Neuropsychological Test Performances

"One characteristic of a developed scientific discipline is the availability of proper measurement models and instruments... Neuropsychology has to take up the challenge and has to incorporate these measurement models into its body of assessment procedures... For the vast majority of psychological test procedures in neuropsychology, only the classical test-theory model has been employed, although it is weak in terms of its measurement properties. Item parameters, like item difficulty [p-values] or item discrimination [point biserials], are dependent on the distribution of ability levels in the respective sample used to estimate them. Thus no specifically objective comparisons of both item difficulties and person abilities are possible." (Willmes 1992 p.103, 109, italics his).

Willmes remarks that "In aphasia testing is often useful to require a more differentiated item scoring, expressing different degrees of deviation from a correct solution." He then gives an example of the application of Masters' partial credit model to the "reading aloud" section of the Written Language subtest of the Aachen Aphasia Test (AAT).

He demonstrates how the graphical presentation of item step difficulties both confirms and provokes thought about how aphasic patients respond to the reading items. 378 patients were asked to read aloud the sentence: Why does he want to give it to me? If 3 words or less were read correctly (in any order) the rating was 0. 4-6 words were rated 1. 7-9 words were rated 2, but if all 9 words were read correctly, in the right order, the rating was 3. From these data, Rasch "partial credit model" calibrations were estimated.

How does the linear-appearing categorization of the rating scale actually relate to performance? On inspection of the plot of category probabilities, (reproduced here from his Fig. 2,) Willmes perceives that, since the words are simple, it is plausible that a relatively small increase in ability would advance the patient from little success, a rating of 0, to considerable success, a rating of 2. Perfection, a rating of 3, would be difficult to obtain for an aphasia patient. Hence the much wider zone corresponding to a rating of 2 than a rating of 1. He points out that this information could be used to improve the item. He also notes that the partial credit analysis shows very different step structures for similarly defined 0-1-2-3 scales for other items, demonstrating that similar category definitions do not mandate similar performance intervals.

He concludes his discussion by noting that the Rasch approach facilitates large scale studies of aphasia, because person fit statistics reduce the clinical diagnostic effort by verifying that each of the subjects do indeed exhibit the same pattern of symptoms.

Willmes K. (1992) Psychometric evaluation of neuropsychological test performances. In N. von Steinbüchel, D.Y. von Cramon, E. Pöppel (Eds), Neuropsychological Rehabilitation, p. 103-113. New York: Springer

Neuropsychological test performances. Willmes K. Rasch Measurement Transactions 1994 7:4 p.331

Neuropsychological test performances. Willmes K. … Rasch Measurement Transactions, 1994, 7:4 p.331

Rasch-Related Resources: Rasch Measurement YouTube Channel
Rasch Measurement Transactions & Rasch Measurement research papers - free	An Introduction to the Rasch Model with Examples in R (eRm, etc.), Debelak, Strobl, Zeigenfuse	Rasch Measurement Theory Analysis in R, Wind, Hua	Applying the Rasch Model in Social Sciences Using R, Lamprianou	El modelo métrico de Rasch: Fundamentación, implementación e interpretación de la medida en ciencias sociales (Spanish Edition), Manuel González-Montesinos M.
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar	Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch	Rasch Models for Measurement, David Andrich	Constructing Measures, Mark Wilson	Best Test Design - free, Wright & Stone Rating Scale Analysis - free, Wright & Masters
Virtual Standard Setting: Setting Cut Scores, Charalambos Kollias	Diseño de Mejores Pruebas - free, Spanish Best Test Design	A Course in Rasch Measurement Theory, Andrich, Marais	Rasch Models in Health, Christensen, Kreiner, Mesba	Multivariate and Mixture Distribution Rasch Models, von Davier, Carstensen
Rasch Books and Publications: Winsteps and Facets
Applying the Rasch Model (Winsteps, Facets) 4th Ed., Bond, Yan, Heene	Advances in Rasch Analyses in the Human Sciences (Winsteps, Facets) 1st Ed., Boone, Staver	Advances in Applications of Rasch Measurement in Science Education, X. Liu & W. J. Boone	Rasch Analysis in the Human Sciences (Winsteps) Boone, Staver, Yale	Appliquer le modèle de Rasch: Défis et pistes de solution (Winsteps) E. Dionne, S. Béland
Introduction to Many-Facet Rasch Measurement (Facets), Thomas Eckes	Rasch Models for Solving Measurement Problems (Facets), George Engelhard, Jr. & Jue Wang	Statistical Analyses for Language Testers (Facets), Rita Green	Invariant Measurement with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments (Facets), George Engelhard, Jr. & Stefanie Wind	Aplicação do Modelo de Rasch (Português), de Bond, Trevor G., Fox, Christine M
Exploring Rating Scale Functioning for Survey Research (R, Facets), Stefanie Wind	Rasch Measurement: Applications, Khine	Winsteps Tutorials - free Facets Tutorials - free	Many-Facet Rasch Measurement (Facets) - free, J.M. Linacre	Fairness, Justice and Language Assessment (Winsteps, Facets), McNamara, Knoch, Fan

Forum

Rasch Measurement Forum to discuss any Rasch-related topic

Go to Top of Page
Go to index of all Rasch Measurement Transactions
AERA members: Join the Rasch Measurement SIG and receive the printed version of RMT
Some back issues of RMT are available as bound volumes
Subscribe to Journal of Applied Measurement

Go to Institute for Objective Measurement Home Page. The Rasch Measurement SIG (AERA) thanks the Institute for Objective Measurement for inviting the publication of Rasch Measurement Transactions on the Institute's website, www.rasch.org.

The URL of this page is www.rasch.org/rmt/rmt74q.htm

Website: www.rasch.org/rmt/contents.htm