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Winthrop, ME, United States

Hajiaghamemar M.,University of Maine, United States | Seidi M.,University of Maine, United States | Ferguson J.R.,Alba-Technic, LLC | Caccese V.,University of Maine, United States
Annals of Biomedical Engineering | Year: 2015

The kinematics and kinetics of head impact due to a standing fall onto a hard surface are summarized. Head injury due to impact from falls represents a significant problem, especially for older individuals. When the head is left unprotected during a fall, the impact severity can be high enough to cause significant injury or even death. To ascertain the range of head impact parameters, the dynamic response was captured for the pedestrian version of the 5th percentile female and 50th percentile male Hybrid III anthropomorphic test dummies as they were dropped from a standing position with different initial postures. Five scenarios of falls were considered including backward falls with/without hip flexion, forward falls with/without knee flexion and lateral falls. The results show that the head impact parameters are dependent on the fall scenario. A wide range of impact parameters was observed in 107 trials. The 95% prediction interval for the peak translational acceleration, peak angular acceleration, peak force, impact translational velocity and peak angular velocity are 146–502 g, 8.8–43.3 krad/s2, 3.9–24.5 kN, 2.02–7.41 m/s, and 12.9–70.3 rad/s, respectively. © 2015, Biomedical Engineering Society.

Caccese V.,University of Maine, United States | Ferguson J.,Alba-Technic, LLC | Lloyd J.,FL | Edgecomb M.,University of Maine, United States | And 2 more authors.
Experimental Techniques | Year: 2014

A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus for use in the development of protective headgear designed to prevent injury due to falls. By including angular acceleration in the test protocol it becomes possible to assess and intentionally reduce this component of acceleration. Comparisons of standard and reduced durometer necks, various anvils, front, rear, and side drop orientations, and response data on performance of the apparatus are provided. Injury measures summarized for an unprotected drop include maximum linear and angular acceleration, head injury criteria (HIC), rotational injury criteria (RIC), and power rotational head injury criteria (PRHIC). Coefficient of variation for multiple drops ranged from 0.4 to 6.7% for linear acceleration. Angular acceleration recorded in a side drop orientation resulted in highest coefficient of variation of 16.3%. The drop test apparatus results in a reasonably repeatable test method that has potential to be used in studies of headgear designed to reduce head impact injury. © 2014, Society for Experimental Mechanics.

Caccese V.,University of Maine, United States | Ferguson J.R.,Alba-Technic, LLC | Edgecomb M.A.,University of Maine, United States
Composite Structures | Year: 2013

This paper presents a study of the impact resistance of honeycomb structure with the purpose to mitigate impact forces. The objective is to aid in the choice of optimal parameters to minimize the thickness of the honeycomb structure while providing adequate protection to prevent injury due to head impact. Studies are presented using explicit dynamic finite element analysis representing the case of an unprotected drop of a rigid impactor onto a simulated floor consisting of vinyl composition tile and concrete. Analysis of honeycomb material to reduce resulting accelerations is also presented where parameters such as honeycomb material modulus, wall thickness, cell geometry and structure depth are compared to the unprotected case. A simplified optimization analysis technique using a genetic algorithm is presented to demonstrate the use of this method to select a minimum honeycomb depth to achieve a desired acceleration level at a given level of input energy. It is important to select a minimum material depth in that smaller dimensions lead toward more aesthetic design that increase the likelihood that the device is used. © 2013 Elsevier Ltd.

Seidi M.,University of Maine, United States | Hajiaghamemar M.,University of Maine, United States | Ferguson J.,Alba-Technic, LLC | Caccese V.,University of Maine, United States
SAE Technical Papers | Year: 2015

Falls in the elderly population is an important concern to individuals and in the healthcare industry. When the head is left unprotected, head impact levels can reach upwards of 500 g (gravitational acceleration), which is a level that can cause serious injury or death. A protective system for a fall injury needs to be designed with specific criteria in mind including energy protection level, thickness, stiffness, and weight among others. The current study quantifies the performance of a protective head gear design for persons prone to falls. The main objective of this paper is to evaluate the injury mitigation of head protection gear made from a patented system of polyurethane honeycomb and dilatant materials. To that end, a twin wire fall system equipped with a drop arm that includes a Hybrid-III head/neck assembly was used. The head was instrumented with an accelerometer array. The test apparatus captures impact velocity and translational acceleration components simultaneously. Tests were performed on two different material systems for frontal, side and rear impact cases. The honeycomb-dilatant system for each design consists of a cast 6mm thick, polyurethane honeycomb in the front section and a 6mm thick, honeycomb in the rear, that are nominally 55 Shore A and 40 Shore A durometer, respectively and the outer shell was a dilatant material. The peak translational acceleration at the head center of gravity (C. G.) and the Head Injury Criterion (HIC) were captured to evaluate the performance of two material systems. A reduction of the peak translational acceleration and HIC during impact was observed. Dropping the head/neck assembly equipped with the protection system from 45cm height (rear impact) resulted in translational acceleration and HIC reduction from 308g to 82g and 879 to 136, respectively for the thicker material system. Copyright © 2015 SAE International.

Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 933.70K | Year: 2010

DESCRIPTION (provided by applicant): The Centers for Disease Control (CDC) has identified falls-related traumatic brain injury (TBI) in older adults as a significant and unrecognized public health issue; with 8000 deaths from falls- related TBI in older adults and 56,000 hospitalizations, at a mean cost of 16,006/ 19,191 for women/men gt64 years reported in 2005; prompting a public service campaign4. The challenges of maintaining independence in mobility and physiologic conditioning for wellness while avoiding injury due to impaired balance can contribute to the downward spiraling to frailty and loss of independence. The very deficits associated with many chronic conditions with aging that lead to mobility and balance difficulties, often contribute to cognitive changes that limit the effectiveness of rehabilitation and safety training and overall awareness of self-limitations15. Some of the increase incidence in and mortality from TBI is associated with anticoagulation therapy, including aspirin and the 2 million new users of warfarin each year12. To address this challenge, with the support of NIH Phase I SBIR funds, a new lightweight, un-obtrusive medical headgear with over 90% impact force reduction using was developed using advanced composites. The goal of the research component of the Phase II proposal is to 1) optimize material characteristics using data from Phase I impact testing and conduct numerical modeling using finite element analysis, 2) conduct biochemical evaluation of these advanced materials on designer-enhanced prototypes, 3) perform clinical trials with qualitative analysis based on indepth interviews and focus groups on patients, family members and staff to develop tools to evaluate compliance and decisions to use the product and 4) Develop a standard for headgear protection for patients at risk of same level falls. PUBLIC HEALTH RELEVANCE: Falls-related traumatic brain injury has become a significant and unrecognized public health issue. There is a need for a new lightweight, attractive, unobtrusive medical headgear that can be customized to the style, needs, comfort and protection to provide higher compliance and application to patient populations that includes older adults with balance impairment, dementia, active seniors on blood thinners, acute care hospital cases at very high risk for falls to reduce the health consequences of falls-related traumatic brain injury. Outcomes tools to evaluate the effectiveness of social marketing and academic detailing will be developed.

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