43 NA-CONTROL STUDY PROTOCOL 2 Discussion NA is a common peripheral nervous system disorder, which leaves many patients with persistent scapular dyskinesia and resulting residual symptoms that greatly impact quality of life months to years after onset. To date, there are no clinical trials targeting these debilitating residual symptoms, and no explanation as to why these residual symptoms persist. The NA-CONTROL study is the first trial to evaluate a rehabilitation program for residual symptoms after NA that is focused on cerebral processes by relearning motor control and self-management strategies. This program has been shown to increase functional capability of the upper extremity in a pilot study of patients with NA. The study design allows for comparison of the rehabilitation program offered at the Radboudumc to usual care in NA patients. Moreover, the lateralized nature of this disorder allows the use of the unaffected, contralateral upper extremity of NA patients as an additional withinpatient control method. The NA-CONTROL study will investigate the effect of a specific rehabilitation program on functional capability of the upper extremity. It thus aims to provide evidence for a tailored intervention to reduce residual complaints in NA. It additionally aims to provide insight into the cerebral mechanisms that might underlie the persistent motor problems in NA. This could confirm the clinical intuition that peripheral nervous system disorders (i.e. NA), may lead to maladaptive cerebral neuroplasticity, ultimately resulting in persistent symptoms, such as impaired motor control. Moreover, it will demonstrate whether such cerebral motor (mal-)adaptations associated with scapular dyskinesia can be targeted by a specific rehabilitation program. Knowledge on the extent of involvement of these cerebral mechanisms could help guide how much and which aspects of existing treatments should be focused on them. This knowledge may greatly aid in the further development of mechanism-based interventions for disturbed motor control in NA as well as in other peripheral neurological disorders. As the NA-CONTROL study combines clinical and nonclinical expertise and approaches, it is an example of translational research. Trial status The protocol this study is based on is dated December 5th 2017 and has the following version numbers: NL63327.091.17-03 Algemeen Beoordelings- en Registratieformulier number (ABR-number) and 2017-3740 v3.0 Commissie Mensgebonden Onderzoek Arnhem-Nijmegen (medical ethical committee). Patient recruitment has started in March 2018 and is ongoing at the time of submission of this study protocol. Recruitment is expected to be completed by January 2020. List of abbreviations 3D: 3 dimensional; AEs: adverse events; BDI-FS: Beck depression inventory – fast screen; BOLD: blood-oxygen-level dependent; CIS-fatigue: checklist individual strength – fatigue; COPM: Canadian occupational performance measure; DASH: disability of arm, should and hand; EHI: Edinburgh handedness inventory; EMG: electromyography; GCP: good clinical practice; HLJT: hand laterality judgment task; KVIQ-10: kinaesthetic and visual imagery questionnaire-10; MPQ: McGill pain questionnaire; MRI: magnetic resonance imaging; NA: neuralgic amyotrophy; NENS: neuromotor encoding in neuromuscular scapular dyskinesia; PAM: patient activation measure; PSEQ: pain self-efficacy questionnaire;