Question from Asheville, North Carolina, USA:

How much do high blood sugars affect cognitive ability? My son has had a lot of issues at school recently, such as forgetting assignments and/or homework, materials to take home for homework or to the classroom, which is not typical behavior. His IQ is 130 and he has never been a disipline issue. Yet, since the start of school he has had five morning detentions for forgetting homework and assignments. During that time, his blood sugars were in the 250 mg/dl [13.9 mmol/L] to 400 mg/dl [22.2 mmol/L] range. We consulted our endocrinologist and made adjustments to his basal rate and insulin to carbohydrate ratio for the high blood sugars, but we are still working on stabilizing his sugars in his target range, which is 80 mg/dl [4.4 mmol/L] to 150 mg/dl [8.3 mmol/L]. I know low and high blood sugars affect concentration, staying on task and cognitive ability, but I have been unable to find out to what degree. I’m trying to be an advocate for my son and his diabetes with his teachers, but I don’t want to make excuses for him if it is not due to his blood sugars. My son also has ADD and is on Concerta.