28 CHAPTER 2 Inclusion criteria The treating rehabilitation physician or his/her physician assistant will judge whether a potential participant meets the inclusion criteria. In order to be eligible to participate in this study, a participant must meet all of the following criteria: 1. Diagnosis (suspected) of NA 2. Initially, the (suspected) diagnosis of NA will be deduced from the information in the referral letter from the patient’s referring general physician or neurologist. If any uncertainty about the diagnosis remains, the rehabilitation physician or his/ her physician assistant will contact the referring physician and/or patient. All patients will visit the specialised outpatient clinic, where the diagnosis will be either confirmed or discarded. 3. NA predominantly present in the right upper extremity 4. Being in the subacute or chronic phase of NA (i.e. no inflammation of the plexus, in practice, > 8weeks after attack onset) 5. Presenting with scapular dyskinesia 6. Age ≥18 years 7. Right-hand dominance (as indicated with an Edinburgh Handedness Inventory (EHI) score > + 40) 8. Able to provide informed consent Exclusion criteria For the patients with NA, the treating rehabilitation physician or his/her physician assistant will judge whether a potential participant meets one or more of the exclusion criteria. A potential participant who meets any of the following criteria will be excluded: 1. Prior NA attacks of the lumbosacral plexus or the left upper extremity 2. Previous participation in the specific rehabilitation programme offered at the Radboudumc or the rehabilitation centre KINOS 3. Other neuromuscular disease affecting the shoulder girdle 4. Central nervous system disorder or neurological disorder (e.g. Parkinson disease, stroke etc.) 5. Pre-existing (bio)mechanical constraints of the shoulder girdle 6. A history of or recent periarticular fractures of the shoulder 7. Past surgery of the shoulder 8. Depressive mood disorder, as indicated by a score > 5 on the Beck Depression Inventory Fast Screen (BDI-FS) 9. Severe comorbidity 10. Ongoing participation in another scientific study that might interfere with the current study Exclusion criteria for undergoing MRI are: 1. Pregnancy (current or planned within the study period) 2. The presence of metal parts that cannot be removed, in or on the upper body (including plates, screws, aneurysm clips, metal splinters, piercings, medical plasters or ossicle prosthesis but with the exception of dental fillings or crowns) 3. The presence of an electric implant (e.g. pacemaker, neurostimulator, insulin pump)