Ires Ghielen

24 Chapter 2 Methods Subjects For this cross-sectional study, we used data collected during routine clinical assessments at the outpatient clinic for movement disorders of the VU University medical center (VUmc) in Amsterdam, the Netherlands, between May 2008 and January 2013. In this period, 383 PD patients were assessed. Patients were clinically diagnosed with idiopathic PD using the United Kingdom PD Society Brain Bank (UKPDSBB) criteria. The clinical diagnosis was supported by both magnetic resonance imaging (MRI) and dopamine transporter single-photon emission computed tomography (DAT-SPECT) scans in 244 patients, by MRI only in 37 patients and by DAT-SPECT scan only in 23 patients. In the remaining 79 patients, no brain imaging was performed. All included patients gave written informed consent to use their clinical data for scientific purposes. Patients with severe cognitive decline, defined as a Mini Mental State Examination (MMSE) score < 24, were excluded. Measurements Anxiety Symptoms of anxiety were measured with the BAI. The BAI is a 21-item self-report instrument asking for symptoms of anxiety over the past week [11]. Patients answer on a four-point Likert scale, ranging from 0 (not at all) to 3 (severely). In patients with PD, clinically relevant anxiety is defined as a BAI-score > 12 [14]. This cut-off score is lower than in the general population, due to a lower construct validity of the BAI in PD patients [14]. Clinical and demographic factors Age, gender and the use of dopaminergic medication (0 = no, 1 = yes) were registered for use in statistical analyses. The independent variables of major interest were symptoms of depression, motor dysfunction and autonomic failure. We evaluated symptoms of depression with the Beck Depression Inventory (BDI) [15]. Severity of motor symptoms was assessed using section III and V (Hoehn and Yahr stage) of the Unified Parkinson Disease Rating Scale (UPDRS) [16]. We used the Scales for Outcomes in Parkinson’s disease – Autonomic (SCOPA-AUT) [17] to assess autonomic failure. The SCOPA-AUT includes five questions on sexual function: item 22, 23 and 23a apply to men, and item 24 and 25 to women. The answers to these questions were unreliable on multiple occasions, e.g. patients