How does a dog know when a seizure will occur? No one knows for sure, but there are three major theories:
"Firstly there may be micro expressions that the dog can pick up which precede a seizure, there may be a particular scent generated which the dog is sensitive to and finally it may be that the dog can sense disturbances in the electric field which are caused by a seizure."
Whatever the cause, the seizure dogs not only help prepare an owner for the seizure, but it gives the owner a sense of comfort, reducing the overall number of seizures.