Evidence-based Test Method Development

Jon PearlmanAnand Mhatre- International Society for Wheelchair Professionals - Department of Rehab Science & Technology

Agenda• Motivation• Project Goals• Test Method Development• Free Resources• Focus on Caster Test Method • Takeaways & Future Work

Motivation: Evidence of Poor WC Quality

1 in 3 experienced at least one adverse consequence

(Mcclure, 2009). (Toro, 2016). (Worobey, 2012). (Mann, 1996). (Hansen, 2004).

Work completed in USA, Mexico & Indonesia.

Motivation: Evidence of Poor WC QualityAdverse Incidence 2009-2017: Frequency of Component Type involved in

Powered Wheelchair incidenceSource: WestMARC Adverse Incidence Database (n-1100)

0

5

10

15

20

25

30

Castor

sW

heels

Other

Non/no

t app

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leElec

trical

Footre

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eArm

rests

Acces

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olster

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ting

Backre

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Suppo

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eatin

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Headre

stCus

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Seatin

g Inte

rface

Component

Freq

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Com

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ype

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(%)

Projects & Goals1. Identify and address gaps in test methods for adverse

conditions (USAID Funded)• WHO Guidelines on MWCs in Less Resourced Settings• AJOD Publication listing priorities

2. Use Standards To guide Clinical Decisions• Supported by NIDILRR (US GOVT)• Standards Development: Cushions, Casters, Rolling Res.• Data mining of failure data to identify gaps in standards

Test Method Development

Test Method Development

Free Resources www.wheelchairnet.org

Focus on Castor Test Method

Castor Failures• Among all parts, castors fails most often with different failure modes based on research

evidenceScotland Kenya Indonesia Mexico

Castor Testing• Develop reliable castor testing protocol• ISO & ICWM Standards do not reproduce field failures

• Lack of environmental factors

• Testing needs• Include environmental factors• Include a range of shock conditions• Ability to change caster load, speed and direction of travel

Shock Validation

0

100

200

300

400

500

600

-10 to -9 -9 to -8 -8 to -7 -7 to -6 6 to 7 7 to 8 8 to 9 9 to 10 10 to 11 11 to 12 12 to 13 13 to 14

Num

ber o

f acc

eler

atio

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ta p

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Data bins in g

Field data ISWP Chakra shock exposure ISO Double drum shock exposure

2 half inch obstacles

2 half + 1 three quarter inch obstacles

Corrosion Validation

Abrasion (tire wear) validation

Castor Testing Study

Testing Outcomes• Field failures comparison

• 73% testing failures match field failures

• Environmental factors have impact on• Durability – 25% models• Failure mode change – 75% models

• 2/3 changed failures modes pose higher risk for user injuries

Takeaways• Environmental conditions affect wheelchair quality

• No progress towards inclusion of environmental conditions in testing• Outcomes from caster testing showed impact of environmental factors on quality• Inclusion of environmental factors in wheelchair testing

• Need for Evidence-Based Test Method Development • Field data collection• Include impacts, heat and other testing factors

• Free Resources• Castor design guidelines • Test equipment assembly instructions

AcknowledgementsGrantsAPC/USAID: APC-GM-0068 & 0107NIDILRR: 90REGE0001, 90SI5014, 90DP0078, 90DP0025

Team at Pitt, ISWP, NHSjpearlman@pitt.eduanand.mhatre@pitt.eduwww.wheelchairnet.org (resource hub)