Ires Ghielen

33 BAI factor analysis in PD patients the sample. Moreover, this is the first study that has successfully performed a factor analysis of the BAI in a sample of PD patients. Conclusions In this study, we demonstrated that anxiety in PD patients, as measured with the BAI, comprises one affective and four somatic symptom dimensions. Scores on the BAI and BDI are highly correlated, which can be explained by symptom overlap and frequent co-occurrence of anxiety and depression in PD. The score on the somatic subscales of the BAI is significantly influenced by autonomic failure and motor dysfunction, whereas the affect subscale is not. This finding suggests that the affect subscale may be a more reliable measure of anxiety in PD patients. However, somatic symptoms cannot be completely disregarded in the diagnostic process of anxiety disorders. Furthermore, anxiety, autonomic failure and motor dysfunction in PD may share underlying etiological mechanisms. The strong interplay between motor and non-motor symptoms in PD warrants a holistic approach to anxiety in clinical practice. Hopefully, the findings in this study will stimulate the development of new and more specific measures of anxiety in PD. 2