title: Short-term effects of improved glycemic control on cognitive function in patients with type 2 diabetes.
abstract: BACKGROUND
  According to numerous studies, type 2 diabetes is associated with mild cognitive dysfunction, and there is some evidence suggesting favorable effects of improved metabolic control on the mental capability of elderly diabetic patients.
  
  
  OBJECTIVE
  To compare patients with type 2 diabetes to normal controls with respect to cognitive performance and to investigate the consequences of glycemic adjustment.
  
  
  METHODS
  53 patients with type 2 diabetes, most of them in secondary failure on oral antidiabetic drugs, but free from conditions which may cause brain dysfunction, were included (mean age 58.8 +/- 6.1 years, duration of disease 12.0 +/- 6.4 years). They were examined prior to (t1), and following (t2) glycemic adjustment with a time interval of approximately 2 weeks. 29 non-diabetic controls, comparable with regard to age, gender, education and verbal intelligence were examined twice with a corresponding time interval. Cognitive performance was assessed by well-standardized tests with a focus on attention/concentration, psychomotor speed, verbal fluency and verbal memory; mood status by two self-rating scales. Restoration of glycemic control included insulin treatment in the majority of patients (46/53).
  
  
  RESULTS
  Diabetic subjects scored significantly lower in all cognitive tests used, while they did not differ from controls in mood status. From t1 to t2 they improved in those tests measuring attention/concentration, and psychomotor speed. With regard to similar changes in controls, we interpret these improvements as practice effects rather than the consequence of altered metabolic control.
  
  
  CONCLUSIONS
  In a sample of patients with long-standing type 2 diabetes we could not confirm previous reports of improved cognitive capacity with restoration of glycemic control. Further studies on the effects of changes in control of blood glucose on cognitive performance in type 2 diabetes should be conducted with special regard to drugs used to lower blood glucose.
authors.affiliation: Central Institute of Mental Health, Department of Psychiatry and Psychotherapy Mannheim, Germany. w.hewer@VvPH.de
authors.forename: W
authors.initials: W
authors.lastname: Hewer
authors.forename: M
authors.initials: M
authors.lastname: Mussell
authors.forename: F
authors.initials: F
authors.lastname: Rist
authors.forename: B
authors.initials: B
authors.lastname: Kulzer
authors.forename: K
authors.initials: K
authors.lastname: Bergis
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D000704:Analysis of Variance; D001288:Attention; D001786:Blood Glucose / Q000032:analysis*; D016000:Cluster Analysis; D003071:Cognition; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents