高浓度氧供更有益于老年人认知功能

doi:10.3969/j.issn.1673-5374.2013.03.009

摘要/Abstract

摘要：

高浓度氧对健康年青人认知功能有提高作用，但对老年人的影响呢？实验观察了3种不同水平的氧供(21% (1L/min), 93% (1L/min)和93% (5L/min))对认知功能正常的老年人群认知功能、血氧饱和度和心率的影响。实验包括3个阶段：3 min的氧供后的适应阶段，倒数N项测验前的2 min的控制阶段，以及2 min执行倒数N项测验的任务阶段。在这3个阶段给予不同水平的氧供，并检测血氧饱和度和心率。随着供氧浓度和流量的增加，老年人群认知功能改善，血氧饱和度上升，心率下降。说明充足的氧供有助于提高老年人认知功能。

关键词: 神经再生, 临床实践, 高浓度氧, 氧浓度, 氧流量, 认知任务, 倒数N项测验, 认知, 血氧饱和度, 心率, 生理反应, 老年人, 基金资助文章

Abstract:

The supply of highly concentrated oxygen positively affects cognitive processing in normal young adults. However, there have been few reports on changes in cognitive ability in elderly subjects following highly concentrated oxygen administration. This study investigated changes in cognitive ability, blood oxygen saturation (%), and heart rate (beats/min) in normal elderly subjects at three different levels of oxygen [21% (1 L/min), 93% (1 L/min), and 93% (5 L/min)] administered during a 1-back task. Eight elderly male (75.3 ± 4.3 years old) and 10 female (71.1 ± 3.9 years old) subjects, who were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea, participated in the experiment. The experiment consisted of an adaptation phase after the start of oxygen administration (3 minutes), a control phase to obtain stable baseline measurements of heart rate and blood oxygen saturation before the task (2 minutes), and a task phase during which the 1-back task was performed (2 minutes). Three levels of oxygen were administered throughout the three phases (7 minutes). Blood oxygen saturation and heart rate were measured during each phase. Our results show that blood oxygen saturation increased, heart rate decreased, and response time in the 1-back task decreased as the concentration and amount of administered oxygen increased. This shows that administration of sufficient oxygen for optimal cognitive functioning increases blood oxygen saturation and decreases heart rate.

. 高浓度氧供更有益于老年人认知功能[J]. 中国神经再生研究(英文版), 2013, 8(3): 264-269.

Hyun-Jun Kim, Hyun-Kyung Park, Dae-Woon Lim, Mi-Hyun Choi, Hyun-Joo Kim, In-Hwa Lee, Hyung-Sik Kim, Jin-Seung Choi, Gye-Rae Tack, Soon-Cheol Chung. Effects of oxygen concentration and flow rate on cognitive ability and physiological responses in the elderly[J]. Neural Regeneration Research, 2013, 8(3): 264-269.

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引言

材料方法

Design

A block design for repeated 1-back tasks.

Time and setting

This study was performed at the Brain Science Laboratory, Department of Biomedical Engineering, College of Biomedical & Health Science, Konkuk University, between January and February 2011.

Subjects

Eighteen elderly subjects aged 72.9 ± 4.5 years were recruited by an advertisement. The subjects consisted of eight males (75.3 ± 4.3 years old) and 10 females (71.1 ± 3.9 years old) who did not have any physical or mental diseases and were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea (MMSE-K)^[28]. The experimental design controlled for external factors that could influence physiological signals (e.g. smoking, alcohol, coffee). The overall procedure was explained to all subjects, who subsequently gave their consent for the procedure.

Methods

Experimental setup

An oxygen supply system (OXUS. Co., Seoul, Republic of Korea) that could maintain a constant oxygen level of 21% or 93% and control a flow of 1 L/min or 5 L/min was used for the experiment. To maintain a steady flow and constant concentration, oxygen was administered to the subjects through masks.

As shown in Figure 2, the experiment consisted of three phases over a total of 7 minutes: an adaptation phase after the start of oxygen administration (3 minutes), a control phase (2 minutes), and a task phase in which the 1-back task was performed (2 minutes)^[29-30]. The control phase was a 2-minute stabilization period before the 1-back task was started. The control phase was used to obtain stable baseline measurements of HR and SpO₂. The 1-back task was performed using the E-prime system (Psychology Software Tools Inc., Sharpsburg, PA, USA). During the task, 24 Arabic numbers (0–9) were presented on a monitor at 5-second intervals. If a number was repeated, participants were asked to press a response button on a keyboard as quickly as possible. The number of correct answers (repeated numbers) in each experiment was 10. All subjects performed the experiment at three different levels of oxygen 21% (1 L/min), 93% (1 L/min) or 93% (5 L/min), which were supplied throughout all three phases (7 minutes) of the experiment. All subjects participated in all three experiments with a 1-hour rest period between experiments. The order of the experiments was counter balanced.

Data analysis

The accuracy rate (the number of correct answers/total number of problems × 100) and response time of the 1-back task were calculated. The response time was recorded automatically for each experiment using the E-DataAid option in the E-prime software. SpO₂ (%) and HR (beats/min) were measured using a pulse oximeter (8600 Series, Nonin Medical, Inc., Plymouth, MN, USA) on the subject’s left index finger. SpO₂ and HR were measured for all phases while the subjects sat comfortably on chairs. The mean SpO₂ and HR were calculated for each phase in each subject.

Statistical analysis

Repeated measures analysis of variance (PASW version 18.0, SPSS, Chicago, IL, USA) was used with 21% (1 L/min), 93% (1 L/min), and 93% (5 L/min) as independent variables to determine significant differences in response time and accuracy rates among the conditions. Repeated measures analysis of variance (PASW version 18.0) was used with 21% (1 L/min), 93% (1 L/min), and 93% (5 L/min) and phases (control, task) as independent variables to determine significant differences in SpO₂ and HR among conditions and phases. Post-hoc adjustments for multiple comparisons were made using Bonferroni’s test. Since the adaptation phase was an adaptation period after the start of the oxygen supply, this phase was excluded from the analyses. The level of significance was set at 0.05 for all statistical analyses.