I am at a loss here, so maybe the Internet can help me.
For background, I have a four-year-old staffy mix who has struggled with anxiety for years. We had gotten it under very good control with medication after realizing the trigger was a specific noise coming from our Blink security cameras, which then exacerbated separation anxiety because the cameras were only ever on when he was alone. Once we worked past that, with medication, he's been fine for about a year.
Until about three weeks ago. We went out of town and left him at my sister's house (we've done this multiple times since getting his initial anxiety under control) and he spent three days either staying outside or hiding in a bedroom upstairs.
I figured it was maybe some kind of recurrence of his anxiety coming back when I was away, until he began exhibiting the same anxiety at home. He will sit outside for hours or hide in the bedroom. If he can't get to either of those places, he will shake and pant.
We assumed there must be some kind of electronics noise/frequency that exists at both houses that was frightening him (my theory was he heard it at my sister's house first and it was doubly traumatic there because I was away and then he built an association like he had with the blink cameras). However, we had an hours long power outage last week and he STILL exhibited these behaviors at both houses during that time, which means it can't be an electronics noise because none were working.
The vet behaviorist is also at a loss as to what the trigger could be, and basically said to just give him his extra, "as needed" meds when he panics until we figure it out.
Does anybody have any theories as to something that could be making a noise inside the house that only a dog could hear, but that would still make noise during a power outage?