To the Editor: DMS are very rarely dementia-related with Parkinson’s disease (PD).1–3 Our first patient, a 69-year-old man, developed resting tremor and bradykinesia on his left arm at the age of 56 years. Neurological examination revealed resting tremor (left>right), bilateral bradykinesia, and rigidity. He was treated with levodopa for 2 years, and then consulted with the PD surgery committee for progressive increase in tremor and motor complications of levodopa. The patient had a successful right pallidotomy operation. Following surgery, he developed rapid cognitive impairment and visual hallucinations. He recognized his family members with their correct names but felt that they were strangers looking very similar to his relatives. Soon after, he claimed that his wife and children were not ‘in reality’ who they were but some other people who just looked like his wife and children. He claimed that he was kept in a location other than his house that resembled his house.