Balance testing consists of the modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces. This test examines the participant’s ability to stand unassisted under four test conditions that are designed to specifically test the sensory inputs that contribute to balance— the vestibular system, vision, and proprioception (Table 1; 7)
Balance testing was scored on a pass/fail basis. Test failure was defined as a subject 1)
needing to open their eyes, 2) moving their arms or feet in order to achieve stability, or 3)
beginning to fall or requiring operator intervention to maintain balance within a 30 second
interval. Each subject who failed a Test Condition was eligible for one more attempt to pass.
Because each successive Test Condition was more difficult than the condition preceding it,
balance testing was concluded whenever a subject failed to pass a Test Condition (during the
initial test or in the re-test). We focused on Test Condition 4 -- standing with eyes closed on
a 16”×18”×3” foam pad – in which participants relied primarily on vestibular input. Of 5086
participants, 257 did not pass prior test conditions and did not participate in Test Condition
4. An additional 86 participants had missing data for Test condition 4, for a total of 343
excluded participants (6.7%). The time to failure (measured manually by stopwatch in
seconds) was recorded in all subjects who participated in Test Condition 4; for subjects who
passed Test Condition 4 the time to failure was set as 30 seconds (the maximum testing
time). Further details of balance testing procedures are available
(http://www.cdc.gov/nchs/data/nhanes/ba.pdf; 8).