Prism adaptation improves egocentric but not allocentric unilateral neglect: a case study

BACKGROUND: Rehabilitation of unilateral neglect has focused on the ego-centric form of the disturbance. However, allocentric neglect is known to predict failure in the activities of daily life even more than egocentric neglect. CASE REPORT: We submitted a patient with severe egocentric and allocentric left-sided neglect to an extensive prism adaptation training. After treatment, the patient persisted in errors on the left side of targets (allocentric neglect) and actually it increased in parallel with her increased exploration of left space (egocentric neglect). Despite the improvement in a number of cognitive and motor areas, the patient showed limited improvement in activities of daily living (ADL). CLINICAL REHABILITATION IMPACT: These observations confirm the dissociation between egocentric and allocentric neglect and the selective efficacy of the prism adaptation method on the former form. There is a need to develop new rehabilitation methods for allocentric neglect as this limits the complete recovery of patients particularly in terms of ADL.