Design and validation of a new instrument to assess fear of falling in Parkinson's disease.

BACKGROUND: Fear of falling may be significantly associated with falls in Parkinson's disease (PD) and may have a negative impact on quality of life. Nevertheless, there are no valid and reliable tools to examine this condition in PD. The objective of this study was to design and determine the psychometric attributes of an instrument to assess fear of falling in PD. METHODS: A prospective 1-year, 2-phase study was conducted to validate the Fear of Falling Scale, a self-assessed instrument for assessing fear of falling in PD. During phase 1, we designed a scale to measure the severity of fear of falling and determine its baseline psychometric characteristics, whereas phase 2 was a 1-year follow-up study to assess the frequency of falls and other clinical factors linked to fear of falling. Convergent and discriminant validity were assessed against the Fear of Falling Measure and the Starkstein Apathy Scale, respectively. RESULTS: The Fear of Falling Scale showed high internal consistency, test-retest reliability, and strong convergent and discriminant validity. There was a significant association between fear of falling score and the presence of both generalized anxiety disorder and major depression, poor balance-related motor ability, increased nonmotor symptoms of PD, more severe impairments in activities of daily living, and increased motor fluctuations. Finally, generalized anxiety disorder was a significant predictor of number of falls during a 12-month follow-up period. CONCLUSIONS: The Fear of Falling Scale is a valid and reliable instrument to assess fear of falling in PD. Fear of falling in PD is associated with specific psychiatric and motor disorders and is significantly related to the performance of balance-related motor functions. © 2019 International Parkinson and Movement Disorder Society.

Diagnostic criteria for depression in Parkinson's disease: a study of symptom patterns using latent class analysis.

Although major depression is one of the most frequent psychiatric disorders among patients with Parkinson's disease, diagnostic criteria have yet to be validated. The main aim of our study was to validate depressive symptoms using latent class analysis for use as diagnostic criteria for major depression in Parkinson's disease. We examined a consecutive series of 259 patients with Parkinson's disease admitted to 2 movement disorders clinics for regular follow-ups. All patients were assessed with a comprehensive psychiatric interview that included structured assessments for depression, anxiety, and apathy. The main finding was that all 9 Diagnostic and Statistical Manual (4th edition) diagnostic criteria for major depression (ie, depressed mood, diminished interest or pleasure, weight or appetite changes, sleep changes, psychomotor changes, loss of energy, feelings of worthlessness or inappropriate guilt, poor concentration, and suicidal ideation) identified a patient class (severe depression group) with high statistical significance. Latent class analysis also demonstrated a patient class with minimal depressive symptoms (no-depression group), and a third patient class with intermediate depressive symptoms (moderate depression). Anxiety and apathy were both significant comorbid conditions of moderate and severe depression. Taken together, our findings support the use of the full Diagnostic and Statistical Manual (4th edition) criteria for major depression for use in clinical practice and research in Parkinson's disease and suggest that anxiety may be included as an additional diagnostic criterion.