Head biomechanics of video recorded falls involving children in a childcare setting

The objective of this study was to characterize head biomechanics of video-recorded falls involving young children in a licensed childcare setting. Children 12 to < 36 months of age were observed using video monitoring during daily activities in a childcare setting (in classrooms and outdoor playground) to capture fall events. Sensors (SIM G) incorporated into headbands worn by the children were used to obtain head accelerations and velocities during falls. The SIM G device was activated when linear acceleration was ≥ 12 g. 174 video-recorded falls activated the SIM G device; these falls involved 31 children (mean age = 21.6 months ± 5.6 SD). Fall heights ranged from 0.1 to 1.2 m. Across falls, max linear head acceleration was 50.2 g, max rotational head acceleration was 5388 rad/s², max linear head velocity was 3.8 m/s and max rotational head velocity was 21.6 rad/s. Falls with head impact had significantly higher biomechanical measures. There was no correlation between head acceleration and fall height. No serious injuries resulted from falls—only 1 child had a minor injury. In conclusion, wearable sensors enabled characterization of head biomechanics during video-recorded falls involving young children in a childcare setting. Falls in this setting did not result in serious injury.

Femur morphology in healthy infants and young children

The objective of this study was to characterize femur morphology in healthy infants and young children. Anterior-posterior (AP) radiographs of the femur from children age 0-3 years with no history of bone disease were obtained from two children's hospitals and one medical examiner's office. Femur morphological measures (bone length, minimum diaphysis diameter, growth plate width, and femur radius of curvature) and sectional structural measures were determined. Measures were described and compared based on subject age and mass. Relationships between measures and age and mass were evaluated. The 169 AP femur radiographs were obtained from 99 children (59.6% males, median age = 12.0 months, IQR = 0-27.5 months, median body weight = 10.0 kg, IQR = 4.4-15.6 kg). Femur length (r_s  = 0.97, p < 0.001; r_s  = 0.89, p < 0.001), trochanter width (r_s  = 0.86, p < 0.001; r_s  = 0.85, p < 0.001), minimum diaphysis diameter (r_s  = 0.91, p < 0.001; r_s  = 0.87, p < 0.001), and growth plate width (r_s  = 0.91, p < 0.001; r_s  = 0.84, p < 0.001) increased with age and weight, respectively. Cross-sectional area (r_s  = 0.87; r_s  = 0.86; p < 0.01), polar moment of inertia (r_s  = 0.91; r_s  = 0.87; p < 0.001), moment of inertia (r_s  = 0.91; r_s  = 0.87; p < 0.001), polar modulus (r_s  = 0.91; r_s  = 0.87; p < 0.001) and medullary canal diameter (r_s  = 0.83, p < 0.001; r_s  = 0.73, p < 0.001) at the minimum diaphysis also increased with age and weight, respectively. Changes during rapid bone growth are important to understanding fracture risk in infants and young children as they transition to independent walking. Femur length, trochanter width, minimum diaphysis diameter and growth plate width increased with age and weight. Structural properties associated with fracture resistance also increased with age and weight.

Overturned abusive head trauma and shaken baby syndrome convictions in the United States: Prevalence, legal basis, and medical evidence

BACKGROUND

Media reports and the Innocence Network assert that wrongful Abusive Head Trauma (AHT)/Shaken Baby Syndrome (SBS) convictions pervade the United States (U.S.) criminal justice system. Yet, no empirical evaluation of overturned AHT/SBS convictions has been conducted.

OBJECTIVE

To evaluate the prevalence, legal basis, and characteristics of appellate rulings of AHT/SBS convictions.

PARTICIPANTS AND SETTING

U.S. appellate cases in a legal database, Westlaw.

METHODS

Retrospective review of AHT/SBS convictions that had appellate rulings from January 2008 through December 2018. Multiple search terms ensured all potential AHT/SBS cases were included. A mixed-methods analysis was conducted on overturned AHT/SBS convictions.

RESULTS

We identified a total of 1431 unique AHT/SBS criminal convictions that had appellate rulings since 2008. Of those, 49 convictions (3%) were overturned, and 1382 (97%) were affirmed/upheld. Of those overturned, 20 cases (1% overall) were overturned on medical evidence-related grounds. The most common themes from the medical evidence-related reversals were controversy over the AHT/SBS diagnosis (n = 12) and accidental injury mechanism (n = 11). After being overturned on appeal, upon retrial, 42% of defendants either re-plead guilty to or were convicted again of the same offense.

CONCLUSION(S)

AHT/SBS convictions are rarely overturned on medical evidence-related grounds. When overturned, medical evidence-related themes seldom reflect new scientific or clinical discoveries, but rather are alternative or differing medical opinions from those offered at the original trial. Our data tends to support the concerns of other authors regarding irresponsible communication of medical information in AHT/SBS cases.

Validation of a Clinical Decision Rule to Predict Abuse in Young Children Based on Bruising Characteristics

IMPORTANCE

Bruising caused by physical abuse is the most common antecedent injury to be overlooked or misdiagnosed as nonabusive before an abuse-related fatality or near-fatality in a young child. Bruising occurs from both nonabuse and abuse, but differences identified by a clinical decision rule may allow improved and earlier recognition of the abused child.

OBJECTIVE

To refine and validate a previously derived bruising clinical decision rule (BCDR), the TEN-4 (bruising to torso, ear, or neck or any bruising on an infant <4.99 months of age), for identifying children at risk of having been physically abused.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cross-sectional study was conducted from December 1, 2011, to March 31, 2016, at emergency departments of 5 urban children's hospitals. Children younger than 4 years with bruising were identified through deliberate examination. Statistical analysis was completed in June 2020.

EXPOSURES

Bruising characteristics in 34 discrete body regions, patterned bruising, cumulative bruise counts, and patient's age. The BCDR was refined and validated based on these variables using binary recursive partitioning analysis.

MAIN OUTCOMES AND MEASURES

Injury from abusive vs nonabusive trauma was determined by the consensus judgment of a multidisciplinary expert panel.

RESULTS

A total of 21 123 children were consecutively screened for bruising, and 2161 patients (mean [SD] age, 2.1 [1.1] years; 1296 [60%] male; 1785 [83%] White; 1484 [69%] non-Hispanic/Latino) were enrolled. The expert panel achieved consensus on 2123 patients (98%), classifying 410 (19%) as abuse and 1713 (79%) as nonabuse. A classification tree was fit to refine the rule and validated via bootstrap resampling. The resulting BCDR was 95.6% (95% CI, 93.0%-97.3%) sensitive and 87.1% (95% CI, 85.4%-88.6%) specific for distinguishing abuse from nonabusive trauma based on body region bruised (torso, ear, neck, frenulum, angle of jaw, cheeks [fleshy], eyelids, and subconjunctivae), bruising anywhere on an infant 4.99 months and younger, or patterned bruising (TEN-4-FACESp).

CONCLUSIONS AND RELEVANCE

In this study, an affirmative finding for any of the 3 BCDR TEN-4-FACESp components in children younger than 4 years indicated a potential risk for abuse; these results warrant further evaluation. Clinical application of this tool has the potential to improve recognition of abuse in young children with bruising.

Investigation of femur fracture potential in common pediatric falls using finite element analysis

A finite element (FE) model of an 11-month-old child's femur was developed to evaluate fracture risk in short-distance feet-first falls and bed falls. Pediatric material properties were applied to the FE model. Femur loading was derived from previously conducted fall experiments using a child surrogate where fall conditions (e.g., fall height, impact surface) were varied. Fracture thresholds based on principal stress and strain were used to examine potential for fracture. Peak stress/strain were significantly greater for feet-first falls from greater heights and onto harder impact surfaces. Feet-first falls exceeded some, but not all fracture thresholds. Bed falls did not exceed any fracture thresholds.

Ramps remain a barrier to safe wheelchair user transit bus ingress/egress

Background: Wheelchair users (WCUs) often rely on ramps for access to transit buses. Previous studies indicate WCUs have difficulty using ramps for bus ingress/egress and many transportation-related incidents occur on ramps. However, experiences of WCU ramp usage during ingress/egress have not been fully described.Methods: Cross-sectional, internet-based survey of WCUs who ride transit buses was conducted. The participants were queried on frequency of bus usage, difficulty and incidents involving ramps, and factors contributing to difficulty and incidents. Wheelchair characteristics, primary condition, and whether participants received travel training were also captured. Chi-square was used to describe relationships between wheelchair type and frequency of difficulties and incidents, and odd ratios were used to determine likelihood of the incidents.Results: The majority (55.7%) of 384 participants reported using public transportation ≥ 1 per week. Seventy-eight percent of WCUs had ≥ 1 ramp incident over the past 3 years, with an increased likelihood of incidents occurring during ingress (OR = 1.53; CI 1.21-1.86). Of those who had an incident, 22% were injured or had damage to their wheelchair. Over 60% of those who had an incident identified steep ramp slope as being the contributing factor. Steep ramp slope, exterior ramp thresholds and wet surfaces were the most common contributing factors to difficulty using ramps.Conclusion: This is the first large-scale US study enabling WCUs to describe their experiences using transit bus ramps. Despite ADA guidelines, steep ramps remain the primary factor contributing to incidents and difficulty when using ramps to access transit buses.Implications for rehabilitationThe discrepancy between ADA maximum allowable ramp slopes for the built environment and transit buses may require an increased level of effort that is a barrier to transportation accessibility for some wheelchair users.Wheelchair users who access transit buses should be made aware of, and trained, to navigate ramp configurations found in the environment.We suggest rehabilitation therapists provide skills training specific to navigating transit bus ramp slopes that may be steeper and narrower than building ramps.

Long bone fracture characteristics in children with medical conditions linked to bone health

BACKGROUND

Knowledge of fracture characteristics among children with medical conditions affecting bone could help to distinguish medical causes from child abuse.

OBJECTIVE

Characterize long bone fracture morphology among children diagnosed with medical conditions linked to bone health.

PARTICIPANTS AND SETTING

Patients <18 years at a single pediatric hospital diagnosed with a medical condition linked to bone health and ≥1 long bone fracture were studied.

METHODS

This retrospective medical record review categorized underlying medical diagnoses as: metabolic bone disease, genetic disorder of connective tissue, neurologic disorder and other chronic disease. A pediatric radiologist reviewed plain films to determine fracture type and location. Descriptive statistics, as well as logistic regression were used to compare fracture types by clinical characteristics.

RESULTS

Ninety-four patients were included and their diagnoses were genetic connective disorder (19; 20.2 %), metabolic bone disease (16; 17.0 %), neurologic disorder (27; 28.7 %), and other (32; 34.0 %). A total of 216 long bone fractures were sustained; 52.1 % of children had >1 long bone fracture. Of the 216 fractures, 55 (25.5 %) were in children < 1 year, 118 (54.6 %) were associated with known trauma, and 122 (56.5 %) were in non-ambulatory patients. Lower extremity fractures occurred with greatest frequency and most fractures occurred at the mid-diaphysis. Transverse was the most common fracture type in all diagnostic categories. Children with metabolic disorders had highest odds of transverse fracture (COR 3.55, CI 1.45-8.67; neurologic disorders as reference group).

CONCLUSIONS

Diseases affecting bone health can influence fracture morphology. Transverse fractures were most common in bones impacted by disease.

Retraction Note to: Radiographic characteristics that delineate abusive from accidental skull fractures, including the significance of fracture extension to sutures

The authors have retracted the abstract #029 "Radiographic characteristics that delineate abusive from accidental skull fractures, including the significance of fracture extension to sutures".

Classifying Injuries in Young Children as Abusive or Accidental: Reliability and Accuracy of an Expert Panel Approach

OBJECTIVE

To assess interrater reliability and accuracy of an expert panel in classifying injuries of patients as abusive or accidental based on comprehensive case information.

STUDY DESIGN

Data came from a prospective, observational, multicenter study investigating bruising characteristics of children younger than 4 years. We enrolled 2166 patients with broad ranges of illnesses and injuries presenting to one of 5 pediatric emergency departments in whom bruises were identified during examination. We collected comprehensive data regarding current and past injuries and illnesses, and provided deidentified, standardized case information to a 9-member multidisciplinary panel of experts with extensive experience in pediatric injury. Each panelist classified cases using a 5-level ordinal scale ranging from definite abuse to definite accident. Panelists also assessed whether report to child protective services (CPS) was warranted. We calculated reliability coefficients for likelihood of abuse and decision to report to CPS.

RESULTS

The interrater reliability of the panelists was high. The Kendall coefficient (95% CI) for the likelihood of abuse was 0.89 (0.87, 0.91) and the kappa coefficient for the decision to report to CPS was 0.91 (0.87, 0.94). Reliability of pairs and subgroups of panelists were similarly high. A panel composite classification was nearly perfectly accurate in a subset of cases having definitive, corroborated injury status.

CONCLUSIONS

A panel of experts with different backgrounds but common expertise in pediatric injury is a reliable and accurate criterion standard for classifying pediatric injuries as abusive or accidental in a sample of children presenting to a pediatric emergency department.

Femur loading in feet-first fall experiments using an anthropomorphic test device

BACKGROUND

Femur fractures are a common orthopedic injury in young children. Falls account for a large portion of accidental femur fractures in young children, but there is also a high prevalence of femur fractures in child abuse, with falls often provided as false histories. Objective information regarding fracture potential in short distance fall scenarios may aid in assessing whether a child's injuries are the result of abuse or an accidental fall. Knowledge of femur loading is the first step towards understanding likelihood of fracture in a fall.

OBJECTIVE

Characterize femur loading during feet-first free falls using a surrogate representing a 12-month-old child.

METHODS

The femur and hip joint of a surrogate representing a 12-month-old were modified to improve biofidelity and measure femur loading; 6-axis load cells were integrated into the proximal and distal femur. Femur modification was based upon CT imaging of cadaveric femurs in children 10-14 months of age. Using the modified 12-month-old surrogate, feet-first free falls from 69 cm and 119 cm heights onto padded carpet and linoleum were conducted to assess fall dynamics and determine femur loading. Femur compression, bending moment, shear and torsional moment were measured for each fall.

RESULTS

Fall dynamics differed across fall heights, but did not substantially differ by impact surface type. Significant differences were found in all loading conditions across fall heights, while only compression and bending loads differed between carpet and linoleum surfaces. Maximum compression, bending, torsion and shear occurred in 119 cm falls and were 572 N, 23 N-m, 11 N-m and 281 N, respectively.

CONCLUSIONS

Fall dynamics play an important role in the biomechanical assessment of falls. Fall height was found to influence both fall dynamics and femur loading, while impact surface affected only compression and bending in feet-first falls; fall dynamics did not differ across carpet and linoleum. Improved pediatric thresholds are necessary to predict likelihood of fracture, but morphologically accurate representation of the lower extremity, along with accurate characterization of loading in falls are a crucial first step.

Impact sites representing potential bruising locations associated with bed falls in children

Bruising can occur as a result of accidental or abusive trauma in children. Bruises are an early sign of child abuse and their locations on the body can be an effective delineator of abusive trauma. Since falls are often reported as false histories in abuse, the ability to predict potential bruising locations in falls could be valuable when attempting to differentiate between abuse and accident. In our study we used an anthropomorphic test device (ATD), a surrogate representing a 12 month old child, adapted with a custom developed force sensing skin to predict potential bruising locations during simulated bed falls. The sensing skin is made of custom resistive force sensors integrated into a conformable skin, adapted to fit the contours of the ATD. The sensing skin measured and displayed recorded force data on a computerized body image mapping system when sensors were activated. Simulated bed fall experiments were performed from two initial positions (FF - facing forward and FR - facing rearward) and two fall heights of 61cm (24 in) and 91cm (36 in) onto a padded carpet impact surface. Findings indicated potential bruising primarily in two planes of the ATD body. The majority of contact regions and greater forces were recorded in one plane, with fewer regions of contact and decreased force exhibited in an adjoining second plane. Additionally, no contact was recorded in the two planes opposite the impact planes. Differences in contact regions were observed for varying heights and initial position. Limitations of ATD biofidelity and soft tissue properties must be considered when interpreting these findings.

Wheelchair tiedown and occupant restraint practices in paratransit vehicles

The purpose of this study was to characterize wheelchair tiedown and occupant restraint system (WTORS) usage in paratransit vehicles based on observations of wheelchair and scooter (wheeled mobility devices, collectively, “WhMD”) passenger trips. A retrospective review of on-board video monitoring recordings of WhMD trips was conducted. Four hundred seventy-five video recordings were collected for review and analysis. The use of all four tiedowns to secure the WhMD was observed more frequently for power WhMDs (82%) and manual WhMDs (80%) compared to scooters (39%), and this difference was significant (p< 0.01). Nonuse or misuse of the occupant restraint system occurred during 88% of WhMD trips, and was most frequently due to vehicle operator neglect in applying the shoulder belt. Despite the absence of incidents or injuries in this study, misuse and nonuse of WTORS potentially place WhMD seated passengers at higher risk of injury during transit. These findings support the need for improved vehicle operator training and passenger education on the proper use of WTORS and development of WTORS with improved usability and/or alternative technologies that can be automated or used independently.

Aquatic treadmill water level influence on pelvic limb kinematics in cranial cruciate ligament-deficient dogs with surgically stabilised stifles

OBJECTIVE

To compare pelvic limb joint kinematics and temporal gait characteristics during land-based and aquatic-based treadmill walking in dogs that have undergone surgical stabilisation for cranial cruciate ligament deficiency.

MATERIALS AND METHODS

Client-owned dogs with surgically stabilised stifles following cranial cruciate ligament deficiency performed three walking trials consisting of three consecutive gait cycles on an aquatic treadmill under four water levels. Hip, stifle and hock range of motion; peak extension; and peak flexion were assessed for the affected limb at each water level. Gait cycle time and stance phase percentage were also determined.

RESULTS

Ten client-owned dogs of varying breeds were evaluated at a mean of 55·2 days postoperatively. Aquatic treadmill water level influenced pelvic limb kinematics and temporal gait outcomes. Increased stifle joint flexion was observed as treadmill water level increased, peaking when the water level was at the hip. Similarly, hip flexion increased at the hip water level. Stifle range of motion was greatest at stifle and hip water levels. Stance phase percentage was significantly decreased when water level was at the hip.

CLINICAL SIGNIFICANCE

Aquatic treadmill walking has become a common rehabilitation modality following surgical stabilisation of cranial cruciate ligament deficiency. However, evidence-based best practice guidelines to enhance stifle kinematics do not exist. Our findings suggest that rehabilitation utilising a water level at or above the stifle will achieve the best stifle kinematics following surgical stifle stabilisation.

Healthcare utilization and associated barriers experienced by wheelchair users: A pilot study

BACKGROUND

More than twenty-five years after passage of the ADA, little remains known about the experiences of wheelchair users when attempting to access health care and how accessibility may influence health care utilization.

OBJECTIVE/HYPOTHESIS

To describe health care utilization among wheelchair users and characterize barriers encountered when attempting to obtain access to health care.

METHODS

An internet-based survey of wheelchair users was conducted. Measures included demographics, condition, socioeconomic status, health care utilization and receipt of preventive services within the past year, physical barriers encountered at outpatient facilities, and satisfaction with care.

RESULTS

Four hundred thirty-two wheelchair users responded to the survey. Nearly all respondents (97.2%) had a primary care appointment within the past year and most reported 3-5 visits to both primary and specialty care providers. Most encountered physical barriers when accessing care (73.8% primary, 68.5% specialty). Participants received most preventive interventions at rates similar to national averages with the exception of Pap tests. Most participants remained clothed for their primary care evaluation (76.1%), and were examined seated in their wheelchair (69.7%). More than half of participants (54.1%) felt they received incomplete care, and 57% believed their physician had no more than a moderate understanding of their disability-specific medical concerns.

CONCLUSIONS

Wheelchair users face persistent barriers to care, may receive less than thorough physical evaluations, receive fewer screenings for cervical cancer, and largely believe they receive incomplete care.

Biomechanical Response of the Infant Head to Shaking: An Experimental Investigation

Controversy exists regarding whether violent shaking is harmful to infants in the absence of impact. In this study, our objective was to characterize the biomechanical response of the infant head during shaking through use of an instrumented anthropomorphic test device (commonly referred to as a "crash test dummy" or surrogate) representing a human infant and having improved biofidelity. A series of tests were conducted to simulate violent shaking of an infant surrogate. The Aprica 2.5 infant surrogate represented a 5th percentile Japanese newborn. A 50th percentile Japanese adult male was recruited to shake the infant surrogate in the sagittal plane. Triaxial linear accelerometers positioned at the center of mass and apex of the head recorded accelerations during shaking. Five shaking test series, each 3-4 sec in duration, were conducted. Outcome measures derived from accelerometer recordings were examined for trends. Head/neck kinematics were characterized during shaking events; mean peak neck flexion was 1.98 radians (113 degrees) and mean peak neck extension was 2.16 radians (123 degrees). The maximum angular acceleration across all test series was 13,260 radians/sec² (during chin-to-chest contact). Peak angular velocity was 105.7 radians/sec (during chin-to-chest contact). Acceleration pulse durations ranged from 72.1 to 168.2 ms. Using an infant surrogate with improved biofidelity, we found higher angular acceleration and higher angular velocity than previously reported during infant surrogate shaking experiments. Findings highlight the importance of surrogate biofidelity when investigating shaking.

Accessibility of outpatient healthcare providers for wheelchair users: Pilot study

The Americans with Disabilities Act (ADA) requires full and equal access to healthcare services and facilities, yet studies indicate individuals with mobility disabilities receive less than thorough care as a result of ADA noncompliance. The objective of our pilot study was to assess ADA compliance within a convenience sample of healthcare clinics affiliated with a statewide healthcare network. Site assessments based on the ADA Accessibility Guidelines for Buildings and Facilities were performed at 30 primary care and specialty care clinics. Clinical managers completed a questionnaire on standard practices for examining and treating patients whose primary means of mobility is a wheelchair. We found a majority of restrooms (83%) and examination rooms (93%) were noncompliant with one or more ADA requirements. Seventy percent of clinical managers reported not owning a height-adjustable examination table or wheelchair accessible weight scale. Furthermore, patients were examined in their wheelchairs (70%-87%), asked to bring someone to assist with transfers (30%), or referred elsewhere due to an inaccessible clinic (6%). These methods of accommodation are not compliant with the ADA. We recommend clinics conduct ADA self-assessments and provide training for clinical staff on the ADA and requirements for accommodating individuals with mobility disabilities.

Ramp-related incidents involving wheeled mobility device users during transit bus boarding/alighting

OBJECTIVES

To estimate the prevalence of wheeled mobility device (WhMD) ramp-related incidents while boarding/alighting a public transit bus and to determine whether the frequency of incidents is less when the ramp slope meets the proposed Americans with Disabilities Act (ADA) maximum allowable limit of ≤9.5°.

DESIGN

Observational study.

SETTING

Community public transportation.

PARTICIPANTS

WhMD users (N=414) accessing a public transit bus equipped with an instrumented ramp.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Prevalence of boarding/alighting incidents involving WhMD users and associated ramp slopes; factors affecting incidents.

RESULTS

A total of 4.6% (n=35) of WhMD users experienced an incident while boarding/alighting a transit bus. Significantly more incidents occurred during boarding (6.3%, n=26) than during alighting (2.2%, n=9) (P<.01), and when the ramp was deployed to street level (mean slope=11.4°) compared with sidewalk level (mean slope=4.2°) (P=.01). The odds ratio for experiencing an incident when the ramp slope exceeded the proposed ADA maximum allowable ramp slope was 5.4 (95% confidence interval, 2.4-12.2; P<.01). The odds ratio for assistance being rendered to board/alight when the ramp slope exceeded the proposed ADA maximum allowable ramp slope was 5.1 (95% confidence interval, 2.9-9.0; P<.01).

CONCLUSIONS

The findings of this study support the proposed ADA maximum allowable ramp slope of 9.5°. Ramp slopes >9.5° and ramps deployed to street level are associated with a higher frequency of incidents and provision of assistance. Transit agencies should increase awareness among bus operators of the effect kneeling and deployment location (street/sidewalk) have on the ramp slope. In addition, ramp components and the built environment may contribute to incidents. When prescribing WhMDs, skills training must include ascending/descending ramps at slopes encountered during boarding/alighting to ensure safe and independent access to public transit buses.

Public transit bus ramp slopes measured in situ

PURPOSE

The slopes of fixed-route bus ramps deployed for wheeled mobility device (WhMD) users during boarding and alighting were assessed. Measured slopes were compared to the proposed Americans with Disabilities Act (ADA) maximum allowable ramp slope.

METHODS

A ramp-embedded inclinometer measured ramp slope during WhMD user boarding and alighting on a fixed-route transit bus. The extent of bus kneeling was determined for each ramp deployment. In-vehicle video surveillance cameras captured ramp deployment level (street versus sidewalk) and WhMD type.

RESULTS

Ramp slopes ranged from -4° to 15.5° with means of 4.3° during boarding (n = 406) and 4.2° during alighting (n = 405). Ramp slope was significantly greater when deployed to street level. During boarding, the proposed ADA maximum allowable ramp slope (9.5°) was exceeded in 66.7% of instances when the ramp was deployed to street level, and in 1.9% of instances when the ramp was deployed to sidewalk level. During alighting, the proposed ADA maximum allowable slope was exceeded in 56.8% of instances when the ramp was deployed to street level and in 1.4% of instances when the ramp was deployed to sidewalk level.

CONCLUSIONS

Deployment level, built environment and extent of bus kneeling can affect slope of ramps ascended/descended by WhMD users when accessing transit buses. Implications for Rehabilitation Since public transportation services are critical for integration of wheeled mobility device (WhMD) users into the community and society, it is important that they, as well as their therapists, are aware of conditions that may be encountered when accessing transit buses. Knowledge of real world ramp slope conditions that may be encountered when accessing transit buses will allow therapists to better access capabilities of WhMD users in a controlled clinical setting. Real world ramp slope conditions can be recreated in a clinical setting to allow WhMD users to develop and practice necessary skills to safely navigate this environment. Knowing that extent of bus kneeling and ramp deployment level can influence ramp slope, therapists can educate WhMD users to request bus operators further kneel the bus floor and/or redeploy the ramp to a sidewalk level when appropriate, so that the least practicable slope will be presented for ingress/egress.

Ergonomic evaluation of a wheelchair transportation securement system

The Americans with Disabilities Act (ADA) specifies guidelines covering the securement system and environment for wheeled mobility device (WhMD) passengers on the public bus system in the United States, referred to as the wheelchair tiedown and occupant restraint system (WTORS). The misuse or disuse of the WTORS system can be a source of injury for WhMD passengers riding the buses. The purpose of this study was to quantify the risks posed to the bus driver while performing the WTORS procedure using traditional ergonomic analysis methods. Four bus drivers completed the WTORS procedure for a representative passenger seated in three different WhMDs: manual wheelchair (MWC), scooter (SCTR), and power wheelchair (PWC). Potential work-related risks were identified using the four most applicable ergonomic assessment tools: PLIBEL, RULA, REBA, and iLMM. Task evaluation results revealed high levels of risk to be present to drivers during the WTORS procedure. The securement station space design and equipment layout were identified as contributing factors forcing drivers to adopt awkward postures while performing the WTORS task. These risk factors are known contributors to injury and the drivers could opt to improperly secure the passengers to avoid that risk.

Health care utilization and barriers experienced by individuals with spinal cord injury

OBJECTIVES

To identify from whom individuals with spinal cord injury (SCI) seek health care, the percentage who receive preventative care screenings, and the frequency and types of barriers they encounter when accessing primary and specialty care services; and to examine how sociodemographic factors affect access to care and receipt of preventative screenings.

DESIGN

Cross-sectional, observational study using an Internet-based survey.

SETTING

Internet based.

PARTICIPANTS

Adults (N=108) with SCI who use a wheelchair as their primary means of mobility in the community.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Health care utilization during the past year, barriers encountered when accessing health care facilities, and receipt of routine care and preventative screenings.

RESULTS

All but 1 participant had visited a primary care provider within the past 12 months, and 85% had had ≥ 1 visit to specialty care providers. Accessibility barriers were encountered during both primary care (91.1%) and specialty care (80.2%) visits; most barriers were clustered in the examination room. The most prevalent barriers were inaccessible examination tables (primary care=76.9%; specialty care=51.4%) and lack of transfer aids (primary care=69.4%; specialty care=60.8%). Most participants had not been weighed during their visit (89%) and had remained seated in their wheelchair during their examinations (85.2%). Over one third of individuals aged ≥ 50 years had not received a screening colonoscopy, 60% of women aged ≥ 50 years had not had a mammogram within the past year, 39.58% of women had not received a Papanicolaou smear within the previous 3 years, and only 45.37% of respondents had ever received bone density testing.

CONCLUSIONS

Individuals with SCI face remediable obstacles to care and receive fewer preventative care screenings than their nondisabled counterparts. We recommend that clinics conduct Americans with Disabilities Act self-assessments, ensure that their clinical staff are properly trained in assisting individuals with mobility disabilities, and take a proactive approach in discussing preventative care screenings with their patients who have SCI.

Pediatric bed fall computer simulation model: parametric sensitivity analysis

Falls from beds and other household furniture are common scenarios that may result in injury and may also be stated to conceal child abuse. Knowledge of the biomechanics associated with short-distance falls may aid clinicians in distinguishing between abusive and accidental injuries. In this study, a validated bed fall computer simulation model of an anthropomorphic test device representing a 12-month-old child was used to investigate the effect of altering fall environment parameters (fall height, impact surface stiffness, initial force used to initiate the fall) and child surrogate parameters (overall mass, head stiffness, neck stiffness, stiffness for other body segments) on fall dynamics and outcomes related to injury potential. The sensitivity of head and neck injury outcome measures to model parameters was determined. Parameters associated with the greatest sensitivity values (fall height, initiating force, and surrogate mass) altered fall dynamics and impact orientation. This suggests that fall dynamics and impact orientation play a key role in head and neck injury potential. With the exception of surrogate mass, injury outcome measures tended to be more sensitive to changes in environmental parameters (bed height, impact surface stiffness, initiating force) than surrogate parameters (head stiffness, neck stiffness, body segment stiffness).

Wheelchair securement and occupant restraint system (WTORS) practices in public transit buses

The purpose of this study was to characterize wheelchair tiedown and occupant restraint system (WTORS) usage in public transit buses based on observations of wheelchair and scooter (wheeled mobility device: WhMD) passenger trips. A retrospective review of on-board video surveillance recordings of WhMD trips on fixed-route, large accessible transit vehicles (LATVs) was performed. Two hundred ninety-five video recordings were collected for review and analysis during the period June 2007-February 2009. Results showed that 73.6% of WhMDs were unsecured during transit. Complete use of all four tiedowns was observed more frequently for manual wheelchairs (14.9%) and power wheelchairs (5.5%), compared to scooters (0.0%), and this difference was significant (p=0.013). Nonuse or misuse (lap belt use only) of the occupant restraint system occurred during 47.5% of WhMD trips. The most frequently observed (52.5%) use of the lap belt consisted of bus operators routing the lap belt around the WhMD seatback in an attempt to secure the WhMD. These findings support the need for development and implementation of WTORS with improved usability and/or WTORS that can be operated independently by WhMD passengers and improved WTORS training for bus operators.

Investigation of wheelchair instability during transport in large accessible transit vehicles

Large accessible transit vehicles (LATVs, fixed-route intracity buses), generally considered safe, may not be as safe for wheelchair-seated passengers. Transit provider practices vary regarding use of wheelchair tiedown and occupant restraint systems (WTORSs), while recent research suggests high levels of WTORS disuse and misuse. We sought to better understand wheelchair and wheelchair passenger instabilities related to WTORS disuse and misuse on LATVs. This article presents a retrospective review of 295 video surveillance records of wheelchair passenger trips on LATVs. Wheelchair trips involving disuse and misuse of WTORS were quantified and categorized based on WTORS configurations. Cases of wheelchair and wheelchair passenger instability were categorized based on severity, type, and direction. Three adverse events involving severe wheelchair and/or passenger instability were examined in greater detail. Results showed 20.3% of records involved wheelchair-related adverse events (95% minor instabilities, 5% severe instabilities). Scooters were most likely to be unstable, followed by manual and power wheelchairs. In most instability cases, no tiedowns were used to secure the wheelchair and no lap belt was used to restrain the wheelchair passenger properly. In many instances, the lap belt was misused in an attempt to secure the wheelchair, whereas the shoulder belt was never used.

Assessment of injury potential in pediatric bed fall experiments using an anthropomorphic test device

Falls from beds and other furniture are common scenarios provided to conceal child abuse but are also common occurrences in young children. A better understanding of injury potential in short-distance falls could aid clinicians in distinguishing abusive from accidental injuries. Therefore, this study investigated biomechanical outcomes related to injury potential in falls from beds and other horizontal surfaces using an anthropomorphic test device representing a 12-month-old child. The potential for head, neck, and extremity injuries and differences due to varying impact surfaces were examined. Linoleum over concrete was associated with the greatest potential for head and neck injury compared to other evaluated surfaces (linoleum over wood, carpet, wood, playground foam). The potential for severe head and extremity injuries was low for most evaluated surfaces. However, results suggest that concussion and humerus fracture may be possible in these falls. More serious head injuries may be possible particularly for falls onto linoleum over concrete. Neck injury potential in pediatric falls should be studied further as limitations in ATD biofidelity and neck injury thresholds based solely on sagittal plane motion reduce accuracy in pediatric neck injury assessment. In future studies, limitations in ATD biofidelity and pediatric injury thresholds should be addressed to improve accuracy in injury potential assessments for pediatric short-distance falls. Additionally, varying initial conditions or pre-fall positioning should be examined for their influence on injury potential.

RESNA's position on wheelchairs used as seats in motor vehicles

This position paper is based on the premise that those who ride seated in wheelchairs are entitled to equivalent occupant safety when they are traveling in motor vehicles. The document summarizes research and best practice for safety and selection of crashworthy wheelchairs with the requisite features required by the WC19 safety standard when it is necessary for individuals to use a wheelchair as a seat in a motor vehicle. Recommendations are based on data from accident and injury databases, prior research and a synopsis of the design, testing, performance and labeling requirements of ANSI and ISO voluntary industry standards for wheelchair transportation safety. This paper is intended for an audience of consumers, rehabilitation and health care professionals, manufacturers of wheelchairs and wheelchair transportation equipment and those who make reimbursement and public policy decisions.

Wheeled mobility device transportation safety in fixed route and demand-responsive public transit vehicles within the United States

An overview of the current status of wheelchair transportation safety in fixed route and demand-responsive, non-rail, public transportation vehicles within the US is presented. A description of each mode of transportation is provided, followed by a discussion of the primary issues affecting safety, accessibility, and usability. Technologies such as lifts, ramps, securement systems, and occupant restraint systems, along with regulations and voluntary industry standards have been implemented with the intent of improving safety and accessibility for individuals who travel while seated in their wheeled mobility device (e.g., wheelchair or scooter). However, across both fixed route and demand-responsive transit systems a myriad of factors such as nonuse and misuse of safety systems, oversized wheeled mobility devices, vehicle space constraints, and inadequate vehicle operator training may place wheeled mobility device (WhMD) users at risk of injury even under non-impact driving conditions. Since WhMD-related incidents also often occur during the boarding and alighting process, the frequency of these events, along with factors associated with these events are described for each transit mode. Recommendations for improving WhMD transportation are discussed given the current state of

Pediatric short-distance household falls: biomechanics and associated injury severity

OBJECTIVES

Short-distance household falls are a common occurrence in young children, but are also a common false history given by caretakers to conceal abusive trauma. The purpose of this study was to determine the severity of injuries that result from accidental short-distance household falls in children, and to investigate the association of fall environment and biomechanical measures with injury outcomes.

METHODS

Children aged 0-4 years who presented to the Emergency Department with a history of a short furniture fall were included in the study. Detailed case-based biomechanical assessments were performed using data collected through medical records, interviews, and fall scene investigations. Injuries were rated using the Abbreviated Injury Scale (AIS). Each case was reviewed by a child abuse expert; cases with a vague or inconsistent history and cases being actively investigated for child abuse were excluded.

RESULTS

79 subjects were enrolled in the study; 15 had no injuries, 45 had minor (AIS 1) injuries, 17 had moderate (AIS 2) injuries, and 2 had serious (AIS 3) injuries. No subjects had injuries classified as AIS 4 or higher, and there were no fatalities. Children with moderate or serious injuries resulting from a short-distance household fall tended to have fallen from greater heights, have greater impact velocities, and have a lower body mass index than those with minor or no injuries.

CONCLUSION

Children aged 0-4 years involved in a short-distance household fall did not sustain severe or life-threatening injuries, and no children in this study had moderate or serious injuries to multiple body regions. Biomechanical measures were found to be associated with injury severity outcomes in short-distance household falls. Knowledge of relationships between biomechanical measures and injury outcomes can aid clinicians when assessing whether a child's injuries were the result of a short-distance fall or some other cause.

Injury biomechanics and child abuse

Child abuse is a leading cause of morbidity and mortality in young children and infants in the United States. Medical care providers, social services, and legal systems make critical decisions regarding injury and history plausibility daily. Injury plausibility judgments rely on evidence-based medicine, individualized experiences, and empirical data. A poor outcome may result if abuse is missed or an innocent family is accused, therefore evidence and science-based injury assessments are required. Although research in biomechanics has improved clinical understanding of injuries in children, much work is still required to develop a more scientific, rigorous approach to assessing injury causation. This article reviews key issues in child abuse and how injury biomechanics research may help improve accuracy in differentiating abuse from accidental events. Case-based biomechanical investigations, human surrogate, and computer modeling biomechanics research applied to child abuse injury are discussed. The goal of this paper is to provide an overview of key research studies rather than on review or commentary articles. Limitations and future research needs are also reviewed.

Wheelchair tiedown and occupant restraint loading associated with adult manual transit wheelchair in rear impact

Proper securement of wheelchairs in motor vehicles is vital to providing wheelchair users an adequate level of safety in a crash. Thus far, wheelchair tiedown and occupant restraint systems (WTORS) loading has mostly been examined under frontal impact conditions. Because of the inherent crash dynamic differences, rear-impact loading of WTORS is expected to differ greatly. In this study, three identical, reinforced, manual, folding, X-braced ANSI/RESNA WC19 wheelchairs were subjected to an International Organization for Standardization-proposed rear-impact crash pulse. WTORS loads (front tiedowns, rear tiedowns, lap belt, and shoulder belt) were measured and compared with frontal impact WTORS loading. Rear impact produced substantially higher loads (up to 7,851 N) in the front tiedowns than frontal impact. The rear tiedowns experienced relatively negligible loading (up to 257 N) in rear impact, while rear-impact dynamics caused the lap belt (maximum load of 1,865 N) to be loaded substantially more than the shoulder belt (maximum load of 68 N). Considering differences in frontal and rear impact WTORS loading is important to proper WTORS design and, thus, protection of wheelchair-seated occupants subjected to rear-impact events.

State of the science workshop on wheelchair transportation safety

The Rehabilitation Engineering Research Center on Wheelchair Transportation Safety held a state-of-the-science workshop on wheelchair transportation. The workshop had three purposes: reviewing and documenting the status of wheelchair transportation safety, identifying deficiencies, and formulating, discussing, and prioritizing recommendations for future action. The final goal was to disseminate the workshop outcomes for utilization in formatting future research priorities. A nominal group technique was used to facilitate focused open discussion by knowledgeable persons, resulting in the identification and ranking of existing deficiencies according to priority. Participants then formulated potential short-term solutions and speculated what wheelchair transportation safety should be in the future. This document presents four white papers, prepared prior to the workshop and modified according to participant feedback, and summarizes the outcomes of the workshop. The results identify and prioritize recommendations for future action.

Characterization of pediatric wheelchair kinematics and wheelchair tiedown and occupant restraint system loading during rear impact

This study characterizes pediatric wheelchair kinematic responses and wheelchair tiedown and occupant restraint system (WTORS) loading during rear impact. It also examines the kinematic and loading effects of wheelchair headrest inclusion in rear impact. In two separate rear-impact test scenarios, identical WC19-compliant manual pediatric wheelchairs were tested using a seated Hybrid III 6-year-old anthropomorphic test device (ATD) to evaluate wheelchair kinematics and WTORS loading. Three wheelchairs included no headrests, and three were equipped with slightly modified wheelchair-mounted headrests. Surrogate WTORS properly secured the wheelchairs; three-point occupant restraints properly restrained the ATD. All tests used a 26km/h, 11g rear-impact test pulse. Headrest presence affected wheelchair kinematics and WTORS loading; headrest-equipped wheelchairs had greater mean seatback deflections, mean peak front and rear tiedown loads and decreased mean lap belt loads. Rear-impact tiedown loads differed from previously measured loads in frontal impact, with comparable tiedown load levels reversed in frontal and rear impacts. The front tiedowns in rear impact had the highest mean peak loads despite lower rear-impact severity. These outcomes have implications for wheelchair and tiedown design, highlighting the need for all four tiedowns to have an equally robust design, and have implications in the development of rear-impact wheelchair transportation safety standards.

Annual risk of death resulting from short falls among young children: less than 1 in 1 million

OBJECTIVE

The objective of the work was to develop an estimate of the risk of death resulting from short falls of <1.5 m in vertical height, affecting infants and young children between birth and the fifth birthday.

METHODS

A review of published materials, including 5 book chapters, 2 medical society statements, 7 major literature reviews, 3 public injury databases, and 177 peer-reviewed, published articles indexed in the National Library of Medicine, was performed.

RESULTS

The California Epidemiology and Prevention for Injury Control Branch injury database yielded 6 possible fall-related fatalities of young children in a population of 2.5 million young children over a 5-year period. The other databases and the literature review produced no data that would indicate a higher short-fall mortality rate. Most publications that discuss the risk of death resulting from short falls say that such deaths are rare. No deaths resulting from falls have been reliably reported from day care centers.

CONCLUSIONS

The best current estimate of the mortality rate for short falls affecting infants and young children is <0.48 deaths per 1 million young children per year. Additional research is suggested.

Injury biomechanics and child abuse

Child abuse is a leading cause of morbidity and mortality in young children and infants in the United States. Medical care providers, social services, and legal systems make critical decisions regarding injury and history plausibility daily. Injury plausibility judgments rely on evidence-based medicine, individualized experiences, and empirical data. A poor outcome may result if abuse is missed or an innocent family is accused, therefore evidence and science-based injury assessments are required. Although research in biomechanics has improved clinical understanding of injuries in children, much work is still required to develop a more scientific, rigorous approach to assessing injury causation. This article reviews key issues in child abuse and how injury biomechanics research may help improve accuracy in differentiating abuse from accidental events. Case-based biomechanical investigations, human surrogate, and computer modeling biomechanics research applied to child abuse injury are discussed. The goal of this paper is to provide an overview of key research studies rather than on review or commentary articles. Limitations and future research needs are also reviewed.

Injury risk of a 6-year-old wheelchair-seated occupant in a frontal motor vehicle impact--'ANSI/RESNA WC-19' sled testing analysis

Children with disabilities are transported on a daily basis to schools and developmental facilities. When they travel, they often remain seated in their wheelchairs in vehicles. To study injury risk of pediatric wheelchair users in motor vehicle crashes, three of the same pediatric manual wheelchairs were sled impact tested with a seated Hybrid III 6-year-old ATD using a 20 g/48 km/h frontal crash pulse. The sled test results were compared to kinematic limitations and injury criteria specified in the ANSI/RESNA WC-19, FMVSS 213 and FMVSS 208. All sled test results were below the limits specified in the ANSI/RESNA WC-19 standard and FMVSS 213. All tests exceeded the N(ij) limit of 1 specified in FMVSS 208, and one test exceeded the limit of peak neck tension force. Chest deflection resulting from one of three tests was at the limit specified in FMVSS 208. Our results suggest that children with disabilities who remain seated in their wheelchairs in vehicles may be at risk of neck injury in a frontal impact motor vehicle crash. However, limitations in the biofidelity of the Hybrid III ATD neck raise concern as to the translatability of these findings to the real world. Additional studies are needed to investigate the influence of neck properties and ATD neck biofidelity on injury risk of children who travel seated in their wheelchairs.

Influence of wet surfaces and fall height on pediatric injury risk in feet-first freefalls as predicted using a test dummy

INTRODUCTION

Falls are a major cause of morbidity and mortality in children, but are also reported falsely in child abuse. Therefore, it is of interest to understand those factors which may lead to a higher likelihood of injury in a feet-first freefall.

METHODS

We used laboratory freefall experiments and a 3-year-old Hybrid III anthropomorphic test dummy (ATD) to assess head and femur injury risk. Wet and dry linoleum impact surfaces were used from three fall heights: 22, 35 and 47 in.

RESULTS

For a given fall height, dry surfaces were associated with higher head injury criteria (HIC) values than wet surfaces. Changes in fall height 22-47 in. did not significantly affect HIC values for falls onto either surface. Generally, compressive and bending femur loading increased significantly for wet as compared to dry linoleum.

CONCLUSIONS

In simulated feet first freefall experiments up to 47 in. using a 3-year-old test dummy, a low risk of contact type head injury and femur fracture was found. However, both fall height and surface conditions influenced femur loading and head injury measures. Future efforts should explore the risk of head injury associated with angular acceleration in freefalls.

The effects of wheelchair-seating stiffness and energy absorption on occupant frontal impact kinematics and submarining risk using computer simulation

Many wheelchair users must travel in motor vehicles while seated in their wheelchairs. The safety features of seat assemblies are key to motor vehicle occupant crash protection. Seating system properties such as strength, stiffness, and energy absorbance have been shown to have significant influence on risk of submarining. This study investigated the effects of wheelchair seat stiffness and energy absorption properties on occupant risk of submarining during a frontal motor vehicle 20 g/30 mph impact using a validated computer crash simulation model. The results indicate that wheelchair-seating stiffness and energy absorption characteristics influence occupant kinematics associated with the risk of submarining. Softer seat surfaces and relatively high energy absorption/permanent deformation were found to produce pelvis excursion trajectories associated with increased submarining risk. Findings also suggest that the current American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America (ANSI/RESNA) WC-19 seating integrity may not adequately assess submarining risk.

Evaluation of wheelchair sling seat and sling back crashworthiness

Many wheelchairs are used as vehicle seats by those who cannot transfer to a vehicle seat. Although ANSI/RESNA WC-19 has been recently adopted as a standard to evaluate crashworthiness of the wheelchairs used as motor vehicle seats, replacement or after-market seats may not be tested to this standard. This study evaluated the crashworthiness of two specimens each of three unique sling backs and three unique sling seats using a static test procedure intended to simulate crash loading conditions. To pass the test, a sling back is required to withstand a 2290 lb load, and a sling seat should be capable of withstanding a 3750 lb load. All, but two sling back specimens which failed at 1567 lb and 1787 lb, withstood the test criterion load. Two of six tested sling seats failed to pass the test: one failed at 3123 lb and the other failed to sustain the load for 5 s although it reached the test criterion load. Most of the failures occurred at the seams of the side openings of upholsteries where the wheelchair frame inserts for attachment.

Experience with wood lamp illumination and digital photography in the documentation of bruises on human skin

Bruising is very common in children. Examination of bruising can guide the clinician in ordering radiographic imaging studies of children who have suffered trauma. Additionally, bruising in infants and patterns of bruising that do not match the injury scenario offered by caretakers can raise the suspicion of abuse. This article reports preliminary experience with Wood lamp enhancement of faint bruises and visualization of bruises that are not visible. It describes the method for digital photography of bruises visualized in this way. Finally, it suggests future applications and areas of further study.

Wheelchairs used as motor vehicle seats: seat loading in frontal impact sled testing

Wheelchairs are not typically designed to function as motor vehicle seats. However, many wheelchair users are unable to transfer to a vehicle seat and instead travel seated in their wheelchair. ANSI/RESNA WC19: Wheelchairs Used as Seats in Motor Vehicles provides design and testing requirements, but does not provide wheelchair manufacturers with design guidance related to expected loads imposed upon wheelchair components during a crash. To provide manufacturers with crashworthy design guidance, our study measured wheelchair seat loading during 20g/48kph frontal impact sled tests with a 50th percentile male test dummy. Loading conditions were assessed using two different rear securement point positions. Results of four sled impact tests revealed downward loads ranging from 17 019 to 18 682 N, depending upon rear securement point configuration. Maximum fore/aft shear loads ranged from 4424 to 6717 N across the tests.

Evaluation of wheelchair drop seat crashworthiness

Wheelchair seating crash performance is critical to protecting wheelchair users who remain seated in their wheelchairs during transportation. Relying upon computer simulation and sled testing seat loads associated with a 20 g/48 kph (20 g/30 mph) frontal impact and 50th percentile male occupant were estimated to develop test criteria. Using a static test setup we evaluated the performance of various types of commercially available drop seats against the loading test criteria. Five different types of drop seats (two specimens each) constructed of various materials (i.e. plastics, plywood, metal) were evaluated. Two types of drop seats (three of the total 10 specimens) met the 16650 N (3750 lb) frontal impact test criteria. While additional validation of the test protocol is necessary, this study suggests that some drop seat designs may be incapable of withstanding crash level loads.

Evaluation of wheelchair seating system crashworthiness: "drop hook"-type seat attachment hardware

OBJECTIVE

To evaluate the crashworthiness of commercially available hardware that attaches seat surfaces to the wheelchair frame.

DESIGN

A low cost static crashworthiness test procedure that simulates a frontal impact motor vehicle crash.

SETTING

Safety testing laboratory.

SPECIMENS

Eleven unique sets of drop-hook hardware made of carbon steel (4), stainless steel (4), and aluminum (3).

INTERVENTIONS

Replicated seat-loading conditions associated with a 20g/48 kph frontal impact. Test criterion for seat loading was 16,680 N (3750 lb).

MAIN OUTCOME MEASURES

Failure load and deflection of seat surface.

RESULTS

None of the hardware sets tested met the crashworthiness test criterion. All failed at less than 50% of the load that seating hardware could be exposed to in a 20g/48 kph frontal impact. The primary failure mode was excessive deformation, leading to an unstable seat support surface.

CONCLUSIONS

Results suggest that commercially available seating drop hooks may be unable to withstand loading associated with a frontal crash and may not be the best option for use with transport wheelchairs.

Evaluation of wheelchair back support crashworthiness: combination wheelchair back support surfaces and attachment hardware

Automotive seats are tested for compliance with federal motor vehicle safety standards (FMVSS) to assure safety during impact. Many wheelchair users rely upon their wheelchairs to serve as vehicle seats. However, the crashworthiness of these wheelchairs during impact is often unknown. This study evaluated the crashworthiness of five combinations of wheelchair back support surfaces and attachment hardware using a static test procedure simulating crash loading conditions. The crashworthiness was tested by applying a simulated rearward load to each seat-back system. The magnitude of the applied load was established through computer simulation and biodynamic calculations. None of the five tested wheelchair back supports withstood the simulated crash loads. All failures were associated with attachment hardware.

Proposed test method for and evaluation of wheelchair seating system (WCSS) crashworthiness

Safety of motor vehicle seats is of great importance in providing crash protection to the occupant. An increasing number of wheelchair users use their wheelchairs as motor vehicle seats when traveling. A voluntary standard requires that compliant wheelchairs be dynamically sled impact tested. However, testing to evaluate the crashworthiness of add-on wheelchair seating systems (WCSS) independent of their wheelchair frame is not addressed by this standard. To address this need, this study developed a method to evaluate the crash-worthiness of WCSS with independent frames. Federal Motor Vehicle Safety Standards (FMVSS) 207 test protocols, used to test the strength of motor vehicle seats, were modified and used to test the strength of three WCSS. Forward and rearward loads were applied at the WCSS center of gravity (CGSS), and a moment was applied at the uppermost point of the seat back. Each of the three tested WCSS met the strength requirements of FMVSS 207. Wheelchair seat-back stiffness was also investigated and compared to motor vehicle seat-back stiffness.

Wheeled mobility device database for transportation safety research and standards

To address the issue of safely accessing and securing wheeled mobility devices in motor vehicles, more information characterizing current-production devices was needed. In a recent effort, frame characteristics of wheeled mobility devices were defined and a database developed for recording characteristics relevant to access and securement. A representative number of devices have been surveyed to measure key characteristics, and these measures have been recorded in the database. This paper details the development of the database and frame characterization scheme, the methods used to survey currently available wheeled mobility devices, and some descriptive statistics resulting from an analysis of the data. A discussion of how this information is being used in research aimed at developing technology and safety standards to ensure vehicle access and safe transportation, as well as other potential uses, is also included.