thank you for your query. Dementia is a chronic progressive illness, in which a person gradually starts losing his memory (particularly recent memory, that associated with his day to day life) along with atleast one other higher mental function like judgement/ planning/ executive functions etc. gradually there is change in personality and behavior, with the person becoming incapable of maintaining his activities of daily living by himself in later stages. popular medications to manage dementia are Donepezil (Acetyl Cholinesterase inhibitors), Memantine (NMDA antagonist) etc, given formanaging memory and gognitive symptoms. also sometimes atypical antipsychotics like Quetiapine, Olanzapine, Risperidone etc are given to manage aggression and behavioral problems. Among these, Donepezil can cause itching. the restlessness (moving head, arms, legs constantly) can be due to a condition called akathisia, caused by mostly antipsychotics. the facial grimaces may be due to a condition called Tardive dyskinesia , another side effect of antipsychotics. the exact cause of the given symptoms, can however, only be clarified after a thorough assessment of the exact medications that he is having, both prescription and OTC, and their duration of use. Also, physical examination is of utmost importance in this case, as observation of the movements in necessary for diagnosis. I would suggest you to consult a Psychiatrist with all your current medications for the same and reduce the OTC medicines as much as possible. Hope i ve been able to satisfy your query. please feel free to contact me for any further clarifications if needed. best of luck.