Enhanced Neurobehavioral Outcomes of Action Observation Prosthesis Training

Background. Previous studies have demonstrated improved neurobehavioral outcomes when prosthesis users learn task-specific behaviors by imitating movements of prosthesis users (matched limb) compared with intact limbs (mismatched limb). Objective. This study is the first to use a unique combination of neurophysiological and task performance methods to investigate prosthetic device training strategies from a cognitive motor control perspective. Intact nonamputated prosthesis users (NAPUs) donned specially adapted prosthetic devices to simulate the wrist and forearm movement that persons with transradial limb loss experience. The hypothesis is that NAPUs trained with matched limb imitation would show greater engagement of parietofrontal regions and reduced movement variability compared with their counterparts trained with a mismatched limb. Methods. Training elapsed over 3 days comprised alternating periods of video demonstration observation followed by action imitation. At the beginning and end of the training protocol, participants performed a cued movement paradigm while electroencephalography and electrogoniometry data were collected to track changes in cortical activity and movement variability, respectively. Results. Matched limb participants showed greater engagement of motor-related areas while mismatched limb participants showed greater engagement of the parietooccipital system. Matched limb participants also showed lower movement variability. Conclusions. These results indicate that the type of limb imitated influences neural and behavioral strategies for novel prosthetic device usage. This finding is important, as customary prosthetic rehabilitation with intact therapists involves mismatched limb imitation that may exacerbate challenges in adapting to new motor patterns demanded by prosthesis use.