Assessing the non-motor symptoms of Parkinson's disease: MDS-UPDRS and NMS Scale.

BACKGROUND AND PURPOSE: Although Parkinson's disease (PD) is characterized by typical motor manifestations, non-motor symptoms (NMS) are an outstanding part of the disease. At present, several specific instruments for assessment of NMS are available. The objective of our study was to determine the performance of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Part I - Non-Motor Aspects of Experiences of Daily Living (nM-EDL) compared with the Non-Motor Symptoms Scale (NMSS). METHODS: To this purpose, 434 consecutive patients with PD were included in an international, observational, cross-sectional study. The association between scores of both scales was determined by the Spearman rank correlation coefficient. Equations for transformation of total score of a scale to the other were constructed from weighted regression models and both, transformed and observed score, contrasted by means of the Lin's Concordance Correlation Coefficient (LCCC) and Bland-Altman plot. RESULTS: As a whole, the prevalence of the NMS according to each scale was quite similar, and most of the correlations between their corresponding components were high (r(S) > 0.60). The total score correlation of the MDS-UPDRS Part I with the NMSS was high (r(S) = 0.81). Concerning the transformed scores, estimated scores only partially approach the observed ones (sharing about 60-64% of the variance) because residual variance increased with increasing magnitudes of the scores, i.e. the most severe patients (Bland-Altman plot; LCCC < 0.60 for severe patients). CONCLUSIONS: (i) MDS-UPDRS Part I (nM-EDL) and NMSS showed a strong convergent validity; (ii) however, transformed scores using the equations from weighted regression models showed that for patients with the most severe NMS they are not concordant.

Designing a new scale to measure anxiety symptoms in Parkinson's disease: item selection based on canonical correlation analysis.

BACKGROUND AND PURPOSE: The lack of appropriate measures has hindered the research on anxiety syndromes in Parkinson's disease (PD). The objective of the present cross-sectional, international study was to identify shared elements and grouping of components from anxiety scales as a basis for designing a new scale for use in PD. METHODS: For this purpose, 342 consecutive PD patients were assessed by means of the Mini International Neuropsychiatric Inventory (depression and anxiety sections), the Clinical Global Impression of severity of the anxiety symptoms, the Hamilton Anxiety Rating Scale (HARS), the Neuropsychiatric Inventory (section E), the Beck Anxiety Inventory (BAI) and the Anxiety subscale of the Hospital Anxiety and Depression Scale (HADS-A). RESULTS: As the HADS-A showed a weak correlation with the HARS and BAI, it was not considered for more analyses. HARS and BAI exploratory factor analysis identified nine factors (62% of the variance), with only two of them combining items from both scales. Therefore, a canonical correlation model (a method to identify relations between components of two groups of variables) was built and it showed four factors grouping items from both scales: the first factor corresponded to 'generalized anxiety'; the second factor included muscular, sensory and autonomic 'non-specific somatic symptoms'; the third factor was dominated by 'respiratory symptoms'; and the fourth factor included 'cardiovascular symptoms'. CONCLUSIONS: BAI is heavily focused on panic symptoms, whilst HARS is more focused towards generalized anxiety symptoms. The new scale should include additional components in order to assess both episodic and persistent anxiety as well as items for evaluation of avoidance behaviour.

Dementia associated with Parkinson's disease: applying the Movement Disorder Society Task Force criteria.

BACKGROUND: Diagnostic criteria and procedures for dementia in Parkinson's disease (PDD) have been proposed by a Movement Disorders Society Task Force (MDS-TF). The objective of this study was to explore the utility of the new MDS-TF criteria and procedures in clinical practice. METHODS: Two hundred ninety nine PD patients (36.5% with PDD as per MDFS-TF criteria; 33.1% according the DSM-IV) were included in the study. A variety of standardized motor, cognitive, psychiatric, and global severity measures were administered. A multivariate logistic regression model was built to determine the variables producing discrepancy between the MDS-TF and DSM-IV criteria for PDD and the clinical features that distinguished false negative cases. RESULTS: Agreement between MDS-TF and DSM-IV criteria was substantial (87.3%; kappa = 0.72), but the DSM-IV criteria failed to identify 22% of patients fulfilling MDS-TF criteria. False negative cases were older and had more severe motor symptoms but less psychosis than those true non-demented PD. False positives had less severe motor symptoms than true PDD, although the difference did not reach statistical significance. CONCLUSIONS: Our findings suggest that the MDS-TF criteria are more sensitive than the DSM-IV for a diagnosis of PDD. Old age, absence of psychiatric symptoms, and severe motor impairment can hinder the diagnosis of PDD.