Diabetes Care, Vol 23, Issue 3 305-312, Copyright © 2000 by American Diabetes Association
Recovery of cognitive function and mood after severe hypoglycemia in adults with insulin-treated diabetes
MW Strachan, IJ Deary, FM Ewing and BM Frier
Department of Diabetes, Royal Infirmary of Edinburgh, Scotland, UK.
OBJECTIVE: Acute hypoglycemia in humans impairs cognitive functions and
alters mood states. The time required for cognitive functions and moods to
return to normal after an acute episode of severe hypoglycemia is unknown.
RESEARCH DESIGN AND METHODS: Cognitive functions and moods were studied
prospectively in 20 subjects with insulin-treated diabetes who had recently
experienced a spontaneous episode of severe hypoglycemia ("hypo" subjects)
and 20 matched control subjects with insulin-treated diabetes who had not
experienced severe hypoglycemia during the preceding year. The hypo
subjects had a history of a greater number of episodes of severe
hypoglycemia (P = 0.000). Cognitive function tests and mood scales were
administered at 1.5, 9, and 30 days after the severe hypoglycemia and at
similar intervals for the control subjects. RESULTS: For most of the
cognitive tests, no evidence of a "hangover" effect of the acute
hypoglycemia on cognitive function was observed (P > 0.05). A trend was
noted for levels of hedonic tone (P = 0.082) and energetic arousal (P =
0.053) to improve with time in the hypo subjects but not in the control
subjects. However, the hypo subjects had chronically elevated levels of
depression (P = 0.011) and anxiety (P = 0.049) and persistently performed
more poorly in several cognitive tests, such as the Digit Symbol Test (P =
0.009) and the Stroop Task (P = 0.007). CONCLUSIONS: These results suggest
that, in general, recovery from any acute cognitive decrement after severe
hypoglycemia was complete by 1.5 days. The cognitive decrements and altered
mood states noted in the hypo subjects may be persistent and may be a
consequence of previous exposure to recurrent episodes of severe
hypoglycemia.