Test-retest reliability of the Dot Test of Visuospatial Working Memory in patients with schizophrenia and controls

To determine the test-retest reliability of the Dot Test of Visuospatial Wo rking Memory, this task was administered to 29 patients with schizophrenia and 19 normal controls on two consecutive days. The test involved "copying" trials followed by "delay" recall trials. For "copying" trials, subjects s aw a dot and then drew it on a blank sheet of paper. For "delay" trials, su bjects drew the dot following a 10-, 20-, or 30-s delay. The distance betwe en the stimulus and the drawn dot was measured for each trial. The composit e score, termed "working memory deficit," is calculated by subtracting the average of the copying trials from the average of the delay trials. Pearson correlations revealed that overall performance in each group was comparabl e for days 1 and 2. Intra-class correlations of "working memory deficit" on days 1 and 2 were moderate in patients and controls, suggesting that task performance for each subject was similar on the testing days. Test-retest r eliability tended to be higher for 10-s delay performance in patients and c ontrols than for longer delay periods. Further analyses suggested that ther e was no significant learning effect on the task from day 1 to day 2 for ei ther group on any measure. The Dot Test of Visuospatial Working Memory, esp ecially the composite score, has moderate test-retest reliability and is a valuable tool that can be used to assess working memory functions in studie s using a repeated-measures design. (C) 2000 Elsevier Science B.V. All righ ts reserved.