Effects of cable car ascent to 2700 meters on mean EEG frequency and event-related desynchronization (ERD).
In the Eastern Alps, the Dachstein massif with a height of almost 3000 m is an ideal location for investigating the effects of changes in altitude on the human body. A cable car allows an ascent within a few minutes to 2700 m, where the partial pressure of oxygen is about 550 mm of mercury compared to 760 mm at sea level. Ten healthy subjects performed a reaction time task at an altitude of 990 m and 2700 m. The subjects were instructed to perform a right hand index finger movement as fast as possible after a green light had flashed. The green light flashed 50 times. Simultaneously to the task, the electroencephalogram (EEG) was recorded. The event-related desynchronization (ERD) analysis of the EEG data showed that changes in alpha ERD values are not significant, but event-related synchronization (ERS) values in the beta band decrease significantly from around 50 % to 10 %. Furthermore, the mean frequency of the beta band increased from 16.68 Hz to 16.81 Hz (p = 0.0019) with the ascent. The suppressed post-movement beta ERS at an altitude of 2700 m may therefore be interpreted as a result of an increased cortical excitability level when compared with the reference altitude of 990 m above sea level.
Guger
Christoph
C
ARGE-Alpinmedizin, Graz, Austria. guger@gtec.at
Domej
Wolfgang
W
Lindner
Gerhard
G
Edlinger
Günter
G
D000328:Adult; D000513:Alpha Rhythm; D000531:Altitude; D001288:Attention / Q000502:physiology; D001317:Austria; D001611:Beta Rhythm; D002540:Cerebral Cortex / Q000502:physiology; D003344:Cortical Synchronization; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D012984:Software; D014186:Transportation