127 CEREBRAL ADAPTATION ASSOCIATED WITH PERIPHERAL NERVE RECOVERY IN NA 6 reported here suggest that the activation pattern of NA patients moves towards that of healthy people, indicating a trend towards normalization of visuomotor processing in NA along with peripheral recovery. This identifies visuomotor processing as a potential target for treatment strategies to further facilitate clinical recovery in NA. Patients also improved their overall behavioral task performance (i.e. overall decrease in errors from baseline to follow-up), which could raise the question of whether the reported cerebral changes can be explained by general learning effects. 192 Such an explanation can however be ruled out, since both cerebral and behavioral changes involve interactions between time and laterality, which makes them specific to the affected upper extremity. The generalizability of our findings to the wider NA population may have limits, despite the heterogeneity of our sample. We excluded patients with severe comorbidities, bilateral or unilateral left-sided involvement, left hand dominance or ambidexterity, and patients who suffered a recurrent attack during the study. Although it is likely that cerebral adaptations also occur in those patients, the underlying mechanisms and their response to rehabilitation and peripheral neve recovery are unknown and could be different. In a similar vein, drop-out was greater in the usual care than in the multidisciplinary rehabilitation group, which is a potential source of bias that should be acknowledged. Conclusions and clinical implications We observed no cerebral group differences despite multidisciplinary rehabilitation elicited greater clinical improvement than usual care. This shows that specific rehabilitation can accelerate recovery in NA patients, and underlines the importance of a multidisciplinary approach. Importantly, patients in both groups showed increased cerebral activity in visuomotor brain regions, where their activity was decreased compared to healthy people at baseline. 2 This indicates that altered cerebral sensorimotor representations of the upper extremity can recover towards normality in NA. Rehabilitation may be further optimized by implementing strategies that target visuomotor processes, and sensorimotor integration in particular, as both initial (mal)adaptation and recovery occur in visuomotor brain areas involved in forming sensorimotor representations. Visuomotor strategies that have been successfully applied in other neurological disorders include mirror visual feedback, 179 action observation180 and graded motor imagery. 181 Future research could focus on identifying rehabilitation strategies to effectively target cerebral mechanisms in NA and other peripheral nerve disorders. To better understand cerebral (treatment) effects in NA, future studies could employ different paradigms (other tasks such as motor execution or explicit motor imagery, and/or alternative neuroimaging techniques such as EEG), and compare cerebral mechanisms between patients that respond well to existing treatment and those who do not. Acknowledgments We thank our participants for their time and commitment to the study. We also thank Melissa Bakkenes, Eline van de Ven, and Elze Wolfs for their contributions to data collection, Paul Gaalman for his technical support, Renske Janssen, Jos IJspeert, Judith Kanters, Yvonne Veenhuizen, Thomas Verheggen, Allan Pieterse and Jessica ten BroekPastoor for providing the multidisciplinary rehabilitation program, Ellis Gielink-Kersten for her secretarial support, and Saskia Lassche, Fran Smulders and Juerd Wijntjes for their
RkJQdWJsaXNoZXIy MjY0ODMw