Testing the Assumption of Measurement Invariance in the SAMHSA Mental Health and Alcohol Abuse Stigma Assessment in Older Adults

This study examined the assumption of measurement invariance of the SAMSHA Mental Health and Alcohol Abuse Stigma Assessment. This is necessary to make valid comparisons across time and groups. The data come from the Primary Care Research in Substance Abuse and Mental Health for Elderly trial, a longitudinal multisite, randomized trial examining two modes of care (Referral and Integrated). A sample of 1,198 adults over the age of 65 who screened positive for depression, anxiety, and/or at-risk drinking was used. Structural equation modeling was used to assess measurement invariance in a two-factor measurement model (Perceived Stigma, Comfort Level). Irrespective of their stigma level, one bias indicated that with time, respondents find it easier to acknowledge that it is difficult to start treatment if others know they are in treatment. Other biases indicated that sex, mental quality of life and the subject of stigma had undue influence on respondents' feeling people would think differently of them if they received treatment and on respondents' comfort in talking to a mental health provider. Still, in the present study, these biases in response behavior had little effect on the evaluation of group differences and changes in stigma. Stigma decreased for patients of both the Referral and Integrated care group

Using structural equation modeling to detect response shift in performance and health-related quality of life scores of multiple sclerosis patients

To illustrate how structural equation modeling (SEM) can be used for response shift detection with random measurement occasions and health state operationalized as fixed group membership (Study 1) or with fixed measurement occasions and health state operationalized as time-varying covariates (Study 2). In Study 1, we explored seven items of the Performance Scales measuring physical and mental aspects of perceived disability of 771 stable, 629 progressive, and 1,552 relapsing MS patients. Time lags between the three measurements varied and were accounted for by introducing time since diagnosis as an exogenous variable. In Study 2, we considered the SF-12 scales measuring physical and mental components of HRQoL of 1,767 patients. Health state was accounted for by exogenous variables relapse (yes/no) and symptoms (worse/same/better). In Study 1, progressive and relapsing patients reported greater disability than stable patients but little longitudinal change. Some response shift was found with stable and relapsing patients. In Study 2, relapse and symptoms were associated with HRQoL, but no change and only little response shift was found. While small response shifts were found, they had little impact on the evaluation of true change in performance and HRQo

Motor function in Parkinson's disease and supranuclear palsy: simultaneous factor analysis of a clinical scale in several populations

BACKGROUND: In order to better understand the similarities and differences in the motor behaviour of different groups of patients, their scores on the Motor Examination section of the Unified Parkinson's Disease Rating Scale (UPDRS) were analysed simultaneously. The three groups consisted, respectively, of patients with Parkinson's disease (PD) on medication, patients with Parkinson's disease withdrawn from anti-parkinsonian medication for at least 12 hours, and patients diagnosed with a specific Parkinsonism syndrome: Progressive Supranuclear Palsy (PSP). METHODS: A total of 669 consecutively sampled patients from three separate hospital-based clinics participated (294 PD on medication; 200 PD off medication: 175 PSP). The Motor Examination section of the UPDRS was administered by neurologists at the three participating clinics. The patient scores on each item were recorded. To assess similarities and differences among the components of the UPDRS in these samples, we performed simultaneous or multigroup factor analysis on the covariance matrices of the three groups. In addition, it was investigated whether a single model for the Motor Examination section of the UPDRS could be developed which would be valid for all three groups at the same time. RESULTS: A single six-dimensional factor solution was found that fitted all groups, although this was not straightforward due to differences between the tremor-at-rest variables. The factors were identified as Tremor-at-rest, Postural Tremor, Axial Dysfunctioning, Rigidity, Left Bradykinesia and Right Bradykinesia. The analysis also pointed to a somewhat lower lateralization in bradykinesia for PSP patients. The groups differed in intensity of motor impairment, especially with respect to Tremor-at-Rest, but the overall relationships between the variables were shared by the three groups. In addition, apart from the common factor structure evidence of differences in body part-specific and motor-specific variances was found. CONCLUSION: From a clinical point of view, the analyses showed that using the Motor Examination section of the UPDRS is also appropriate for patients with PSP, because the correlational structure of the items is directly comparable to that of Parkinson's patients. Methodologically, the analysis of all groups together showed that it is possible to evaluate similarities and differences between factor structures in great detail

Profiling Dizziness in Older Primary Care Patients: An Empirical Study

The diagnostic approach to dizzy, older patients is not straightforward as many organ systems can be involved and evidence for diagnostic strategies is lacking. A first differentiation in diagnostic subtypes or profiles may guide the diagnostic process of dizziness and can serve as a classification system in future research. In the literature this has been done, but based on pathophysiological reasoning only