Altered motor imagery-related cerebral activity in patients with Neuralgic Amyotrophy
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2019-07-16
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en
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Peripheral nerve disorders often lead to central neuroplasticity and cerebral functional reorganization. We hypothesize that this also occurs in patients with the peripheral neuromuscular disorder Neuralgic Amyotrophy (NA). Patients with NA generally cannot move their arm properly due to damage to brachial plexus nerves. We hypothesize that, when there is damage, motor planning in the central nervous system changes. Fortunately, these peripheral nerves recover after time, but patients can often still not move their affected arm as before. Therefore, there may be maladaptive motor planning. In our study population of 22 patients and 11 age- and gender matched healthy controls, motor planning was assessed by use of Parson’s laterality judgement task, an implicit motor imagery task, inside the MRI scanner. All participants were right-handed and all NA patients were affected on the right side. Behaviorally, participants performed in accordance with previous research on this task on reaction time. Participants were slower to identify non-dominant (left) hands compared to dominant (right) hands and they were slower on biomechanically complex movements (indicating motor imagery). NA patients were slower when their posture did not match the stimulus (indicating first-person motor imagery), but healthy controls were equally fast for matching and non-matching stimuli, which could be an indication of third-person motor imagery. All patients were affected unilateral on the right side, but there was no association between errors made for the right or left side. The only behavioral difference found between NA patients and healthy controls was the effect of posture. Cerebrally, all participants on average showed activation in brain areas previously associated with motor imagery, such as the parietal-frontal network, Extrastriate Body Area and several motor areas. In addition, we found that NA patients, in comparison with healthy controls, showed additional activation at the ipsilateral Supramarginal Gyrus/Post-Central Gyrus when performing motor imagery for right hand stimuli compared to left hand stimuli. This could be an indication of a compensatory mechanism that patients use to be able to move their affected hand. However, this activity could also solely be an effect of a noisy baseline. More data is necessary to provide a clearer view on the difference in motor planning between NA patients and healthy controls and to provide insights into future rehabilitation programs.
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Faculteit der Sociale Wetenschappen