Action observation and imagination to reduce hemineglect : a multiple-case study

Montedoro, Vincenza [UCL] Grade, Stéphane [UCL] Coyette, Françoise [UCL] Prairial, Cécile [UCL] Ivanoiu, Adrian [UCL] Edwards, Martin [UCL]

Hemineglect is a condition where brain-damaged patients are impaired at perceiving contralesional objects and space. The condition significantly hinders functional daily activities, and although treatments exist, none are completely effective. In the present study, we evaluated the efficacy of a new rehabilitation method. Using Mirror Neuron System (MNS) theory of co-activation between action execution, observation and imagination, we investigated if action observation and imagination could prime attention in hemineglect. We tested five patients with hemineglect using a counterbalanced design. The experimental condition involved forty video clips of daily life first-person perspective actions (25 minutes) starting in the center of the screen and moving to the contralesional hemifield of the screen, followed by a white screen during which the patients had to imagine the actions that they had just observed. The control condition featured the same observation and imagination of video clips as the experimental condition, but flipped so that the actions were made to the ipsilesional hemifield. The study lasted for three weeks, with four repeated measures of hemineglect severity across the period. Results were analyzed using single case 95% confidence interval analyses. Every patient showed some reduced hemineglect on at least one measure following the experimental compared to the control condition. Moreover, patients having the most neglect-related difficulties in their daily life (Catherine Bergego scale) benefited the most from the rehabilitation method. The results are discussed in terms of the development of new potential clinical treatments for hemineglect.