My young son has a history of tics. Fortunately we have been able to control them with dietary changes, nutritional therapy, and avoiding triggers in the environment that we found through observation. We worked very hard to get to this stage. Fortunately he is a good kid and compliant with his diet, which helped our efforts. But 3 months ago a persistent eye blink started up that really had my husband and me stumped.
We tried adjusting his diet with no improvement, and then did some testing. It was the testing that gave us the answer we needed.