Acquisition and long-term retention of a gross motor skill in Alzheimer's disease patients under constant and varied practice conditions.

This study examined the acquisition and long-term retention of a gross motor skill, namely, tossing, in 23 moderately to severely demented Alzheimer's disease (AD) patients and 22 health older adults. To identify optimal learning strategies, subjects received 10 weeks of training under either constant or variable practice conditions. Accuracy at the tossing task was assessed immediately, one week, and one month following training. AD patients given constant practice were able to learn and retain the tossing task as well as healthy adults. Although controls performed equally well in both conditions, AD patients showed significantly less improvement when practiced at various distances from the target. By the one-month post-test, these patients had lost any minimal gains achieved through practice. In comparison, AD patients receiving constant practice showed essentially no forgetting across post-tests. The inability to benefit from varied practice suggests that AD patients may have difficulty accessing and/or forming motor schemas.