Parkinson disease Balestrino, R.; Schapira, A.H.V.
European journal of neurology,
January 2020, Volume:
27, Issue:
1
Journal Article
Peer reviewed
Parkinson disease (PD) is the most common neurodegenerative movement disorder. In Europe, prevalence and incidence rates for PD are estimated at approximately 108–257/100 000 and 11–19/100 000 per ...year, respectively. Risk factors include age, male gender and some environmental factors. The aetiology of the disease in most patients is unknown, but different genetic causes have been identified. Although familial forms of PD account for only 5%–15% of cases, studies on these families provided interesting insight on the genetics and the pathogenesis of the disease allowing the identification of genes implicated in its pathogenesis and offering critical insights into the mechanisms of disease. The cardinal motor symptoms of PD are tremor, rigidity, bradykinesia/akinesia and postural instability, but the clinical picture includes other motor and non‐motor symptoms. Its diagnosis is principally clinical, although specific investigations can help the differential diagnosis from other forms of parkinsonism. Pathologically, PD is characterized by the loss of dopaminergic neurons in the pars compacta of the substantia nigra and by accumulation of misfolded α‐synuclein, which is found in intra‐cytoplasmic inclusions called Lewy bodies. Currently available treatments offer good control of motor symptoms but do not modify the evolution of the disease. This article is intended to provide a comprehensive, general and practical review of PD for the general neurologist.
Parkinson’s disease (PD) is a neurodegenerative disease with a 200 year-long research history. Our understanding about its clinical phenotype and pathogenesis remains limited, although dopaminergic ...replacement therapy has significantly improved patient outcomes. Autonomic dysfunction is an essential category of non-motor phenotypes that has recently become a cutting edge field that directs frontier research in PD. In this review, we initially describe the epidemiology of dysautonomic symptoms in PD. Then, we perform a meticulous analysis of the pathophysiology of autonomic dysfunction in PD and propose that the peripheral autonomic nervous system may be a key route for α-synuclein pathology propagation from the periphery to the central nervous system. In addition, we recommend that constipation, orthostatic hypotension, urinary dysfunction, erectile dysfunction, and pure autonomic failure should be viewed as prodromal dysautonomic markers in PD prediction and diagnosis. Finally, we summarize the strategies currently available for the treatment of autonomic dysfunction in PD and suggest that high-quality, better-designed, randomized clinical trials should be conducted in the future.
Parkinson disease (PD), the most common neurodegenerative movement disorder, is associated with selective degeneration of nigrostriatal dopamine neurons. Although the underlying mechanisms ...contributing to neurodegeneration in PD seem to be multifactorial, mitochondrial impairment and oxidative stress are widely considered to be central to many forms of the disease. Whether oxidative stress is a cause or a consequence of dopaminergic death, there is substantial evidence for oxidative stress both in human PD patients and in animal models of PD, especially using rotenone, a complex I inhibitor. There are many indices of oxidative stress, but this review covers the recent evidence for oxidative damage to nucleic acids, lipids, and proteins in both the brain and the peripheral tissues in human PD and in the rotenone model. Limitations of the existing literature and future perspectives are discussed. Understanding how each particular macromolecule is damaged by oxidative stress and the interplay of secondary damage to other biomolecules may help us design better targets for the treatment of PD.
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► Oxidative stress is a key player in Parkinson disease. ► Oxidative damage to nucleic acids, proteins, and lipids is found in Parkinson disease. ► The rotenone model recapitulates macromolecule oxidative damage in Parkinson disease.
Parkinson's disease is a debilitating, age-associated movement disorder. A central aspect of the pathophysiology of Parkinson's disease is the progressive demise of midbrain dopamine neurons and ...their axonal projections, but the underlying causes of this loss are unclear. Advances in genetics and experimental model systems have illuminated an important role for defects in intracellular transport pathways to lysosomes. The accumulation of altered proteins and damaged mitochondria, particularly at axon terminals, ultimately might overwhelm the capacity of intracellular disposal mechanisms. Cell-extrinsic mechanisms, including inflammation and prion-like spreading, are proposed to have both protective and deleterious functions in Parkinson's disease.
The concept of 'idiopathic' Parkinson's disease (PD) as a single entity has been challenged with the identification of several clinical subtypes, pathogenic genes and putative causative environmental ...agents. In addition to classic motor symptoms, non-motor manifestations (such as rapid eye movement sleep disorder, anosmia, constipation and depression) appear at prodromic/premotor stage and evolve, along with cognitive impairment and dysautonomia, as the disease progresses, often dominating the advanced stages of the disease. The key molecular pathogenic mechanisms include α-synuclein misfolding and aggregation, mitochondrial dysfunction, impairment of protein clearance (associated with deficient ubiquitin-proteasome and autophagy-lysosomal systems), neuroinflammation and oxidative stress. The involvement of dopaminergic as well as noradrenergic, glutamatergic, serotonergic and adenosine pathways provide insights into the rich and variable clinical phenomenology associated with PD and the possibility of alternative therapeutic approaches beyond traditional dopamine replacement therapies.One of the biggest challenges in the development of potential neuroprotective therapies has been the lack of reliable and sensitive biomarkers of progression. Immunotherapies such as the use of vaccination or monoclonal antibodies directed against aggregated, toxic α-synuclein.as well as anti-aggregation or protein clearance strategies are currently investigated in clinical trials. The application of glucagon-like peptide one receptor agonists, specific PD gene target agents (such as GBA or LRRK2 modifiers) and other potential disease modifying drugs provide cautious optimism that more effective therapies are on the horizon. Emerging therapies, such as new symptomatic drugs, innovative drug delivery systems and novel surgical interventions give hope to patients with PD about their future outcomes and prognosis.
Dysphagia in Parkinson’s Disease Suttrup, Inga; Warnecke, Tobias
Dysphagia,
02/2016, Volume:
31, Issue:
1
Journal Article, Book Review
Peer reviewed
More than 80 % of patients with Parkinson’s disease (PD) develop dysphagia during the course of their disease. Swallowing impairment reduces quality of life, complicates medication intake and leads ...to malnutrition and aspiration pneumonia, which is a major cause of death in PD. Although the underlying pathophysiology is poorly understood, it has been shown that dopaminergic and non-dopaminergic mechanisms are involved in the development of dysphagia in PD. Clinical assessment of dysphagia in PD patients is challenging and often delivers unreliable results. A modified water test assessing maximum swallowing volume is recommended to uncover oropharyngeal dysphagia in PD. PD-specific questionnaires may also be useful to identify patients at risk for swallowing impairment. Fiberoptic endoscopic evaluation of swallowing and videofluoroscopic swallowing study are both considered to be the gold standard for evaluation of PD-related dysphagia. In addition, high-resolution manometry may be a helpful tool. These instrumental methods allow a reliable detection of aspiration events. Furthermore, typical patterns of impairment during the oral, pharyngeal and/or esophageal swallowing phase of PD patients can be identified. Therapy of dysphagia in PD consists of pharmacological interventions and swallowing treatment by speech and language therapists (SLTs). Fluctuating dysphagia with deterioration during the off-state should be treated by optimizing dopaminergic medication. The methods used during swallowing treatment by SLTs shall be selected according to the individual dysphagia pattern of each PD patient. A promising novel method is an intensive training of expiratory muscle strength. Deep brain stimulation does not seem to have a clinical relevant effect on swallowing function in PD. The goal of this review is giving an overview on current stages of epidemiology, pathophysiology, diagnosis, and treatment of PD-associated dysphagia, which might be helpful for neurologists, speech-language therapists, and other clinicians in their daily work with PD patients and associated swallowing difficulties. Furthermore areas with an urgent need for future clinical research are identified.
The exact cause of Parkinson disease is unknown, but it is assumed to be the result of a combination of environmental influences superimposed on genetic predisposition or susceptibility (Table ...2).14-16 There is increasing evidence that the genetic and environmental insults leading to Jankovic J. Parkinson disease commonly lead to abnormal forms of a normal protein, α-synuclein, which seems to contribute to cell death.16,23 The onset of Parkinson disease can be categorized as juvenile (age < 21 yr), early onset (21-50 yr) and late onset (generally > 60 yr).24,25 The juvenile form is rare, is often familial (in as many as 50% of cases), is most frequently associated with a parkin gene mutation and has an atypical presentation.25,26 Of patients with Parkinson disease, 10%-16% have an affected first- or second-degree relative; first-degree relatives may have double the risk of Parkinson disease compared with the general population.26-29 In early- and late-onset Parkinson disease, the frequency of a positive family history is not statistically different.24 In advanced Parkinson disease, the efficacy of levodopa can decline and fluctuate throughout the day switching between "on" and "off' medication periods.92 The motor and nonmotor fluctuations mirror those seen in levodopa plasma concentrations resulting from levodopa's short half-life.93 Providing continuous dopaminergic stimulation is the goal of treating fluctuations in patients with advanced Parkinson disease.94-96 We now have surgical options, including deep brain stimulation and levodopacarbidopa intestinal gel, to provide treatment to such patients. Currently, deep brain stimulation has the highest level of evidence with the largest number of randomized controlled trials.97 Emerging therapies currently being studied in Parkinson disease are listed in Appendix 7, available at www.cmaj.ca/lookup/suppl/doi :10.1503/cmaj.151179/-/DC1. The response to deep brain stimulation is equal to the best response on levodopa, but more effective than medical therapy in improving "on" time without troublesome dyskinesias.101,102 Deep brain stimulation typically improves levodoparesponsive symptoms (e.g., tremor, bradykinesia, rigidity) and on-off fluctuations and dyskinesias, whereas impairments in gait, balance and speech are less likely to improve. Patients should be considered for deep brain stimulation only if adequate trials of multiple medications for Parkinson disease (e.g., levodopa-carbidopa, dopamine agonists, monoamine oxidase B inhibitors and amantadine) have been unsuccessful.100 Although duration of efficacy is not clearly established, patients who undergo deep brain stimulation may have sustained benefit for at least 10 years.100 A recent study suggests that deep brain stimulation for Parkinson disease may be offered earlier for patients (mean age 52 yr, disease duration 7.5 yr) just beginning to have motor fluctuations.103 Thalamic deep brain stimulation may be considered as an option in patients who predominantly have disabling tremor where subthalamic nucleus stimulation cannot be performed.57
Parkinson's disease (PD) is clinically, pathologically, and genetically heterogeneous, resisting distillation to a single, cohesive disorder. Instead, each affected individual develops a virtually ...unique form of Parkinson's syndrome. Clinical manifestations consist of variable motor and nonmotor features, and myriad overlaps are recognized with other neurodegenerative conditions. Although most commonly characterized by alpha-synuclein protein pathology throughout the central and peripheral nervous systems, the distribution varies and other pathologies commonly modify PD or trigger similar manifestations. Nearly all PD is genetically influenced. More than 100 genes or genetic loci have been identified, and most cases likely arise from interactions among many common and rare genetic variants. Despite its complex architecture, insights from experimental genetic dissection coalesce to reveal unifying biological themes, including synaptic, lysosomal, mitochondrial, andimmune-mediated mechanisms of pathogenesis. This emerging understanding of Parkinson's syndrome, coupled with advances in biomarkers and targeted therapies, presages successful precision medicine strategies.
The diagnosis of Parkinson's disease Tolosa, Eduardo; Wenning, Gregor; Poewe, Werner
Lancet neurology,
2006, 2006-Jan, 2006-01-00, 20060101, Volume:
5, Issue:
1
Journal Article
Peer reviewed
The correct diagnosis of Parkinson's disease is important for prognostic and therapeutic reasons and is essential for clinical research. Investigations of the diagnostic accuracy for the disease and ...other forms of parkinsonism in community-based samples of patients taking antiparkinsonian medication confirmed a diagnosis of parkinsonism in only 74% of patients and clinically probable Parkinson's disease in 53% of patients. Clinicopathological studies based on brain bank material from the UK and Canada have shown that clinicians diagnose the disease incorrectly in about 25% of patients. In these studies, the most common reasons for misdiagnosis were presence of essential tremor, vascular parkinsonism, and atypical parkinsonian syndromes. Infrequent diagnostic errors included Alzheimer's disease, dementia with Lewy bodies, and drug-induced parkinsonism. Increasing knowledge of the heterogeneous clinical presentation of the various parkinsonisms has resulted in improved diagnostic accuracy of the various parkinsonian syndromes in specialised movement-disorder units. Also genetic testing and various other ancillary tests, such as olfactory testing, MRI, and dopamine-transporter single-photon-emission computed-tomography imaging, help with clinical diagnostic decisions.
Circuitry models of Parkinson’s disease (PD) are based on striatal dopamine loss and aberrant striatal inputs into the basal ganglia network. However, extrastriatal mechanisms have increasingly been ...the focus of attention, whereas the status of striatal discharges in the parkinsonian human brain remains conjectural. We now report the activity pattern of striatal projection neurons (SPNs) in patients with PD undergoing deep brain stimulation surgery, compared with patients with essential tremor (ET) and isolated dystonia (ID). The SPN activity in ET was very low (2.1 ± 0.1 Hz) and reminiscent of that found in normal animals. In contrast, SPNs in PD fired at much higher frequency (30.2 ± 1.2 Hz) and with abundant spike bursts. The difference between PD and ET was reproduced between 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated and normal nonhuman primates. The SPN activity was also increased in ID, but to a lower level compared with the hyperactivity observed in PD. These results provide direct evidence that the striatum contributes significantly altered signals to the network in patients with PD.
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