Date on Master's Thesis/Doctoral Dissertation

4-2021

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Bioengineering

Degree Program

JB Speed School of Engineering

Committee Chair

Bertocci, Gina

Committee Co-Chair (if applicable)

Thompson, Angela

Committee Member

Bertocci, Karen

Author's Keywords

Falls; Children; Biomechanics; Modelling; Impacts; Injury

Abstract

Background: A fall is the most common falsely reported injury scenario when a young child presents for medical care and the caregiver is concealing abuse. There is a lack of reliably witnessed falls with known outcomes to aid in the distinction between accidental and abusive injuries.

Objectives: The objectives of this study were to characterize video-recorded short distance falls involving young children in a childcare setting, to identify body regions most commonly impacted in these short distance falls, to characterize the head biomechanics of these falls, and describe fall characteristics. Additionally, physics-based models were used to predict fall biomechanics in a subset of these falls.

Methods: This study included children aged 12-25 months. Two childcare classrooms and a playground were each equipped with 3 digital video cameras. Video recordings involving falls were extracted for analysis. Falls were characterized by various factors (such as fall type; initial condition; fall dynamics; etc.), and these were analyzed for frequency. Descriptive statistics were performed on outcome measures. The distribution of impacted/contacted body regions was described and projected onto a child body map. Falls with biomechanical data from wearable devices were characterized by head impact and analyzed. It was hypothesized that head accelerations and velocities will be greater in falls with head impact than in falls without head impact. To analyze the accuracy and usefulness of physics-based biomechanical models, lumped mass, single rod, and inverted pendulum physics-based models were developed for previously conducted ATD falls and falls involving head impact from the childcare center. It was hypothesized that these models could accurately predict head biomechanical measures.

Results: 100 video-recorded falls involving 8 children, age 17-25 months (mean ± SD: 20 ± 2 months) were characterized. 65% of falls involved boys, and 64% of falls occurred indoors in a classroom. No injuries occurred in any fall. The most common first contact body regions were the soles of the feet. The most common primary impact body region was the palms of the hands; bilateral shins, bilateral knees, and buttocks were also commonly impacted. Replicated ATD falls and select childcare center falls with SIM G outputs were mathematically modelled, and it was determined that mathematical physics-based models could reasonably predict biomechanical outcomes from short-distance falls.

Conclusions: This study resulted in a dataset of 100 reliably witnessed video-recorded falls involving young children in a childcare center setting. Body region contact/impact maps for first contact, primary impact, and secondary impact of these common short-distance falls were developed. This study found that head biomechanical measures were not significantly different in falls with head impact versus without head impact. This study also found that the methodology used to evaluate lumped mass, single rod, and inverted pendulum models was an important factor in predicting head biomechanical outcomes. The most accurate physics-based models were the lumped mass and inverted pendulum models. No falls in this study resulted in injury. The outcomes from this study may aid in the investigation of injury histories of a short-distance fall, further increasing the understanding and differentiation of accidental versus abusive injuries.

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