J.S.
Has he had any other symptoms?
The reason I ask my son who is almost 5 now, was diagnosed at 2-3 with something called sensory integration disorder. It is a neuro condition and we had to do about 1-2 yrs of occupational therapy. He could not go to bed with out a melt down, bath time or any kind of transitioning to one environment to another was very difficult for him. He is done a TOTAL 360 and so much better. I am not sure if your son has any other symptoms but I know Josh can be very OCD about CERTAIN things as well. Here are 2 good websites if you have any questions http://www.brighttots.com/sensory_integration.html, http://www.sensorynation.com/index.html. Hope this helps