Other professionals can diagnose "SPD" although that is not what they will call it as SPD is not in the DSM manual and is not an approved diagnosis for insurance purposes. My daughter was diagnosed by an OT, but I've read of others being diagnosed by a developmental pediatrician or a child psychologist. We saw a child psychologist and he said he thought it was PDD-NOS, which in my thinking is saying nothing. The OT diagnosed dyspraxia, and recently the school psychologist administered a test which was sent to the pediatrician, and she was diagnosed with ADD. It sounds to me like you are on the right track. It may be helpful to print off the symptom checklist from this site, complete it, and bring it with you to the appointment with the psychologist. If you don't get an answer you believe is accurate, keep pursuing it and try an OT. Sometimes it takes several "professionals" before you get an accurate diagnosis. I wish the best for you and your son! Welcome.