Q: Can Parkinson’s disease cause dementia?A: Parkinson’s disease (PD) was first described in 1817 by Dr. James Parkinson who was evaluating patients with a progressive motor system neurological disorder, but as noted below there are many possible non-motor system manifestations of PD and this includes dementia. Today there are over a million Americans living with this PD, and 60,000 more are diagnosed every year.