Zhang Ya Qing, Zhang Wen Juan, Liu Jin Hao, Ji Wei Zhong
Qinghai Provincial People's Hospital, Xining, China.
Front Aging Neurosci. 2022 May 6;14:788322. doi: 10.3389/fnagi.2022.788322. eCollection 2022.
This study aimed to investigate the effects of long-term hypoxic environment exposure on cognitive ability and neuroimaging characteristics in a highland population in China.
Health system workers in Maduo County (4,300 m above sea level) and Minhe County (1,700 m above sea level) were selected as research participants and divided into a high-altitude (HA) group and low-altitude (LA) group, respectively. Cognitive ability was assessed using the Montreal Cognitive Assessment (MoCA), Verbal Fluency Test (VFT), Symbol Digit Modalities Test (SDMT), Trail Making Test A and B (TMT), Digit Span Test (DST), and Rey Auditory Verbal Learning Test (RAVLT). All participants underwent a magnetic resonance imaging (MRI) scan, resting state functional MRI scan, and diffusion tensor imaging to clarify changes in regional gray matter (GM) volume, anisotropy index (FA), local consistency (ReHo), and low-frequency oscillation amplitude (ALFF).
The HA group had significantly lower MoCA, DST, VFT, RAVLT, and TMT scores compared to the control group. No significant differences were found in SDMT score. Furthermore, compared to the LA group, the HA group had significantly lower GM density of the left olfactory cortex, right medial orbital superior frontal gyrus, bilateral insula, left globus pallidus, and temporal lobe (left superior temporal gyrus temporal pole, bilateral middle temporal gyrus temporal pole, and right middle temporal gyrus). In terms of FA, compared with the LA group, the HA group had lower values for the corpus callosum, corpus callosum knee, bilateral radiative corona, and left internal capsule. The HA group had lower ALFF values of the left cerebellum, left putamen, left orbital inferior frontal gyrus, and left precuneus, but higher ALFF values of the left fusiform gyrus, bilateral inferior temporal gyrus, left orbital superior frontal gyrus and medial superior frontal gyrus, compared to the LA group. There was no significant group difference in ReHo values.
Our findings suggest that a chronic hypoxic environment can induce extensive cognitive impairment. Decreased GM density in multiple brain regions, damaged nerve fibers, and unbalanced neuronal activity intensity in different brain regions may be the structural and functional basis of cognitive impairment due to hypoxia.
本研究旨在探讨长期暴露于低氧环境对中国高原人群认知能力和神经影像学特征的影响。
选取玛多县（海拔4300米）和民和县（海拔1700米）的卫生系统工作人员作为研究对象，分别分为高海拔（HA）组和低海拔（LA）组。采用蒙特利尔认知评估量表（MoCA）、语言流畅性测试（VFT）、符号数字模式测试（SDMT）、连线测验A和B（TMT）、数字广度测试（DST）以及雷伊听觉词语学习测验（RAVLT）评估认知能力。所有参与者均接受磁共振成像（MRI）扫描、静息态功能MRI扫描和扩散张量成像，以明确区域灰质（GM）体积、各向异性指数（FA）、局部一致性（ReHo）和低频振荡幅度（ALFF）的变化。
与对照组相比，HA组的MoCA、DST、VFT、RAVLT和TMT得分显著更低。SDMT得分未发现显著差异。此外，与LA组相比，HA组左侧嗅觉皮质、右侧眶内侧额上回、双侧岛叶、左侧苍白球和颞叶（左侧颞上回颞极、双侧颞中回颞极和右侧颞中回）的GM密度显著更低。在FA方面，与LA组相比，HA组胼胝体、胼胝体膝部、双侧放射冠和左侧内囊的值更低。与LA组相比，HA组左侧小脑、左侧壳核、左侧眶额下回和左侧楔前叶的ALFF值更低，但左侧梭状回、双侧颞下回、左侧眶额上回和额上回中部的ALFF值更高。ReHo值在两组间无显著差异。
我们的研究结果表明，慢性低氧环境可诱发广泛的认知障碍。多个脑区GM密度降低、神经纤维受损以及不同脑区神经元活动强度失衡可能是低氧导致认知障碍的结构和功能基础。
