The effect of interference on temporal order memory in individuals with Parkinson’s disease

Abstract Memory for the temporal order of items or events in a sequence has been shown to be impaired in older adults and individuals with Parkinson’s disease (PD). The present study examined the effects of high and low interference on temporal order memory in individuals diagnosed with PD (n = 20) and demographically similar healthy older adults (n = 20) utilizing a computerized task used in previously published studies. During the sample phase of each trial, a series of eight circles were randomly presented one at a time in eight different spatial locations. Participants were instructed to remember the sequence in which the circles appeared in the locations. During the choice phase, participants were presented with two circles in two different locations and were asked to indicate which circle appeared earliest in the sample phase sequence. The two circles were separated by one of four possible temporal separation lags (0, 2, 4, and 6), defined as the number of circles occurring in the sample phase sequence between the two choice phase circles. Shorter temporal lags (e.g., 0 and 2 lags) were hypothesized to result in higher interference compared to longer temporal lags (e.g., 4 and 6 lags). The results demonstrated that on trials involving high interference, no differences were found between the two groups. However, healthy older adults significantly outperformed individuals with PD ( p p