Assessment of the AccuSwayPLUS System in Measuring the Effect of Lorazepam on Body Sway in Healthy Volunteers

Abstract

Aim:To assess the AccuSway PLUS system, which aims to quantify deficiency in human balance, using the measurement of the effect of lorazepam on body sway in healthy volunteers. Methods: A double-blind, randomised, placebo-controlled, two-way crossover study in 12 healthy male and female volunteers. Participants received a single oral dose of lorazepam 2mg and placebo, 1 week apart. Body sway was assessed using the AccuSway PLUS system, by measuring the length of the path of the centre-of-pressure (COP), and the area of the 95% confidence ellipse enclosing the COP (A95). Body sway was assessed at baseline and at 2, 3, 4, 6, 12, 18 and 24 hours after administration, in two positions: with the participants' eyes open and feet apart at hip's width (EOFA), and with their eyes shut and feet together (ESFT). Results: Statistically significant differences in body sway between lorazepam and placebo were detected for up to 18 hours after administration. The largest change in body sway was 2 hours post-dose, in the EOFA position; the mean (95% confidence interval) difference between lorazepam and placebo in fold change of A95 was 7.67 (3.88, 15.17), and in length of COP was 1.61 (1.23, 2.10). Conclusion: The findings confirm that the AccuSway PLUS system is a useful tool for detecting changes in body sway induced by centrally acting drugs. ORIGINAL RESEARCH ARTICLEInt J Pharm Med 2005; 19 (4): 233-238 1364-9027/05/0004-0233/$34.95/0

Effects of prolonged‐release melatonin and zolpidem on postural stability in older adults

“…The increase in body sway with zolpidem was further indicated from the measurement of the COP path length at 1 h 30 min post‐dosing that declined at 4 h post‐dosing to placebo treatment values. Notably, COP path length is considered less sensitive to the effects of hypnotics on body sway than A95 (Norris et al , ). This is also demonstrated in the current study wherein at 1 h 30 min after dosing at “eyes closed”, A95 with zolpidem was 4.8‐fold higher than with placebo, whereas COP path length was only 1.21‐fold higher than placebo.…”

“…Following previous studies in which A95 was shown to be a more sensitive measure of postural stability than the length of COP (Norris et al, 2005), A95 was the primary measure (Boyle et al, 2009). Increase in A95 reflects increased body sway, which means impairment (Norris et al, 2005). Each participant took a double legged stance on the platform with their arms along the side of the body, looking in front of them.…”

The Complexity of Standing Postural Control in Older Adults: A Modified Detrended Fluctuation Analysis Based upon the Empirical Mode Decomposition Algorithm

“…COP speed was computed by dividing total path length by trial duration. COP area was determined by calculating by area of a confidence ellipse enclosing 95% of the center-of-pressure trajectory [36].…”

Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability of Mirogabalin When Coadministered With Lorazepam, Zolpidem, Tramadol, or Ethanol: Results From Drug‐Drug Interaction Studies in Healthy Subjects

“…In the lorazepam study, body sway was measured with use of a validated [24][25][26] AccuSway PLUS Platform (Advanced Medical Technology Inc, Watertown, Massachusetts), which analyzes input from strain gauges located under the 4 quadrants of the platform to calculate the center of pressure (COP). 27 Extent of COP movement is directly related to the subject's ability to balance in a steady, upright position with eyes opened. For body sway, the average of 3 measurements lasting 40 seconds each was calculated.…”