Do you have the report from the first time he was tested for gifted?
If they are willing, I think it would be a good idea for your son to get back on the meds, at least until he
a) is retested
b) tries to give school another chance. It's possible that he is tuning out because it's boring but it's also possible that with the medication's help to overcome the ADHD, it wouldn't be as boring. Very subtle stuff
Also - has he been tested for 'central auditory processing' problems? If not - get it done through school or pay for it.
Do you have numbers for achievement testing? If so, post the numbers. And post the testing from age 5 too. We may be able to see some patterns.
Has he been in the gifted program this year? How many hours does it meet? Has he been paying attention or tuning out? Does the program change much between this year and next year?
Is depression or anxiety part of the picture? Bullying? Trama or abuse?
Has there every been a diagnosis or therapy for the 'finding shoes' problem? If you gave him challenges, like the Mentalist TV show, does he improve? This is worth a week or two experiment on your part if you can make it fun. Did you ever try that card game called, 'Consentration?'
Looking forward to hearing more -
Grinity
