Dissociations

Programs: RSDT.EXE and DISSOCS.EXE

These PC programs (RSDT.EXE and DISSOCS.EXE) accompany the paper: Crawford, J. R. & Garthwaite, P.H. (2005).“Testing for suspected impairments and dissociations in single-case studies in neuropsychology: Evaluation of alternatives using MonteCarlo simulations and revised tests for dissociations”.  Neuropsychology, 19, 318-331 .

Crawford & Garthwaite (2005) argued that previous definitions of a dissociation used in single-case research in neuropsychology are insufficiently rigorous and lack precision. Building on criteria initially proposed by Crawford, Garthwaite & Gray (2003), they presented revised and fully specified criteria for classical and strong dissociations. Monte Carlo simulations show that the Type I error rate is low using these criteria

The program DISSOCS.EXE can be used to apply Crawford & Garthwaite’s (2005) revised criteria for classical and strong dissociations. To achieve this it tests whether a patient’s scores on tasks X and Y are significantly lower than those of a control sample, it then tests whether the standardized difference between a patient’s X and Y scores are statistically significant (using the Revised Standardized Difference Test; see below). Finally, it reports whether the patient’s pattern of performance meets the criteria for a classical or strong dissociation. A patient is considered to fulfill the criteria for a classical dissociation if they are significantly different from controls on one of the two tasks and their standardized difference between tasks is significantly different from controls. A patient is considered to fulfill the criteria for a strong dissociation if they are significantly different from controls on both tasks and their standardized difference between tasks is significantly different from controls.

We have also written a program RSDT.EXE. This program can be used when a researcher or clinician is interested only in whether the standardized difference between a patients X and Y scores is significantly different from controls (i.e. this program could be used when a researcher does not want to test whether X or Y is lower than controls nor in whether a patient meets criteria for classical or strong dissociation).  This program applies Crawford & Garthwaite’s Revised Standardized Difference Test (RSDT)

Click here to download RSDT.EXE (463Kb). If your browser security settings don’t permit you to download executables, or if you have a slow connection, then you can download a zipped version of the program (231Kb).

Click here to download DISSOCS.EXE (463Kb). If your browser security settings don’t permit you to download executables, or if you have a slow connection, then you can download a zipped version of the program (231Kb).

Your web browser is most probably configured to recognise that the files are executable. If you have any problems (i.e. the browser treats them as text files), hold down the shift key when clicking.

Once downloaded, the programs can be run by any of the normal Windows procedures i.e. by clicking on file in File Manager or by placing on desktop etc.

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Thanks to Professor Patrizio Tressoldi, University of Padua, italian translations of RSDT.exe and dissocs.exe are now available. Click here for italian version of RSDT.exe ( a zipped version is also available) and here for italian version of dissocs.exe (a zipped version is also available)

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Vielen Dank an Patricia Bestelmeyer, University of Glasgow die meine Programme ins Deutsche übersetzt hat. Klicken Sie bitte hier um sich die deutsche Version von RSDT.exe herunterzuladen (oder hier für die "zipped" Version) und hier für die deutsche Version von dissocs.exe (dissocs_deutsche.exe), oder hier für die "zipped" Version)

For essential background details on the methods implemented in these programs (and worked examples) see the following paper:

Crawford, J. R. & Garthwaite, P.H. (2005). Testing for suspected impairments and dissociations in single-case studies in neuropsychology: Evaluation of alternatives using Monte Carlo simulations and revised tests for dissociations”.  Neuropsychology, 19, 318-331.

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Further background can be found in the following paper:

Crawford, J.R., Garthwaite, P.H., & Gray, C. D. (2003).  Wanted: Fully operational definitions of dissociations in single-case studies. Cortex, 39, 357-370.

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For further evaluation of these methods (including their robustness in the face of severely skewed or leptokurtic data) see the following paper:

Crawford, J. R. & Garthwaite, P. H. (2005b). Evaluation of criteria for classical dissociations in single-case studies by Monte Carlo simulation. Neuropsychology, 19, 664-678.

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Reprint

This latter paper also compares conventional criteria for classical dissociations with criteria based on the above methods: the conventional criteria are associated with alarmingly high Type I error rates


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Disclaimer:

The author of this software (John R Crawford) and the University of Aberdeen make no representations about the suitability of the software or about any content or information made accessible by the software, for any purpose.

The software is provided 'as is' without express or implied warranties, including warranties of merchantability and fitness for a particular purpose or noninfringement.

The software is provided gratuitously and, accordingly, the author shall not be liable under any theory or any damages suffered by you or any user of the software.

If there are any problems please e-mail me at j.crawford@abdn.ac.uk. Further contact details are available in the footer of this page.