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目的 探讨听力损失对脑葡萄糖代谢活动的影响。方法 对12例有听力损失但无耳鸣患者进行正电子发射断层成像(PET)研究,其中2例双耳全聋,10例双耳中度聋。分别在静息(视听封闭)和声刺激(2kHz短纯音130dBSPL)条件下进行PET成像。与13例听力正常者在静息条件下和4例听力正常者在声刺激条件下的PET作对照。PET示踪剂为~(18)F标记的去氧葡萄糖(~(18)F-FDG)。用专门统计分析软件(SPM)以及感兴趣区技术(ROI)进行统计分析。结果 2例全聋患者的听皮层葡萄糖代谢活动显著低于正常人(P<0.001),而视皮层及体感皮层的代谢活动显著高于正常人(P<0.001)。另10例听力下降患者的听皮层代谢活动低于正常人(P<0.05),声刺激后听皮层兴奋区域显著大于正常人(P<0.001)。提示听力下降引起听皮层神经元葡萄糖代谢活动的相应下降,但与听力下降相邻频率的声刺激却引起相应听皮层的代谢活动的显著增加,而且兴奋区域扩大。表明听皮层发生了功能重组。全聋患者的结果提示,视觉功能显著增强了,这是系统间功能重组的重要证据。结论 PET作为新型脑功能成像仪器,为研究听觉与脑功能提供了新方法,为听系功能重组和中枢神经系统的可塑性提供了有力证据。
Objective To investigate the effects of hearing loss on brain glucose metabolism. Methods Positron emission tomography (PET) was performed in 12 patients with hearing loss but without tinnitus, including 2 cases of binaural deafness and 10 cases of binaural hearing loss. PET imaging was performed at rest (audiovisual occlusion) and acoustic stimulation (2kHz short pure 130dBSPL) respectively. And 13 cases of normal hearing in resting conditions and 4 cases of normal hearing in the stimulation of PET under the conditions of contrast. The PET tracer was ~ (18) F-labeled deoxyglucose (~ (18) F-FDG). Statistical analysis was performed using specialized statistical analysis software (SPM) and ROI. Results The activity of glucose metabolism in the auditory cortex of two patients with deafness was significantly lower than that of the normal controls (P <0.001), while the metabolic activity of the visual cortex and somatosensory cortex was significantly higher than that of the normal controls (P <0.001). The auditory cortical metabolic activity of the other 10 patients with hearing loss was lower than that of normal people (P <0.05). The excitatory area of auditory cortex after acoustic stimulation was significantly larger than that of normal people (P <0.001). It is suggested that the hearing loss causes a corresponding decrease of glucose metabolism activity in the auditory cortices, but the acoustic stimulation adjacent to the hearing loss causes a significant increase in the metabolic activity of the corresponding auditory cortex, and the excitement area is enlarged. Indicating that the auditory cortex has undergone functional reorganization. The results of the deaf patients suggest that visual function is significantly enhanced, which is important evidence of functional recombination between the systems. Conclusion PET, as a new brain imaging instrument, provides a new method for the study of hearing and brain function. It provides strong evidence for the functional reorganization of the hearing system and the plasticity of the central nervous system.