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Hallucinatory experiences in extreme-altitude climbers
P Brugger1, M Regard, T Landis
1Department of Neurology, University Hospital Zürich, Switzerland. pbrugger@npsy.unizh.ch
Neuropsychiatry, Neuropsychology, and Behavioral Neurology
|March 19, 1999
Summary
Extreme-altitude climbers frequently experience anomalous perceptual phenomena, including visual and auditory hallucinations, particularly above 6000 meters. These experiences are linked to factors like solo climbing and stress, not cognitive impairment.
Area of Science:
- Altitude Medicine
- Neuroscience
- Psychology
Background:
- Anecdotal reports suggest high incidence of anomalous perceptual experiences in high-altitude mountaineering.
- Extreme altitudes pose unique physiological and psychological challenges.
Purpose of the Study:
- To systematically investigate the incidence, type, and circumstances of anomalous perceptual experiences in elite high-altitude climbers.
- To explore potential triggers and correlations with cognitive function.
Main Methods:
- Structured interviews with eight world-class climbers who summited above 8500m without supplemental oxygen.
- Comprehensive neuropsychological, electroencephalographic (EEG), and magnetic resonance imaging (MRI) evaluations.
Main Results:
- Over 87% of climbers reported somesthetic illusions and pseudohallucinations (visual, auditory).
- Experiences were more frequent above 6000m; solo climbing and danger were identified triggers.
- No correlation found between reported experiences and neuropsychological impairment, EEG, or MRI abnormalities.
Conclusions:
- Confirms high incidence of hallucinatory experiences in high-altitude climbing.
- Hypoxia, social deprivation, and acute stress are likely contributors to these perceptual anomalies.