Accession Number:

ADA446071

Title:

Saccadic Velocity and Pupillary Reflexes During Acclimatization to Altitude (4300m)

Descriptive Note:

Journal article

Corporate Author:

ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA THERMAL AND MOUNTAIN MEDICINE DIVISION

Report Date:

2005-07-01

Pagination or Media Count:

9.0

Abstract:

Oculometrics have been shown to be responsive to hypoxemia. We investigated whether oculometrics could be used as an objective index of a hypoxic effect on the central nervous system CNS and altitude acclimatization. We hypothesized that oculomotor reflexes pupil diameter PD, constriction amplitude CA, constriction latency CL, and saccadic velocity SV changed in concert with a select number of accepted acclimatization variables and that these changes correlated with the severity of acute mountain sickness AMS. After sea-level, baseline SLB measurements were obtained, 18 men 19-33 yrs were transported to Pikes Peak, CO 4,300 m where they remained for 14 days. Periodic measurements days 1-4, 6, 7, 9, 10, and 12 were made of PD, CA, CL, and SV in addition to heart rate HR, pulse oximetry SpO2, end-tidal PO2 and PCO2, 24-h urinary catecholamine concentrations, and AMS severity environmental symptoms questionnaire, ESQ. PD and CL decreased from SLB for first 1-4 days and subsequently returned toward SLB these changes paralleled changes in ventilatory and circulatory variables. CA decreased on days 1 and 2 and remained decreased for 12 days. SV increased over the first 6 days then returned toward SLB with continued exposure, similar to the changes in urinary catecholamines. With acclimatization, CL con-elated with HR and SpO2 SV correlated with PCO2, HR, and SpO2. AMS severity peaked during days 2-4, followed by a return toward SLB over the next 10 days. Oculometrics did not correlate with the severity of AMS. Oculometrics can be used as an indicator of CNS hypoxia and altitude acclimatization, although there was no strong correlation with AMS severity.

Subject Categories:

  • Medicine and Medical Research
  • Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE