Cognitive effects of dexamethasone at high altitude.
OBJECTIVE
The major therapeutic effect of dexamethasone on persons affected by high-altitude illness may be upon vascular leakiness with a consequent decrease in cerebral edema. We set out to determine if dexamethasone ameliorates the cognitive/psychomotor effects of acute exposure to high altitude on asymptomatic subjects.


METHODS
Six adult subjects were tested at baseline (2500 m) with standard, computerized cognitive and psychomotor tests. Over the next 4 days, subjects were acclimatized to an altitude of 3700 m. On the fifth day, subjects ascended to 4800 m where predexamethasone testing was administered. No subject had symptoms of frank altitude illness at 4800 m. To limit acclimatization, subjects descended to 3700 m within 4 hours. The first 4-mg dose of oral dexamethasone was given in the evening of day 5. A second 4-mg dose of dexamethasone was given the following morning, and subjects reascended to 4800 m where postdexamethasone testing was performed.


RESULTS
All cognitive and psychomotor tests showed improved reaction times in subjects who were given dexamethasone. Mean reaction time (+/- SD) for shape recognition went from 1.20 +/- 0.36 seconds at 2500 m to 1.40 +/- 0.37 seconds at 4800 m. After dexamethasone administration, mean shape recognition time declined to 1.26 +/- 0.32 seconds (P = .052).


CONCLUSIONS
These data show a trend toward decreased cognitive deficits in subjects pretreated with dexamethasone. One possibility for this trend is that cognitive deficits in otherwise asymptomatic subjects exposed to high altitude are caused by subclinical cerebral edema.
Lafleur
John
J
Department of Emergency Medicine, Lincoln Medical and Mental Health Center, Bronx, NY 10451, USA. JEL57@Columbia.edu
Giron
Miguel
M
Demarco
Michael
M
Kennedy
Robert
R
BeLue
Rhonda
R
Shields
Christopher
C
D000284:Administration, Oral; D000328:Adult; D000532:Altitude Sickness / Q000473:pathology / Q000517:prevention & control*; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D003071:Cognition; D003907:Dexamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance
D000893:Anti-Inflammatory Agents; D003907:Dexamethasone