Cognitive Function Deficits Associated With Type 2 Diabetes and Retinopathy: Volumetric Brain MR Imaging Study

Ece Ozdemir Oktem; Dila Sayman; Sevilay Ayyildiz; Çaglar Oktem; Lutfiye Ipek; Behcet Ayyildiz; Fatih Aslan; Emin Utku Altindal; Nilay Yagci; Rumeysa Dikici; Ramazan Karaca; Şeyda Cankaya; Seda Avnioglu; Halil Aziz Velioglu; Burak Yulug

doi:10.1002/brb3.70387

Cognitive Function Deficits Associated With Type 2 Diabetes and Retinopathy: Volumetric Brain MR Imaging Study

Brain Behav. 2025 Mar;15(3):e70387. doi: 10.1002/brb3.70387.

Authors

Affiliations

¹ Department of Neurology and Neuroscience, Alanya Alaaddin Keykubat University, Antalya, Turkey.
² School of Medicine, TUM-NIC Neuroimaging Center, Technical University of Munich, Munich, Germany.
³ Department of Ophthalmology, Alanya Alaaddin Keykubat University, Antalya, Turkey.
⁴ Department of Anatomy, Kocaeli University, Kocaeli, Turkey.
⁵ Department of anatomy, Alanya Alaaddin Keykubat University, Antalya, Turkey.
⁶ Center for Psychiatric Neuroscience, Feinstein Institute for Medical Research, Manhasset, New York, USA.

Abstract

Introduction: Type 2 diabetes mellitus is a ubiquitous chronic inflammatory disease with deleterious effects on various tissues, including the kidney, retina, and peripheral nerves. Studies using histopathology and magnetic resonance imaging have revealed that diabetes-related chronic hyperglycemia may impact the brain's essential functioning by causing microvascular damage. The aim of this study was to examine the cognitive functioning of type 2 diabetic individuals with and without retinopathy by evaluating their morphological, structural, and biochemical differences.

Methods: Demographic characteristics, education level, type of diabetes mellitus (DM), disease duration, treatment received, other diabetic complications, such as nephropathy and neuropathy, and detailed medical histories were recorded. All participants underwent an extensive neuropsychological examination with Montreal Cognitive Assessment (MoCA) testing. Brain magnetic resonance imaging was performed to evaluate gray matter volume differences between the groups.

Results: Gray matter volume differences between the groups were observed. Differences were observed after multiple corrections (age, education, and total intracranial volume [TIV]). First, the diabetic retinopathy group exhibited a significantly smaller gray matter volume in the right inferior temporal gyrus than the diabetic group (p = 0.032). In addition, the diabetic retinopathy group exhibited a significantly smaller gray matter volume than the control group in the right insula (lateral and central part) (p = 0.011). In addition, MoCA scores exhibited significant correlation with the two regions emerging as statistically significant in our analyses (the right inferior temporal gyrus and right insula) (p = 0.003, p = 0.002, respectively).

Conclusion: Our results suggest the presence of a neurodegenerative process associated with cognitive dysfunction that is particularly prominent in the retinopathy stage of DM.

Keywords: MRI; retinopathy; type 2 diabetes.

MeSH terms

Aged
Brain* / pathology
Cognitive Dysfunction* / diagnostic imaging
Cognitive Dysfunction* / etiology
Cognitive Dysfunction* / pathology
Cognitive Dysfunction* / physiopathology
Diabetes Mellitus, Type 2* / complications
Diabetes Mellitus, Type 2* / pathology
Diabetes Mellitus, Type 2* / physiopathology
Diabetes Mellitus, Type 2* / psychology
Diabetic Retinopathy* / complications
Diabetic Retinopathy* / diagnostic imaging
Diabetic Retinopathy* / pathology
Diabetic Retinopathy* / physiopathology
Female
Gray Matter / diagnostic imaging
Gray Matter / pathology
Humans
Magnetic Resonance Imaging / methods
Male
Middle Aged
Neuropsychological Tests