Table_1_Identifying Cognitive Impairment in Elderly Using Coupling Functions Between Cerebral Oxyhemoglobin and Arterial Blood Pressure.DOCX

BackgroundThis study aimed to assess brain oxygenation status and cerebral autoregulation function in subjects with cognitive dysfunction.
MethodsThe Montreal Cognitive Assessment (MoCA) was applied to divide the subjects into three groups: cognitive impairment (Group CI, 72.50 ± 10.93 y), mild cognitive impairment (Group MCI, 72.02 ± 9.90 y), and normal cognition (Group NC, 70.72 ± 7.66 y). Near-infrared spectroscopy technology and a non-invasive blood pressure device were used to simultaneously measure changes in cerebral tissue oxygenation signals in the bilateral prefrontal lobes (LPFC/RPFC) and arterial blood pressure (ABP) signals from subjects in the resting state (15 min). The coupling between ABP and cerebral oxyhemoglobin concentrations (Δ [O2Hb]) was calculated in very-low-frequency (VLF, 0.02–0.07 Hz) and low-frequency (LF, 0.07–0.2 Hz) bands based on the dynamical Bayesian inference approach. Pearson correlation analyses were used to study the relationships between MoCA scores, tissue oxygenation index, and strength of coupling function.
ResultsIn the interval VLF, Group CI (p = 0.001) and Group MCI (p = 0.013) exhibited significantly higher coupling strength from ABP to Δ [O2Hb] in the LPFC than Group NC. In the interval LF, coupling strength from ABP to Δ [O2Hb] in the LPFC was significantly higher in Group CI than in Group NC (p = 0.001). Pearson correlation results showed that MoCA scores had a significant positive correlation with the tissue oxygenation index and a significant negative correlation with the coupling strength from ABP to Δ [O2Hb].
ConclusionThe significantly increased coupling strength may be evidence of impaired cerebral autoregulation function in subjects with cognitive dysfunction. The Pearson correlation results suggest that indicators of brain oxygenation status and cerebral autoregulation function can reflect cognitive function. This study provides insights into the mechanisms underlying the pathophysiology of cognitive impairment and provides objective indicators for screening cognitive impairment in the elderly population.

**背景** 本研究旨在评估认知功能障碍受试者的脑组织氧合状态与脑自动调节功能。
**方法** 采用蒙特利尔认知评估量表（Montreal Cognitive Assessment, MoCA）将受试者分为三组：认知障碍组（CI组，年龄72.50±10.93岁）、轻度认知障碍组（MCI组，年龄72.02±9.90岁）及正常认知组（NC组，年龄70.72±7.66岁）。采用近红外光谱技术与无创血压设备，同步采集受试者静息状态下（15分钟）双侧前额叶（左前额叶LPFC/右前额叶RPFC）的脑组织氧合信号变化及动脉血压（arterial blood pressure, ABP）信号。基于动态贝叶斯推断方法，计算极低频（very-low-frequency, VLF, 0.02~0.07 Hz）与低频（low-frequency, LF, 0.07~0.2 Hz）频段内动脉血压与脑氧合血红蛋白浓度（Δ[O₂Hb]）之间的耦合关系。采用Pearson相关分析，探究MoCA评分、脑组织氧合指数与耦合功能强度之间的相关性。
**结果** 在极低频频段，CI组（p=0.001）与MCI组（p=0.013）左前额叶的动脉血压至脑氧合血红蛋白浓度的耦合强度均显著高于NC组。在低频频段，CI组左前额叶的动脉血压至脑氧合血红蛋白浓度的耦合强度显著高于NC组（p=0.001）。Pearson相关分析结果显示，MoCA评分与脑组织氧合指数呈显著正相关，与动脉血压至脑氧合血红蛋白浓度的耦合强度呈显著负相关。
**结论** 耦合强度的显著升高可作为认知功能障碍受试者脑自动调节功能受损的佐证。Pearson相关分析结果表明，脑组织氧合状态与脑自动调节功能的相关指标可反映认知功能水平。本研究为认知障碍的病理生理机制提供了新的视角，并为老年人群认知障碍的筛查提供了客观指标。