Brain Abnormalities in Type 1 Diabetes: Magnetoencephalographic Evidence

Presentation Number: MON 633
Date of Presentation: April 3rd, 2017

Kaitlin G Brau*1, Tony W Wilson2, Andjela T Drincic1, Cyrus V Desouza1 and Christine M Embury2
1University of Nebraska Medical Center, Omaha, NE, 2University of Nebraska Medical Center

Abstract

Complications of type 1 diabetes mellitus (T1 DM) include cognitive dysfunction, in addition to micro and macrovascular disease. The process by which cognitive dysfunction occurs is largely unknown, however glucose hemostasis and related vasculature effects may be contributing factors (1). Magnetoencephalography (MEG), a noninvasive functional neuroimaging tool that directly evaluates neural activity by measuring the magnetic fields that naturally emanate from electrically active brain cells (2), has been developed to better study brain abnormalities.
We hypothesized that MEG brain function parameters would be abnormal in patients with T1 DM when compared to a control group and would correlate with metabolic parameters between the two groups.
To evaluate this hypothesis, a cross sectional case control study was performed. A total of 62 participants, 32 patients with T1 DM and 30 controls, completed a computerized battery of neuropsychological assessments and cognitive tasks. Inclusion criteria for patients with T1 DM were diabetes duration for 1-25 years, limited to patients ages 19-35. Patients with micro and macrovascular disease, untreated thyroid or vitamin B12 deficiency, and major neurologic and psychiatric disease were excluded. Demographics, medical history, and glucose data was gathered via questionnaire. Routine blood work, including hemoglobin A1c, was obtained. The two groups were matched based on age, sex, ethnicity, handedness, education level, and BMI. Sixteen patients with T1 DM and 16 controls (n = 32) performed a specific verbal working memory task while seated in the MEG instrument. During this task, participants first viewed a visual array containing 4-6 letters, which disappeared after 2 seconds. Three seconds later, a new letter was shown. Participants were asked to identify if it was one of the original 4-6 letters. Patient accuracy and reaction time were collected simultaneously with the MEG brain imaging data through a button box connected to the MEG system. The imaging data were analyzed using a voxel-wise mass univariate approach based on the general linear model.
The mean age of our T1 DM subjects and controls, was 25.4 and 26.0 years, respectively. Average duration of diabetes was 12.5 years. Average hemoglobin A1c was 8.2%. The results from this working memory task test showed that participants with T1 DM performed about 5% worse when compared to controls, and showed abnormal neural activity (p < 0.05, corrected) in brain regions known to serve verbal working memory function (e.g., left parietal and supramarginal gyrus).
In conclusion, cognitive and neurological function were significantly impaired in subjects with T1 DM versus the control group. These findings in this young population may suggest that the cognitive impairment seen in T1 DM begins early on and is related to diabetes-related factors rather than confounding factors.

 

Nothing to Disclose: KGB, TWW, ATD, CVD, CME