Wu, L C; Nangia, V; Bui, K; Hammoor, B; Kurt, M; Hernandez, F; Kuo, C; Camarillo, D B
In Vivo Evaluation of Wearable Head Impact Sensors Journal Article
In: Annals of Biomedical Engineering, vol. 44, no. 4, pp. 1234–1245, 2016.
Abstract | BibTeX | Tags: *Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording
@article{Wu2016,
title = {In Vivo Evaluation of Wearable Head Impact Sensors},
author = {Wu, L C and Nangia, V and Bui, K and Hammoor, B and Kurt, M and Hernandez, F and Kuo, C and Camarillo, D B},
year = {2016},
date = {2016-01-01},
journal = {Annals of Biomedical Engineering},
volume = {44},
number = {4},
pages = {1234--1245},
abstract = {Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (\<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for alpha(mag)) and the skull cap (320% NRMS error for a(mag), 500% for alpha(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.},
keywords = {*Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
Hernandez, F; Shull, P B; Camarillo, D B
Evaluation of a laboratory model of human head impact biomechanics Journal Article
In: Journal of Biomechanics, vol. 48, no. 12, pp. 3469–3477, 2015.
Abstract | BibTeX | Tags: *HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY
@article{Hernandez2015,
title = {Evaluation of a laboratory model of human head impact biomechanics},
author = {Hernandez, F and Shull, P B and Camarillo, D B},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biomechanics},
volume = {48},
number = {12},
pages = {3469--3477},
abstract = {This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests ($sim$100 Hz) than field impacts ($sim$10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.},
keywords = {*HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY},
pubstate = {published},
tppubtype = {article}
}
Kettner, M; Ramsthaler, F; Potente, S; Bockenheimer, A; Schmidt, P H; Schrodt, M
Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling Journal Article
In: Forensic Science, Medicine & Pathology, vol. 10, no. 4, pp. 513–517, 2014.
Abstract | BibTeX | Tags: *Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult
@article{Kettner2014,
title = {Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling},
author = {Kettner, M and Ramsthaler, F and Potente, S and Bockenheimer, A and Schmidt, P H and Schrodt, M},
year = {2014},
date = {2014-01-01},
journal = {Forensic Science, Medicine \& Pathology},
volume = {10},
number = {4},
pages = {513--517},
abstract = {Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State's Attorney assigned a forensic expert to examine whether the forces exerted on the victim's head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295-485 g demonstrated that 12-20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.},
keywords = {*Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Ambekar, D; Al-Deneh, Z; Dao, T; Dziech, A L; Subbian, V; Beyette Jr., F R
Development of a point-of-care medical device to measure head impact in contact sports Journal Article
In: Conference Proceedings: ... Annual International Conference of the IEEE Engineering in Medicine & Biology Society, vol. 2013, pp. 4167–4170, 2013.
Abstract | BibTeX | Tags: *Accelerometry/is [Instrumentation], *Head Movements/ph [Physiology], *Models, *Monitoring, *Sports Equipment, *Wireless Technology/is [Instrumentation], Ambulatory/is [Instrumentation], Biological, Biomechanical Phenomena/ph [Physiology], Humans, Point-of-Care Systems, Sports
@article{Ambekar2013,
title = {Development of a point-of-care medical device to measure head impact in contact sports},
author = {Ambekar, D and Al-Deneh, Z and Dao, T and Dziech, A L and Subbian, V and {Beyette Jr.}, F R},
year = {2013},
date = {2013-01-01},
journal = {Conference Proceedings: ... Annual International Conference of the IEEE Engineering in Medicine \& Biology Society},
volume = {2013},
pages = {4167--4170},
abstract = {This paper presents a prototype of a wireless, point-of-care medical device to measure head impacts in contact or collision sports. The device is currently capable of measuring linear acceleration, time, and the duration of impact. The location of the impact can also be recorded by scaling the prototype design to multiple devices. An experimental apparatus was built to simulate head impacts and to verify the data from the device. Preliminary results show that the biomechanical measures from the device are sufficiently accurate.},
keywords = {*Accelerometry/is [Instrumentation], *Head Movements/ph [Physiology], *Models, *Monitoring, *Sports Equipment, *Wireless Technology/is [Instrumentation], Ambulatory/is [Instrumentation], Biological, Biomechanical Phenomena/ph [Physiology], Humans, Point-of-Care Systems, Sports},
pubstate = {published},
tppubtype = {article}
}
McIntosh, A S; Lai, A; Schilter, E
Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests Journal Article
In: Traffic Injury Prevention, vol. 14, no. 5, pp. 501–508, 2013.
Abstract | BibTeX | Tags: *Accidents, *Bicycling/in [Injuries], *Craniocerebral Trauma/et [Etiology], *Head Protective Devices/ut [Utilization], Acceleration, Biological, Biomechanical Phenomena, Computer simulation, Humans, Male, Manikins, Models, Traffic/sn [Statistics & Numerical Dat
@article{McIntosh2013,
title = {Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests},
author = {McIntosh, A S and Lai, A and Schilter, E},
year = {2013},
date = {2013-01-01},
journal = {Traffic Injury Prevention},
volume = {14},
number = {5},
pages = {501--508},
abstract = {OBJECTIVE: To assess the factors, including helmet use, that contribute to head linear and angular acceleration in bicycle crash simulation tests. METHOD: A series of laboratory tests was undertaken using an oblique impact rig. The impact rig included a drop assembly with a Hybrid III head and neck. The head struck a horizontally moving striker plate. Head linear and angular acceleration and striker plate force were measured. The Head Injury Criterion was derived. The following test parameters were varied: drop height to a maximum of 1.5 m, horizontal speed to a maximum of 25 km/h, helmet/no helmet, impact orientation/location, and restraint adjustment. Additional radial impacts were conducted on the same helmet models for comparison purposes. Descriptive statistics were derived and multiple regression was applied to examine the role of each parameter. RESULTS: Helmet use was the most significant factor in reducing the magnitude of all outcome variables. Linear acceleration and the Head Injury Criterion were influenced by the drop height, whereas angular acceleration tended to be influenced by the horizontal speed and impact orientation/location. The restraint adjustment influenced the outcome variables, with lower coefficients of variation observed with the tight restraint. CONCLUSIONS: The study reinforces the benefits of wearing a bicycle helmet in a crash. The study also demonstrates that helmets do not increase angular head acceleration. The study assists in establishing the need for an agreed-upon international oblique helmet test as well as the boundary conditions for oblique helmet testing.},
keywords = {*Accidents, *Bicycling/in [Injuries], *Craniocerebral Trauma/et [Etiology], *Head Protective Devices/ut [Utilization], Acceleration, Biological, Biomechanical Phenomena, Computer simulation, Humans, Male, Manikins, Models, Traffic/sn [Statistics \& Numerical Dat},
pubstate = {published},
tppubtype = {article}
}
Wu, L C; Nangia, V; Bui, K; Hammoor, B; Kurt, M; Hernandez, F; Kuo, C; Camarillo, D B
In Vivo Evaluation of Wearable Head Impact Sensors Journal Article
In: Annals of Biomedical Engineering, vol. 44, no. 4, pp. 1234–1245, 2016.
@article{Wu2016,
title = {In Vivo Evaluation of Wearable Head Impact Sensors},
author = {Wu, L C and Nangia, V and Bui, K and Hammoor, B and Kurt, M and Hernandez, F and Kuo, C and Camarillo, D B},
year = {2016},
date = {2016-01-01},
journal = {Annals of Biomedical Engineering},
volume = {44},
number = {4},
pages = {1234--1245},
abstract = {Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (\<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for alpha(mag)) and the skull cap (320% NRMS error for a(mag), 500% for alpha(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Hernandez, F; Shull, P B; Camarillo, D B
Evaluation of a laboratory model of human head impact biomechanics Journal Article
In: Journal of Biomechanics, vol. 48, no. 12, pp. 3469–3477, 2015.
@article{Hernandez2015,
title = {Evaluation of a laboratory model of human head impact biomechanics},
author = {Hernandez, F and Shull, P B and Camarillo, D B},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biomechanics},
volume = {48},
number = {12},
pages = {3469--3477},
abstract = {This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests ($sim$100 Hz) than field impacts ($sim$10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Kettner, M; Ramsthaler, F; Potente, S; Bockenheimer, A; Schmidt, P H; Schrodt, M
Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling Journal Article
In: Forensic Science, Medicine & Pathology, vol. 10, no. 4, pp. 513–517, 2014.
@article{Kettner2014,
title = {Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling},
author = {Kettner, M and Ramsthaler, F and Potente, S and Bockenheimer, A and Schmidt, P H and Schrodt, M},
year = {2014},
date = {2014-01-01},
journal = {Forensic Science, Medicine \& Pathology},
volume = {10},
number = {4},
pages = {513--517},
abstract = {Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State's Attorney assigned a forensic expert to examine whether the forces exerted on the victim's head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295-485 g demonstrated that 12-20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ambekar, D; Al-Deneh, Z; Dao, T; Dziech, A L; Subbian, V; Beyette Jr., F R
Development of a point-of-care medical device to measure head impact in contact sports Journal Article
In: Conference Proceedings: ... Annual International Conference of the IEEE Engineering in Medicine & Biology Society, vol. 2013, pp. 4167–4170, 2013.
@article{Ambekar2013,
title = {Development of a point-of-care medical device to measure head impact in contact sports},
author = {Ambekar, D and Al-Deneh, Z and Dao, T and Dziech, A L and Subbian, V and {Beyette Jr.}, F R},
year = {2013},
date = {2013-01-01},
journal = {Conference Proceedings: ... Annual International Conference of the IEEE Engineering in Medicine \& Biology Society},
volume = {2013},
pages = {4167--4170},
abstract = {This paper presents a prototype of a wireless, point-of-care medical device to measure head impacts in contact or collision sports. The device is currently capable of measuring linear acceleration, time, and the duration of impact. The location of the impact can also be recorded by scaling the prototype design to multiple devices. An experimental apparatus was built to simulate head impacts and to verify the data from the device. Preliminary results show that the biomechanical measures from the device are sufficiently accurate.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
McIntosh, A S; Lai, A; Schilter, E
Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests Journal Article
In: Traffic Injury Prevention, vol. 14, no. 5, pp. 501–508, 2013.
@article{McIntosh2013,
title = {Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests},
author = {McIntosh, A S and Lai, A and Schilter, E},
year = {2013},
date = {2013-01-01},
journal = {Traffic Injury Prevention},
volume = {14},
number = {5},
pages = {501--508},
abstract = {OBJECTIVE: To assess the factors, including helmet use, that contribute to head linear and angular acceleration in bicycle crash simulation tests. METHOD: A series of laboratory tests was undertaken using an oblique impact rig. The impact rig included a drop assembly with a Hybrid III head and neck. The head struck a horizontally moving striker plate. Head linear and angular acceleration and striker plate force were measured. The Head Injury Criterion was derived. The following test parameters were varied: drop height to a maximum of 1.5 m, horizontal speed to a maximum of 25 km/h, helmet/no helmet, impact orientation/location, and restraint adjustment. Additional radial impacts were conducted on the same helmet models for comparison purposes. Descriptive statistics were derived and multiple regression was applied to examine the role of each parameter. RESULTS: Helmet use was the most significant factor in reducing the magnitude of all outcome variables. Linear acceleration and the Head Injury Criterion were influenced by the drop height, whereas angular acceleration tended to be influenced by the horizontal speed and impact orientation/location. The restraint adjustment influenced the outcome variables, with lower coefficients of variation observed with the tight restraint. CONCLUSIONS: The study reinforces the benefits of wearing a bicycle helmet in a crash. The study also demonstrates that helmets do not increase angular head acceleration. The study assists in establishing the need for an agreed-upon international oblique helmet test as well as the boundary conditions for oblique helmet testing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wu, L C; Nangia, V; Bui, K; Hammoor, B; Kurt, M; Hernandez, F; Kuo, C; Camarillo, D B
In Vivo Evaluation of Wearable Head Impact Sensors Journal Article
In: Annals of Biomedical Engineering, vol. 44, no. 4, pp. 1234–1245, 2016.
Abstract | BibTeX | Tags: *Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording
@article{Wu2016,
title = {In Vivo Evaluation of Wearable Head Impact Sensors},
author = {Wu, L C and Nangia, V and Bui, K and Hammoor, B and Kurt, M and Hernandez, F and Kuo, C and Camarillo, D B},
year = {2016},
date = {2016-01-01},
journal = {Annals of Biomedical Engineering},
volume = {44},
number = {4},
pages = {1234--1245},
abstract = {Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (\<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for alpha(mag)) and the skull cap (320% NRMS error for a(mag), 500% for alpha(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.},
keywords = {*Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
Hernandez, F; Shull, P B; Camarillo, D B
Evaluation of a laboratory model of human head impact biomechanics Journal Article
In: Journal of Biomechanics, vol. 48, no. 12, pp. 3469–3477, 2015.
Abstract | BibTeX | Tags: *HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY
@article{Hernandez2015,
title = {Evaluation of a laboratory model of human head impact biomechanics},
author = {Hernandez, F and Shull, P B and Camarillo, D B},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biomechanics},
volume = {48},
number = {12},
pages = {3469--3477},
abstract = {This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests ($sim$100 Hz) than field impacts ($sim$10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.},
keywords = {*HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY},
pubstate = {published},
tppubtype = {article}
}
Kettner, M; Ramsthaler, F; Potente, S; Bockenheimer, A; Schmidt, P H; Schrodt, M
Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling Journal Article
In: Forensic Science, Medicine & Pathology, vol. 10, no. 4, pp. 513–517, 2014.
Abstract | BibTeX | Tags: *Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult
@article{Kettner2014,
title = {Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling},
author = {Kettner, M and Ramsthaler, F and Potente, S and Bockenheimer, A and Schmidt, P H and Schrodt, M},
year = {2014},
date = {2014-01-01},
journal = {Forensic Science, Medicine \& Pathology},
volume = {10},
number = {4},
pages = {513--517},
abstract = {Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State's Attorney assigned a forensic expert to examine whether the forces exerted on the victim's head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295-485 g demonstrated that 12-20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.},
keywords = {*Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Ambekar, D; Al-Deneh, Z; Dao, T; Dziech, A L; Subbian, V; Beyette Jr., F R
Development of a point-of-care medical device to measure head impact in contact sports Journal Article
In: Conference Proceedings: ... Annual International Conference of the IEEE Engineering in Medicine & Biology Society, vol. 2013, pp. 4167–4170, 2013.
Abstract | BibTeX | Tags: *Accelerometry/is [Instrumentation], *Head Movements/ph [Physiology], *Models, *Monitoring, *Sports Equipment, *Wireless Technology/is [Instrumentation], Ambulatory/is [Instrumentation], Biological, Biomechanical Phenomena/ph [Physiology], Humans, Point-of-Care Systems, Sports
@article{Ambekar2013,
title = {Development of a point-of-care medical device to measure head impact in contact sports},
author = {Ambekar, D and Al-Deneh, Z and Dao, T and Dziech, A L and Subbian, V and {Beyette Jr.}, F R},
year = {2013},
date = {2013-01-01},
journal = {Conference Proceedings: ... Annual International Conference of the IEEE Engineering in Medicine \& Biology Society},
volume = {2013},
pages = {4167--4170},
abstract = {This paper presents a prototype of a wireless, point-of-care medical device to measure head impacts in contact or collision sports. The device is currently capable of measuring linear acceleration, time, and the duration of impact. The location of the impact can also be recorded by scaling the prototype design to multiple devices. An experimental apparatus was built to simulate head impacts and to verify the data from the device. Preliminary results show that the biomechanical measures from the device are sufficiently accurate.},
keywords = {*Accelerometry/is [Instrumentation], *Head Movements/ph [Physiology], *Models, *Monitoring, *Sports Equipment, *Wireless Technology/is [Instrumentation], Ambulatory/is [Instrumentation], Biological, Biomechanical Phenomena/ph [Physiology], Humans, Point-of-Care Systems, Sports},
pubstate = {published},
tppubtype = {article}
}
McIntosh, A S; Lai, A; Schilter, E
Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests Journal Article
In: Traffic Injury Prevention, vol. 14, no. 5, pp. 501–508, 2013.
Abstract | BibTeX | Tags: *Accidents, *Bicycling/in [Injuries], *Craniocerebral Trauma/et [Etiology], *Head Protective Devices/ut [Utilization], Acceleration, Biological, Biomechanical Phenomena, Computer simulation, Humans, Male, Manikins, Models, Traffic/sn [Statistics & Numerical Dat
@article{McIntosh2013,
title = {Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests},
author = {McIntosh, A S and Lai, A and Schilter, E},
year = {2013},
date = {2013-01-01},
journal = {Traffic Injury Prevention},
volume = {14},
number = {5},
pages = {501--508},
abstract = {OBJECTIVE: To assess the factors, including helmet use, that contribute to head linear and angular acceleration in bicycle crash simulation tests. METHOD: A series of laboratory tests was undertaken using an oblique impact rig. The impact rig included a drop assembly with a Hybrid III head and neck. The head struck a horizontally moving striker plate. Head linear and angular acceleration and striker plate force were measured. The Head Injury Criterion was derived. The following test parameters were varied: drop height to a maximum of 1.5 m, horizontal speed to a maximum of 25 km/h, helmet/no helmet, impact orientation/location, and restraint adjustment. Additional radial impacts were conducted on the same helmet models for comparison purposes. Descriptive statistics were derived and multiple regression was applied to examine the role of each parameter. RESULTS: Helmet use was the most significant factor in reducing the magnitude of all outcome variables. Linear acceleration and the Head Injury Criterion were influenced by the drop height, whereas angular acceleration tended to be influenced by the horizontal speed and impact orientation/location. The restraint adjustment influenced the outcome variables, with lower coefficients of variation observed with the tight restraint. CONCLUSIONS: The study reinforces the benefits of wearing a bicycle helmet in a crash. The study also demonstrates that helmets do not increase angular head acceleration. The study assists in establishing the need for an agreed-upon international oblique helmet test as well as the boundary conditions for oblique helmet testing.},
keywords = {*Accidents, *Bicycling/in [Injuries], *Craniocerebral Trauma/et [Etiology], *Head Protective Devices/ut [Utilization], Acceleration, Biological, Biomechanical Phenomena, Computer simulation, Humans, Male, Manikins, Models, Traffic/sn [Statistics \& Numerical Dat},
pubstate = {published},
tppubtype = {article}
}