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Page 1: Screening Test Sensitivity

Physiotherapy January 2000/vol 86/no 1

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LettersScreening TestSensitivityA FASCINATING paper reporting thedevelopment of a new tool for assessmentof children (Michell and Wood, 1999) waslacking one point of information that mayalter the interpretation.

When I see the words ‘screening tool’, I understand that to intepret theusefulness of the tool it is helpful toreport the sensitivity and specificityvalues. Test sensitivity has been describedas the proportion of patients (children)who have a positive test result.

In contrast, specificity has beendescribed as a test’s ability to identifycorrectly the absence of the targetdisorder (Sackett et al, 1991). In thiscontext sensitivity can be calculated usingcut-off scores that have been determinedrelative to the performance of the controlsubjects’ average scores and standarddeviations.

In the Michell and Wood (1999) article,without an indication of whether a scoreof ‘1’ (partially completed) is consideredpass or fail, it is not possible to calculatethe sensitivity or specificity of each sub-test. However, having a look at table 4,‘ankles cross-over’ is the only test with100% specificity (all controls passed, ifscoring 2 and 3 can be taken to count),and 26% sensitivity (study group whofailed).

From this consideration of the data, isthis analysis at odds with Michell andWood’s conclusion that the upper limbtest is the ‘most indicative’?

Andrew BatemanPhD MCSPUniversity of East London

ReferencesMichell, D and Wood, D (1999). ‘Aninvestigation of midline crossing in three-year-old children’, Physiotherapy, 85, 11, 613-621.

Sackett, D L, Haynes, R B, Guyatt, G Hand Tugwell, P (1991). ClinicalEpidemiology: A basic science for clinicalmedicine, Little Brown, Boston, 2nd edn.

Elder AwarenessI WRITE regarding the article by Simpsonet al (1999) entitled ‘Raising awareness ofolder people in undergraduatephysiotherapy education’ as I currentlyhold a post as proposed in the article.

I am a lecturer on the BScPhysiotherapy (Hons) course at BrunelUniversity and lead a module in elderrehabilitation that covers many if not all ofthe aspects described in the article. Themodule was designed by Sarah Tysonwithin the more rigid framework of theCSP Curriculum (1991). However I doagree the more recent CSP curriculumframework (1996) does offer moreopportunity for innovative course design.

As Simpson et al state, manual handlingpolicies and procedures are a major issuewith older clients with multipathology, andthe elder rehabilitation module at Brunelincludes problem solving seminars thatfollow European Union manual handlingdirectives.

Simpson et al advocate that studentsshould undertake their elderrehabilitation clinical placement withinthe module. However this is idealistic andthe present difficulties with clinicalplacement provision mean that thissuggestion is impractical.

At Brunel we have good communicationwithin the different clinical strands of thecourse and do not feel the necessity to‘ensure that the needs of older people areconsidered during all skill developmentsessions’. However, as we head forrevalidation, should the need arise, I willbe there.

I would finally like to thank Simpson etal for their interpretation of the CSPcourse framework (1996) as related toolder people, and for raising the issuescovered in this article.

Janet LewisMCSPBrunel University, Middlesex

ReferencesSimpson, J, Waterman, C and Zouhar, K(1999). ‘ Raising awareness of olderpeople in undergraduate physiotherapyeducation’, Physiotherapy, 85, 11, 587-592.

Chartered Society of Physiotherapy andCouncil for Professions Supplementary toMedicine (1991). The CurriculumFramework, CSP, London.

Chartered Society of Physiotherapy andCouncil for Professions Supplementary toMedicine (1996). The CurriculumFramework, CSP, London.

Physiotherapy Evidence DatabaseREADERS of Physiotherapy may beinterested to know of a new resource, thePhysiotherapy Evidence Database (orPEDro). This contains bibliographicdetails and abstracts of most randomisedcontrolled trials in physiotherapy.

As such it archives the best availableinformation about the effectiveness oftherapies administered byphysiotherapists. The database has beenspecifically designed to support evidence-based clinical decision-making. All trialson the database have been rated on thebasis of their methodological quality tomake it easy to identify quickly thosestudies which are most likely to be valid.

The database is freely available onwebsite:<http:/ptwww.cchs.usyd.edu.au/pedro>.

By the end of November 1999 thedatabase contained details of more than 1,800 randomised controlled trials

and over 200 systematic reviews.PEDro has been developed by the

newly-formed Centre for Evidence-basedPhysiotherapy based at the University ofSydney. The project has received generoussupport from the Australian PhysiotherapyAssociation, the Rehabilitation andRelated Therapies Field of the CochraneCollaboration, the School ofPhysiotherapy and the University ofSydney, and volunteer physiotherapistsfrom Australia and other countries.

We hope that PEDro will be used byphysiotherapists, doctors, consumers ofphysiotherapy services, and physiotherapyservice providers. Readers of Physiotherapyare encouraged to explore the website.

Rob Herbert Anne MoseleyCathie Sherrington Chris MaherCentre for Evidence-based PhysiotherapyUniversity of Sydney