Change from baseline body sway (A) in the middle of the night and (B) upon morning awakening. *P ≤ .0001, †P < .05, ‡P ≤ .001 vs placebo; §P ≤ .0001 vs zolpidem based on mixed-effect model repeated measurement analysis with treatment, sequence, period, baseline (time-matched), time (hours postdose), treatment × time, and baseline × time as fixed effects, and time with participant as a random effect and a repeated effect for time, with participant within sequence. aA unit of body sway is defined as 1/3 degree angle of arc movement of the ataxiameter. ER = extended release, LS = least squares, SE = standard error.