My DS 6yrs old is having some behavior problems in class. He is consistently making inappropriate noises and saying inappropriate things. ... They were going to do a case study on him because they thing he may be ADHD but I told them that he doesn't behavior like this at home and most of the time he can play for long periods of time by himself. He loves Legos and will play with them for hours. Plus when they were going to the testing he all of sudden started behaving well. Now I get notes again saying he is acting up. Should I tell them to go ahead and do a case study on him? Do you think this will help him?
You have nothing to lose by having them evaluate. School personnel are NOT allowed to diagnose any disorders outright (like ADHD or autism) but they are allowed to notice whether his behaviors are negatively impacting his or others' ability to learn. Having them take a closer look will let them gather data on when he's making the noises or behaving inappropriately, which will let them tailor a program for dealing with it, including prompts to help him behave correctly.
If they evaluate, this will likely also include IQ and achievement testing, which may help them decide if he is learning at his correct level, or needs something different academically.
If they did find that his behavior was suggestive of ADHD or another disorder, you could then go to an outside professional to seek help.
If they are telling you that something unusual is going on, I'd tend to trust their judgment that assessment is needed. Deciding not to assess and ignoring the problem only wastes valuable time that could be used solving the problem. And if they test him and don't find anything, you haven't lost anything.
DeeDee