Hello and thank you for your question. I am a neurologist and will try to answer your question. I have noted that in the elderly, the most common reason for behavioral symptoms is often dementia. Certainly the recent strokes, if involving areas of Heschl's gyrus, can also lead to hallucinations. I have also noted that the elderly who have issues with anxiety also tend to hum or sing on a routine basis. It may calm their generalized sense of anxiety.
please get back to me if you have any further questions. Thank you.