If the symptoms are intermittent and lasting minutes at a time, then seizures may be possible. If the symptoms are longer, it is unlikely, but not impossible to be seizures. I would ask your doctor if the MRI's were done with contrast. Occasionally extra findings can be seen with contrast. Also, blood work for inflmmatory disease, connective tissue disorders, and B12 deficiency should be evaluated. If the symptoms have changed dramatically since your last spine MRI, it may be reasonable to repeat this. If all of this is negative, then an evoked potential of the median nerve and tibial nerve may be helpful. This is a test which measures how well a signal travels from your arm or leg to your brain, and tests the intergrity of the pathway. If this is negative a spinal tap may be performed. If the testing is negative a second opinion with another neurologist may be useful. Good luck