Fig. 3

a Mean visual gain scores at block 1 and 2 for all three groups. Control group (CON) in dark grey squares, external group (EXT) in orange circles, and internal group (INT) in teal diamonds. Error bars are in 95% confidence interval. Significant difference between EXT and CON group after Bonferroni correction and covariate adjustment. b, c, d Scatterplot showing the relationship between visual gain scores to root mean square (RMS) of mediolateral (ML) headset displacement, RMS of ML headset velocity, and total path length of ML headset displacement, respectively