I think putting the radio on quietly in the background sounds like a good idea, just so it's not all quiet in the room, your dog can then have a bit of reassurance and won't feel alone. If this doesn't work, there are quite alot of behaviourists you can speak to. Also there is something called a DAP diffuser or spray that relieves stress and gives them a calming feel, you plug it in the room and it releases a scent that de stresses them. The spray can be sprayed onto bedding which will do the same. Also the spray is good for car journeys and trip to the vets.

All veterinary surgeries should do this, also alot of internet pharmacies. My nan tried the diffuser for her two dogs and it helped greatly, but it may differ for different dogs, may be worth a try though. She got hers from petmedsfromvets online, was easier for her to order as she doesn't drive.

Hope this helps!