Graduate Defense: Sarah Goldrod

Thesis Information

Title: Development And Validation Of An Improved Sagittal Plane Device For Infant Product Safety Testing

Program: Master of Science in Mechanical Engineering

Advisor: Dr. Erin M Mannen, Mechanical and Biomedical Engineering

Committee Members: Dr. Sophia Theodossiou, Mechanical and Biomedical Engineering; and Dr. Trevor Lujan, Mechanical and Biomedical Engineering

Abstract

Infants need constant care and support through the first year of life. To minimize the
burden of constant attending, caregivers frequently use commercial infant products
to enable them to carry out daily tasks without holding the baby. An estimated
11,500 infant injuries involving nursery products were treated in emergency rooms
in 2021, and 58 deaths were reported in some seated nursery products between 2017
and 2019. Head-neck flexion or hyperextension and trunk flexion negatively
influence normal breathing and can contribute to positional asphyxia in infants. The
body position of infants lying within seated products is an important consideration
for safety. Thus, the purpose of this study was to develop an improved testing device
that can be easily manufactured, is simple to use, and is validated with human
subjects’ data to provide valuable body position information to infant product
designers and manufacturers.

First, we developed two anthropometry-based devices to measure the body position
of infants in seated products. The newly developed device and three existing devices
were used to measure the head-neck, trunk, and torso-pelvis flexion angles in four
seated products. Second, a motion capture data collection was conducted to evaluate
the body position of thirteen infants in the same four seated products. An analysis of
the testing device compared to the human subjects data was completed to evaluate
the accuracy of each of the devices in measuring infant body position. This work is
the first to analyze a test-lab-style device that could easily be manufactured and
implemented into product testing regulations compared to in vivo human subjects
data.