Test–retest consistency of Virtual Week: A task to investigate prospective memory

Abstract

The present study reports test–retest consistency of Virtual Week, a well-known measure of prospective memory (PM) performance. PM is the memory associated with carrying out actions at a specific moment in the future. Patients with neurological disorders as well as healthy older adults often report PM dysfunctions that affect their everyday living. In Experiment 1, 19 younger and 20 older adults undertook the standard version of Virtual Week (version A). Older adults showed lower performance compared to younger participants. However, the discrepancy between groups was eliminated at retest. Experiment 2 was conducted to investigate if remembering of PM content determined the improvement observed in older adults at retest in Experiment 1. To this end we created a parallel version (version B) in which we varied the content of the PM actions. Fifty older adults were assigned to one of the two experimental conditions: Version A at test and version B at retest or vice versa (25 participants in each condition). Results showed no group differences in PM performance between version A and version B; moreover, no effect of test–retest was found. The study confirmed that Virtual Week is a reliable measure of PM performance and also provided a new parallel version that can be useful in clinical setting.

Keywords:

• Prospective memory
• Virtual Week
• Test–retest
• Ageing

Peter Rendell's contribution was supported by an Australian Research Council Discovery Grant. The authors gratefully acknowledge all the participants who kindly participated in the study and Chiara Seminati, Veronica Rossetti, Rosita Garbuio and Irene Scarpa who cooperated with the present study. The authors also acknowledge the help of Trevor Daniels with programming Virtual Week and the help of Kathryn Biernacki in analysing the data.

Notes

¹For a more detailed presentation of PM impairment in clinical populations please see West (2008) and Kliegel, Jäger, Altgassen, & Shum (2008).

²To control for the different years of education between younger and older adults an ANCOVA was carried out with years of education as covariate. Results showed only a main effect of years of education, F(1, 36) = 7.24, p = .01, η²_p = .16.

³An ANCOVA was also carried out with years of education as covariate. The main effect of education did not reach significance, F(1, 36) = .33, p = .56, η²_p = .01.

⁴An ANCOVA was also carried out with years of education as covariate. Results showed a significant main effect of education, F(1, 36) = 5.16, p = .03, η²_p = .12.

⁵Analyses were also conducted controlling for the effect of age. Participants were divided into two groups: old adults aged 61–67 years and old-old aged 68–82 years. No differences on years of education or MMSE scores were found between the two groups (all ps > .360). Results showed a significant main effect of age (p < .05) indicating that old-old adults were less accurate than old adults. Age did not interact with any other variable (all ps > .211).