Adaptive deep brain stimulation (aDBS) for Parkinson’s disease recently joined responsive neurostimulation (RNS) for epilepsy as an approved closed-loop brain stimulation therapy in the United States. In addition to improving quality of life for patients, these bi-directional brain-computer interfaces (BCIs) are invaluable tools for improving our understanding of brain circuits and eventually translating this knowledge into novel therapies and further evolution of BCIs. This talk will cover differences in recording and stimulating capabilities between aDBS and RNS, state of the art clinical use of each device, and research efforts to improve current clinical therapies as well as expand to new indications, like obsessive compulsive disorder.