Validation of the Japanese translation of the Swallowing Disturbance Questionnaire in Parkinson’s disease patients

The Swallowing Disturbance Questionnaire (SDQ) was developed as a self-rated screening tool for dysphagia in patients with
Parkinson’s disease (PD). We developed the Japanese version of this questionnaire (SDQ-J), according to the cross-cultural
adaptation guidelines, and examined its reliability.

Subjects were 61 Japanese patients with PD (mean age, 67.0 ± 9.2 years) who answered the SDQ-J before undergoing videofluoroscopic
examination of swallowing (VF). We compared the findings of the questionnaire with the patients’ aspiration status during
VF.

Cronbach’s alpha coefficient for the 15 questions of the SDQ-J was 0.84. According to the SDQ-J, 15 patients (24.6%) were
diagnosed with dysphagia, while 9 patients (14.8%) aspirated liquid during VF. The sensitivity and specificity of the SDQ-J
in predicting aspiration were 77.8 and 84.6%, respectively; therefore, the SDQ-J significantly predicted aspiration during
VF (P < 0.01). The positive predictive value (PPV) and negative predictive value (NPV) for the SDQ-J were 0.46 and 0.96, respectively.

The SDQ-J appears to be a reliable and useful screening tool for Japanese PD patients with aspiration. As the NPV was higher
than the PPV in the SDQ-J, this questionnaire could potentially be used for early identification of severe dysphagia in patients
with PD.