Pun Matiram, Guadagni Veronica, Bettauer Kaitlyn M, Drogos Lauren L, Aitken Julie, Hartmann Sara E, Furian Michael, Muralt Lara, Lichtblau Mona, Bader Patrick R, Rawling Jean M, Protzner Andrea B, Ulrich Silvia, Bloch Konrad E, Giesbrecht Barry, Poulin Marc J
Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Front Physiol. 2018 Aug 21;9:1131. doi: 10.3389/fphys.2018.01131. eCollection 2018.
Neurocognitive functions are affected by high altitude, however the altitude effects of acclimatization and repeated exposures are unclear. We investigated the effects of acute, subacute and repeated exposure to 5,050 m on cognition among altitude-naïve participants compared to control subjects tested at low altitude. Twenty-one altitude-naïve individuals (25.3 ± 3.8 years, 13 females) were exposed to 5,050 m for 1 week ( and re-exposed after a week of rest at sea-level (). Baseline (BL, 520 m), acute (Day 1, HA1) and acclimatization (Day 6, HA6, 5,050 m) measurements were taken in both cycles. Seventeen control subjects (24.9 ± 2.6 years, 12 females) were tested over a similar period in Calgary, Canada (1,103 m). The Reaction Time (RTI), Attention Switching Task (AST), Rapid Visual Processing (RVP) and One Touch Stockings of Cambridge (OTS) tasks were administered and outcomes were expressed in milliseconds/frequencies. Lake Louise Score (LLS) and blood oxygen saturation (SpO) were recorded. In both cycles, no significant changes were found with acute exposure on the AST total score, mean latency and SD. Significant changes were found upon acclimatization solely in the altitude group, with improved AST Mean Latency [HA1 (588 ± 92) vs. HA6 (526 ± 91), < 0.001] and Latency SD [HA1 (189 ± 86) vs. HA6 (135 ± 65), < 0.001] compared to acute exposure, in . No significant differences were present in the control group. When entering Acute SpO (HA1-BL), Acclimatization SpO (HA6-BL) and LLS score as covariates for both cycles, the effects of acclimatization on AST outcomes disappeared indicating that the changes were partially explained by SpO and LLS. The changes in AST Mean Latency [ΔBL (-61.2 ± 70.2) vs. ΔHA6 (-28.0 ± 58), = 0.005] and the changes in Latency SD [ΔBL (-28.4 ± 41.2) vs. ΔHA6 (-0.2235 ± 34.8), = 0.007] across the two cycles were smaller with acclimatization. However, the percent changes did not differ between cycles. These results indicate independent effects of altitude across repeated exposures. Selective and sustained attention are impaired at altitude and improves with acclimatization.The observed changes are associated, in part, with AMS score and SpO. The gains in cognition with acclimatization during a first exposure are not carried over to repeated exposures.
神经认知功能会受到高海拔的影响，然而，适应和反复暴露于高海拔的影响尚不清楚。我们研究了与在低海拔测试的对照受试者相比，急性、亚急性和反复暴露于5050米对未适应高海拔的参与者认知的影响。21名未适应高海拔的个体（25.3±3.8岁，13名女性）暴露于5050米高度1周（并在海平面休息1周后再次暴露（）。在两个周期中均进行了基线（BL，520米）、急性（第1天，HA1）和适应（第6天，HA6，5050米）测量。17名对照受试者（24.9±2.6岁，12名女性）在加拿大卡尔加里（1103米）的相似时间段内进行了测试。进行了反应时间（RTI）、注意力转换任务（AST）、快速视觉处理（RVP）和剑桥单触式长袜（OTS）任务，并以毫秒/频率表示结果。记录了路易斯湖评分（LLS）和血氧饱和度（SpO）。在两个周期中，急性暴露对AST总分、平均潜伏期和标准差均未发现显著变化。仅在高海拔组适应后发现了显著变化，与急性暴露相比，AST平均潜伏期有所改善[HA1（588±92）对HA6（526±91），<0.001]，潜伏期标准差也有所改善[HA1（189±86）对HA6（135±65），<0.001]，在。对照组中未发现显著差异。当将急性SpO（HA1 - BL）、适应SpO（HA6 - BL）和LLS评分作为两个周期的协变量时，适应对AST结果的影响消失，表明这些变化部分由SpO和LLS解释。两个周期中AST平均潜伏期的变化[ΔBL（-61.2±70.2）对ΔHA6（-28.0±58），=0.005]和潜伏期标准差的变化[ΔBL（-28.4±41.2）对ΔHA6（-0.2235±34.8），=0.007]在适应后较小。然而，两个周期之间的百分比变化没有差异。这些结果表明反复暴露于高海拔的独立影响。在高海拔时选择性和持续注意力受损，适应后会改善。观察到的变化部分与急性高山病评分和SpO有关。首次暴露期间适应带来的认知提升在反复暴露时并未延续。
