Oral Presentation Asia Pacific Stroke Conference 2024

Initial validation of a new measure of pre and post stroke outcome – the DBS24 (107416)

Helen M Badge 1 2 3 , Lauren Christie 1 4 , Dennis Cordato 2 3 5 , Christopher Blair 2 3 5 , Rumbi Teramayi 2 3 5 , Jane Liu 3 , Peter Thomas 5 , Mark Parsons 2 3 5
  1. School of Allied Health, Australian Catholic University, North Sydney, NSW, Australia
  2. Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
  3. University of New South Wales, Liverpool, NEW SOUTH WALES, Australia
  4. Allied Health, St Vincent's Health Network , Darlinghurst, NSW, Australia
  5. Liverpool Hospital, Neurology & Neurophysiology Department, South Western Sydney Local Health District, Liverpool, NSW, Australia

Introduction

Rapid assessment of pre-stroke function is essential to determine eligibility for time-critical, hyper-acute reperfusion therapies. The modified Rankin Scale (mRS) is the gold standard post-stroke outcome measure but is less reliable for measuring pre-stroke function. This study will investigate the psychometric properties of a new measure, the DBS24, which assesses independence in complex daily activities.

Methods

Prospective patients in this single-centre observational study provided opt-out consent. A waiver was approved for retrospective data (Ethical approval SWSLHD HREC, 2022/ETH00483). Data collection included demographic/medical data and pre/post-stroke DBS24 and mRS. Data analyses (item response theory and classical test theory) were conducted using R and Winsteps.

Results:

Data included 334 DBS24 measures collected from 173 (51.8%) participants with pre-stroke DBS24, and remainder post-stroke. Participants (median age=72,IQR=63-82) were mostly male (57.5%), experienced LVO stroke (90.9%), and born overseas (57.5%).

 

Cronbach’s alpha (α=0.88) and Rasch item reliability (0.94) supported internal consistency. The Rasch item-person map indicated a ceiling effect, a higher mean for persons than for items, and close item difficulty for ‘Banking’ and ‘Shopping’ (47.0,46.5).

The Rasch infit/outfit statistics summarising items (Mean square [MNSQ]: 0.95/1.17; Standardised [ZSTD]: 0.0/0.1) and for ‘Banking’, ‘Shopping’, and ‘Home for 24 hours’ met Rasch model expectations, providing evidence of uni-dimensionality. Only the Driving/domestics Infit MNSQ was acceptable (1.3, others>2). The Rasch Principal Components Analysis may indicate a second dimension (Eigenvalue=4.000, unexplained variance=65.2%).

Concurrent validity was demonstrated by correlation with pre-stroke (0.78,p<0.001) and three months (0.79,p<0.001) mRS. 

Conclusion:

This study provides evidence for preliminary validation of the DBS24.

 

 

 

  1. Quinn, T.J., et al. Pre-stroke modified Rankin scale: Evaluation of validity, prognostic accuracy, and association with treatment. Frontiers in Neurology 8, 275 (2017).
  2. Broderick, J.P., Adeoye, O. & Elm, J. Evolution of the modified Rankin scale and its use in future stroke trials. Stroke 48, 2007-2012 (2017).
  3. Cappelleri, J.C., Jason Lundy, J. & Hays, R.D. Overview of Classical Test Theory and Item Response Theory for the Quantitative Assessment of Items in Developing Patient-Reported Outcomes Measures. Clinical Therapeutics 36, 648-662 (2014).
  4. Bond, T. & Fox, C. Applying the Rasch Model, (Routledge, 2015).
  5. Petrillo, J., Cano, S.J., McLeod, L.D. & Coon, C.D. Using Classical Test Theory, Item Response Theory, and Rasch Measurement Theory to Evaluate Patient-Reported Outcome Measures: A Comparison of Worked Examples. Value in Health 18, 25-34 (2015).