Neurodegenerative disorders are associated with a high prevalence of neurogenic
dysphagia. Depending on the underlying disease, the prevalence can affect up to 80% of
patients. Dysphagia is associated with dehydration, malnutrition, facilitates aspiration
pneumonia and thereby determines the prognosis of neurodegenerative diseases. For most of
them, dysphagia-associated complications are the leading cause of death.
Multiple system atrophy (MSA) is a sporadic progressive neurodegenerative disorder caused
by oligodendroglial aggregation of α-synuclein affecting predominantly the nigrostriatal,
olivo-ponto-cerebellar, and autonomic systems,resulting in a clinical presentation of
dysautonomia combined with either predominantly parkinsonian (MSA-P) or cerebellar
(MSA-C) symptoms of varying severity.In its early stage, the diagnosis of MSA according
to the second consensus criteria can be challenging. Therefore, the Movement Disorders
Society MSA study group recently addressed the importance of developing valuable
diagnostic tools for securing an early diagnosis in patients with MSA not only to
estimate disease prognosis but also to early initiate novel, potentially
disease-modifying treatments in clinical trials. Despite laryngopharyngeal dysfunction
being associated with decreased life expectancy and quality of life, systematic
assessment of these functions in MSA is scarce. Previously, an easy-to-implement MSA-FEES
task-protocol was suggested to systematically assess laryngopharyngeal function.
A pilot study on 8 patients with MSA not only showed that the task protocol was feasible
and well tolerated, but also that laryngopharyngeal symptoms where highly prevalent
despite the lack of clinical presentation (Warnecke et. al 2019). Moreover, irregular
arytenoid cartilages movements where present in all MSA-patients when performing this
task protocol, suggesting this symptom could serve as a clinical marker to identify
MSA-patients. Following this pilot study, an observational two center study assessed 57
MSA patients with this protocol and compared findings to an age-matched cohort of
PD-patients (Gandor et al. 2020). While only 43.9% of MSA patients had clinical symptoms
of laryngeal dysfunction, 93% showed laryngeal abnormalities during FEES performing the
task-protocol. 91.2% of MSA-patients showed irregular arytenoid cartilages movements. In
contrast, only one PD patient showed laryngeal abnormalities with vocal fold motion
impairment, but not irregular arytenoid cartilages movements. This study suggests that
irregular arytenoid cartilages movements allow differentiating MSA from PD with a
sensitivity of 0.9 and a specificity of 1.0.
4repeat tauopathies (4RT) are caused by an intraneuronal accumulation of 4repeat tau.
4RT, also known as progressive supranuclear palsy (PSP) with all its clinical subtypes,
is a rapidly progressive neurodegenerative disease that leads to increasing impairment of
cortical and subcortical function in the affected person due to the accumulation of tau
protein in the brain (Höglinger 2017). Due to the clinical variability of the
presentation, early diagnostic certainty is desirable. Depending on the affected area in
the central nervous system, different clinical phenotypes result. The most commonly
described and researched entity is Progressive Supranuclear P, also known as Richardson
Syndrome, or PSP-RS. Further clinical presentations include a Parkinsonian variant
(PSP-P), corticobasal syndrome (PSP-CBS), pure akinesia with gait freezing (PSP-PAGF),
speech/language dominant presentations (PSP-SL), frontotemproal dementia variants
(PSP-FTD), and cerebellar presentations (PSP-C) (Höglinger 2017).
4RT is also associated with swallowing and speech problems, and aspiration pneumonia is
one of the most common causes of death in this disease entity (Tilley 2016). In addition,
dystonic dysinnervation of laryngeal muscles can lead to laryngeal motion abnormalities
(Panegyres 2007).
Equally, patients with motor neurone disease (MND) are affected by dysphagia early in the
disease. In a FEES study by Steven B. Leder and colleagues (2004), which included 17 ALS
patients subjectively complaining of dysphagia, fluid aspiration or an increased risk of
fluid aspiration was found in almost 60% of cases, regardless of whether the disease
initially mainly affected the bulbar musculature or the limb musculature. As the disease
progressed, the depth of penetration of fluids into the hypopharynx prior to triggering
the swallowing reflex increased, so these patients were advised to thicken fluids.
Initially, residues of solid food consistencies were detected in the valleculae, piriform
sinus and/or laryngeal inlet in three patients after swallowing. As a result of
progressive paresis of the pharyngeal muscles, the residuals increased in the ALS
patients examined during the course of the disease. If this disorder pattern was
detected, it was advised to reduce the size of the food bolus and to clear the pharynx by
swallowing water or reswallowing several times. In a further small case series (n = 11),
the FEES showed that dysphagic ALS patients are particularly at risk of
penetration/aspiration when swallowing liquids. Penetration and aspiration occur
particularly frequently intradeglutitively (D'Ottaviano et al. 2013). A recent
publication reports on FEES examinations in 202 ALS patients (w/m 95/107; bulbar/spinal
onset 66/136; mean age 64.68 +/- 11.12 years). A close positive correlation with disease
severity (measured using the ALSFRS-R) was found for all FEES parameters (leaking,
aspiration, residuals), regardless of the three consistencies tested (liquid, semi-solid,
solid) (Fattori et al. 2017).
The aim of this FEEMSA trial is to continue recruitment of patients with
neurodegenerative diseases and systematically assess laryngopharyngeal function in large
cohorts, to categorise the dysphagia phenotypes and better correlate them with the
disease subtypes (MSA Parkinson vs cerebellar; PSP variants, MND variants, etc). If
available, laryngeal EMG will also be recorded.