Evaluation of optic and peripheral nerve conduction in children with vitamin B12 deficiency

Yucel, Evaluation of Optic and Peripheral Nerve Conduction in Children with Vitamin B12 Deficiency, Eskisehir Osmangazi University Faculty of Medicine, Department of Pediatrics, Medical Specialty Thesis, Eskisehir, 2025. Vitamin B12 deficiency is an important public health issue that affects multiple systems due to its critical role in neuronal myelination and erythropoiesis. The aim of this study was to evaluate hematological and neurophysiological improvements (visual evoked potentials and nerve conduction studies) in pediatric patients before and after replacement therapy. A total of 40 cases, aged 9 to 18 years (mean age 176.8 ± 39.6 months), were included. 20 of the cases were female and 20 were male, and the gender distribution is equal. Age and gender distributions were similar, and no significant demographic difference was observed between the groups according to B12 levels (p>0.05). The cases were divided into two subgroups according to serum vitamin B12 levels (<200 pg/ml and 200–300 pg/ml). After treatment, significant increases in hemoglobin (Hb), red blood cell count (RBC), and serum vitamin B12 levels were observed, especially in the <200 pg/ml group (p < 0.05). Electrophysiological evaluation revealed a significant decrease in the P100 latency of visual evoked potentials (p = 0.000) and a general shortening of peripheral motor latencies (p < 0.05) in all cases. Significant increases in motor nerve conduction velocity and CMAP amplitudes (p < 0.05) Significant increases (p < 0.05) were recorded in motor nerve conduction velocity and CMAP amplitudes, especially in the vitamin B12 < 200 pg/ml group (median, ulnar and peroneal nerves), while a significant improvement was observed in the sural nerve sensory CMAP amplitude in the vitamin B12 200-300 pg/ml group. No significant changes were observed in F-wave responses. In conclusion, vitamin B12 replacement therapy corrects hematological parameters and provides partial improvements in central and peripheral nerve functions. Our findings suggest that electrophysiological assessments for early diagnosis and follow-up of subclinical neuropathy in childhood vitamin B12 deficiency will play a critical role in preventing adverse effects on neurodevelopment. Key Words: Vitamin B12 deficiency, visual evoked potentials, electromyography, neuropathi