My Mother, age 79, has started seeing animals and people in her yard. The animals she describes as strange looking and the people are wearing brightly colored clothing. That escalated to her hearing them at night on the roof and now she thinks they are trying to look in her windows. She has seen a neurologist and had a chemical analysis of her blood run, an MRI of her brain, a chest xray, a CAT scan and now we are wondering where else to turn. She has no signs of dementia like forgetting people or what she last ate etc. What can this be?