PHD, Kent State University, 2024, College of Arts and Sciences / School of Biomedical Sciences

Successful infant feeding requires effective milk acquisition, followed by the transport of ingested material across the oral cavity and through the pharynx, ultimately culminating in esophageal peristalsis. Several elements that underlie the neural control of swallowing are underexplored, including the neurological relationships among different aspects of swallowing (oral, pharyngeal, and esophageal). The works described here aim to improve our understanding of the sensorimotor relationships that drive infant swallowing, primarily by stimulating specific areas with capsaicin. To begin, we use an animal model of superior laryngeal nerve lesion to assess the effects of oropharyngeal capsaicin administration on feeding physiology. Next, we analyze the impacts of esophageal afferents on upstream feeding behaviors using a model of simulated gastroesophageal reflux. Finally, we explore the role of mandibular afferents in infant feeding, and determine whether capsaicin administration can recover any deficits resulting from anesthetization of these afferents. All experiments were conducted using infant pigs, a validated model for the study of infant feeding. Common methodology across specific aims includes videofluoroscopy (to assess kinematics and feeding performance) and electromyography (to assess motor outputs to muscles of interest). These experiments ultimately shed light on the extent of brainstem sensorimotor integration across feeding behaviors. Additionally, the results of these studies provide insights into the mechanisms by which specific sensory signals are integrated during feeding. These insights are critical and will ultimately facilitate the design of targeted interventions for specific feeding pathophysiologies in infants.

Committee: Rebecca German (Advisor); Jesse Young (Committee Member); Douglas Delahanty (Committee Member); Ron Seese (Committee Member); Frank Beck (Committee Member); Merri Rosen (Committee Member) Subjects: Animals; Biomechanics; Biomedical Research; Experiments; Neurobiology; Neurosciences; Physiology

Master of Science, The Ohio State University, 2023, Biomedical Engineering

The shoulder girdle complex, through engagement with the seat belt, influences motor vehicle occupant upper body movement during frontal impacts, affecting the movement of the head, neck, and thorax. The recently developed LODC ATD was designed with flexible shoulder girdle structures that capture the unique kinematics in pediatric occupants. However, the LODC shoulder has not been evaluated for biofidelity due to the lack of biomechanical data available on pediatric shoulder responses. This study evaluated quasi-static pediatric shoulder girdle complex responses through non-invasive displacement measurements. These data were obtained to compare to the LODC ATD, to assess its biofidelity. Shoulder range of motion and anthropometric measurements were obtained from 25 pediatric volunteers, ages 8-12 years old. Loads were applied bilaterally exclusively to the shoulder complexes in increments of 25 N up to 150 N per shoulder at 90, 135, and 170 degrees of shoulder flexion. Still photos were used to determine shoulder displacement in the sagittal plane from images captured prior to and following the load applications. Data analysis consisted of motion tracking to evaluate the absolute and relative displacement of the right acromion and T1. The displacements for each volunteer were normalized based on the volunteer's shoulder width compared to the shoulder width of the LODC ATD. For the 90° load, the acromion moved relative to T1 an average of 28.1 mm forward and 3.1 mm downward at maximum displacement. For the 135° load, the acromion moved relative to T1 an average of 12.4 mm forward and 40.0 mm upward at maximum displacement. Similar displacements at higher loads indicated that the volunteers achieved their maximum range of motion. The same test procedure was completed for the LODC ATD, resulting in a biofidelity comparison in displacements using Biofidelity Ranking Score. Results from this analysis indicated that the LODC was found to have better biofidelity in the fo (open full item for complete abstract)

Committee: John Bolte IV (Committee Member); Julie Mansfield (Advisor) Subjects: Biomechanics; Biomedical Engineering; Engineering

Doctor of Philosophy, The Ohio State University, 2022, Biomedical Engineering

Motor vehicle crashes (MVCs) remain a leading cause of death and injury for children who may be of the appropriate age (4–12 years) and size (33–63”, 40–125 lbs) to be restrained by belt-positioning booster seats (BPBs). Of these injuries, head injuries due to contact to the vehicle interior are most frequent and are often influenced by variations in pre-crash seatbelt placement. BPBs help to protect children primarily by raising their seated height to improve the fit of the adult seatbelt, especially on the child's torso and pelvis. However, current metrics of static shoulder and lap belt fit may not fully characterize if a BPB provides optimal belt fit and good seatbelt-to-torso interaction during a crash. Previous work has identified that degree of initial shoulder belt-to-torso contact (or, presence of belt gap at the lower torso) may also influence child kinematics and belt interaction during low-speed vehicle maneuvers, ultimately influencing the potential for shoulder belt slip-off. Additionally, naturalistic variation in child postures while restrained by BPBs may also influence belt fit outcomes and warrants investigation. The studies presented here seek to further understanding of the static belt fit, posture, and dynamic crash outcomes for children restrained by BPBs. Novel metrics of seatbelt fit (belt gap) for BPB-seated occupants are introduced and investigated, alongside conventional belt fit metrics and 3D postural analysis, for two cohorts of child volunteers across a range of BPB, vehicle, and postural conditions. The static belt fit of six pediatric anthropomorphic test devices (ATDs) are evaluated and compared to child outcomes across conditions as well. Finally, dynamic sled tests of the pediatric ATDs were completed to evaluate the influence of static belt fit on kinematic and injury outcomes in frontal and oblique crash scenarios. Novel metrics of belt gap were successfully developed and utilized to quantify differences in belt-to-torso c (open full item for complete abstract)

Committee: John Bolte IV (Advisor); Alan Litsky (Committee Member); Yun Seok Kang (Committee Member); Katarina Bohman (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Mechanical Engineering

Doctor of Philosophy in Engineering, Cleveland State University, 2020, Washkewicz College of Engineering

Gait impairments from disorders such as cerebral palsy are important to address early in life. A powered lower-limb orthosis can offer therapists a rehabilitation option using robot-assisted gait training. Although there are many devices already available for the adult population, there are few powered orthoses for the pediatric population. The aim of this dissertation is to embark on the first stages of development of a powered lower-limb orthosis for gait rehabilitation and assistance of children ages 6 to 11 years with walking impairments from cerebral palsy. This dissertation presents the design requirements of the orthosis, the design and fabrication of the joint actuators, and the design and manufacturing of a provisional version of the pediatric orthosis. Preliminary results demonstrate the capabilities of the joint actuators, confirm gait tracking capabilities of the actuators in the provisional orthosis, and evaluate a standing balance control strategy on the under-actuated provisional orthosis in simulation and experiment. In addition, this dissertation presents the design methodology for an anthropometrically parametrized orthosis, the fabrication of the prototype powered orthosis using this design methodology, and experimental application of orthosis hardware in providing walking assistance with a healthy adult. The presented results suggest the developed orthosis hardware is satisfactorily capable of operation and functional with a human subject. The first stages of development in this dissertation show encouraging results and will act as a foundation for further development of the device for rehabilitation and assistance of children with walking impairments.

Committee: Jerzy Sawicki (Committee Chair); Ryan Farris (Committee Member); Dan Simon (Committee Member); Antonie van den Bogert (Committee Member); Ulrich Zurcher (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Design; Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2020, Biomedical Engineering

Motor vehicle crashes (MVC) are the leading cause of cervical spine (c-spine) injuries in children below 18 years of age. However, there have been reports of increasing injury trends around five year of age. In automotive safety, this age typically corresponds with a transition of child restraint systems: from a harnessed device to a booster seat which use the adult seatbelt. Anthropomorphic test devices (ATDs) and finite element modeling are commonly used to predict the biomechanical responses of pediatric occupants during MVC. However, a lack of experimental pediatric c-spine data results in the use of scaling techniques of adult male biomechanical responses to assess pediatric injury risks. These scaling techniques seldom represent the vast changes the c-spine undergoes from childhood to adulthood. Pediatric ATDs lack the ability to represent the nuances of growth and development of the pediatric c-spine and often result in poor biofidelity, or the ability to accurately predict and reproduce biomechanical responses of children. There is a need to understand the biomechanical response of the pediatric c-spine in a way that accounts for anatomical and developmental differences between children and adult males. Therefore, the objective of this study is to quantify the cervical spine range of motion, strength and stiffness of children 5–7 years old. A custom testing device was developed and validated to quantify pediatric c-spine strength and stiffness in the sagittal and coronal planes while range of motion (ROM) was quantified for all major planes of motion. Isometric strength was measured at a neutral neck position, 0° of axial deviation, and at mid-range of motion, 30° of axial deviation in each plane. During testing muscle activation was assessed and maximum voluntary isometric contractions (MVIC) were quantified for each participant. Dynamic concentric strength and stiffness values were quantified at a dynamic rate of 30°/s. Children had equal ROM in all pl (open full item for complete abstract)

Committee: John Bolte IV (Advisor); Laura Boucher (Committee Member); Yun Seok Kang (Committee Member); Alan Litsky (Committee Member) Subjects: Biomechanics; Biomedical Engineering

Doctor of Philosophy, The Ohio State University, 2019, Mechanical Engineering

Millions of head and brain injuries occur each year in the United States with severities ranging from mild to traumatic. Mild traumatic brain injuries, commonly known as concussions are common among sporting activities, specifically American Football. Most research of football concussion injuries focuses on professional and collegiate level athletes. Work is needed to quantify how modern football helmets protect against concussion injuries at the youth level. For this investigation, two studies were carried out. These studies focused on determining how both helmet mass and head-helmet relative motion may affect a youth athlete's concussion risk during impact events. In these studies, impacts were carried out on a child crash test dummy (ATD) wearing youth football helmets of varying mass. The relative motion between the ATD head and football helmets was quantitatively measured throughout each impact using a motion capture system. Results from these studies displayed that both helmet mass and head-helmet relative motion can have a significant effect on injury metrics commonly used to predict concussion. However, helmet mass was found to have less of an effect on injury criteria values than other parameters such as helmet brand and impact direction. Additionally, head-helmet relative motion was found to be positively related to rotationally based injury criteria. The amount of relative motion between the head and helmet was dependent on each helmet's stand-off distance and padding design. While concussions are a mild brain injury with a large prevalence, drone, or UAS head impacts pose a risk for more traumatic head injuries but currently have a low prevalence. However, the rate of drone impacts is likely to increase as the industry is expanding at a rapid rate and benefits associated with drone use are driving new federal regulations which would allow for more widespread UAS flights over people. Before UAS flight over people is made legal, the risk of huma (open full item for complete abstract)

Committee: John H. Bolte IV PhD (Advisor); Yun-Seok Kang PhD (Committee Member); Laura C. Boucher PhD (Committee Member); James W. Gregory PhD (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Mechanical Engineering

Master of Science, The Ohio State University, 2017, Mechanical Engineering

Motor vehicle safety is developed through the testing of anthropomorphic test devices (ATDs). The goal of ATD manufacturers is to ensure that these devices are as biofidelic as possible. Pediatric ATDs were originally created as scaled-down adults, although currently research has been implemented to update these models to be more realistic to mimic an actual pediatric response. Unlike with adults, pediatric cadavers cannot be used to verify the impact properties such as force, deflection, and stiffness. Thus, other methods must be used to predict a pediatric response during a collision. This study developed a transformation sequence to predict the oblique y-direction pediatric shoulder response based on data gathered from adult PMHS and adult and child volunteers. Based on this method, the estimated shoulder stiffness for a 6yo is 59 N/mm and for a 10yo is 106 N/mm.

Committee: John Bolte IV, PhD (Advisor); Amanda Agnew PhD (Committee Member); Yun Seok Kang PhD (Committee Member) Subjects: Mechanical Engineering