Author reply to "Oropharyngeal dysphagia in Parkinson's disease: comments on paper by Kalf et al." by Boot & Chaudhuri

Critical Dysphagia is Common in Parkinson Disease and Occurs Even in Early Stages: A Prospective Cohort Study

To assess the prevalence of dysphagia and its typical findings in unselected "real-world" Parkinson patients using an objective gold-standard method. This was a prospective, controlled, cross-sectional study conducted in 119 consecutive Parkinson patients of all stages independent of subjective dysphagia. Patients and 32 controls were clinically and endoscopically examined by flexible endoscopic evaluation of swallowing (FEES) to evaluate the deglutition with regard to three consistencies (water, biscuit, and bread). Typical findings of dysphagia like penetration and aspiration, residues, and leakage were assessed. Dysphagia was common in Parkinson patients and occurred in all, even early, disease stages. Only 5% (6/119) of patients showed a completely unremarkable deglutition. Aspiration was seen in 25% (30/119) of patients and always related to water. Residues occurred in 93% (111/119), most commonly for bread. Leakage was much less frequent and was found in only 3-18%, depending on consistency. In a significant fraction of patients, objective dysphagia was not subjectively perceived. A total of 16% of asymptomatic patients suffered from critical aspiration. Significant swallowing deficiencies already occurred in early disease. Aspiration was found in 4 of 20 (20%) patients with disease duration of less than 2 years. Seven of 57 patients (12%) with Hoehn and Yahr stage 2 suffered from severe aspiration. Given the high frequency of critical aspiration in Parkinson disease, these patients should be evaluated early for dysphagia to avoid complications and recommend an adequate therapy. FEES is a simple, cost efficient, minimally invasive method that is ideally suited for this purpose.

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.