EEG topography during insulin-induced hypoglycemia in patients with insulin-dependent diabetes mellitus

• Published in: European neurology Vol. 36; no. 5; p. 303
• Main Authors: Tribl, G, Howorka, K, Heger, G, Anderer, P, Thoma, H, Zeitlhofer, J
• Format: Journal Article
• Language: English
• Published: Switzerland 1996
• Subjects: Adult; Awareness; Brain Mapping; Diabetes Mellitus, Type 1 - blood; Electroencephalography; Female; Humans; Hypoglycemia - chemically induced; Hypoglycemia - physiopathology; Hypoglycemia - psychology; Insulin; Male; Self Concept
• ISSN: 0014-3022
• DOI: 10.1159/000117277

A group of young patients with insulin-dependent diabetes mellitus (n = 14; 8 men, 6 women; 33.1 +/- 8.9 years) were examined by topographic EEG mapping under normoglycemic and hypoglycemic conditions (glucose levels after intravenous insulin injection down to 32.6 +/- 7.6 mg/dl). From the clinical aspect, 7 of them had a good and 7 had a poor awareness of hypoglycemia. During hypoglycemia, a decrease in alpha activity (p < 0.05), an increase in delta (p < 0.05), and especially in theta activity (p < 0.05) were found. The most sensitive parameter was the alpha/theta ratio. In the range of slight hypoglycemia (50-60 mg/dl) the increase in delta and theta activity showed a topographic maximum in lateral frontal regions. During deep hypoglycemia there was a topographic maximum of slow frequencies in posterior parts of the brain (centrotemporal to parieto-occipital regions). The differences between the group with good and with poor awareness of hypoglycemia were most pronounced during slight hypoglycemia in C3, C4, and Pz (p < 0.05). At lower glucose levels group distinction was no longer possible. These EEG changes correspond to a temporary organic brain syndrome.