Abstract
Background: "Practice effects" (PE), or performance improvements due to prior exposure to testing, are known to confound cognitive test results, particularly when short intervals occur between two test sessions. Objective: We examined two subsamples with short or long re-test intervals from a recent clinical trial. Methods: Thirty-four non-depressed adults with mild Huntington Disease (HD) participated. Three cognitive tests were administered at screening and again at baseline, before active treatment randomization. Half the sample had a 24-hour retest interval while the other half was >6-days. Results: The two groups differed on demographic/clinical factors (age, Total Motor Score and Total Functional Capacity). After controlling for age and motor score, PE differences were found on three of the five UHDRS cognitive tests: the longer interval group showed larger PE on Symbol-Digit Modalities and Stroop color, while the rapid interval group had larger PE on Stroop interference. Controlling for screening cognitive performance yielded similar results. Conclusions: Length of interval between screening and baseline visits and level of disease severity may influence stability of UHDRS cognitive test results in clinical trials in HD.
Original language | English (US) |
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Pages (from-to) | 139-144 |
Number of pages | 6 |
Journal | Journal of Huntington's Disease |
Volume | 3 |
Issue number | 2 |
DOIs | |
State | Published - 2014 |
Keywords
- Huntington disease
- cognitive disorders/dementia
- neuropsychological assessment
- practice effects
ASJC Scopus subject areas
- Clinical Neurology
- Cellular and Molecular Neuroscience