How accurate is the ENG test

I have been diagnosed with nerve damage in both ears after having the ENG test. I was told it was probably due to a virus. Given my background of headaches, anxiety, etc. i truly believe that I may have tightened my muscles in my neck and head. I also feel that perhaps I had true dizziness and continued on with my symptoms due to my strong anxiety. I am wondering how accurate the caloric tests are. Is it possible to get a false reading and under what circumstances?
I’m a healthy individual and believe that the virus diagnosis is another way of saying, “We don’t know.”