ABSTRACT
BACKGROUND: Parkinson's disease (PD) is associated with psychosocial distress that affects patients' quality of life. The distress thermometer (DT) is an 11-point visual analogue scale that is used as a screening tool for the assessment of psychosocial distress, originally developed for oncological diseases. OBJECTIVES: To validate the DT for PD and to explore contributing factors. METHODS: The DT scale was administered to 105 people with Parkinson's Disease (PwPD). Along with it, we assessed motor symptoms (Unified Parkinson's Disease Rating Scale part III [UPDRS III], Hoehn and Yahr-stage [H&Y]), non-motor symptoms (Non-motor Symptom Questionnaire [NMSQ]), anxiety and depression (Hospital Anxiety and Depression Scale [HADS], Fear of Progression-Questionnaire Short Form [FOP-Q-SF], Generalized Anxiety Disorder Scale-7 [GAD-7], 9-question Patient Health Questionnaire [PHQ-9]), the feeling of hope (Herth Hope Index [HHI]) and quality of life (Schedule for the Evaluation of Individual Quality of Life [SEIQoL]). RESULTS: With a cut-off of 4, the DT identified PwPD with distress with a sensitivity of 97% and a specificity of 38%. With this cut-off, the DT will yield false negative results in 1 out of 100 cases. Factor analyses and a random forest regression of the dataset revealed that distress can be predicted by two factors, which we termed "anxiety" and "depression/resilience/motor symptoms". CONCLUSION: The DT is an ultra-short and reliable screening tool for distress in PwPD. DT values below 4 rule out distress with a high degree of certainty. Anxiety and depression are important factors in distress but are counterbalanced by the individuals' psychological resilience.
