Does interval between screening and baseline matter in HD cognitive clinical trials?

Area of Science:

• Neuroscience
• Clinical Trials
• Cognitive Assessment

Background:

• Practice effects (PE) are performance improvements from repeated testing.
• PE can confound cognitive test results, especially with short retest intervals.

Purpose of the Study:

• To investigate how retest interval length influences practice effects in cognitive tests.
• To examine these effects in individuals with mild Huntington Disease (HD).

Main Methods:

• Study involved 34 adults with mild HD undergoing cognitive tests.
• Two groups were formed: one with a 24-hour retest interval, another with >6-day interval.
• Cognitive tests were administered at screening and baseline before treatment randomization.

Main Results:

• Practice effects varied between groups on specific UHDRS cognitive tests after controlling for age and motor scores.
• Longer intervals showed greater PE on Symbol-Digit Modalities and Stroop color.
• Shorter intervals showed greater PE on Stroop interference.

Conclusions:

• Retest interval length and HD severity may affect the stability of UHDRS cognitive test results.
• Findings are crucial for interpreting cognitive data in HD clinical trials.
• Consideration of these factors is essential for robust trial design.