Test-retest reliability and practice effects for the ANAM General Neuropsychological Screening battery.

OBJECTIVE: As the use of computer-based neurocognitive assessment is rapidly expanding, the need to systematically study and document key psychometric properties of these measures has become increasingly more salient. To meet this aim, this study examined test-retest reliability and practice effects for the Automated Neuropsychological Assessment Metrics General Neuropsychological Screening battery (ANAM GNS) in a sample of 94 community dwelling adults.

METHOD: ANAM GNS was administered and then repeated (alternate form) after 30 days. Test-retest reliability, practice effects, and the standard error of measurement were calculated. Using these estimates, reliable change indices were calculated to determine degree of performance change needed to exceed chance and measurement error (with 90% confidence interval).

RESULTS: The test-retest reliability for the ANAM composite score was .91. Performance significantly improved upon retest, but the effect size was small consistent with minimal practice effects. The threshold indicating change beyond chance or measurement error with 90% certainty was .9 (z-score).

CONCLUSIONS: Findings suggest that the ANAM GNS has excellent test-retest reliability upon retest at 30 days. Small practice effects can be expected. Change greater than .9 standard deviations in the ANAM composite score is likely to represent meaningful clinical change. This paper presents initial psychometric data from the ANAM GNS and supports its use as a reliable measure of cognition.