Minimal effects on human memory following long-term living at moderate altitude

A number of studies describe memory deficits at extremely high altitudes. However, little is known about the effect of long-term living at moderate altitude (MA). The subjects for this study were 52 college students originally from sea level (SL), but studying at a MA of 2260 m over a 7-month period, with a return to SL for 30 days in the middle of the period. Fifty-two matched college students who stayed at SL all the time were the control group. The neuropsychological battery of assessments included the Chinese revised version of Wechsler Memory Scale tests (WMS-CR), verbal and spatial two-back working memory tests, long-term explicit memory (word recall and recognition of words, faces, and pictures) tests, Rey Auditory Verbal Learning test, Rey-Osterrieth Complex Figure (ROCF) test, degraded picture naming test, and the Serial Reaction Time Test. We found that the MA subjects showed significantly poorer performances than SL controls only in short-term visual construction assessed in the visual reproduction test from WMS-CR and in the ROCF immediate test. There were no significant differences in all other tasks between the MA group and SL group. These findings suggest that long-term hypoxic exposure at moderate altitude has minimal effects on human memory.