Lewy body dysphagia

Neuropathology and molecular diagnosis of Synucleinopathies

Synucleinopathies are clinically and pathologically heterogeneous disorders characterized by pathologic aggregates of α-synuclein in neurons and glia, in the form of Lewy bodies, Lewy neurites, neuronal cytoplasmic inclusions, and glial cytoplasmic inclusions. Synucleinopathies can be divided into two major disease entities: Lewy body disease and multiple system atrophy (MSA). Common clinical presentations of Lewy body disease are Parkinson's disease (PD), PD with dementia, and dementia with Lewy bodies (DLB), while MSA has two major clinical subtypes, MSA with predominant cerebellar ataxia and MSA with predominant parkinsonism. There are currently no disease-modifying therapies for the synucleinopathies, but information obtained from molecular genetics and models that explore mechanisms of α-synuclein conversion to pathologic oligomers and insoluble fibrils offer hope for eventual therapies. It remains unclear how α-synuclein can be associated with distinct cellular pathologies (e.g., Lewy bodies and glial cytoplasmic inclusions) and what factors determine neuroanatomical and cell type vulnerability. Accumulating evidence from in vitro and in vivo experiments suggests that α-synuclein species derived from Lewy body disease and MSA are distinct "strains" having different seeding properties. Recent advancements in in vitro seeding assays, such as real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA), not only demonstrate distinct seeding activity in the synucleinopathies, but also offer exciting opportunities for molecular diagnosis using readily accessible peripheral tissue samples. Cryogenic electron microscopy (cryo-EM) structural studies of α-synuclein derived from recombinant or brain-derived filaments provide new insight into mechanisms of seeding in synucleinopathies. In this review, we describe clinical, genetic and neuropathologic features of synucleinopathies, including a discussion of the evolution of classification and staging of Lewy body disease. We also provide a brief discussion on proposed mechanisms of Lewy body formation, as well as evidence supporting the existence of distinct α-synuclein strains in Lewy body disease and MSA.

Role of the Peripheral Nervous System in PD Pathology, Diagnosis, and Treatment

Studies on Parkinson disease (PD) have mostly focused on the central nervous system—specifically, on the loss of mesencephalic dopaminergic neurons and associated motor dysfunction. However, the peripheral nervous system (PNS) is gaining prominence in PD research, with increasing clinical attention being paid to non-motor symptoms. Researchers found abnormal deposition of α-synuclein and neuroinflammation in the PNS. Attempts have been made to use these pathological changes during the clinical diagnosis of PD. Animal studies demonstrated that combined transplantation of autologous peripheral nerves and cells with tyrosine hydroxylase activity can reduce dopaminergic neuronal damage, and similar effects were observed in some clinical trials. In this review, we will systematically explain PNS performance in PD pathology and its clinical diagnostic research, describe PNS experimental results [especially Schwann cell (SC) transplantation in the treatment of PD animal models] and the results of clinical trials, and discuss future directions. The mechanism by which SCs produce such a therapeutic effect and the safety of transplantation therapy are briefly described.

The spectrum of nonmotor symptoms in early Parkinson disease

OBJECTIVE

Nonmotor symptoms (NMS) are common in patients with established Parkinson disease (PD) but their frequency in early PD has not been extensively studied. Our aim was to determine the frequency of NMS in a cohort of patients with newly diagnosed PD.

METHODS

A total of 159 patients with early PD and 99 healthy controls participated in this study. NMS were screened for using the nonmotor symptom questionnaire. Other assessments included measures of motor disability (Movement Disorders Society-revised unified Parkinson's disease rating scale [MDS-UPDRS]), disease severity (Hoehn & Yahr staging), depression (geriatric depression scale), and global cognitive function (Mini-mental state examination and Montreal cognitive assessment).

RESULTS

The PD group reported a significantly greater number of NMS compared with controls (8.4 [4.3] vs. 2.8 [2.6]). In the PD group, the most commonly experienced NMS were excessive saliva, forgetfulness, urinary urgency, hyposmia, and constipation. Patients with higher MDS-UPDRS III scores and those with the postural instability gait subtype experienced a greater number of NMS.

CONCLUSION

NMS are common in early PD and reflect the multisystem nature of the disorder. Even in the earliest stages of PD, NMS may be detrimental to patients' functional status and sense of well-being.

Motor neurone disease: diagnostic pitfalls

The misdiagnosis of MND (particularly of the ALS phenotype), is uncommon. Atypical presentations, particularly of focal onset and with pure LMN or UMN signs, present a more difficult diagnostic challenge, although perhaps reassuringly, treatable mimics are rare. A working knowledge of potential alternative conditions and MND diagnostic pitfalls should help to reduce the misdiagnosis rate, particularly if the key points are considered.

Involvement of the peripheral nervous system in synucleinopathies, tauopathies and other neurodegenerative proteinopathies of the brain

Involvement of the peripheral nervous system (PNS) is relatively common in some neurodegenerative proteinopathies of the brain and may be pathogenetically and diagnostically important. In Parkinson's disease, neuronal alpha-synuclein aggregates are distributed throughout the nervous system, including the central nervous system (CNS), sympathetic ganglia, enteric nervous system, cardiac and pelvic plexuses, submandibular gland, adrenal medulla and skin. The pathological process may target the PNS and CNS at the same time. In multiple system atrophy, numerous glial cytoplasmic inclusions composed of filamentous alpha-synuclein are widely distributed in the CNS, while alpha-synuclein accumulation is minimal in the sympathetic ganglia and is restricted to neurons. Neurofibrillary tangles can occur in the sympathetic and spinal ganglia in tauopathy, although they appear to develop independently of cerebral Alzheimer's disease pathology. In amyotrophic lateral sclerosis, neuronal loss with TDP-43-positive neuronal cytoplasmic inclusions in the spinal ganglia is more frequent than previously thought. Peripheral ganglia and visceral organs are also involved in polyglutamine diseases. Further elucidation and characterization of PNS lesions will have implications for intravital biopsy diagnosis in neurodegenerative proteinopathy, particularly in Parkinson's disease.

The premotor phase of Parkinson's disease

There is growing evidence that a variety of symptoms can precede the classical motor features of Parkinson's disease (PD). The period when these symptoms arise can be referred to as the premotor phase of the disease. Well-documented premotor symptoms in PD include constipation, loss of smell, sleep disturbances such as REM sleep behavior disorder (RBD), and mood disturbances like depression. Diagnostic and therapeutic implications linked to improved identification of these premotor features are discussed.

Lewy body dysphagia

The presence of Lewy bodies (LB) in autonomic structures of the central and peripheral nervous system in Parkinson's disease (PD) is well known and could explain clinical signs of pure autonomic failure (PAF) or dysphagia, frequently associated with the disorder. There are many neuropathological reports in the literature with detailed descriptions of PAF, however, LB dysphagia has thus far only been reported once. In the present study, we describe two cases of isolated dysphagia without extrapyramidal syndrome, diagnosed clinically as progressive supranuclear palsy and amyotrophic lateral sclerosis, where detailed neuropathological examination identified LBs in the dorsal vagal motor nuclei in the medulla. These findings confirm the existence of isolated LB dysphagia and emphasize the importance of detailed neuropathological and immunohistochemical examination in cases of dysphagia.

Accumulation of phosphorylated alpha-synuclein in aging human brain

Alpha-synuclein in Lewy bodies (LBs) is phosphorylated at Ser129. We raised monoclonal and polyclonal antibodies to this phosphorylation site (psyn) and examined 157 serial autopsy brains from a geriatric hospital. Anti-psyn immunoreactivity was observed in 40 of these cases (25.5%). Immunohistochemistry revealed 4 novel types of pathology: diffuse neuronal cytoplasmic staining (pre-LB); neuropil thread-like structures (Lewy threads); dot-like structures similar to argyrophilic grains (Lewy dots); and axons in the white matter (Lewy axons). This novel pathology was abundantly present around LBs and also involved the limbic subcortical white matter, the cerebral cortical molecular layer, and the spongiform changes of the medial temporal lobe associated with cases of dementia with LBs (DLB). The phosphorylated alpha-synuclein was limited to the temporal lobe in cases of Parkinson disease, spread from the temporal lobe to the frontal lobe in cases of DLB transitional form and further spread to the parietal and occipital lobes in DLB neocortical form. Our findings suggest that LB-related pathology initially involves the neuronal perikarya, dendrites, and axons, causes impairment of axonal transport and synaptic transmission, and later leads to the formation of LBs, a hallmark of functional disturbance long before neuronal cell death.

Lumping and splitting the Parkinson Plus syndromes: dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, and cortical-basal ganglionic degeneration

The atypical parkinsonian or Parkinson Plus syndromes are often difficult to differentiate from Parkinson's disease and each other. In this article, the clinicopathological characteristics of dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, and cortical-basal ganglionic degeneration are discussed. These disorders, although clinically distinct, may have more similarities than previously thought, based on modern immunocytochemical techniques and new genetic findings. These intriguing interconnections at a basic molecular level have provided the scientific rationale for lumping these diseases into two groups, the synucleinopathies and the tauopathies.

Dementia with Lewy bodies. A distinct non-Alzheimer dementia syndrome?

Lewy body formation is central to the pathological phenotype of a spectrum of disorders. The most familiar of these is the extrapyramidal syndrome of idiopathic Lewy-body Parkinson's disease (PD). Studies of dementia in the elderly suggest that another manifestation of Lewy body pathology is equally or more common than Parkinson's disease. This syndrome of Dementia with Lewy bodies (DLB) has been given a number of diagnostic labels and is characterised by dementia, relatively mild parkinsonism, visual hallucinations, and fluctuations in conscious level. Although many of these features can arise in Parkinson's disease, the patients with DLB tend to have early neuropsychiatric features which predominate the clinical picture, and the diagnosis of the syndrome in practice is more concerned with the differential diagnosis of Alzheimer's disease (AD). Distinction from AD has clinical importance because of potentially differing therapeutic implications. Diagnostic guidelines for the clinical diagnosis and pathological evaluation of DLB are reviewed. Research into the disorder has centered around characterising the clinical, neuropsychological, pathological, neurochemical and genetic relationships with Alzheimer's disease on the one hand, and Parkinson's disease on the other. Many cases of DLB have prominent pathological features of AD and there are some shared genetic risk factors. Differences from the pathology of PD are predominantly quantitative rather than qualitative and evidence is discussed which suggests that DLB represents a clinicopathological syndrome within the spectrum of Lewy body disorders. The possibility that the syndrome represents a chance association of PD and AD is not supported by published studies.

Pathological diagnostic criteria for dementia associated with cortical Lewy bodies: review and proposal for a descriptive approach

In recent years dementia histologically characterised by the presence of cortical Lewy bodies has been increasingly recognised. There is now need for a scheme for an internationally acceptable scheme for pathological diagnosis and classification so that clinical, pathological and molecular features of disease can be correlated. Recent observations made by different groups in large patient series have used slightly different pathological criteria resulting in at least seven different diagnostic terms. In some patients the only cortical pathology is the presence of Lewy bodies, while in the majority of patients there are coexisting pathological changes which either overlap with those seen in Alzheimer's disease (AD). Cortical Lewy bodies can also be present in patients who do not have any obvious cognitive abnormality. A problem with equating studies from different groups is that different criteria have been used to define AD, so that establishing the relevance of cortical Lewy bodies themselves to cognitive decline and separating this from the contribution which may be related to the AD pathology is problematic. The lesions which appear to be of most relevance to potential cognitive decline in DLB are cortical Lewy bodies, Lewy-related neurites, senile plaques, neurofibrillary tangles, neuronal and synaptic loss, spongiform change, and cortical cholinergic deficits. It is possible to operationally classify patients with cognitive decline and cortical Lewy bodies into three main groups, Cortical Lewy body disease, Cortical Lewy body disease with plaques, and Cortical Lewy body disease with plaques and tangles. There are frequent cases which overlap these groups making operational classification difficult in practice. A descriptive classification, in which the severity of different pathological changes is rated, is easy to use in practice. As new molecular risk factors for AD or DLB are revealed they will need to be related to morphological and clinical features. A descriptive diagnostic assessment for DLB will facilitate such studies and makes no judgements as to what these relationships will be.

Referral criteria for speech and language therapy assessment of dysphagia caused by idiopathic Parkinson's disease

OBJECTIVE

To examine the prevalence of dysphagia in idiopathic Parkinson's disease (IPD) in the outpatient setting and to determine what assessment criteria to use to select patients with dysphagia for referral to speech and language therapists.

MATERIAL AND METHODS

Sixty-four patients with IPD and 80 age-matched controls were interviewed in clinic about their swallowing history and an objective swallowing test administered. All patients were assessed over the next few weeks by an experienced speech and language therapist and dysphagia rated according to a modified Rehabilitation Institute of Chicago Dysphagia Rating Scale and a novel global rating scale. The ability of various clinic criteria to predict patients with severe dysphagia were examined.

RESULTS

Dysphagia for food was found in 30% of patients, significantly more than in controls. Swallowing speed and bolus volume were significantly lower in patients compared with controls and were correlated with declining Hoehn and Yahr score. Swallowing speed fell significantly on withdrawal of medication. The therapist's global rating score and Chicago score declined with Hoehn and Yahr score and duration of disease. However, only 10% of patients required dietary advice and none needed gastrostomy or tracheostomy. Discriminant analysis showed that various combinations of clinic selection criteria were no better than the presence of dysphagia for food at predicting which patients had significant dysphagia requiring advice from a therapist.

CONCLUSIONS

Patients with idiopathic Parkinson's disease should be questioned about dysphagia for food on a regular basis and, if present, should be referred to a speech and language therapist for further assessment and treatment. The outcome of this protocol should be tested prospectively.