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Introduction: Research investigating LAS and CAI has essentially focused on local adaptations. Recently, growing evidence is supporting the hypothesis neural plasticity occurs at both the spinal and cortical levels following (repeated) ligamentous ankle injury. These alterations might explain persisting dysfunctions, an increased injury risk, and the increased probability of developing CAI. This systematic review synthesizes the literature on brain plasticity following LAS and CAI. Methods: Studies eligible for this systematic review investigated the brain with direct outcomes measures in patients with LAS or CAI. The following electronic databases were used for the systematic search from their conception to 19/10/2021: Pubmed, Web of Science, Embase, Scopus, PEDro, The Cochrane Central Registry for Controlled Trials (CENTRAL) and SPORTDiscus. Three authors independently screened 1227 articles from 7 databases using a two-staged process to include 16 studies. The quality assessment tool for observationaland cross-sectional studies was used for the risk of bias assessment. The authors extracted and summarised relevant outcomes from each study in table 1. Results: Patients with LAS showed lower superior cerebellar peduncles (white matter microstructure) compared with healthy controls. CAI populations displayed an increased sensitivity of intermediate inhibitory neurons and a decreased sensitivity of excitatory neurons in the corticospinal pathway. They also found more variability in cortical activation in the superior parietal lobe, pre-and postcentral gyrus and the supplementary motor area with lower corticomotor excitability in several lower limb muscles in patients with CAI. Conclusion: Whilst these findings may support the hypothesis of brain plasticity in patients with ligamentous ankle injuries, all studies were retrospective in nature and most used different measurement methods which makes direct comparisons difficult and limits the strength of evidence of this review. Future research should focus on the understanding of the underlying neurophysiological mechanisms. Correspondence e-mail: alexandre.maricot@vub.be

Prosthetic devices that replace a lost limb have become increasingly performant in recent years. Recent advances in both software and hardware allow for the decoding of electroencephalogram (EEG) signals to improve the control of active prostheses with brain-computer interfaces (BCI). Most BCI research is focused on the upper body. Although BCI research for the lower extremities has increased in recent years, there are still gaps in our knowledge of the neural patterns associated with lower limb movement. Therefore, the main objective of this study is to show the feasibility of decoding lower limb movements from EEG data recordings. The second aim is to investigate whether well-known neuroplastic adaptations in individuals with an amputation have an influence on decoding performance. To address this, we collected data from multiple individuals with lower limb amputation and a matched able-bodied control group. Using these data, we trained and evaluated common BCI methods that have already been proven effective for upper limb BCI. With an average test decoding accuracy of 84% for both groups, our results show that it is possible to discriminate different lower extremity movements using EEG data with good accuracy. There are no significant differences (p = 0.99) in the decoding performance of these movements between healthy subjects and subjects with lower extremity amputation. These results show the feasibility of using BCI for lower limb prosthesis control and indicate that decoding performance is not influenced by neuroplasticity-induced differences between the two groups.