Dysphagia in Parkinson's disease is responsive to levodopa

rTMS improves dysphagia by inhibiting NLRP3 inflammasome activation and caspase-1 dependent pyroptosis in PD mice

High incidence, severe consequences, unclear mechanism, and poor treatment effect happened in Parkinson's disease-related dysphagia. Repetitive transcranial magnetic stimulation is an effective treatment for dysphagia in Parkinson's disease. However, the therapeutic effect and underlying mechanism of repetitive transcranial magnetic stimulation for dysphagia in Parkinson's disease are still unknown. Neuroinflammation has been proven to be associated with dysphagia in Parkinson's disease, and NLRP3 inflammasome activation and pyroptosis are common neuroinflammatory processes. Therefore, we compared swallowing quality, NLRP3 inflammasome activation, and caspase-1 dependent pyroptosis among NS control, repetitive transcranial magnetic stimulation control, sham repetitive transcranial magnetic stimulation control, and L-Dopa control mice by tongue muscle tone detection, immunohistochemistry, immunofluorescence, western blotting, co-immunoprecipitation, and quantitative PCR. The results showed that NLRP3 inflammasome activation and caspase-1-dependent pyroptosis were involved in dysphagia in MPTP-induced Parkinson's disease mice model. Repetitive transcranial magnetic stimulation and L-dopa inhibited the above two pathways to alleviate dopaminergic neuronal damage and improve the quality of dysphagia. Repetitive transcranial magnetic stimulation (1 Hz, 1 time/3 days, 6 weeks) had the same effect on dysphagia as L-Dopa treatment (25 mg/kg/day, 6 weeks). Finally, we conclude that repetitive transcranial magnetic stimulation will be the preferred option for the treatment of dysphagia in Parkinson's disease in certain conditions such as motor complications secondary to L-Dopa and L-Dopa non-response dysphagia.

Parkinson's disease is associated with low striated esophagus contractility potentially contributing to the development of dysphagia

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and more than 80% of PD patients will develop oropharyngeal dysphagia. Despite its striated histology, proximity to airway, and potential negative impact of its dysfunction on bolus transport and airway safety, the contractile function of the striated esophagus in PD patients has not been systematically studied.

METHODS

Using our repository of clinical manometry and the Milwaukee ManoBank, we analyzed high-resolution manometry (HRM) studies of 20 PD patients, mean age 69.1 (range 38-87 years); 30 non-PD patients with dysphagia, mean age 64.0 (44-86 years); and 32 healthy volunteers, mean age 65.3 (39-86 years). Patients with abnormal findings based on Chicago Classification 4.0 were identified. Repeat analysis was performed in 20% of the manometric tracings by a different investigator with inter-rater concordance between 0.91 and 0.99.

KEY RESULTS

The striated esophageal contractile integral in PD patients was significantly lower than that in non-PD dysphagic patients and healthy controls (p = 0.03 and <0.01, respectively). This significant difference persisted after excluding patients with concurrent Chicago Classification motility disorders (p = 0.02 and 0.01, respectively). In both analyses, the distal esophageal contractile integral did not show any significant difference between groups (p = 0.58 and 0.93, respectively).

CONCLUSIONS & INFERENCES

PD is associated with a significant decrease in striated esophagus contractility compared to non-PD and healthy controls. This finding may play a pathophysiologic role in development of dysphagia in this patient population.

[Dysphagia in Parkinsonian Syndromes]

Dysphagia is a clinically relevant problem in Parkinson's disease as well as in atypical Parkinsonian syndromes, such as multiple system atrophy and diseases from the spectrum of 4‑repeat tauopathies, which affect most patients to a varying degree in the course of their disease. This results in relevant restrictions in daily life due to impaired intake of food, fluids, and medication with a subsequent reduction in quality of life. This article not only gives an overview of the pathophysiological causes of dysphagia in the various Parkinson syndromes, but also presents screening, diagnostic and treatment procedures that have been investigated for the different diseases.

An intensive neurorehabilitation programme with sEMG biofeedback to improve swallowing in idiopathic Parkinson's disease (IPD): A feasibility study

BACKGROUND

Studies suggest swallow intervention programmes that incorporate visual biofeedback and motor programming principles can improve swallowing and quality of life for people with idiopathic Parkinson's disease (IPD) and dysphagia. Few studies have examined outcomes using instrumentation.

AIMS

Using fibreoptic endoscopic examination of swallowing (FEES), this study examines the effectiveness of a neurorehabilitation intervention involving biofeedback via surface electromyography (sEMG) to improve swallowing in people with IPD, and to explore the feasibility of the intervention approach.

METHODS & PROCEDURES

We recruited 12 participants with IPD and dysphagia. A total of 10 completed the study. Intervention was delivered for 1 h per day, 5 days per week, for 4 weeks (20 h). Swallowing tasks using sEMG biofeedback incorporated principles of motor learning and neuroplasticity. Instrumental and non-instrumental assessment, including quality-of-life measures carried out at four different time points (two pre-treatment and two post-treatment). The final assessment was at 3 months post-intervention.

OUTCOME & RESULTS

Statistically significant improvement (p < 0.05) in oral intake methods (95% confidence interval (CI) = 4.70-5.50) and in pharyngeal residue from saliva (95% CI = 2.14-3.15) and solids (95% CI = 2.4-3.5) post-intervention were confirmed using FEES with improvements at 3 months. The intervention protocol was well tolerated. Participants reported positive change in saliva control and duration of mealtimes as well as unanticipated improvements in voice and cognitive attention.

CONCLUSIONS & IMPLICATIONS

An intensive neurorehabilitation with biofeedback shows positive effects in improving swallow function in IPD. This protocol is feasible with amendments to inform a larger clinical trial.

WHAT THIS PAPER ADDS

What is already known on the subject Biofeedback has positive effects on increasing swallowing function and quality of life in people with IPD and dysphagia. sEMG is the most common method used to deliver swallowing biofeedback in this population. The quality of the evidence on the intervention, based on findings from a recent systematic review, is low. Included studies in this review were heterogeneous in terms of type and frequency of biofeedback, study design and outcome measures. The majority of outcome measures were subjective and higher quality studies to examine the efficacy of biofeedback using sEMG are needed. What this study adds Recognizing the limitations of earlier studies, this within-subject feasibility study examined the efficacy and effectiveness of an intensive biofeedback intervention using sEMG in a sample of people with dysphagia and IPD. Valid and reliable outcome measures were used and repeated after a 3-month period. The feasibility of the methodological approach was also tested and a qualitative component was included in the study. Positive findings were evident. Qualitative information added new perspectives and provided direction for new outcomes to be included in future studies. This study helps to inform further research trials as well as clinical practice. Clinical implications of this study This intensive intervention using principles of neuroplasticity and motor programming with sEMG biofeedback led not only to positive swallowing outcomes but also to unexpected benefits such as improved voice production and general attention skills. No adverse events were reported. Improvement in function was retained at 3 months post-intervention. Despite the small sample size, participants described the benefits of the treatment, and enjoyed sEMG biofeedback tasks, especially using an sEMG game mode. This suggests that intensive biofeedback not only improved swallowing but also was acceptable to these participants. This intensive protocol has merit and is worth considering further in clinical practice.

Similarities, differences and overlaps between frailty and Parkinson's disease

Parkinson's disease is a neurodegenerative disorder clinically characterized by bradykinesia, rest tremor, rigidity, and postural and gait disturbances, which are frequently observed in older people. It also shows non-motor symptoms, such as depression, anxiety, cognitive impairment and dementia. The number of patients is gradually increasing worldwide. Aging is a risk factor for the onset of Parkinson's disease, and various physiological effects of aging influence its progression. Frailty is a geriatric syndrome in which the reversible and vulnerable status between robustness and disability is affected by various physiological stressors with aging. Frailty consists of physical, psychological and social aspects. Furthermore, sarcopenia, a syndrome characterized by the loss of muscle mass, strength and function, is also significantly associated with frailty. To maintain the quality of life of older people, frailty, including sarcopenia, should be quickly and appropriately managed. Polypharmacy is an important factor causing the progression of frailty in geriatric syndrome. Although Parkinson's disease and frailty have similar symptoms, and are considered to affect each other, the clinical features and mechanisms of both largely remain unclear. Nevertheless, little literature on the relationship between frailty and Parkinson's disease is currently available. This narrative review aims to clarify the relationships between Parkinson's disease and frailty, not only on the physical, but also on the mental, cognitive, and social aspects and issues regarding polypharmacy in Parkinson's disease explored by previous studies. Geriatr Gerontol Int 2022; 22: 259-270.

Gastrointestinal involvement in Parkinson's disease: pathophysiology, diagnosis, and management

Growing evidence suggests an increasing significance for the extent of gastrointestinal tract (GIT) dysfunction in Parkinson's disease (PD). Most patients suffer from GIT symptoms, including dysphagia, sialorrhea, bloating, nausea, vomiting, gastroparesis, and constipation during the disease course. The underlying pathomechanisms of this α-synucleinopathy play an important role in disease development and progression, i.e., early accumulation of Lewy pathology in the enteric and central nervous systems is implicated in pharyngeal discoordination, esophageal and gastric motility/peristalsis impairment, chronic pain, altered intestinal permeability and autonomic dysfunction of the colon, with subsequent constipation. Severe complications, including malnutrition, dehydration, insufficient drug effects, aspiration pneumonia, intestinal obstruction, and megacolon, frequently result in hospitalization. Sophisticated diagnostic tools are now available that permit more detailed examination of specific GIT impairment patterns. Furthermore, novel treatment approaches have been evaluated, although high-level evidence trials are often missing. Finally, the burgeoning literature devoted to the GIT microbiome reveals its importance for neurologists. We review current knowledge about GIT pathoanatomy, pathophysiology, diagnosis, and treatment in PD and provide recommendations for management in daily practice.

[Relevance of COMT inhibitors in the treatment of motor fluctuations]

Catechol O‑methyltransferase (COMT) inhibitors have been established in the treatment of Parkinson's disease for more than 20 years. They are considered the medication of choice for treating motor fluctuations. The available COMT inhibitors, entacapone, opicapone and tolcapone, differ pharmacokinetically in terms of their half-lives with implications for the dose frequency, in their indication requirements and in their spectrum of side effects, including diarrhea and yellow discoloration of urine. Many patients with motor fluctuations are currently not treated with COMT inhibitors and are, therefore, unlikely to receive individually optimized drug treatment. This manuscript summarizes the results of a working group including several Parkinson's disease experts, in which the value of COMT inhibitors was critically discussed.

Sars-Cov-19 associated with aspiration pneumonia in a patient with Parkinson disease: A case report

Coronaviruses can cause multiple systemic infections respiratory complications are the most recognizable symptoms similar to severe acute respiratory syndrome coronavirus (SARS-CoV). Aspiration pneumonia was the most common reason for the Emergency admission of patients with PD.Here we report the case a patient with Parkinson’s disease admitted for respiratory insufficiency secondary to Covid-19 and aspiration pneumonia.

A 78-years- old male patient, treated for Parkinson’s disease, was admitted to the emergency department with symptoms of acute respiratory insufficiency. Four days before his admission, the patient suffered from solid dysphagia. On physical examination, the patient was obnibulated, febrile at 39 °, with clinical signs of respiratory insuffisiency. Computed tomography of the neck and Chest showed patchy areas of subpleural ground glass opacities with vascular dilatation associated with bilateral posterobasal and anterior consolidations with air overlapping imaging characteristics of aspiration and covid 19 pneumonia. The CT scan also showed an oesophageal hypodensity consistant with endoluminal foreign body.

Reverse transcription-polymerase chain reaction (RT-PCR) for COVID-19 was positive.The diagnosis of Sars-cov 19 associated with aspiration pneumonia were retained. An esophagoscopy was realized, a foreign body visualized in the upper sphincter of the esophagus and an impacted food bolus was retracted.

We would like to emphasize the challenging differential diagnosis of pneumonia caused by aspiration of different materials and Sars-cov 19. Definite discrimination of the two diagnoses might be impossible. Some radiologic features may suggest one diagnos over the other. While lobar or segmental pneumonia, lung abscess, and empyema have been reported as Complications of aspirations pneumonia these outcomes are rarely Considered Complications of COVID-19 pneumonia. Centrilobular nodules and tree-in-bud sign are commonly seen in cases with aspiration. Interestingly, these CT findings are not frequent in COVID-19 pneumonia and have been categorized as “Atypical” by the Radiological Society of North America (RSNA), and therefore could be of some Value in proposing a differential diagnosis. Bilateral subpleural patches of ground-glass opacity (GGO), especially in basal distribution, have been described as typical for the diagnosis of COVID-19 pneumonia in suspected Cases. Such a presentation is also fairly common in aspiration Pneumonia.

Potential Prognostic Impact of Dopamine Receptor D1 (rs4532) Polymorphism in Post-stroke Outcome in the Elderly

Background: Single-nucleotide polymorphisms (SNPs) may affect post-stroke motor recovery, and some SNPs have been implicated in swallowing disturbances after stroke. Certain SNPs may also have altered influences according to different age. Objective: This post-hoc study investigated whether SNPs have different effects on dysphagia recovery between the elderly vs. young stroke patients. Methods: Analysis was conducted from a previous study including 218 stroke subjects with dysphagia. They were stratified into two groups, aged <65 and aged ≥65 years. The primary outcome was persistence of nil per mouth (NPM) at 3 months post-stroke onset. Association between outcome and nine different SNPs were investigated. Results: The elderly group (50%, n = 103) showed poorer swallowing outcomes than the young group. The minor allele of the dopamine receptor D1 (DRD1, rs4532) polymorphism showed potential association (p = 0.022) with an increased risk of NPM at 12 weeks post-stroke in the elderly, both in the additive (OR, 2.94; 95% CI, 1.17-7.37) and dominant models (OR, 2.93; 95% CI, 1.04-8.23) but did not reach statistical significance after Bonferonni correction. Logistic regression analysis showed that in those aged ≥65 years, models including the minor allele of rs4532 predicted the risk of the poor outcome with good accuracies even after adjustment of clinical factors, such as previous pneumonia episodes (AUROC, 0.86; 95% CI, 0.79-0.93) or the National Institutes of Health Stroke Scale (AUROC, 0.82; 95% CI, 0.67-0.92). In contrast, those aged <65 years seemed not to be affected by the presence of the rs4532 polymorphism, and models that included intubation history (AUROC, 0.81; 95% CI, 0.73-0.90) or previous pneumonia episodes (AUROC, 0.77; 95% CI, 0.68-0.87) showed modest levels of accuracies in predicting NPM at 12 weeks poststroke. Conclusions: Our study suggests a possible association between the rs4532 and post-stroke swallowing recovery, primarily in those aged ≥65 years. Certain SNPs may lead to less favorable outcomes in the elderly. The gene-age interaction should be considered in post-stroke swallowing recovery. Clinical Trial Registration: https://www.clinicaltrials.gov, Unique identifier [NCT03577444].

Network Pharmacology Analysis on Zhichan Powder in the Treatment of Parkinson's Disease

AIMS AND OBJECTIVE

Effective components and the mechanism of action of Zhichan powder for the treatment of Parkinson's disease were researched at a systematic level.

MATERIALS AND METHODS

Screening of active components in Zhichan powder for the treatment of Parkinson's disease was conducted using the Traditional Chinese Medicine Systems Pharmacology database, and a medicine-target-disease network was established with computational network pharmacology.

RESULTS

By using network pharmacology methods, we identified 18 major active components in Zhichan powder through screening, indicating a connection between chemical components of this Traditional Chinese Medicine and Parkinson's disease-related targets.

CONCLUSION

The medicine-target-disease system of Zhichan powder established by network pharmacology permitted visualization of clustering and differences among chemical components in this prescription, as well as the complex mechanism of molecular activities among those effective components, relevant targets, pathways, and the disease. Thus, our results provide a new perspective and method for revealing the mechanism of action of Traditional Chinese Medicine prescriptions.

Expiratory Muscle Strength Training for Therapy of Pharyngeal Dysphagia in Parkinson's Disease

BACKGROUND

Pharyngeal dysphagia in Parkinson's disease (PD) is a common and clinically relevant symptom associated with poor nutrition intake, reduced quality of life, and aspiration pneumonia. Despite this, effective behavioral treatment approaches are rare.

OBJECTIVE

The objective of this study was to verify if 4 week of expiratory muscle strength training can improve pharyngeal dysphagia in the short and long term and is able to induce neuroplastic changes in cortical swallowing processing.

METHODS

In this double-blind, randomized, controlled trial, 50 patients with hypokinetic pharyngeal dysphagia, as confirmed by flexible endoscopic evaluation of swallowing, performed a 4-week expiratory muscle strength training. Twenty-five participants used a calibrated ("active") device, 25 used a sham handheld device. Swallowing function was evaluated directly before and after the training period, as well as after a period of 3 month using flexible endoscopic evaluation of swallowing. Swallowing-related cortical activation was measured in 22 participants (active:sham; 11:11) using whole-head magnetencephalography.

RESULTS

The active group showed significant improvement in the flexible endoscopic evaluation of swallowing-based dysphagia score after 4 weeks and after 3 months, whereas in the sham group no significant changes from baseline were observed. Especially, clear reduction in pharyngeal residues was found. Regarding the cortical swallowing network before and after training, no statistically significant differences were found by magnetencephalography examination.

CONCLUSIONS

Four-week expiratory muscle strength training significantly reduces overall dysphagia severity in PD patients, with a sustained effect after 3 months compared with sham training. This was mainly achieved by improving swallowing efficiency. The treatment effect is probably caused by peripheral mechanisms, as no changes in the cortical swallowing network were identified. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Autonomic Dysfunctions in Parkinson's Disease: Prevalence, Clinical Characteristics, Potential Diagnostic Markers, and Treatment

Parkinson's disease (PD) is a common neurodegenerative disease in the middle-aged and the elderly. Symptoms of autonomic dysfunctions are frequently seen in PD patients, severely affecting the quality of life. This review summarizes the epidemiology, clinical manifestations, and treatment options of autonomic dysfunctions. The clinical significance of autonomic dysfunctions in PD early diagnosis and differential diagnosis is also discussed.

Gastrointestinal dysfunction in the synucleinopathies

Interest in gastrointestinal dysfunction in Parkinson's disease has blossomed over the past 30 years and has generated a wealth of investigation into this non-motor aspect of the disorder, research that has encompassed its pathophysiology, its clinical features, and its impact on quality of life. The question of gastrointestinal dysfunction in the other synucleinopathies has not received nearly as much attention, but information and knowledge are growing. In this review, the current knowledge, controversies, and gaps in our understanding of the pathophysiology of gastrointestinal dysfunction in Parkinson's disease and the other synucleinopathies will be addressed, and extended focus will be directed toward the clinical problems involving saliva management, swallowing, gastric emptying, small intestinal function, and bowel function that are so problematic in these disorders.

Respiratory dysfunction in Parkinson's disease: a narrative review

The presence of respiratory symptoms in Parkinson's disease (PD) has been known since the first description of the disease, even though the prevalence and incidence of these disturbances are not well defined. Several causes have been reported, comprising obstructive and restrictive pulmonary disease and changes in the central ventilatory control, and different pathogenetic mechanisms have been postulated accordingly. In our review, we encompass the current knowledge about respiratory abnormalities in PD, as well as the impact of anti-Parkinsonian drugs as either risk or protective factors. A description of putative pathogenetic mechanisms is also provided, and possible treatments are discussed, focusing on the importance of recognising and treating respiratory symptoms as a key manifestation of the disease itself. A brief description of respiratory dysfunctions in atypical Parkinsonism, especially α-synucleinopathies, is also provided.

This review addresses current knowledge about respiratory dysfunctions in Parkinson's disease, from the aetiopathology to pharmacological and invasive treatments, describing the different clinical phenotypeshttps://bit.ly/2X7OLtN

Pathophysiology of Swallowing Dysfunction in Parkinson Disease and Lack of Dopaminergic Impact on the Swallow Function and on the Effect of Thickening Agents

(1) Background: The effect of dopaminergic treatment on swallowing response in patients with Parkinson's disease (PD) suffering oropharyngeal dysphagia (OD) is not understood. Aim: To characterize OD pathophysiology in PD and to assess whether dopaminergic states affect swallow function and the effect of thickeners. (2) Methods: Fifty patients with PD (40 evaluated in OFF/ON states) and 12 healthy volunteers (HVs) were evaluated with videofluoroscopy (VFS) to assess the swallowing biomechanics and kinematics of the swallowing response at three different shear-viscosities (<50, 120, and 4000 mPa·s); (3) Results: Patients presented a mean age of 70.46 ± 10.03 years. Disease evolution was 5.09 ± 3.86 year and Hoehn-Yahr stage was 2.32 ± 0.81. For HVs, mean age was 40.20 ± 2.50 year. Penetrations were present in 37.50% of PD patients and were associated with delayed laryngeal vestibule closure (LVC = 293.33 ± 90.07 ms). In contrast, HVs presented a LVC = 164.00 ± 39.78 ms (p < 0.05). An LVC ≥ 260 ms cutoff predicted unsafe swallow (sensitivity ≥ 0.83, specificity ≥ 0.57, AUC = 0.80) in PD. Increasing bolus viscosity improved deglutition safety but increased oropharyngeal residue. There were no differences in swallowing between the OFF/ON states. (4) Conclusions: In initial PD stages, oropharyngeal swallow response is severely delayed, while mildly impaired swallow safety improves with increasing bolus viscosity, which increases residue. Dopaminergic treatment does not affect swallowing or the therapeutic effect of thickeners.

A comprehensive review of the diagnosis and treatment of Parkinson's disease dysphagia and aspiration

INTRODUCTION

Bulbar dysfunction is common in Parkinson's disease (PD) with more than 80% of affected individuals developing dysphagia during the course of the disease. Symptoms can begin in the preclinical stage and individuals may remain clinically asymptomatic for years. Furthermore, patients may be unaware of swallowing changes, which contributes to the difference between the prevalence of self-reported dysphagia and deficits identified during instrumental evaluations. Dysphagia is underrecognized and contributes to the development of aspiration pneumonia which is the leading cause of death in PD. Dysphagia in PD is complex and not completely understood. Both dopaminergic and nondopaminergic pathways likely underpin dysphagia.

AREAS COVERED

This comprehensive review will cover the epidemiology, pathophysiology, clinical evaluation, and expert management of dysphagia and aspiration in patients with PD.

EXPERT OPINION

A multidisciplinary team approach is important to properly identify and manage PD dysphagia. Regular clinical screenings with objective instrumental assessments are necessary for early detection of dysphagia. Studies are needed to better understand the mechanism(s) involved in PD dysphagia, establish markers for early detection and progression, and develop evidence-based treatment options.

Predictors of Residue and Airway Invasion in Parkinson's Disease

Dysphagia is a highly prevalent disorder in Parkinson's Disease (PD) characterized by changes in swallowing kinematics, residue, and airway invasion. These changes can lead to serious medical morbidities including malnutrition, aspiration pneumonia, and death. However, little is known about the most predictive causes of residue and airway invasion in this patient population. Therefore, the aims of this study were to (1) assess how disease severity affects residue, airway invasion, and swallowing kinematics in PD; and (2) determine which swallowing kinematic variables were most predictive of residue and airway invasion. A secondary analysis of forty videofluoroscopic swallow studies (VFSS) from individuals with early through mid-stage PD was performed. Airway invasion (Penetration-Aspiration Scale 'PAS'), residue (Bolus Clearance Ratio 'BCR'), and ten spatiotemporal swallowing kinematic variables were analyzed. Statistical analyses were used to determine if disease severity predicted residue, depth of airway invasion, and swallowing kinematics, and to examine which swallowing kinematic variables were most predictive of residue and the presence of airway invasion. Results revealed that residue and the presence of airway invasion were significantly predicted by swallowing kinematics. Specifically, airway invasion was primarily influenced by the extent and timing of airway closure, while residue was primarily influenced by pharyngeal constriction. However, disease severity did not significantly predict changes to swallowing kinematics, extent of residue, or depth of airway invasion during VFSS assessment. This study comprehensively examined the pathophysiology underlying dysphagia in people with early to mid-stage PD. The results of the present study indicate that disease severity alone does not predict swallowing changes in PD, and therefore may not be the best factor to identify risk for dysphagia in PD. However, the swallowing kinematics most predictive of residue and the presence of airway invasion were identified. These findings may help to guide the selection of more effective therapy approaches for improving swallowing safety and efficiency in people with early to mid-stage PD.

Multilingual Validation of the First French Version of Munich Dysphagia Test-Parkinson's Disease (MDT-PD) in the Luxembourg Parkinson's Study

Introduction: The Munich Dysphagia Test for Parkinson's disease (MDT-PD) was initially developed and validated in the German population as a highly sensitive and specific self-reported screening questionnaire to detect early oropharyngeal symptoms and aspiration risk in patients with idiopathic Parkinson's disease (iPD). In order to make this tool accessible for prevention in the French speaking populations worldwide, we performed the first French translation and provide a linguistic and psychometric validation in the unique multilingual environment of the Luxembourg Parkinson's Study.

Methods: We performed the translation of the MDT-PD into French according to WHO guidelines and subsequently performed the linguistic validation including native speakers. For psychometric validation, 46 patients with parkinsonism from Luxembourg and the Greater Region without severe cognitive impairment were recruited in the frame of the Luxembourg Parkinson's Study. All patients were fluent in French and German completed the MDT-PD in both languages (three times in total).

Results: Linguistic and psychometric validation of the French MDT-PD was reflected by a high test-retest (10/26 questions with K > 0.6 and 10/26 with 0.4 < K ≤ 0.6) and language reliability (12/26 K > 0.6 and 8/26 0.4 < K ≤ 0.6), with an internal consistency for the French (Cronbach's alpha 0.84) and German version (0.87); strong item collinerarity strengthens the internal consistency. No significant differences between MDT-PD score distribution and clinical parameters assessing, for example, disease progression, motor state, or cognition has been observed.

Conclusion: Based on a multilingual approach in the Luxembourg Parkinson Study, we validated the translation of the first French MDT-PD as a non-invasive tool for early detection of dysphagia in patients with parkinsonism. The unexpectedly high number of positively screened patients at earlier disease stages indicate options for new prevention strategies in large French speaking populations worldwide. Diagnostic validation using clinical and endoscopic swallowing evaluation will be continued soon.

Research-based Updates in Swallowing and Communication Dysfunction in Parkinson Disease: Implications for Evaluation and Management

PURPOSE

Individuals with Parkinson disease (PD) present with complex and variable symptoms, with recent findings suggesting that the etiology of PD extends beyond the involvement of just the basal ganglia. These symptoms include significant impairments in the speech and swallowing domains, which can greatly affect quality of life and therefore require therapeutic attention. This research-based update reviews the neurophysiological basis for swallowing and speech changes in PD, the effectiveness of various types of treatments, and implications for symptom evaluation and management.

CONCLUSION

The mechanisms responsible for swallowing and speech symptoms in PD remain largely unknown. Dopaminergic medication and deep-brain-stimulation do not provide consistent benefits for these symptoms suggesting a non-dopaminergic network is involved. Importantly, evidence suggests that symptoms of dysphagia and hypokinetic dysarthria may be early indications of PD, so it is critical to investigate the cause of these changes.

Oro-Pharyngeal Dysphagia in Parkinson's Disease and Related Movement Disorders

Oro-pharyngeal dysphagia is a common symptom in patients with Parkinson’s disease (PD) and related disorders, even in their early stage of diseases. Dysphagia in these patients has been underdiagnosed, probably due to poor the self-awareness of the conditions and the underuse of validated tools and objective instruments for assessment. The early detection and intervention of dysphagia are closely related to improving the quality of life and decreasing the mortality rate in these patients. The purpose of this paper is to give an overview of the characteristics of dysphagia, including the epidemiology, pathophysiology, and clinical symptomatology, in patients with PD compared with other parkinsonian disorders and movement disorders. The management of dysphagia and future research directions related to these disorders are also discussed.

Pharyngeal Area Changes in Parkinson's Disease and Its Effect on Swallowing Safety, Efficiency, and Kinematics

Pharyngeal area can increase as a function of normal healthy aging and muscle atrophy. These increases in pharyngeal area can negatively affect swallowing function in healthy older adults (HOA). However, the presence of pharyngeal area changes and their effects on swallowing function in Parkinson's disease (PD) remain unknown. Therefore, we compared the pharyngeal area of people with PD to HOA to determine if pharyngeal area changes were present in PD above and beyond what is seen in HOA. Within PD, we also evaluated if and how an increase in pharyngeal area affects swallowing kinematics, swallowing safety, and swallowing efficiency. A secondary analysis of videofluoroscopic swallow studies was completed comparing 41 HOA and 40 people with PD. Measures of pharyngeal area, swallowing kinematics, swallowing safety (penetration/aspiration), and swallowing efficiency (residue) were analyzed. An analysis of covariance (ANCOVA) was used to determine if pharyngeal area was significantly different between the HOA and PD groups while controlling for age, sex, and height. Regression analyses were used to examine if and how pharyngeal area influenced swallowing kinematics, swallowing safety, and swallowing efficiency in PD. Pharyngeal areas were significantly larger for people with PD when compared to HOA (p = .008). An increase in pharyngeal area was associated with less pharyngeal constriction (p = .022), shorter duration of airway closure (p = .017), worse swallowing safety (p < .0005), and worse swallowing efficiency (p = .037). This study revealed that pharyngeal areas are larger in people with PD when compared to HOA, and that this increase in pharyngeal area is associated with maladaptive changes to swallowing kinematics, residue, and penetration/aspiration. These findings support the notion that pharyngeal muscle atrophy may be exacerbated in PD above and beyond what is seen in normal, healthy aging group. Results from this study highlight the need to consider pharyngeal muscle atrophy as a source for swallowing dysfunction in PD, and as a potential treatment target for swallowing rehabilitation.

Gastrointestinal Dysfunction in Parkinson's Disease

PURPOSE OF REVIEW

During the past 25 years, there has been an explosion of information regarding the occurrence of gastrointestinal dysfunction in Parkinson's disease. In this review, the clinical features of gastrointestinal dysfunction in Parkinson's disease will be described and information regarding the potential role of the enteric nervous system and the gut microbiome in the genesis of Parkinson's disease will be addressed.

RECENT FINDINGS

Recognition is growing regarding the role that gastroparesis and small intestinal dysfunction may play in Parkinson's disease, especially with regard to erratic responses to anti-Parkinson medication. The presence of enteric nervous system involvement in Parkinson's disease is now well established, but whether the enteric nervous system is the starting point for Parkinson's disease pathology remains a source of debate. The potential role of the gut microbiome also is beginning to emerge. Gastrointestinal dysfunction is a prominent nonmotor feature of Parkinson's disease and dysfunction can be found along the entire length of the gastrointestinal tract. The enteric nervous system is clearly involved in Parkinson's disease. Whether it is the initial source of pathology is still a source of controversy. There also is growing recognition of the role that the gut microbiome may play in Parkinson's disease, but much more research is needed to fully assess this aspect of the disorder.

Treatment of autonomic dysfunction in Parkinson disease and other synucleinopathies

Dysfunction of the autonomic nervous system afflicts most patients with Parkinson disease and other synucleinopathies such as dementia with Lewy bodies, multiple system atrophy, and pure autonomic failure, reducing quality of life and increasing mortality. For example, gastrointestinal dysfunction can lead to impaired drug pharmacodynamics causing a worsening in motor symptoms, and neurogenic orthostatic hypotension can cause syncope, falls, and fractures. When recognized, autonomic problems can be treated, sometimes successfully. Discontinuation of potentially causative/aggravating drugs, patient education, and nonpharmacological approaches are useful and should be tried first. Pathophysiology-based pharmacological treatments that have shown efficacy in controlled trials of patients with synucleinopathies have been approved in many countries and are key to an effective management. Here, we review the treatment of autonomic dysfunction in patients with Parkinson disease and other synucleinopathies, summarize the nonpharmacological and current pharmacological therapeutic strategies including recently approved drugs, and provide practical advice and management algorithms for clinicians, with focus on neurogenic orthostatic hypotension, supine hypertension, dysphagia, sialorrhea, gastroparesis, constipation, neurogenic overactive bladder, underactive bladder, and sexual dysfunction. © 2018 International Parkinson and Movement Disorder Society.

Implementation of a standardized out-of-hospital management method for Parkinson dysphagia

OBJECTIVE

Our objective is to explore the effectiveness and feasibility of establishing a swallowing management clinic to implement out-of-hospital management for Parkinson disease (PD) patients with dysphagia.

METHOD

Two-hundred seventeen (217) voluntary PD patients with dysphagia in a PD outpatient clinic were divided into a control group with 100 people, and an experimental group with 117 people. The control group was given dysphagia rehabilitation guidance. The experimental group was presented with the standardized out-of-hospital management method as overall management and information and education materials. Rehabilitation efficiency and incidence rate of dysphagia, as well as relevant complications of both groups were compared after a 6-month intervention.

RESULTS

Rehabilitation efficiency and the incidence rate of dysphagia including relevant complications of patients treated with the standardized out-of-hospital management were compared with those seen in the control group. The differences have distinct statistics meaning (p<0.01).

CONCLUSION

Establishing a swallowing management protocol for outpatient setting can effectively help the recovery of the function of swallowing, reduce the incidence rate of dysphagia complications and improve the quality of life in patients with PD.

Considerations for general anaesthesia in Parkinson's disease

Parkinson's disease is a common neurodegenerative disorder in the elderly which when present has a significant influence on surgical management. These patients necessitate additional perioperative and anaesthetic considerations across disease specific domains as well as in relation to the respiratory and cardiovascular systems. This brief review focuses on the factors which contribute to perioperative morbidity, including the use of medications that may exacerbate symptoms or adversely interact with treatments for Parkinson's disease. Recommended dosing practices to reduce complications during hospitalisation are covered. In addition, recent concerns regarding anaesthetic exposure in early childhood as a risk factor for the development of Parkinson's disease are discussed in light of data from animal models of anaesthetic neurotoxicity and epidemiological studies.

Continuum theory: presbyphagia to dysphagia? Functional assessment of swallowing in the elderly

OBJECTIVES

To investigate whether disclosed symptoms (coughing, choking and throat clearing) can be used as early predictors of swallowing disorders in non-hospitalized elderly population. In addition, to determine the presence of early findings of swallowing disorders through fiber optic endoscopic evaluation of swallowing (FEES).

MATERIALS AND METHODS

One hundred subjects older than 60 years were recruited from local community social meetings for seniors, they fulfilled inclusion criteria, and were given an oral interview and underwent FEES, with findings classified as: (1) saliva stasis; (2) pharyngeal residue; (3) penetration; (4) aspiration; (5) laryngeal sensitivity.

RESULTS

Twenty-one percent of subjects declared previous choking, 10% coughing, and 7% throat clearing, 39% had pharyngeal residue; 6% saliva stasis; 9% penetration; 2% aspiration; and 92% laryngeal sensitivity present. Thirty-three percent showed pharyngeal residue without saliva stasis, while only 6% showed positivity for both (p = 0.003).

CONCLUSIONS

Our data suggest that health care professionals should be aware that among an apparently healthy population, some subjects may have swallowing disorders without clinical complaints and that a nasolaryngoscopy exam may not be enough to predict dysphagia. We suggest that FEES should be performed to look for surrogate of dysphagia such as pharyngeal residue, laryngeal penetration, and aspiration.

Evolution of Orofacial Symptoms and Disease Progression in Idiopathic Parkinson's Disease: Longitudinal Data from the Jönköping Parkinson Registry

BACKGROUND

Orofacial symptoms are common in Parkinson's disease (PD) both as initial manifestations and late markers of disease complications. We aimed to investigate the evolution of orofacial manifestations and their prognostic value throughout PD progression.

METHODS

Data was obtained from "Jönköping Parkinson Registry" database on routine care visits of 314 people with idiopathic PD in southern Sweden. Information on baseline symptomatology, orofacial features, UPDRS, and medications was recorded at baseline and during each follow-up visit within an average of 4.2 (range: 1-12) years.

RESULTS

Hypomimia, affected speech, drooling, and impaired swallowing were present in 37.3%/91.6%, 14.1%/65.5%, 11.7%/55.3%, and 10.2%/34.5% at baseline/follow-up, respectively. Male sex [OR = 2.4 (95% CI: 1.0-5.9)], UPDRS motor scores [OR = 1.2 (95% CI: 1.1-1.3)], dominant rigidity [OR = 5.2 (95% CI: 1.4-19.1)], and autonomic disturbance [OR = 3.4 (95% CI: 1.1-10.9)] were risk factors for drooling. Individuals with more severe orofacial burden at baseline had shorter median time to develop UPDRS-Part III > 28 [3rd tertile = 4.7 yr, 2nd tertile = 6.2 yr, and 1st tertile = 7.8 yr; p = 0.014].

CONCLUSIONS

Majority of people with PD manifest orofacial manifestations at either early or late stages of the disease. PD severity, symmetry of motor disturbances, and autonomic disorders correlate with orofacial symptoms. Individuals with more severe orofacial burden at baseline progressed faster to more advanced stages.

Swallowing in Parkinson's disease: clinical issues and management

Changes to swallowing affect most people with Parkinson's disease (PD). Changes may not initially exercise a decisive impact, but can later pose significant threats to nutritional, hydration and respiratory health and psychosocial quality of life. This review, from a largely clinical viewpoint, outlines the nature of changes in PD and considers the issue of how many people are affected and in what ways. It outlines main approaches to assessment and management, with an emphasis on aspects relevant to PD. Dysphagia contributes to drooling in PD. The review therefore also touches on the nature and management of this condition that has its own set of health and psychosocial quality-of-life issues.

Analysis of resources assisting in coping with swallowing difficulties for patients with Parkinson's disease: a cross-sectional study

BACKGROUND

Malnutrition induced by swallowing difficulties (SD) impairs the quality of life and gives rise to SD-related costs in Parkinson's disease (PD) patients. With results of a swallowing difficulty questionnaire and data of resources specifically obtained such as SD-related costs, caregivers, and dietary therapies, this study is to suggest statistically supported ideas for improvements in arrangements for how participants cope with SD and maintain general well-being.

METHODS

We interviewed 237 PD patients. The SD-related costs involved those incurred by the provision of dietary modifications, care oriented foods, alternatives, and supplements. Dietary therapies included rice porridge and commercially available care foods. The relationships between BMI (body mass index) and the severity of SD assumed in this paper as indicators for general well-being and as resources for coping with SD for PD patients were statistically analyzed.

RESULTS

A lower BMI was found in participants eating porridge consistency rice (p = 0.003) and eating porridge rice is significantly related to the severity of SD (p < 0.0001) and PD (p = 0.002). The severity of SD increased with age and PD duration (p = 0.035, p = 0.0005). Outlays for dietary modifications are the lowest reported here (p < 0.004) but the number of participants using dietary modifications is the largest among the SD-related items (n = 58). Eating care foods were reported for 11 older participants (p < 0.0001), most female (10/11). No lower BMI was found in participants eating care foods when compared with participants eating ordinary foods. Dietary modifications were performed by caregivers (OR: 6.8, CI: 3.1-15.2, p < 0.0001) and were related to the presence of children (OR: 3.4, CI: 1.2-11.4. p = 0.024). Older participants commonly live with spouses and children.

CONCLUSIONS

Severe SD is associated with higher costs of coping with SD. A lower BMI is associated with modified foods, mostly eaten to cope with SD. Presence of caregivers and other persons residing with the participants here are related to dietary modifications but not to care food-related costs. Care foods may be effective in preventing malnutrition although the number who are able to cover the added expenses is limited because of the higher prices and shortage of information on the usefulness of care foods.

Gut dysfunction in Parkinson's disease

Early involvement of gut is observed in Parkinson’s disease (PD) and symptoms such as constipation may precede motor symptoms. α-Synuclein pathology is extensively evident in the gut and appears to follow a rostrocaudal gradient. The gut may act as the starting point of PD pathology with spread toward the central nervous system. This spread of the synuclein pathology raises the possibility of prion-like propagation in PD pathogenesis. Recently, the role of gut microbiota in PD pathogenesis has received attention and some phenotypic correlation has also been shown. The extensive involvement of the gut in PD even in its early stages has led to the evaluation of enteric α-synuclein as a possible biomarker of early PD. The clinical manifestations of gastrointestinal dysfunction in PD include malnutrition, oral and dental disorders, sialorrhea, dysphagia, gastroparesis, constipation, and defecatory dysfunction. These conditions are quite distressing for the patients and require relevant investigations and adequate management. Treatment usually involves both pharmacological and non-pharmacological measures. One important aspect of gut dysfunction is its contribution to the clinical fluctuations in PD. Dysphagia and gastroparesis lead to inadequate absorption of oral anti-PD medications. These lead to response fluctuations, particularly delayed-on and no-on, and there is significant relationship between levodopa pharmacokinetics and gastric emptying in patients with PD. Therefore, in such cases, alternative routes of administration or drug delivery systems may be required.

Levodopa responsiveness of dysphagia in advanced Parkinson's disease and reliability testing of the FEES-Levodopa-test

BACKGROUND

It is still controversially discussed whether central dopaminergic stimulation improves swallowing ability in Parkinson's disease (PD). We evaluated the effect of oral levodopa application on dysphagia in advanced PD patients with motor fluctuations.

METHODS

In 15 PD patients (mean age 71.93 ± 8.29 years, mean disease duration 14.33 ± 5.94 years) with oropharyngeal dysphagia and motor fluctuations endoscopic swallowing evaluation was performed in the off state and on state condition following a specifically developed protocol (FEES-levodopa-test). The respective dysphagia score covered three salient parameters, i. e. premature spillage, penetration/aspiration events and residues, each tested with liquid as well as semisolid and solid food consistencies. An improvement of >30% in this score indicated levodopa responsiveness of dysphagia. Measures were compared between the off- and on-state condition by using the Wilcoxon Test and marginal homogeneity test. Inter- and intrarater reliability was also investigated.

RESULTS

Severity of swallowing dysfunction in the off state varied widely. The lowest dysphagia score was 15 points (dysphagia without any aspiration risk). The highest dysphagia score was 84 points (dysphagia with aspiration of all consistencies). Seven patients showed a marked improvement of dysphagia in the on state condition. Eight PD patients did not respond. Inter- and intrarater reliability was excellent for all three subscales in the off state and on state conditions.

CONCLUSIONS

A significant proportion of advanced PD patients with motor fluctuations and mild to moderate oropharyngeal dysphagia may demonstrate a clinically relevant improvement of swallowing after levodopa challenge. The FEES-levodopa-test is a reliable and sensitive tool to differentiate these responders from non-responders.

Dysphagia in Parkinson's Disease

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.

Rate of aspiration pneumonia in hospitalized Parkinson's disease patients: a cross-sectional study

BACKGROUND

Aspiration pneumonia is an important cause of morbidity and mortality in Parkinson's disease (PD). Clinical characteristics of PD patients in addition to specific alterations in swallowing mechanisms contribute to higher swallowing times and impairment in the effective clearance of the airway. These issues may render patients more prone to dysphagia and aspiration events. We aimed to determine the frequency of aspiration events in a hospitalized PD cohort, and to report the number of in-hospital swallow evaluations.

METHODS

A retrospective single center chart review of 212 PD patients who had 339 hospital encounters was performed from January 2011 to March 2013. Demographics, clinical characteristics, and reasons for encounters were documented. The number of in-hospital aspiration events and the number of swallowing evaluations and also the implementation of aspiration precautions were recorded.

RESULTS

The cohort had a mean age of 74.1 (SD = 10.1) years with mean disease duration of 6 (SD = 6.3) years. Fifty-two hospital encounters (15.3%) were related to a pulmonary cause. In-hospital aspiration pneumonia events were reported in 8 (2.4%) of the total encounters. Swallow evaluations were performed in 25% of all cases, and aspiration precautions were initiated in 32% of the encounters. The data revealed that 1/8 patient had swallowing evaluations performed prior to an aspiration event.

CONCLUSIONS

In-hospital aspiration pneumonia events were reported in 2.4% of the hospitalized PD cohort. Preventive measures and precautions were not routinely performed, however rates of aspiration were relatively low. The results highlight the need for more research into screening and monitoring of swallowing problems in PD patients during hospital encounters.

Electrophysiological evaluation of oropharyngeal Dysphagia in Parkinson's disease

Parkinson’s disease (PD) is a chronic, neurodegenerative movement disorder that typically affects elderly patients. Swallowing disorders are highly prevalent in PD and can have grave consequences, including pneumonia, malnutrition, dehydration and mortality. Neurogenic dysphagia in PD can manifest with both overt clinical symptoms or silent dysphagia. Regardless, early diagnosis and objective follow-up of dysphagia in PD is crucial for timely and appropriate care for these patients. In this review, we provide a comprehensive summary of the electrophysiological methods that can be used to objectively evaluate dysphagia in PD. We discuss the electrophysiological abnormalities that can be observed in PD, their clinical correlates and the pathophysiology underlying these findings.

Swallowing disturbances in Parkinson's disease: a multivariate analysis of contributing factors

BACKGROUND

Swallowing disturbances are an important issue in Parkinson's disease (PD) as several studies have shown that they are associated with increased risk of aspiration pneumonia and mortality. Information about factors related to swallowing disturbances, such as disease duration, age at assessment and concomitant dementia, is limited and would be useful for their management.

METHODS

All consecutive PD out-patients evaluated at a movement disorders clinic over a 7-year period (2007-2014), were included in the present retrospective study. Presence of symptomatic swallowing disturbances was assessed using the specific item of the Non Motor Symptom Questionnaire.

RESULTS

In the whole PD population (N = 6462), prevalence of symptomatic swallowing disturbances was 11.7% (95%CI, 10.9-12.5). Multivariable logistic regression analysis (adjusted for education) disclosed a significant interaction between disease duration and gender (P = 0.009). In both gender strata, swallowing disturbances were significantly associated with longer disease duration and dementia (P < 0.001 for all). A significant effect for age at assessment was also found in male patients. In non-demented patients, swallowing disturbances were associated with male gender, age and disease duration (P < 0.02 for all). In demented patients an association was found only with male gender (P = 0.018) and disease duration (P < 0.001).

CONCLUSIONS

Gender, age, disease duration and dementia all seem to contribute to the occurrence of swallowing disturbances independently. However, the role played by these factors in sub-groups of patients stratified by gender and concomitant dementia suggests that swallowing disturbances are likely related to different neuro-degenerative patterns within the brain. The underlying mechanisms deserve further investigation.

Treatment effects for dysphagia in Parkinson's disease: a systematic review

BACKGROUND

Dysphagia remains a common problem in Parkinson's disease (PD). Previous systematic reviews on therapy effects for oropharyngeal dysphagia in PD have shown a lack of evidence. In the past 5 years several placebo or sham-controlled trials with varying results have been published.

OBJECTIVE

The aim of this systematic literature review is to summarize and qualitatively analyze the published studies on this matter.

METHOD(S)

Studies published up to December 2013 were found via a systematic comprehensive electronic database search using PubMed, Embase, and The Cochrane Library. Two reviewers independently assessed the studies using strict inclusion criteria.

RESULT(S)

Twelve studies were included and qualitatively analyzed using critical appraisal items. The review includes rehabilitative (exercises, electrical stimulation, bolus modification etc.) and pharmacologic treatment. Some well-designed controlled trials were included. However, none of the included studies fulfilled all criteria for external and internal validity. A meta-analysis was not carried out as most of the studies were not of sufficient quality to warrant doing so.

CONCLUSION

Expiratory Muscle Strength Training (EMST) and Video-Assisted Swallowing Therapy (VAST) may be effective dysphagia treatments solely or in addition to dopaminergic therapy for PD. However, these preliminary results warrant further investigation concerning their clinical applicability, and further research should be based on randomized sham-controlled trials to determine the effectiveness and long-term effects of different therapies for dysphagia in PD.