Trait correlations equalize spread velocity across plant life histories

Aim: Forecasting species migration with climate change and the advance of biological invasions requires a better understanding of species' relative migration capacity. Although theory predicts that species combining high fecundity and dispersal with early maturation should spread the fastest, possible correlations between these traits greatly complicate predictions of species' relative spread velocity. We asked whether the demographic and dispersal rates controlling plant population spread are correlated across species, and which observed association of these traits leads to the fastest spread. Location: Worldwide. Time period: Current. Major taxa studied: Eighty species of herbaceous and woody plants from 35 families and 64 genera. Methods: We examined the relationships between age at maturity, dispersal and fecundity for 80 plant species, ranging from annual herbs to trees. We incorporated these rates into a model predicting spread velocities, in order to estimate species' spread capacity as a function of their life history. Results: Across species, age at maturity was positively associated with both dispersal and fecundity. Given that these traits have opposing effects on spread, our models predict that species widely spaced along an age-at-maturity gradient should spread at comparable rates. This result was driven by variation between rather than within life-forms; the traits controlling spread were not correlated within annual herbs, perennial herbs or trees. The predicted spread velocities for these plant life-forms overlapped considerably, although on average, trees were predicted to spread faster than herbaceous species. Main conclusions: Our results suggest that very different plant life histories allow for similar rates of biological invasion or native species migration under climate change. Determining where species fall within the correlated suite of traits controlling spread might provide the most effective way to predict relative spread velocities

Cerebral adaptation associated with peripheral nerve recovery in neuralgic amyotrophy: A randomized controlled trial

Background: Neuralgic amyotrophy (NA) is a common peripheral nerve disorder caused by auto-immune inflammation of nerves in the brachial plexus territory, characterized by acute pain and weakness of the shoulder muscles, followed by motor impairment. Recent work has confirmed that NA patients with residual motor dysfunction have abnormal cerebral sensorimotor representations of their affected upper extremity. Objective: To determine whether abnormal cerebral sensorimotor representations associated with NA can be altered by specialized, multidisciplinary outpatient rehabilitation focused on relearning motor control. Methods: 27 NA patients with residual lateralized symptoms in the right upper extremity participated in a randomized controlled trial, comparing 17 weeks of multidisciplinary rehabilitation (n = 16) to usual care (n = 11). We used task-based functional MRI and a hand laterality judgment task, which involves motor imagery and is sensitive to altered cerebral sensorimotor representations of the upper extremity. Results: Change in task performance and related brain activity did not differ significantly between the multidisciplinary rehabilitation and usual care groups, whereas the multidisciplinary rehabilitation group showed significantly greater clinical improvement on the Shoulder Rating Questionnaire. Both groups, however, showed a significant improvement in task performance from baseline to follow-up, and significantly increased activity in visuomotor occipito-parietal brain areas, both specific to their affected upper extremity. Conclusions: Abnormal cerebral sensorimotor representations of the upper extremity after peripheral nerve damage in NA can recover toward normality. As adaptations occurred in visuomotor brain areas, multidisciplinary rehabilitation after peripheral nerve damage may be further optimized by applying visuomotor strategies. This study is registered at ClinicalTrials.gov (NCT03441347)

NA-CONTROL: A study protocol for a randomised controlled trial to compare specific outpatient rehabilitation that targets cerebral mechanisms through relearning motor control and uses self-management strategies to improve functional capability of the upper extremity, to usual care in patients with neuralgic amyotrophy

Contains fulltext : 206177.pdf (publisher's version ) (Open Access)Background: Neuralgic amyotrophy (NA) is a distinct peripheral neurological disorder of the brachial plexus with a yearly incidence of 1/1000, which is characterised by acute severe upper extremity pain. Weakness of the stabilising shoulder muscles in the acute phase leads to compensatory strategies and abnormal motor control of the shoulder - scapular dyskinesia. Despite peripheral nerve recovery, scapular dyskinesia often persists, leading to debilitating residual complaints including pain and fatigue. Evidence suggests that persistent scapular dyskinesia in NA may result from maladaptive cerebral neuroplasticity, altering motor planning. Currently there is no proven effective causative treatment for the residual symptoms in NA. Moreover, the role of cerebral mechanisms in persistent scapular dyskinesia remains unclear. Methods: NA-CONTROL is a single-centre, randomised controlled trial comparing specific rehabilitation to usual care in NA. The rehabilitation programme combines relearning of motor control, targeting cerebral mechanisms, with self-management strategies. Fifty patients will be included. Patients are recruited through the Radboud university medical center Nijmegen, the Netherlands. Patients with a (suspected) diagnosis of NA, with lateralized symptoms and scapular dyskinesia in the right upper extremity, who are 18 years or older and not in the acute phase can be included. The primary outcome is the Shoulder Rating Questionnaire score, which measures functional capability of the upper extremity. Secondary clinical outcomes include measures of pain, fatigue, participation, reachable workspace, muscle strength and quality of life. In addition, motor planning is assessed with first-person motor imagery and functional magnetic resonance imaging. In a sub-study the patients are compared to 25 healthy participants, to determine the involvement of cerebral mechanisms. This will enable interpretation of cerebral changes associated with the rehabilitation programme and functional impairments in NA. Discussion: NA-CONTROL is the first randomised trial to investigate the effect of specific rehabilitation on residual complaints in NA. It also is the first study into the cerebral mechanisms that might underlie persistent scapular dyskinesia in NA. It thus may aid the further development of mechanism-based interventions for disturbed motor control in NA and in other peripheral neurological disorders.17 p

Altered sensorimotor representations after recovery from peripheral nerve damage in neuralgic amyotrophy

Neuralgic amyotrophy is a common peripheral nerve disorder caused by acute autoimmune inflammation of the brachial plexus. Subsequent weakness of the stabilizing shoulder muscles leads to compensatory strategies and abnormal motor control of the shoulder. Despite recovery of peripheral nerves and muscle strength over time, motor dysfunction often persists. Suboptimal motor recovery has been linked to maladaptive changes in the central motor system in several nervous system disorders. We therefore hypothesized that neuralgic amyotrophy patients with persistent motor dysfunction may have altered cerebral sensorimotor representations of the affected upper limb. To test this hypothesis, 21 neuralgic amyotrophy patients (mean age 45 ± 12 years, 5 female) with persistent lateralized symptoms in the right upper limb and 20 age- and sex-matched healthy controls, all right-handed, performed a hand laterality judgement task in a cross-sectional comparison. Previous evidence has shown that to solve this task, subjects rely on sensorimotor representations of their own upper limb, using a first-person imagery perspective without actual motor execution. This enabled us to investigate altered central sensorimotor representations while controlling for altered motor output and altered somatosensory afference. We found that neuralgic amyotrophy patients were specifically less accurate for laterality judgments of their affected right limb, as compared to healthy controls. There were no significant group differences in reaction times. Both groups used a first-person imagery perspective, as evidenced by changes in reaction times as a function of participants’ own arm posture. We conclude that cerebral sensorimotor representations of the affected upper limb are altered in neuralgic amyotrophy patients. This suggests that maladaptive central neuroplasticity may occur in response to peripheral nerve damage, thereby contributing to motor dysfunction. Therapies focused on altering cerebral sensorimotor representations may help to treat peripheral nerve disorders such as neuralgic amyotrophy

Evolution during population spread affects plant performance in stressful environments

ISSN:0022-047

Effectiveness of an outpatient rehabilitation programme in patients with neuralgic amyotrophy and scapular dyskinesia: a randomised controlled trial.

BACKGROUND: Neuralgic amyotrophy (NA) is an acute inflammation of nerves within the brachial plexus territory leading to severe pain and multifocal paresis resulting in >60% of patients having residual complaints and functional limitations correlated with scapular dyskinesia. Our primary aim was to compare the effects of multidisciplinary rehabilitation (MR), focused on motor relearning to improve scapular dyskinesia and self-management strategies for reducing pain and fatigue, with usual care (UC) on shoulder, arm and hand functional capability in patients with NA. METHODS: In a non-blinded randomised controlled trial (RCT), patients with NA (aged≥18 years, scapular dyskinesia, >8 weeks after onset) were randomised to either an MR or an UC group. MR consisted of a diagnostic multidisciplinary consultation and eight sessions of physical and occupational therapy. Primary outcome was functional capability of the shoulder, arm and hand assessed with the Shoulder Rating Questionnaire-Dutch Language Version (SRQ-DLV). RESULTS: We included 47 patients with NA; due to drop-out, there were 22 participants in MR and 15 in UC for primary analysis. The mean group difference adjusted for sex, age and SRQ-DLV baseline score was 8.60 (95%CI: 0.26 to 16.94, p=0.044). The proportion attaining a minimal clinically relevant SRQ-DLV improvement (≥12) was larger for the MR group (59%) than the UC group (33%) with a number needed to treat of 4. CONCLUSION: This RCT shows that an MR programme focused on motor relearning to improve scapular dyskinesia, combined with self-management strategies for reducing pain and fatigue, shows more beneficial effects on shoulder, arm and hand functional capability than UC in patients with NA. TRIAL REGISTRATION NUMBER: NCT03441347

Reachable workspace analysis is a potential measurement for impairment of the upper extremity in neuralgic amyotrophy

Introduction/aimsNeuralgic amyotrophy (NA) is a multifocal neuropathy involving the nerves of the upper extremity, limiting functional capability and reducing range of motion. The reachable workspace (RWS) is a computerized three-dimensinal analysis system that evaluates the relative surface area (RSA) of an individual's arm reachability and has shown utility in several neuromuscular disorders. The aims of this study were to examine the ability of the RWS to quantitatively detect limitations in upper extremity active range of motion in patients with NA, and correlate these with other upper extremity functional outcome measures.MethodsForty-seven patients with NA and 25 healthy age- and sex-matched controls were measured with the RWS. Study participants' RSAs were correlated with scores on the Shoulder Rating Questionnaire (SRQ), the Disabilities of Arm Shoulder and Hand (DASH) questionnaire, and upper extremity strength measurements using hand-held dynamometry.ResultsPatients with NA showed significantly lower values in the affected arm for all quadrants (except for the ipsilateral lower quadrant) and total RSA compared with controls (P < 0.001). We found moderate correlations between the reachable workspace, the DASH questionnaire result (r = -0.415), and serratus anterior muscle strength (r = 0.414).DiscussionRWS is able to detect limitations in active range of motion of the affected arm in patients with NA, and is moderately correlated with upper extremity functional measures. RWS can demonstrate impairment of the affected upper extremity in NA and it has potential as a clinical outcome measure