Visual analogue scores in assessment of acute mountain sickness

Acute mountain sickness (AMS) is common on ascent to high altitude, with self assessment being the current method used to assess symptoms. The Lake Louise Self-Report Score (LLSRS) and the Environmental Symptoms Questionnaire (ESQ) are widely used and validated. A Visual Analogue Scale (VAS) may be used as a simpler alternative for AMS assessment. Our aims were to compare a VAS using lines of length 100 mm, for both individual symptoms of AMS and self-assessed overall AMS with both LLSRS and a shortened Environmental Symptoms Questionnaire (ESQc) on ascent to 4392 m. We set out to suggest a specific score as a cut off point for diagnosis of AMS when using the VAS. There were significant positive correlations (p<0.01), between VAS and both LLSRS and ESQc scores for overall AMS and a composite AMS score derived from the individual symptom scores at 4392 m. The sensitivity and specificity of the VAS were calculated as 0.67 and 0.98, respectively, when using the LLSRS as the standard test for comparison, and 0.91 and 0.96, respectively, when using the ESQc for comparison. The cut off point for diagnosis of AMS was calculated to be 22 mm or above when using a VAS for overall AMS or 15 mm or above when using the VAS composite score, when using LLSRS as the comparative test. Our results show significant correlations between the VAS and the LLSRS and ESQc, when assessing AMS at 4392 m. Our study suggests that a VAS could provide a simple alternative method of assessing AMS at high altitude.