Publication

Hypoglycemia during sleep impairs consolidation of declarative memory in type 1 diabetic and healthy humans

Journal Paper/Review - Aug 1, 2007

Units
PubMed
Doi

Citation
Jauch-Chara K, Hallschmid M, Gais S, Schmid S, Oltmanns K, Colmorgen C, Born J, Schultes B. Hypoglycemia during sleep impairs consolidation of declarative memory in type 1 diabetic and healthy humans. Diabetes care 2007; 30:2040-5.
Type
Journal Paper/Review (English)
Journal
Diabetes care 2007; 30
Publication Date
Aug 1, 2007
Issn Electronic
1935-5548
Pages
2040-5
Brief description/objective

OBJECTIVE: Early nocturnal sleep enhances the consolidation of declarative memories acquired during prior wakefulness. Patients with type 1 diabetes frequently experience hypoglycemic episodes during sleep. We investigated whether short-lasting hypoglycemia during early nocturnal sleep affects the sleep-associated consolidation of declarative memories. RESEARCH DESIGN AND METHODS: Sixteen type 1 diabetic patients and 16 healthy subjects matched for age and BMI were tested. On one condition, a linear fall of plasma glucose to 2.2 mmol/l was induced within 60 min by infusing insulin during early sleep. On the control condition, euglycemia (>3.86 mmol/l) was maintained throughout the night. In the morning, subjects recalled word pairs learned in the preceding evening. To assess mood and attention, a symptom questionnaire, an adjective check list, and the Stroop test were applied. Also, auditory event-related brain potentials were recorded. RESULTS: After euglycemia, subjects recalled 1.5 +/- 0.5 more word pairs than after hypoglycemia (P < 0.01), remembering 2.0 +/- 0.6 more word pairs than at immediate recall before sleep (P = 0.002). Across the hypoglycemic night, no such gain occurred (+0.5 +/- 0.6 words; P = 0.41). Hypoglycemia during sleep also impaired mood (P < 0.05) but did not affect attention. Effects compared well between type 1 diabetic patients and healthy control subjects. CONCLUSIONS: Our findings indicate specific sensitivity of declarative memory consolidation during sleep to rather short episodes of mild hypoglycemia. This effect may disable memory processing in type 1 diabetic patients prone to nocturnal hypoglycemic episodes and underlines the importance of considering sleep as a critical period in the treatment of these patients.