estimation was 2% 1.5%, assessed against observer annotation of the video of the experiments. Pilot in-vivo testing was performed in small cohort of 4 female infants, age 6-22 weeks, all consuming breast milk from the IB. The mean absolute error in suck count estimation by IB in reference to video-annotated counts was 14% 51%. These pilot results suggest that that IB may be an accurate instrument to assess infant feeding, however, larger human studies are needed to assess factors affecting accuracy in in vivo.