Background and purpose
The scientific literature on COVID‐19 is increasingly growing.
Methods
In this paper, we review the literature on movement disorders in the context of the COVID‐19 pandemic.
...Results
First, there are a variety of transient movement disorders that may manifest in the acute phase of COVID‐19, most often myoclonus, with more than 50 patients described in the literature. New onset parkinsonism, chorea, and tic‐like behaviours have also been reported. Movement disorders as a side effect after COVID‐19 vaccination are rare, occurring with a frequency of 0.00002–0.0002 depending on the product used, mostly manifesting with tremor. Current evidence for potential long‐term manifestations, for example, long COVID parkinsonism, is separately discussed. Second, the pandemic has also had an impact on patients with pre‐existing movement disorder syndromes, with negative effects on clinical status and overall well‐being, and reduced access to medication and health care. In many parts, the pandemic has led to reorganization of the medical system, including the development of new digital solutions. The movement disorder‐related evidence for this is reviewed and discussed.
Conclusions
The pandemic and the associated preventive measures have had a negative impact on the clinical status, access to health care, and overall well‐being of patients with pre‐existing movement disorders.
New onset movement disorders may occur in the acute phase of an infection with Sars‐CoV‐2, whereas movement disorders as an adverse event after vaccination are rare according to large drug safety report databases. There is concern that Sars‐CoV‐2 may trigger a hit‐and‐run mechanism and predispose to the development of neurodegenerative disorders, similar to what was observed after the Spanish flu in 1918 and the subsequent wave of encephalitis lethargica. The pandemic and the associated preventive measures have had a negative impact on the clinical status, access to health care, and overall well‐being of patients with pre‐existing movement disorders.
In recent years, numerous clinical trials for disease modification in Parkinson’s disease (PD) have failed, possibly because of a “one-size-fits all” approach. Alternatively, a precision medicine ...approach, which customises treatments based on patients’ individual genotype, may help reach disease modification. Here, we review clinical trials that target genetic forms of PD, i.e.,
GBA
-associated and
LRRK2
-associated PD. In summary, six ongoing studies which explicitely recruit
GBA
-PD patients, and two studies which recruit
LRRK2
-PD patients, were identified. Available data on mechanisms of action, study design, and challenges of therapeutic trials are discussed.
Natural fluctuations in flow are important for maintaining the ecological integrity of riverine ecosystems. However, the flow regime of many rivers has been modified. We assessed the impact of water ...chemistry, habitat and streamflow characteristics on macroinvertebrates and benthic algae, comparing 20 regulated with 20 unregulated sites. Flow regime, calculated from daily averaged discharge over the five years preceding sampling, was generally more stable at regulated sites, with higher relative discharges in winter, lower relative discharges in spring and smaller differences between upper and lower percentiles. However, no consistent differences in benthic algal or macroinvertebrate structural and functional traits occurred between regulated and unregulated sites. When regulated and unregulated sites were pooled, overall flow regime, calculated as principal components of discharge characteristics over the five years preceding sampling, affected macroinvertebrate species assemblages, but not indices used for ecosystem status assessment or functional feeding groups. This indicates that, while species identity shifted with changing flow regime, the exchanged taxa had similar feeding habits. In contrast to macroinvertebrates, overall flow regime did not affect benthic algae. Our results indicate that overall flow regime affected the species pool of macroinvertebrates from which recolonization after extreme events may occur, but not of benthic algae. When individual components of flow regime were analyzed separately, high June (i.e. three months before sampling) flow maxima were associated with low benthic algal taxon richness, presumably due to scouring. Macroinvertebrate taxon richness decreased with lower relative minimum discharges, presumably due to temporary drying of parts of the riverbed. However, recolonization after such extreme events presumably is fast. Generally, macroinvertebrate and benthic algal assemblages were more closely related to water physico-chemical than to hydrological variables. Our results suggest that macroinvertebrate and benthic algal indices commonly used for ecological status assessment are applicable also in regulated rivers.
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•River regulation affects both flow regime and water chemistry, but to various degrees.•We analyzed the effects of flow and water chemistry on macroinvertebrates and algae.•We detected no consistent differences between regulated and unregulated rivers.•5-years flow regime affected macroinvertebrates but not benthic algae.•Biota were generally more related to water chemistry than to hydrology.
Disturbance of cerebral iron regulation is almost universal in neurodegenerative disorders. There is a growing body of evidence that increased iron deposits may contribute to degenerative changes. ...Thus, the effect of iron chelation therapy has been investigated in many neurological disorders including rare genetic syndromes with neurodegeneration with brain iron accumulation as well as common sporadic disorders such as Parkinson’s disease, Alzheimer’s disease, and multiple sclerosis. This review summarizes recent advances in understanding the role of iron in the etiology of neurodegeneration. Outcomes of studies investigating the effect of iron chelation therapy in neurodegenerative disorders are systematically presented in tables. Iron chelators, particularly the blood brain barrier-crossing compound deferiprone, are capable of decreasing cerebral iron in areas with abnormally high concentrations as documented by MRI. Yet, currently, there is no compelling evidence of the clinical effect of iron removal therapy on any neurological disorder. However, several studies indicate that it may prevent or slow down disease progression of several disorders such as aceruloplasminemia, pantothenate kinase-associated neurodegeneration or Parkinson’s disease.
In this study, we combined linkage analysis with whole-exome sequencing of two individuals to identify candidate causal variants in a moderately-sized UK kindred exhibiting autosomal-dominant ...inheritance of craniocervical dystonia. Subsequent screening of these candidate causal variants in a large number of familial and sporadic cases of cervical dystonia led to the identification of a total of six putatively pathogenic mutations in ANO3, a gene encoding a predicted Ca2+-gated chloride channel that we show to be highly expressed in the striatum. Functional studies using Ca2+ imaging in case and control fibroblasts demonstrated clear abnormalities in endoplasmic-reticulum-dependent Ca2+ signaling. We conclude that mutations in ANO3 are a cause of autosomal-dominant craniocervical dystonia. The locus DYT23 has been reserved as a synonym for this gene. The implication of an ion channel in the pathogenesis of dystonia provides insights into an alternative mechanism that opens fresh avenues for further research.
Neuronal ceroid lipofuscinoses (NCLs) comprise a heterogeneous group of metabolic storage diseases that present with the accumulation of autofluorescent lipopigment, neurodegeneration and premature ...death. Nine genes have been thus far identified as the cause of different types of NCL, with ages at onset ranging from around birth to adult, although the underlying etiology of the disease still remains elusive. We present a family with typical NCL pathology in which we performed exome sequencing and identified a single homozygous mutation in ATP13A2 that fully segregates with disease within the family. Mutations in ATP13A2 are a known cause of Kufor-Rakeb syndrome (KRS), a rare parkinsonian phenotype with juvenile onset. These data show that NCL and KRS may share etiological features and implicate the lysosomal pathway in Parkinson's disease.
Mass development of macrophytes is an increasing problem in many aquatic systems worldwide. Dense mats of macrophytes can negatively affect activities like boating, fishing or hydropower production ...and one of the management measures often applied is mechanical removal. In this study, we analyzed the effect of mechanical macrophyte removal on phytoplankton, zooplankton, and macroinvertebrate (pelagic and benthic samples) assemblages. Our study covered five sites in four countries in Europe and Africa with highly variable characteristics. In all sites, dense mats of different macrophyte species (Juncus bulbosus in a river in Norway; a mix of native macrophytes in a German river, Elodea nuttallii in a lake in Germany, Ludwigia spp. In a French lake and Pontederia crassipes in a South African lake) are problematic and mechanical removal was applied. In every country, we repeated the same BACI (Before-After-Control-Impact) design, including “before”, “one week after”, and “six weeks after” sampling in a control and an impact section. Repeating the same experimental design at all sites allowed us to disentangle common effects across all sites from site-specific effects. For each taxonomic group, we analyzed three structural and three functional parameters, which we combined in a scoring system. Overall, the removal of macrophytes negatively affected biodiversity, in particular of zooplankton and macroinvertebrate assemblages. In contrast, plant removal had positive effects on the phytoplankton assemblages. Effects were more pronounced one week after removal than six weeks after. Consequently, we suggest a stronger consideration of the effect of plant removal on biodiversity to arrive at more sustainable management practices in the future.
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•We studied the short-term impact of macrophyte removal on aquatic biodiversity.•Overall biodiversity was negatively impacted by plant removal.•The removal negatively impacted zooplankton and macroinvertebrates.•Positive effects were found for phytoplankton.•The greatest impact was observed after one week, with resilience after six weeks.
Macrophytes are generally considered a nuisance when they interfere with human activities. To combat perceived nuisance, macrophytes are removed, and considerable resources are spent every year ...worldwide on this practice. Macrophyte removal can, however, have severe negative impacts on ecosystem structure and functioning and interfere with management goals of healthy freshwater ecosystems. Here, we reviewed the existing literature on mechanical macrophyte removal and summarised current information from 98 studies on short- and long-term consequences for ecosystem structure and functioning. In general, the majority of studies were conducted in rivers and streams and evaluated short-term effects of removal on single ecosystem properties. Moreover, most studies did not address the interrelationships between ecosystem properties and the underlying mechanisms. Contrasting effects of removal on ecosystem structure and function were found and these discrepancies were highly dependent on the context of each study, making meaningful quantitative comparisons across studies very difficult. We illustrated how a Bayesian network (BN) approach can be used to assess the implications of macrophyte removal on interrelated ecosystem properties across a wide range of environmental conditions. The BN approach could also help engage a conversation with stakeholders on the management of freshwater ecosystems.
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•Macrophyte removal affects ecosystem structure and functions.•Most removal studies were done in rivers and evaluated single ecosystem properties.•Modelling of removal on interrelated ecosystem properties with a Bayesian network.
Syndromes with neurodegeneration with brain iron accumulation (NBIA) are a group of neurodegenerative disorders characterized by abnormalities in brain iron metabolism with excess iron accumulation ...in the globus pallidus and to a lesser degree in the substantia nigra and sometimes adjacent areas. They clinically present as neurodegenerative diseases with progressive hypo- and/or hyperkinetic movement disorders and a variable degree of pyramidal, cerebellar, peripheral nerve, autonomic, cognitive and psychiatric involvement, and visual dysfunction. Several causative genes underlying NBIA have been identified which explain about 65 % of cases. Pathophysiologically, many of the NBIA syndromes map into related biochemical pathways and gene networks including mitochondrial pathways, lipid metabolism, and autophagy. Treatment for NBIA disorders remains symptomatic but a placebo-controlled double-blind study is underway. Rapid developments prompted the review of this interesting field.
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