Ires Ghielen

62 Chapter 4 Abstract Introduction: Approximately 45% of patients with Parkinson’s disease (PD) experience clinically relevant anxiety. Anxiety and motor symptoms are highly intertwined and have reciprocal influences. We investigated the associations between motor and anxiety symptoms in patients with high levels of anxiety compared to patients with low levels of anxiety. Methods: Data were collected during routine clinical assessments at the outpatient clinic for movement disorders. Motor symptoms were measured with the motor section of the Unified Parkinson’s Disease Rating Scale (UPDRS-III). A cut-off score of 12 on the Beck Anxiety Inventory (BAI) was used to divide patients into high- anxious versus low-anxious patients. Explorative network analyses and a network comparison test were used to investigate the partial correlations between items of the UPDRS-III and the BAI, and to statistically compare network architecture between the two patient groups. Results: 316 PD patients were included in the high-anxiety group, versus 253 in the low-anxiety group. The high-anxiety group showed significantly worse motor and cognitive function, a higher age, and included more female patients. The high- anxiety group had a higher global strength compared with the low-anxiety group (S=7.33, p <0.001). We found no statistically significant differences in strength of the connections between motor and anxiety symptoms between both groups. Conclusion: In spite of clear differences in demographic and clinical profile, we did not find differences in the associations between motor and anxiety symptoms, comparing high-anxious to low-anxious PD patients. Since associations between motor and anxiety symptoms are apparent in both groups, this shows that these symptoms are associated, even when patients have no to mild anxiety symptoms. These results need to be interpreted with caution and warrant replication in a bigger sample.