Development and validation of a new screening questionnaire for dysphagia in early stages of Parkinson's disease

Background: Dysphagia in patients with Parkinson's disease (PD) significantly reduces quality of life and predicted lifetime. Current screening procedures are insufficiently evaluated. We aimed to develop and validate a patient-reported outcome questionnaire for early diagnosis of dysphagia in patients with PD. Methods: The two-phased project comprised the questionnaire, diagnostic scales construction (N=105), and a validation study (N=82). Data for the project were gathered from PD patients at a German Movement Disorder Center. For validation purposes, a clinical evaluation focusing on swallowing tests, tests of sensory reflexes, and fiberoptic endoscopic evaluation of swallowing (FEES) was performed that yielded a criteria sum score against which the results of the questionnaire were compared. Specificity and sensitivity were evaluated for the detection of noticeable dysphagia and for the risk of aspiration. Results: The Munich Dysphagia Test - Parkinson's disease (MDT-PD) consists of 26 items that show high internal consistency (α=0.91). For the validation study, 82 patients, aged 70.9±8.7 (mean±SD), with a median Hoehn & Yahr stage of 3, were assessed. 73% of patients had dysphagia with noticeable oropharyngeal symptoms (44%) or with penetration/aspiration (29%). The criteria sum score correlated positively with the screening result (r=0.70, p<0.001). The MDT-PD sum score classified not noticeable dysphagia vs. risk of aspiration (noticeable dysphagia) with a sensitivity of 90% (82%) and a specificity of 86% (71%), and yielded similar results in cross-validation, respectively. Conclusions: MDT-PD is a valid screening tool for early diagnosis of swallowing problems and aspiration risk, as well as initial graduation of dysphagia severity in PD patients.