Well, if you don't agree with the vet then I would try another vet. Tell him specifically that you think your cat has this disease and that you want him tested for it. There are many reasons a cat could be "off". You cannot decide what is wrong with your cat and treat it yourself. Try another vet and if he comes up healthy then he probably doesn't have this disease. Here is some stuff I found about it:
Feline hyperesthesia syndrome is not a specific disease, but rather a set of signs, treatment cannot cure an afflicted cat, but merely mitigate the severity of these signs. Some cats respond well to corticosteroids. Others respond to anticonvulsant medications. In any case, a cat suffering repeated episodes should be taken to a veterinarian for a complete physical examination, including a neurological work-up, as the first step in making the correct diagnosis and relieving the cat from this mysterious affliction. It will be helpful for your veterinarian if you keep a diary of any odd "episodes" you witness - date, time of day, duration, after a meal?, after exercise?, etc..
The first signs of the disorder appear between the ages of 1 and 4 years if age. Signs include rippling skin on the cat's back just above the tail, widely dilated pupils, staring into space, persistent loud meowing, and sudden bouts of dashing off madly and aimlessly around the house or yard.
If "your cat" has a seizure disorder, it is relatively mild at this stage and does not require medication. Her behavior may make a diagnosis of feline hyperesthesia syndrome a strong possibility. Some veterinarians believe this syndrome is a form of seizure disorder so the distinction may not be important.
Feline hyperesthesia syndrome is also known as "rolling skin syndrome" (an easily pictured behavior), neurodermatitis and psychomotor epilepsy. It seems to be more common in Siamese cats than other breeds but is not restricted to this breed.
Seizures should not be taken lightly. They have many causes including brain injury, tumors, degenerative diseases, stroke, metabolic disorders and intoxication. The observed events with a seizure can vary from simply being "out of touch" and "staring into space" to a full blown Grand Mal seizure including the loss of consciousness.