Cognitive Changes during Prolonged Stay at High Altitude and Its Correlation with C-Reactive Protein

Abstract

Hypersensitive C-reaction protein (hsCRP) may be a risk factor for cognitive impairment resulting from Alzheimer’s disease (AD), stroke, and vascular dementia. This study explored the correlation of peripheral blood hsCRP level with cognitive decline due to high altitude exposure. The study was conducted on 100 male military participants who had never been to high altitude. Cerebral oxygen saturation monitoring, event related potentials (P300, N200) detection, and neurocognitive assessment was performed and total hsCRP, interleukin-6 (IL-6), and homocysteine was estimated at 500m altitude, 3650m altitude, 3day, 1, and 3 month post arriving at the base camp (4400m), and 1 month after coming back to the 500m altitude. High altitude increased brain oxygen saturation, prolonged P300 and N200 latencies, injured cognitive functions, and raised plasma hsCRP levels. But they all recovered in varying degrees at 1 and 3 month post arriving at the base camp (4400m). P300 latencies and hsCRP levels were strongly correlated to cognitive performances. These results suggested that cognitive deterioration occurred during the acute period of exposure to high altitude and may recover probably owning to acclimatization after extended stay at high altitude. Plasma hsCRP is inversely correlated to neurological cognition and it may be a potential biomarker for the prediction of high altitude induced cognitive dysfunction.

Normobaric hypoxia overnight impairs cognitive reaction time

“…Until now, most studies examined this matter in real altitude with great environmental and subjects-related, constitutional influences [12, 13]. The greater parameter of reaction time was not affected as much by low FiO 2 levels during the night.…”

The interactive effects of acute exercise and hypoxia on cognitive performance: A narrative review

“…Cognitive impairment was observed in the early hours of exposure (day 0), but after 2 days no impairment in response speed was detected (days 2 and 4), although the error rate remained high . Hu et al reported that digit symbol substitution test performance was impaired during the first 3 days at high altitude (4400 m). However, cognitive performance was restored after one and 3 months .…”

“…Hu et al reported that digit symbol substitution test performance was impaired during the first 3 days at high altitude (4400 m). However, cognitive performance was restored after one and 3 months . Pagani et al suggested that acclimatization leads to improved cognitive performance at altitude of 5350 m. Pun et al indicated that impaired cognitive performance was restored after acclimatization.…”

Oxiracetam or fastigial nucleus stimulation reduces cognitive injury at high altitude

“…This examination measures response, attention, and processing speeds (Hu et al., 2016; Wang et al., 2013). The test consists of nine digit‐symbol pairs followed by a list of digits.…”

“…A wide range of past studies have demonstrated that hypoxia at high altitude induces neurophysiological conditions such as dizziness, insomnia, headaches, nausea, vomiting, and fatigue, and even possibly high altitude pulmonary edema, and cerebral edema that is potentially fatal (Basnyat & Murdoch, 2003). Furthermore, it could also trigger neurocognitive dysfunction including learning, memory, language, vision, and mood (Hu, Xiong, Dai, Zhao, & Feng, 2016; Wilson, Newman, & Imray, 2009). In addition, cognitive deficits may last for some time following people's coming back to sea level from plateau (Bonnon, Noel‐Jorand, & Therme, 2000).…”