My 10 year old will not stop howling, especially at night and it's getting worse! It affects my husband and my sleep, and it can't keep on when our new baby is born this October!  She has had hyperthyroid for years, well-managed by medication and levels are checked regularly. This is not a new house, eating and sleeping are totally normal. She's always been a pretty loud cat, but this is now becoming constant. At times it's even when she is curled up sleeping, almost as if she's had a nightmare. I'm pretty confident it is sensory related or aging related but what can I do???  Oh and we have been using 3 different pheromone diffusers and oils daily for her. Helped at first but not now. Help! I don't want to have to restrict her to the basement at night whe the baby comes!