Limb Apraxia and Joint-actions

Apraxia refers to a difficulty in performing actions upon request that is typically less pronounced in response to contextual demands and inner needs. Interacting with others might be one of these needs. Here we aim to investigate whether interacting with another individual facilitates movement execution in apraxic patients. Left hemisphere brain damaged patients with (A+) or without (A-) limb apraxia were required to perform either complementary or imitative reach-to-grasp movements in synchrony with a virtual partner. The movements were performed under two different conditions: 1) Instructed coordination, in which patients received explicit instructions concerning where to grasp an object; 2) Interactive coordination, which required patients to chose where to grasp the object adapting to the partners’ movements. Accuracy and synchrony with the partner were collected together with the patients’ hand kinematics. Results show that, while A- control patients were able to perform both con