# Impact of high-altitude exposure on cerebral lobe functions in climbers: insights from the Nepali Himalayas

## TL;DR

This study explores how high-altitude climbing affects brain functions, finding that the frontal lobe is most impacted by low oxygen levels.

## Contribution

The study identifies specific cognitive decline in frontal lobe functions at high altitudes, particularly during climbs in the Nepali Himalayas.

## Key findings

- Frontal lobe function declines significantly at high altitudes, especially in the Visual Stroop test.
- Attention scores decrease at lower altitudes (800 meters) and remain affected at higher altitudes.
- Manaslu climbing showed greater cognitive challenges compared to Everest or Kanchanjanga.

## Abstract

High-altitude environments challenge cognitive function due to hypoxia, yet their specific effects on cerebral lobe functions remain unclear. This study examines the impact of high-altitude exposure on frontal, parietal, temporal, and occipital lobes in climbers in the Nepali Himalayas, aiming to enhance understanding of altitude-related cognitive decline.

A cross-sectional cohort study was conducted with 76 participants, including 46 non-selected individuals (NOSCL) and 30 selected climbers divided into Everest (EMCL, n = 12), Kanchanjanga (KMCL, n = 9), and Manaslu (MMCL, n = 9) groups. Cognitive function tests (CFT) assessed cerebral lobe function at altitudes ranging from 800 to 5,500 meters using a non-invasive neuropsychological battery.

Significant altitude-related declines were observed in frontal lobe function, particularly in the Visual Stroop test at 800 meters (75%, p < 0.001) and 2,700 meters (86.1%, p < 0.001). Attention scores also decreased at 800 meters (94.4%, p = 0.002). No significant changes were found in parietal, temporal, or occipital lobe functions. The Manaslu climb presented greater cognitive challenges than Everest or Kanchanjanga, with reduced attention and social cognition scores at 4,800 meters (p = 0.145).

The findings indicate that frontal lobe functions are particularly vulnerable to hypoxia at high altitudes. The results support the necessity of region-specific cognitive testing for high-altitude risk assessments. Further research should explore long-term cognitive effects and mitigation strategies for climbers exposed to extreme altitude conditions.