汉语阅读障碍儿童视觉编码和词语成分加工机制的功能性近红外光学成像研究

Study on the Mechanism of Visual Coding and Language Activities of Children with Chinese Dyslexia by fNIRI

目的 探讨汉语阅读障碍 (readdisorder,RD)儿童视觉编码和词语成分加工的脑功能定位及血氧水平依赖 (bloodoxygenationlevel-dependent,BOLD)响应与加工作业之间的关系。方法 以 1 9名RD儿童为病例组 ,以 2 8名正常儿童为对照组 ,2组儿童年龄分别为(9.81± 1 .2 2 )岁和 (9.77± 1 .1 9)岁。运用功能近红外成像技术 ,观察 760nm和 850nm的漫射光强变化 ,测定受试者左前额皮层的血流量和血氧的变化。结果 2组儿童左前额叶的BOLD响应强度在词语成分加工时均显著强于视觉编码加工。视觉编码加工时 ,RD儿童左前额叶的血流量增加 ,对照组的血流量减少 ;词语成分加工时 ,RD儿童和正常儿童左前额叶的血流量均呈现增加趋势 ,但RD儿童脑区域激活强度和激活范围较对照组明显减弱 (P <0 .0 5)。结论 左前额叶参与RD儿童视觉编码和词语成分加工作业。汉语RD儿童在完成上述 2项加工作业时的脑局部血流量的代谢机制和脑功能机制与正常儿童存在明显差异 ,提示汉语RD儿童神经生理机制的异常可能是其发病的大脑物质基础。

Objective To explore the functions of the prefrontal cortex and the changes of cerebral blood oxygenation of children with Chinese dyslexia in visual coding. Methods Nineteen children with Chinese dyslexia were taken as cases matched with 28 uormal children. Their ages were(9.81±1.22)and(9.77±1.19)respectively. When the subjects were accomplishing the tasks of single word component processing and visual coding, functional near infrared imagining (fNIRI)were used to detect the diffusion intensity of 760 nm and 850 nm near infrared penetated through the frontal bone and the left prefrontal cortex and the changes of the cerebral blood volume and blood oxygenation. Results The changes of BOLD were stronger during accomplishing single word component than visual coding processing in dyslexia and control children. During visual coding processing left prefrontal CBV of RD children increased while the control group was on the contrary. And during single word component processing, rCBV increased in both groups, however the intensity and the area of regional cerebral activated were lower in RD children than in normal( P <0.05). Conclusion Left prefrontal lobe takes part in visual coding and single word component processing task. There are significant differences in rCBV metabolic mechanism and cerebral functional mechanism between RD children and normal children. Maybe nerve irregularity is the substance base for reading disorder.