Disassociation of verbal learning and hippocampal volume in type 2 diabetes and major depression

• Published in: International journal of geriatric psychiatry Vol. 30; no. 4; pp. 393 - 399
• Main Authors: Ajilore, O., Lamar, M., Medina, J., Watari, K., Elderkin-Thompson, V., Kumar, A.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.04.2015; Wiley Subscription Services, Inc
• Subjects: Adult; Aged; Aged, 80 and over; Analysis of Variance; Brain; Case-Control Studies; cognition; Comorbidity; depression; Depressive Disorder, Major - physiopathology; Diabetes; Diabetes Mellitus, Type 2 - physiopathology; Female; Geriatric psychiatry; hippocampus; Hippocampus - pathology; Humans; Magnetic Resonance Imaging; Male; medical co-morbidities; Memory; Memory Disorders - physiopathology; Mental depression; Middle Aged; Neuropsychological Tests; Predictive Value of Tests; Verbal learning; Verbal Learning - physiology; Diabetes; depression; medical co-morbidities; cognition; hippocampus
• ISSN: 0885-6230; 1099-1166
• DOI: 10.1002/gps.4149

Objective The purpose of this study was to examine the relationship between verbal learning and memory performance and hippocampal volume in subjects with co‐morbid type 2 diabetes and major depression compared with healthy control subjects and subjects with type 2 diabetes alone. Methods Twenty four subjects with type 2 diabetes and 20 subjects with type 2 diabetes and major depression were recruited from endocrinology clinics and were compared with 32 healthy control subjects recruited from the community. Subjects were scanned on a 1.5 T GE scanner, and hippocampal volumes were measured using Freesurfer. The California Verbal Learning Test assessed learning and memory. Significant predictors of verbal learning performance (e.g., age, gender, education, blood pressure, stroke risk, hemoglobin A1c, and hippocampal volume) were determined using a stepwise linear regression. Results Subjects with diabetes and depression had significantly worse performance on verbal list learning compared with healthy control subjects. Hippocampal volume was a strong predictor of performance in healthy control subjects, and age and hippocampal volume were strong predictors in subjects with type 2 diabetes alone. Age alone was a significant predictor of verbal learning performance in subjects with diabetes and depression. Conclusions The relationship between hippocampal volume and performance on the California Verbal Learning Test is decoupled in subjects with type 2 diabetes and major depression and this decoupling may contribute to poor verbal learning and memory performance in this study population. Copyright © 2014 John Wiley & Sons, Ltd.