Testing for suspected impairments and dissociations in single-case studies in neuropsychology: Evaluation of alternatives using Monte Carlo simulations and revised tests for dissociations

John Robertson Crawford, P. H. Garthwaite

Research output: Contribution to journalArticle

282 Citations (Scopus)

Abstract

In neuropsychological single-case studies, a patient is compared with a small control sample. Methods of testing for a deficit on Task X, or a significant difference between Tasks X and Y, either treat the control sample statistics as parameters (using z and z(D)) or use modified t tests. Monte Carlo simulations demonstrated that if z is used to test for a deficit, the Type I error rate is high for small control samples, whereas control of the error rate is essentially perfect for a modified t test. Simulations on tests for differences revealed that error rates were very high for z(D). A new method of testing for a difference (the revised standardized difference test) achieved good control of the error rate, even with very small sample sizes. A computer program that implements this new test (and applies criteria to test for classical and strong dissociations) is made available.

Original languageEnglish
Pages (from-to)318-331
Number of pages13
JournalNeuropsychology
Volume19
Issue number3
DOIs
Publication statusPublished - May 2005

Keywords

  • single-case studies
  • statistical methods
  • dissociations
  • INFERENTIAL METHODS
  • SCORE DIFFERENCES
  • CONTROL SAMPLE
  • T-TEST
  • ABNORMALITY

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