Ahn S H, Oh S H, Lee J S, Jeong J M, Lim D, Lee D S, Kim C S
Department of Otolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, South Korea.
Hear Res. 2004 Oct;196(1-2):33-8. doi: 10.1016/j.heares.2004.05.012.
It has been reported that the area of decreased glucose metabolism in the FDG-PET of prelingually deaf children correlates significantly with speech performance after cochlear implantation. In this study, we undertook to confirm changes of glucose metabolism in the cerebral cortex using an animal model with age-matching groups to completely exclude the influence of age differences between the deaf and normal-hearing groups. The cochlea was ablated bilaterally at a postnatal 10-14 days in the deaf groups; 3-4 deaf and normal rats were included at each time point at 1, 2, 4 and 8 weeks and 7 months after ablation. After injecting 2-deoxyglucose intraperitoneally, digitalized autoradiographic images were obtained, and analyzed by using two different methods; 3-dimensional voxel-wise statistical analysis and conventional 2-dimensional densitometry. The hypometabolic area analyzed using 3-dimensional analysis and the differences of optical density between normal and deaf as determined by densitometry were widest and most prominent between 4 and 8 weeks after ablation. Differences were not significant before 2 weeks or after 7 months after ablation. This result shows that the hypometabolic area becomes prominent after a critical period and it decreases as the duration of deafness increases. We believe that cross-modal plasticity may be the mechanism of changes in glucose metabolism and that this result reinforced the usefulness of evaluating hypometabolic area using FDG-PET in deaf children.
据报道，语前聋儿童的氟代脱氧葡萄糖正电子发射断层扫描（FDG-PET）中葡萄糖代谢降低的区域与人工耳蜗植入后的言语表现显著相关。在本研究中，我们采用年龄匹配组的动物模型来确认大脑皮质葡萄糖代谢的变化，以完全排除聋组和听力正常组之间年龄差异的影响。在出生后10 - 14天对聋组大鼠双侧进行耳蜗切除；在切除后1、2、4和8周以及7个月的每个时间点纳入3 - 4只聋鼠和正常大鼠。腹腔注射2-脱氧葡萄糖后，获取数字化放射自显影图像，并使用两种不同方法进行分析；三维体素统计分析和传统二维密度测定法。使用三维分析所分析的代谢减低区域以及通过密度测定法确定的正常组和聋组之间的光密度差异在切除后4至8周最为广泛和显著。在切除后2周之前或7个月之后差异不显著。该结果表明，代谢减低区域在关键期后变得突出，并且随着耳聋持续时间的增加而减小。我们认为跨模态可塑性可能是葡萄糖代谢变化的机制，并且该结果加强了使用FDG-PET评估聋童代谢减低区域的实用性。
