Diabetes Care, Vol 16, Issue 10 1391-1393, Copyright © 1993 by American Diabetes Association
Disruptive effects of acute hypoglycemia on speed of cognitive and motor performance
DJ Cox, LA Gonder-Frederick, DB Schroeder, PE Cryer and WL Clarke
University of Virginia, Health Sciences Center, Charlottesville 22908.
OBJECTIVE--To directly examine whether hypoglycemia differentially slows
cognitive versus motor function, to evaluate the reliability of
hypoglycemic-related slowing, and to examine factors contributing to
individual differences. RESEARCH DESIGN AND METHODS--IDDM subjects (n = 10)
were administered a pure cognitive and a pure motor neuropsychological test
at euglycemia (5.4 mmol), blood glucose nadir (2.6 mmol), postnadir (3.6
mmol), and again at euglycemia (6.7 mmol). To assess the practice effect,
matched control subjects were tested at similar time intervals.
RESULTS--Concurrent and test-retest reliability for all tests was robust (r
= 0.68-0.94). Only cognitive tasks demonstrated impairment at nadir (P <
0.04). Individual differences, in terms of cognitive impairment, were
significantly correlated with levels of blood glucose at nadir and baseline
performance. CONCLUSIONS--Cognitive tasks appear to be more sensitive to
neuroglycopenia than motor tasks. Cognitive impairment caused by
hypoglycemia is reliable and differs across subjects. Individuals who show
reliable sensitivity to cognitive impairments of hypoglycemia should avoid
moderately low blood glucose levels.