title: The compressive stiffness of human pediatric heads.
abstract: Head injury is a persistent and costly problem for both children and adults. Globally, approximately 10 million people are hospitalized each year for head injuries. Knowing the structural properties of the head is important for modeling the response of the head in impact, and for providing insights into mechanisms of head injury. Hence, the goal of this study was to measure the sub-injurious structural stiffness of whole pediatric heads. 12 cadaveric pediatric (20-week-gestation to 16 years old) heads were tested in a battery of viscoelastic compression tests. The heads were compressed in both the lateral and anterior-posterior directions to 5% of gauge length at normalized deformation rates of 0.0005/s, 0.01/s, 0.1/s, and 0.3/s. Because of the non-linear nature of the response, linear regression models were used to calculate toe region (<2.5%) and elastic region (>2.5%) stiffness separately so that meaningful comparisons could be made across rate, age, and direction. The results showed that age was the dominant factor in predicting the structural stiffness of the human head. A large and statistically significant increase in the stiffness of both the toe region and the elastic region was observed with increasing age (p<0.0001), but no significant difference was seen across direction or normalized deformation rate. The stiffness of the elastic region increased from as low as 5 N/mm in the neonate to >4500 N/mm in the 16 year old. The changes in stiffness with age may be attributed to the disappearance of soft sutures and the thickening of skull bones with age.
authors.affiliation: Biomedical Engineering, Duke University, 5680 West 35th Street, Saint Louis Park, MN 55416, USA. Electronic address: Andre.M.Loyd@gmail.com.
authors.forename: Andre Matthew
authors.initials: AM
authors.lastname: Loyd
authors.affiliation: Biomedical Engineering, Duke University, Room 1427, FCIEMAS, 101 Science Drive, Box 90281, Durham, NC 27708-0281, USA. Electronic address: rwn@duke.edu.
authors.forename: Roger W
authors.initials: RW
authors.lastname: Nightingale
authors.affiliation: Biomedical Engineering, Duke University, Room 1427, FCIEMAS, 101 Science Drive, Box 90281, Durham, NC 27708-0281, USA. Electronic address: jfl1@duke.edu.
authors.forename: Jason F
authors.initials: JF
authors.lastname: Luck
authors.affiliation: Biomedical Engineering, Duke University, 124 Essex, Dr. Chapel Hill, NC 27514, USA. Electronic address: songniy@gmail.com.
authors.forename: Yin
authors.initials: Y
authors.lastname: Song
authors.affiliation: Duke University, USA. Electronic address: lucy.donnellan@gmail.com.
authors.forename: Lucy
authors.initials: L
authors.lastname: Fronheiser
authors.affiliation: Biomedical Engineering, Duke University, Room 1427, FCIEMAS, 101 Science Drive, Box 90281, Durham, NC 27708-0281, USA. Electronic address: hattie.cutcliffe@duke.edu.
authors.forename: Hattie
authors.initials: H
authors.lastname: Cutcliffe
authors.affiliation: Duke University, Room 1427, FCIEMAS 101 Science Drive Box 90281, Durham, NC 27708-0281, United States. Electronic address: bsm@duke.edu.
authors.forename: Barry S
authors.initials: BS
authors.lastname: Myers
authors.affiliation: Biomedical Engineering, Duke University, Room 1427, FCIEMAS, 101 Science Drive, Box 90281, Durham, NC 27708-0281, USA. Electronic address: dale.bass@duke.edu.
authors.forename: Cameron R
authors.initials: CR
authors.lastname: Dale Bass
mesh_terms: D000293:Adolescent; D002102:Cadaver; D002648:Child; D002675:Child, Preschool; D019245:Compressive Strength; D006259:Craniocerebral Trauma / Q000503:physiopathology*; D005260:Female; D006257:Head; D006801:Humans; D007223:Infant; D016014:Linear Models; D008297:Male; D012886:Skull / Q000648:ultrastructure*
keywords: Biomechanics; Compression; Head; Pediatric; Stiffness