Cat - slow head movement back and forth

[NuggetandWicket]

My cat just had an episode where he seems to become disoriented. He wonders until he finds himself in a corner, then moves his head left and right continuously. This happened a month ago and we took him to emergency. By the time we got there, it had stopped and they couldn’t explain it.
Tonight it lasted longer. He is diabetic so I gave him syrup to make sure he wasn’t in a glucose low. I was also able to get him to eat some kibble by hand. He was too disoriented to eat from his dish. He has been diabetic for almost three years and on a steady dose of insulin. I don’t think this is related to diabetes.
It is not a shaking or tremor like I have seen described elsewhere. More of a slow movement like he is looking for a way out of the corner.
I tried to upload a video but it didn’t work. I will look into it more tomorrow.