A classic idiopathic vestibular incident in a dog is an older patient presenting with a head tilt, horizontal nystagmus and inability to stand (in severe cases and in rabbit it will be rolling) and a loss of appetitie.
The nystagmus is the first to recover - several days.. but may be triggered by rapid sideways movement of the head.
Placing reflexes and paper tests (stand the dogs back leg on a bit of paper and slowly pull it away) are the sorst of tests run on spinal injury and CRDM german shepherd's.
Either you misunderstood or your vet was having a blonde moment....