Mental Ability Not Impaired by Drop in Blood Sugar

NEW YORK (Reuters Health) - A drop in levels of blood sugar, called hypoglycemia, that are severe enough to cause seizures or coma in young children with type 1 diabetes does not appear to result in impairments in mental ability (cognition) or behavior, according to results of a new study.

Among children with type 1 diabetes, also known as juvenile diabetes, those who develop the disease very early in life have shown signs of declines in mental abilities, Dr. Timothy W. Jones, from Princess Margaret Hospital, Perth, Australia, and colleagues report in the Journal of Pediatrics.

"Young children with type 1 diabetes are at greatest risk of severe hypoglycemic events, and this has focused concern on the potential for hypoglycemic insult to impact on central nervous system development," they note. There is some evidence that the region of the brain called the hippocampus is particularly sensitive to prolonged episodes of severe hypoglycemia.

To further investigate, the researchers compared 41 type 1 diabetic children and adolescents who had a history of hypoglycemia with seizure or coma to 43 similar diabetic subjects without a history of severe hypoglycemic events. A subgroup of patients who had early first seizure -- at younger than 6 years of age -- had more episodes of hypoglycemic seizure or coma compared with those who experienced a seizure at an older age.

The team conducted a comprehensive series of learning and memory tests, as well as intellectual and behavioral tests. The researchers observed no significant differences between the seizure and no-seizure groups on the intellectual, memory or behavioral measures.

The number of severe hypoglycemic events was also not significantly correlated with the memory, intellectual, and behavioral scores.

"No difference (was) found between the early first seizure subgroup and no-seizure group, even on those delayed recall tasks studied specifically given the concern about the potential impact of hypoglycemia on memory function," Jones and colleagues report.

They conclude that these results "provide some reassurance to those treating children with type 1 diabetes with intensive treatment that seizures/coma at a young age does not necessarily result in gross cognitive or behavioral impairment."

SOURCE: Journal of Pediatrics, November 2005.