Cognition in movement disorders: where can we hope to be in ten years?

Cognitive impairment and dementia associated with movement disorders represent a major management challenge and area of unmet need. This article has focused upon Parkinson's disease as an exemplar condition, but many of the roadblocks and efforts to overcome these are applicable, in a general sense, to other disorders. Short of a "penicillin moment"-a chance discovery or piece of unintended good fortune-progress is likely to be incremental. Cognitive therapies may end up being multiple and possibly multimodal, parallel with the cancer therapy field. Ultimately, benefit for one condition may extend to others as commonality in protein aggregation, synergistic pathological effects between proteins, and pathological spread emerges.