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.