Cerebral magnetic resonance imaging changes related to cognitive tests in asymptomatic vitamin B12 deficiency

Vitamin B12 plays an important role in the mechanisms which are responsible for myelinisation in the central nervous system. It can particularly lead to hematologic and neuropsychiatric symptoms when serum levels fall due to insufficient intake with diet or absorption problems. Cognitive symptoms of neurological involvement go mostly on insidiously, and sometimes they can be seen as initial findings before haematological manifestations may be present. Routine Magnetic Resonance Imaging (MRI) is insufficient to demonstrate brain damage due to B12 deficiency. Diffusion tensor imaging (DTI) can reveal abnormalities in a number of neurological disorders that can be seen with normal findings on conventional MRI. In this study, we aimed to indicate that cerebral neuronal damage by using DTG method and cognitive disturbance in phenomena vitamin B12 deficiency that have not reached the clinical symptom level by using neuropsychological tests. Between January and August 2016, 60 patients who applied to Adıyaman University Education and Research Hospital Neurology A.D. polyclinics and did not report cognitive complaints and had serum vitamin B12 levels below 200 pg/ml and 42 healthy people were included in this study. Routine blood tests were sent to the hospital's central laboratory for the purpose of excluding possible etiologic causes from all patients. Detailed anamnesis of patients was obtained, systemic and neurological examination was performed. As a neuropsychological test; Standardized Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment Test (MOCA), Rey Auditory Verbal Learning Test (AVLT), Advanced and Reverse Numerical Test (WMS-R), Visual Production Subtest (WMS-III) Categorical Fluency Test (KAS), Trail Trail Test (Trail A-B) and Similarities (BENZ) test for abstraction skill were carried out to the patients. In each case, we realized a detailed investigation of Diffusion Tensor Image (DTI) in some brain regions (Corpus Callosum, Anterior Thalamus, Dorsolateral Prefrontal Cortex, Hippocampus) associated with cognitive functions and previously evaluated in some brain regions due to lack of vitamin B12.