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The role of the observer in the reliability of the Dutch Discomfort Scale-Dementia of Alzheimer Type (DS-DAT). The Discomfort Scale of Dementia of the Alzheimer Type (DS-DAT) is an instrument to assess discomfort in severely demented patients. No data on the reliability of assessment using a Dutch translation were available. In this paper, we analyse the role of the observer in the reliability of rating. This is of importance for studies in which many physicians perform multiple assessments. Twenty-eight nursing home physicians in training rated the DS-DAT in five nursing home patients with dementia presented on videotape. This was repeated after five months. All the physicians were previously trained in the use of the instrument. The results were statistically analysed using random effects analysis of variance. The Intra-class Correlation Coefficient (ICC) was 0.74 for inter-observer reliability and 0.97 for intra-observer reliability. Variance between subsequent assessments was small, but physicians appeared to differ somewhat among themselves in the way they rated the videotaped patients. A future complete reliability assessment of rating the DS-DAT in clinical practice would involve patient variation as well, scoring patients in clinical practice.

In order to gain insight into the production and clinical significance of IgA rheumatoid factor (IgA-RF) in mucosal fluids of patients with rheumatoid arthritis (RA), we examined tear fluid, saliva and serum from 80 patients with RA. Significant correlations were found between IgA-RF levels in tear fluid and saliva (P = 0.002, r = 0.57), saliva and serum (P < 0.001, r = 0.79), and serum and tear fluid (P < 0.001, r = 0.31). No significant correlations were found between total IgA levels in these fluids. Comparison between circulating and mucosal IgA-RF levels after correction for total IgA, revealed that mucosal IgA-RF levels are on average 2.5 times higher than circulating IgA-RF levels. Analysis of IgA-RF specificity showed that lacrimal and salivary IgA-RF reactivity with various IgG subclasses is similar and differs from serum IgA-RF specificity. These results indicate local production of IgA-RF in salivary and lacrimal glands and support the view of a common origin of IgA-RF producing B cells present in mucosal tissues. Mucosal and circulating levels of IgA and IgA-RF were not associated with tests that quantify tear fluid production. This indicates that mucosal and circulating levels of IgA and IgA-RF in patients with RA cannot be regarded as markers for the development of secondary Sjögren's syndrome.