Continuous glucose monitoring system and cognitive function in diabetes mellitus

Diabetes Mellitus (DM) is a common chronic metabolic disorder marked by dysregulation of insulin production and utilization resulting in increased blood glucose concentrations. Epidemiological evidence reveals that patients with DM are at twice the risk of cognitive impairment over 4 to 6 years although the cross-sectional study results are less consistent. Critics of the literature suggest that several comorbidities have not been accounted for in the literature and may be reflected in the inconsistent results. The critics suggest that age, education, duration of DM, duration of hypertension, and depression be assessed in studies examining the relationships between glycemic control and cognitive function. Another potential reason for this incongruity in the literature may lie in the measurement tool, HbA1c, used to determine glycemic control in most studies to date. Additionally, few studies determined blood glucose concentrations during testing. A new glycemic control measurement tool, the Continuous Glucose Monitoring System (CGMS), may provide a more detailed picture of glycemic fluctuations over a 72 hour period.;Objectives. To examine the associations between glycemic control as measured by the CGMS and the cognitive function domains of attention, mental flexibility, verbal fluency, psychomotor speed, and memory. In addition, investigation of the impact that age, education, duration of DM and hypertension, and depression makes on the associations between the CGMS and measures of cognitive function were conducted.;Methods. A total of 37 male veterans were recruited for participation if they agreed to monitoring for approximately 72 hours with the CGMS. After the CGMS was removed, a female research assistant, blind to CGMS results, administered the cognitive tests. Participants glycemic levels were determined prior to testing.;Results. Glycemic control measured by the CGMS was not significantly associated with cognitive function. When age and depression were covaried, the percentage of time spent hyperglycemic measured by CGMS was revealed to be associated with impaired performance on tests of psychomotor speed and incidental memory.;Conclusions. The CGMS has the potential to provide a more detailed picture of blood glucose fluctuations over time and its use in determining the impact hyperglycemic and hypoglycemic effects have on cognitive function should be pursued.