Logo for the Journal of Rehab R and D

Volume 46 Number 4, 2009
   Pages 499 — 514

Abstract – Rear-impact neck protection devices for adult wheelchair users

Ciaran K. Simms, PhD;1* Brian Madden, MS;1 David FitzPatrick, PhD;1-2 John Tiernan, MEngSc3

1Trinity Centre for Bioengineering, Trinity College, Dublin, Ireland; 2School of Electrical, Electronic and Mechanical Engineering, University College, Dublin, Ireland; 3Eastern Region Postural Management Service, Enable Ireland, Dublin, Ireland

Abstract — Many wheelchair users remain in their wheelchairs during transit. Safety research for wheelchair users has focused mainly on frontal impact. However, although they are generally less severe, rear-impact injuries are expensive and difficult to treat and whiplash injury protection for adult wheelchair users remains poorly understood. In this article, 10 g (16 km/h) rear-impact sled tests conducted with the Biofidelic Rear Impact Dummy II or BioRID-II (Denton ATD Inc and Chalmers University of Technology; Gothenburg, Sweden) seated in a rigid wheelchair with no head restraint showed that Abbreviated Injury Scale-score 1 neck injury risk evaluated with the neck injury criterion (NIC) and Nkm criterion is substantially above proposed threshold levels. A prototype wheelchair head restraint was developed and tested together with an existing commercial head restraint (Rolko; Borgholzhausen, Germany) in the same 10 g (16 km/h) rear impact. Both head restraints reduced the injury scores substantially. NIC test scores for the head restraints with no gap ranged from 18 to 24 (approximately 20%-30% chance of neck injury symptoms of duration >1 month) compared with test scores for no head restraints that ranged from 34 to 37 (approximately 95% chance of neck injury). The corresponding extension-posterior Nkm scores with no gap ranged from 0.30 to 0.35 (approximately 5% chance of neck injury) compared with no head restraint of 1.16 (approximately 45% chance of neck injury symptoms). However, the number of sled tests performed was small (three with no head restraint and six with a head restraint), and these results should be considered mainly trends. Preliminary results also showed that the horizontal gap between the head and the wheelchair head-restraint cushion should be as small possible.

Key words: crash test dummy, head restraint, neck injury criteria, occupant protection, rear impact, rehabilitation, restraint, sled test, wheelchair, whiplash.

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