Fig. 1.

Mean pointing deviation error across all 13 patients before and after the prism adaptation procedure (PA), for the visual open-loop pointing task (VOL) and the subjective straight ahead pointing (SSA) task, showing a leftward post-prism shift in both tasks. Numbers on the x-axis represent pointing error in degrees (from the patient's perspective), with positive values indicating deviation to the right and negative values indicating deviation to the left. Note the strong SSA pre-prism error towards the right, and the large difference in the impact of prism adaptation on SSA vs. VOL, with the prism-induced leftward shift being much larger for SSA.