Neurocognitive Impact of Hypoglycemia in Type 1 Diabetes

Inclusion Criteria: * Age 4 - 16 (for MRI, must be 7 or older) Exclusion Criteria: * Pregnant or lactating (females 13+) * Chronic disease other than T1DM, well-controlled asthma, or Hashimoto's thyroiditis. (Exclude for hypothyroidism) * Other current serious medical illness * Co-morbid psychiatric illness: such as mania, ADHD, LD, major depression, mental retardation, or psychoactive drug dependence * Co-morbid neurological illness: stroke, seizure, major loss of consciousness, other brain trauma/surgery, or head injuries (i.e. near drowning), encephalitis, or hydrocephalus, blindness, deafness * EXCEPT T1DM-related * Pre-maturity at birth \>4 wks early (\<36 wk term) w/ sequelae e.g. on respirator at NICU * Use of psychoactive medications or exposure to neuroleptics (except that exposures of less than 1 month, occurring more than 5 years ago, will be allowed) or pts. w/recent tx w/dopamine depleting agents or stimulants such as Ritalin, Cylert, Adderall * Contraindication to MRI scan (e.g. claustrophobia, metal implants, foreign bodies) - N/A if \< 4 years old * Full set (top and bottom) orthodontic braces. (Half set braces, fillings, and retainers are OK)