Evaluation of the Efficacy of a Two-week EMST on Dysphagia in Parkinsonian Patients

This is an interventional therapy study designed to evaluate the efficacy of a two-week intervention, i.e. training with a specialized exhalation training device (called expiratory muscle strength training; EMST150 or EMST75; Aspire Products, Gainsville, FL) on swallowing function in patients with neurodegenerative Parkinsonian disorders. This study involves a routine endoscopic evaluation of swallowing (FEES) to diagnose dysphagia before and after the intervention. Between the two FEES, a two-week exhalation training program takes place, which the patients perform independently following instructions from a speech and lanuage pathologist. In addition demographic and disease-specific data and two questionnaires (Swallowing Disturbance Questionnaire for Parkinson's disease patients, SDQ-PD, and Swallowing specific Quality Of Life Questionnaire SWAL-QoL) are recorded.

Main hypothesis: Two weeks of EMST will lead to a significant improvement of the endoscopic dysphagia score in patients with neurodegenerative Parkinsonian disorders with endoscopically proven oropharyngeal dysphagia. Patients with idiopathic Parkinson's syndrome as well as its differential diagnoses, multiple system atrophy (MSA) and diseases from the group of 4repeat tauopathies, will be examined.

Idiopathic Parkinson's disease (PD):

More than 80% of all patients with PD develop clinically relevant dysphagia during the course of the disease. This can lead to a significant reduction in quality of life, decreased medication efficacy, malnutrition, dehydration, and ultimately aspiration pneumonia in affected patients, which is the most common cause of death in advanced PD patients. The cause of PD-associated dysphagia is a multifactorial genesis with impairment of dopaminergic and non-dopaminergic pathways of the central swallowing network and additional peripheral neuromuscular influences.

Multiple System Atrophy (MSA):

MSA is clinically associated with autonomic dysregulation manifested by neurogenic urinary bladder emptying dysfunction, orthostatic hypotension, sleep-related respiratory dysregulation, etc. in addition to Parkinsonian and/or cerebellar symptoms. Median survival after diagnosis is approximately 7 years. At disease onset, differentiation from idiopathic PD is difficult. However, relatively early in the course of the disease, symptoms such as a brittle voice or stridor may appear during normal breathing, which may be clues to the diagnosis of MSA. Since laryngeal abnormalities are associated with a significantly reduced life expectancy, they require special attention and diagnosis. In this regard, we have recently shown that a high prevalence of laryngeal movement abnormalities is present in MSA patients and can even be used to differentiate them from idiopathic Parkinson's disease. Swallowing function, the regulation of which is associated with autonomic centers of laryngeal function, is also often impaired early in patients with MSA. Because dysphagia can further limit quality of life and life expectancy, this symptom also requires early diagnosis and treatment. We could recently show that the dysphagia pattern also differs between PD and MSA.

4repeat tauopathies (4RT): The form of 4RT, also named progressive supranuclear gaze palsy (PSP) with all clinical subtypes, is a rapidly progressive neurodegenerative disease that leads to progressive functional impairment of cortical and subcortical function in affected individuals due to accumulation of tau protein in the brain. Due to the clinical variability of presentation, early diagnostic certainty is desirable, especially since human IgG4- antibodies directed against extracellular tau protein are currently in clinical trials to modify the course of the disease (see NCT03068468, NCT02985879). 4RT are also associated with swallowing and speech problems, and aspiration pneumonia is among the leading causes of death in this disease group. In addition, characteristic abnormalities may also occur due to dystonic dysinnervation of laryngeal muscles.

For dysphagia in atypical Parkinsonian syndromes, there are no proven interventional or drug therapy options. Previous studies in patients with PD had shown efficacy of a four-week training with a special expiratory muscle strength training (EMST) device. Both swallowing reliability and swallowing efficiency were improved. Studies on the efficacy of EMST on dysphagia of atypical Parkinsonian syndromes do not yet exist. Having demonstrated the efficacy of EMST in a 4-week intervention regime, the first aim is to test whether a shortened intervention duration of two weeks is also effective in patient with PD. In addition, this protocol will be performed in patients with MSA and 4RT to investigate effects, particularly on swallowing safety (reduction of penetration/aspiration events) and swallowing efficiency (reduction of pharyngeal residuals). Currently, all patients with PD, MSA, or 4RT at participating study sites receive a speech and language pathology examination and endoscopic diagnostics according to a defined protocol. In addition to phoniatric and swallowing-specific examinations, an endoscopic evaluation of swallowing (FEES) is routinely performed. Regarding the efficacy of EMST training on pharyngeal dysphagia in patients with PD, two randomized, placebo-controlled studies from recent years with n=60 and n=50 patients, respectively, have already shown an efficacy of training on both swallowing reliability and swallowing efficiency in PD patients. Relevant side effects or risks from training for the patients were not reported in the studies.

Studies using an EMST device have been conducted in recent years not only in patients with IPS, but also in patients with dysphagia due to other primary pathologies (e.g., amyotrophic lateral sclerosis, multiple sclerosis, stroke, etc.). In summary, a positive effect was shown, particularly on laryngeal muscle strengthening, which was reflected in an improvement in dysphagia.

The affected patients receive an initial endoscopic evaluation of the swallowing act in the clinical setting as part of routine diagnostics. In addition, oral and written patient education is provided. After written consent on the informed consent form, the following data are then collected anonymously prior to the start of the intervention:

1. sociographic data
2. disease milestones
3. MDS-UPDRS I-IV
4. UMSARS / PSP-RS
5. SDQ-PD
6. SWAL-QOL
7. Hoehn and Yahr stage
8. Current drug therapy
9. MSA-FEES examination protocol
10. Pulmonary function test

This is followed by the individual adjustment of the EMST device for the respective patient. For this purpose, the maximum expiratory pressure (MEP) is first determined for the respective patient in the pulmonary function examination using a pressure manometer. 75% of the MEP is set for the subsequent training on the EMST device. This is then followed by the actual intervention. For this, the patient receives logopedic instruction on the correct use of the EMST device. The intervention regime then consists of 5x5 breaths per day for 14 consecutive days. Immediately following, items 3-10 will be collected again.

1. The collection of data regarding the effectiveness of EMST in a shortened protocol (two weeks) on swallowing function in patients with PD can help to integrate this form of therapy firmly in the therapy regime of speech and language therapy also in the context of inpatient stays.
2. The evaluation of the efficacy of EMST in atypical Parkinsonian syndromes is the first interventional study with the attempt to improve dysphagia in these disease spectra. If this study demonstrates improvement in dysphagia in MSA and 4RT, appropriate patients would be offered a specific EMST in the future, which may then delay or prevent the development of higher-grade dysphagia. Since consecutive aspiration pneumonia on the floor of neurogenic dysphagia is the leading cause of death in these patients, this could at least delay serious medical complications in the future, improve quality of life, and prolong survival. In addition, new evidence would be gained for the use of activating therapies in the treatment of Parkinson's-associated dysphagia.