Recovery of intentional dynamic balance function after intravenous sedation with midazolam in young and elderly subjects.

BACKGROUND AND OBJECTIVE Computerized dynamic posturography using an intentional postural-sway task can be used to assess body-leaning ability and postural-control ability to prevent falls. Falls are the leading cause of morbidity and mortality for the elderly. The purpose of the present study was to evaluate the recovery of intentional dynamic balance function after intravenous sedation with midazolam in elderly subjects in comparison with that in young subjects. METHODS Midazolam was administered in small, divided doses over 4-5 min until the Wilson sedation score reached three in 20 young and 18 elderly male volunteers. The dynamic limits of the stability test, in which subjects leaned their body intentionally as indicated by a cursor moving on a computer screen, was determined before (baseline) and 50, 70, 90, 110, and 130 min after administration of midazolam. RESULTS The changes from baseline values of path sway and movement time 50 min after the administration of midazolam in elderly subjects (106.8 +/- 101.0%, 4.6 +/- 3.0 s; mean +/- SD) were significantly greater than those (32.9 +/- 87.2%, 1.9 +/- 2.8 s) in young subjects (P = 0.024, P = 0.008), respectively. CONCLUSIONS The elderly show slower recovery of the intentional dynamic balance function than do young adults after intravenous sedation with midazolam.