Long-term effects of prism adaptation on chronic neglect after stroke

Previous studies have discussed the effectiveness or ineffectiveness of prism adaptation for neglect patients. Purpose: The aim of present study was to determine the long-term effect of prism adaptation with activity performance instead of pointing performance on chronic neglect patients. Subjects: Seven patients with chronic unilateral spatial neglect were recruited. Methods: We performed an 8-week intervention using prismatic glasses. Changes in eye movement before and after intervention were measured using an eye mark recorder system. We also assessed intentional spatial bias in terms of center of gravity in the standing position using a tactile sensor scan system. Additionally, regional cerebral blood flow was measured using SPECT (IMP) before and after intervention. Results: Eye movements significantly improved on the neglected side (p < 0.01), and the effects were sustained for up to 6 weeks after the removal of the prism. The center of gravity significantly moved to the left and forward. Furthermore, rCBF showed a significant increase at the parietal cortex, pericalleosal area of the left hemisphere (P < 0.05). Conclusion: These results suggest that intervention using prismatic glasses could improve eye movement on the neglected side and correct intentional spatial bias. Prism intervention might be one valuable method for the activation of the important areas of the brain in neglect patients.