Hi and welcome to the Chiari forum.
You said your son does not have a syrinx so that means they did a complete spine MRI, one of the Brain, cervical, thoracic and lumbar spine? A syrinx can form any where in the spine, but some Drs will only look in the cervical spine....
And another important test is a CINE MRI to check for a CSF obstruction....it is if there is an obstruction that surgery would be considered since surgery is done to restore CSF flow....if flow is fine surgery will not help the current symptoms at least not the decompression for Chiari....then there are related conditions that should be ruled out as they too can cause many of the same symptoms Chiari can.
Finding the right Dr is key.
We do have a list for you use to help you start researching Drs....this list is not a referral nor an endorsement for those listed on it.....also keep in mind you may have to travel.
Know you are not alone.
Hi my son was decompressed in july 2014 at age 8. He has a lot in common with your son as regards memory issues and concentration and had been dx with ADD before his Chairi was discovered. I now like you wonder if his memory issues are a result of the chairi but I don't know. We took the decision to have the surgery as he had a syrinx and his mobility (walking) was being effected. His memory issues have not changed or improved with the surgery. That is only my experience. Just don't rush into a decision and get some expert opinions. Good luck with your son.xxx
Hi Sherry80 & glad you found this forum.......very informative. Sorry to hear about your son. I am in the process of completing all final testing to schedule surgery. Some doctors will do surgery unnecessarily & some doctors brush Chiari off as though it is insignificant. I suggest you find a Chiari specialist for your son first & foremost. Has he had his CSF flow checked or CINE MRI done to see if he has any occlusion or interruption in the flow? There are many things to consider before surgery is done (as it is a major operation). I do know that compression of the hindbrain can cause speech & motor control problems. This is something a Chiari specialist will be able to recognize & will usually order multiple tests to rule out other problems as the cause. There are so many related conditions that could cause problems with recovery after surgery. Good luck with your son & hope all goes well.