Brain-computer interface (BCI)-based rehabilitation techniques have recently shown promisefor restoring motor function in stroke survivors. BCIs detect the intent to move in brain signalsby identifying a pattern of neural activity called event-related desynchronization (ERD), andthen triggering the intended movement by some external modality, such as robotics. BCI-basedtherapy may be improved by enhancing the ability to detect ERD. This study examined theeffect of prompting various motor tasks with action observation (AO) as a paradigm for enhancement of ERD. The magnitude, duration, and latency of ERD as well as the ability of aBCI to detect ERD were compared across several tasks with and without AO-prompting. Itwas found that AO-prompting reliably produced ERD in motor regions of the brain, but AO-prompted tasks were shorter in duration and smaller in magnitude than alternatively-promptedtasks used for comparison.