Determining the extent of cognitive change after coronary surgery: a review of statistical procedures.
Currently, cognitive decline after coronary surgery is said to be significant if the individual's postoperative test score is at least 1 standard deviation (SD) worse than their preoperative score. This "1-SD" technique fails to account for factors that may confound interpretation of serially acquired cognitive test scores, including regression to the mean, measurement error caused by poor test-retest reliability, and practice effects. We review the many alternative and potentially superior statistical techniques that have been described in the neuropsychologic and psychiatric literature for differentiating "true" changes in cognitive test score from changes caused by these factors.
Collie
Alexander
A
Neuropsychology Laboratory, Mental Health Research Institute of Victoria, Parkville, Australia. alex@neuro.mhri.edu.au
Darby
David G
DG
Falleti
Marina G
MG
Silbert
Brendan S
BS
Maruff
Paul
P
D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D006801:Humans; D011594:Psychometrics / Q000706:statistics & numerical data; D012044:Regression Analysis; D015203:Reproducibility of Results