BACKGROUND: In clinical settings, neuropsychological tests and screening instruments are often used to measure cognitive change over time. However, the interpretation of changes in test scores is often difficult. For most instruments there is no information how much change occurs normally in cognitively healthy individuals. AIM: To examine what is a reliable change for a widely used screening instrument for cognitive impairment and dementia. METHODS: A Sample of 119 cognitively normal elderly individuals aged 75 and over participated in the Leipzig Longitudinal Study of the Aged (LEILA 75+). All participants have been tested six times at 1.5 year intervals with the test part of the SIDAM over a mean period of 7.1 years. Reliable change indices (RCI) were computed for a common confidence interval (90%). It is demonstrated how to compute RCI for individual patients. RESULTS: In repeated assessments with 1.5 year intervals, a change in SIDAM score of at least 4 to 7 points (dependent on which of the six assessments were compared) indicates a reliable change at the 90% confidence level. Smaller changes can be interpreted only with high uncertainty. CONCLUSION: The interpretation of changes in test scores in older adults should account for potential practice effect, normal decline and regression to the mean.
BACKGROUND: In clinical settings, neuropsychological tests and screening instruments are often used to measure cognitive change over time. However, the interpretation of changes in test scores is often difficult. For most instruments there is no information how much change occurs normally in cognitively healthy individuals. AIM: To examine what is a reliable change for a widely used screening instrument for cognitive impairment and dementia. METHODS: A Sample of 119 cognitively normal elderly individuals aged 75 and over participated in the Leipzig Longitudinal Study of the Aged (LEILA 75+). All participants have been tested six times at 1.5 year intervals with the test part of the SIDAM over a mean period of 7.1 years. Reliable change indices (RCI) were computed for a common confidence interval (90%). It is demonstrated how to compute RCI for individual patients. RESULTS: In repeated assessments with 1.5 year intervals, a change in SIDAM score of at least 4 to 7 points (dependent on which of the six assessments were compared) indicates a reliable change at the 90% confidence level. Smaller changes can be interpreted only with high uncertainty. CONCLUSION: The interpretation of changes in test scores in older adults should account for potential practice effect, normal decline and regression to the mean.
Authors: Roy Martin; Stephen Sawrie; Frank Gilliam; Melissa Mackey; Edward Faught; Robert Knowlton; Ruben Kuzniekcy Journal: Epilepsia Date: 2002-12 Impact factor: 5.864
Authors: Kevin Duff; Leigh J Beglinger; Mike R Schoenberg; Doyle E Patton; James Mold; James G Scott; Russell L Adams Journal: J Clin Exp Neuropsychol Date: 2005-07 Impact factor: 2.475
Authors: R K Heaton; N Temkin; S Dikmen; N Avitable; M J Taylor; T D Marcotte; I Grant Journal: Arch Clin Neuropsychol Date: 2001-01 Impact factor: 2.813