Visuomotor integration is compromised in Alzheimer's disease patients reaching for remembered targets.

This study examined the ability of neurologically healthy individuals and individuals with Alzheimer's disease (AD) to successfully complete procedures involving short-term spatial visuomotor memory tasks, and tasks involving increasingly complex visuomotor transformations. Participants made sliding finger movements over a clear touch-sensitive screen on two separate spatial planes (vertical and horizontal), to visually constant and remembered target positions. Significant main effects were observed between participant groups on reaction time and movement time measures. As well, significant changes in reaction time and movement time were observed within the patient group over the different of any experimental procedures. In addition, as task increased in complexity significant increases in errors were observed in the AD group. Overall, the results reveal that AD patients show substantial declines in their ability to process and integrate visual information to produce motor responses. Therefore, we believe that this psychophysical research provides further evidence that AD, even early stages of AD, can affect anatomical regions supporting vision for action. Copyright 2007 S. Karger AG, Basel.