Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
J Clin Neurophysiol. 2023 Sep 1;40(6):535-540. doi: 10.1097/WNP.0000000000000920. Epub 2022 Mar 29.
The aim of this study was to investigate the subclinical involvement of the optic nerve in asymptomatic patients with vitamin B12 deficiency using visual evoked potentials.
This study included 40 asymptomatic patients diagnosed with vitamin B12 deficiency (considered as serum levels below 150 pg/mL) and a control group of 40 healthy individuals. All participants underwent a visual evoked potential examination. Routine screening for homocysteine was performed for patients with vitamin B12 deficiency. The levels of vitamin B12 and homocysteine and the presence of megaloblastic anemia were analyzed statistically compared with P100, N75, and N135 latencies and amplitudes.
The mean vitamin B12 level was 96 pg/mL in the patient group and 374 pg/mL in the control group. In the patient group, 24 (60%) patients had hyperhomocysteinemia and 8 (20%) patients had megaloblastic anemia. The P100 wave latency of patients with vitamin B12 deficiency was significantly prolonged compared with the control group ( P < 0.01). There was no significant difference in the P100 amplitude between the patient group and the control group. P100 latencies were significantly longer in patients with hyperhomocysteinemia ( P = 0.002).
Our study showed that patients with vitamin B12 deficiency may have visual evoked potential abnormalities without visual symptoms or examination findings. In addition, high homocysteine levels led to a prolonged P100 latency in the patient group independent of vitamin B12 levels.
本研究旨在通过视觉诱发电位研究亚临床无症状维生素 B12 缺乏患者的视神经受累情况。
本研究纳入了 40 例诊断为维生素 B12 缺乏症（血清水平低于 150 pg/mL）的无症状患者和 40 名健康对照者。所有参与者均进行了视觉诱发电位检查。对维生素 B12 缺乏症患者进行了同型半胱氨酸的常规筛查。对维生素 B12 和同型半胱氨酸水平以及巨幼细胞性贫血的存在进行了统计学分析，并与 P100、N75 和 N135 潜伏期和振幅进行了比较。
患者组平均维生素 B12 水平为 96 pg/mL，对照组为 374 pg/mL。在患者组中，24 例（60%）患者存在高同型半胱氨酸血症，8 例（20%）患者存在巨幼细胞性贫血。维生素 B12 缺乏症患者的 P100 波潜伏期明显长于对照组（P < 0.01）。患者组与对照组的 P100 波幅无显著差异。高同型半胱氨酸血症患者的 P100 潜伏期明显延长（P = 0.002）。
本研究表明，维生素 B12 缺乏症患者可能存在视觉诱发电位异常，而无视觉症状或检查发现。此外，高同型半胱氨酸水平导致患者组 P100 潜伏期延长，与维生素 B12 水平无关。
