Vitamin B12 Deficiency and Cognitive Impairment: is There a Distinctive Cognitive Domain Affected? A Descriptive Study in Buenos Aires

Background Vitamin B12 deficiency is associated with cognitive‐behavioral disorders, which may be potentially reversible. No specific associated cognitive domain has been established and alterations in episodic memory, verbal fluency, attention and executive functions, praxia and visuoconstruction have been described. The objective of this work is to evaluate and describe the cognitive domains affected in patients with cognitive impairment associated with vitamin B12 deficiency. Method Cross‐sectional observational study conducted at the Trinidad Mitre sanatorium of Buenos Aires City. Patients with cognitive impairment and vitamin B12 deficiency were analyzed. Information was collected on the cognitive domain affected (taking as altered value the Z score ≤‐1.5 according to age and educational level, obtained in the neurocognitive evaluations), cognitive profile, magnetic resonance imaging features and mean consultation‐supplementation time. Result 25 patients with vitamin B12 deficiency and cognitive complaint were analyzed, with a mean age of 68.5 years. 83% presented multidomain mild cognitive impairment being 60% with subcortical pattern. Memory and attention were the most affected domains in 80% of the sample, followed by executive functions with 52%. The most deficient tests were the direct digit test (68%), serial memory (56%), deferred logical memory (52%) and Trail Making B (52%). Nearly 52% presented mild depressive symptomatology. A 56% of the sample presented with severe B12 deficiency with 32% elevation of plasma homocysteine. Supplementation was performed intramuscularly in 68% of the patients with a mean symptomatology‐supplementation onset time of 10.8 months. 92% of the patients presented subjective improvement after supplementation, 32% had control global test evaluation with improvement in all of them and 50% of this group presented control cognitive evaluation with improvement in previously deficient domains. Conclusion According to our findings we conclude that these patients with vitamin B12 deficiency present a multidomain pattern with special affectation of memory, attention and executive functions; of mild degree and potentially reversible. The reversibility of the picture could be related to high doses of B12 and early supplementation, using control cognitive assessments as an objective measure of improvement. References Reynolds E. Lancet Neurol. 2006 Nov;5(11):949‐60. Eastley R. Int J Geriatr Psychiatry. 2000 Mar;15(3):226‐33. Robins Wahlin. Biol Psychol. 2001 Jun;56(3):247‐65.