Several recent prospective studies have demonstrated the existence of a preclinical stage of dementia, identifiable by neuropsychological assessment showing impairments with a great variety of cognitive tests. However, test scores are often colinear, largely because common cognitive components are involved in different tests; in spite of an apparent heterogeneity, it is still possible that a common cognitive component may be responsible for the deterioration shown in different tests in the preclinical phase. We studied the cognitive performances of 1159 elderly residents in the PAQUID (Personnes Agées quid) cohort, at a fixed lag time of 2 years before the clinical diagnosis of dementia. Seven neuropsychological tests were administered (Mini-Mental Status Examination, Benton Visual Retention Test, Wechsler Paired-Associates Test, Isaacs Set Test, Zazzo's Cancellation Task, Digit Symbol Substitution Test and Wechsler Similarities Test). Among the initially non-demented 1159 subjects, 25 developed a dementia 2 years later, of whom 16 were classified as cases of Alzheimer's disease. In order to dissect the multicolinearity of the tests we used a multivariate approach with principal component analysis (PCA). The patients' loading on each of the first four PCA factors were subsequently correlated with the risk of dementia and Alzheimer's disease 2 years later. The logistic regression with backward stepwise selected only the first factor as an independent predictor of dementia or Alzheimer's disease. Analysis shows that there are good reasons to suspect that the first PCA factor represents a general factor corresponding to aspects of control in the tasks used. Our results therefore seem to show that preclinical deficits in dementia and Alzheimer's disease reflect the deterioration of a general cognitive factor, which may be interpreted as the disturbance of central, control processes.

SummaryBackground and objectives Uremic xerosis is a bothersome condition that is poorly responsive to moisturizing and emollient therapy.Design, setting, participants, & measurements A randomized, double-blind, intraindividual (left versus right comparison), multicentric clinical study was performed on 100 patients with moderate to severe uremic xerosis for 7 days, during which the patients applied twice daily an emulsion combining glycerol and paraffin (test product) on one allocated lower leg, and the emulsion alone (comparator) on the other lower leg. This was followed by an open-labeled use of the test product on all of the xerotic areas for 49 days. The main efficacy parameter was treatment response on each lower leg, as defined by a reduction from baseline of at least two grades in a five-point clinical score on day 7.Results Among the 99 patients analyzed, the test product was highly effective with a treatment response in 72 patients (73%), whereas 44 patients (44%) responded to the comparator (P Ͻ 0.0001, intergroup analysis). This was associated with an objective reduction in the density and thickness of the scales on day 7 (P Ͻ 0.0001 compared with the comparator) and a substantial improvement of the uremic pruritus (75%) and quality of life of the patients at study end (P Ͻ 0.001, intragroup analysis). The test product was very well tolerated, with product-related local intolerance (exacerbated pruritus, local burning, or erythema) occurring in only five patients (5%).Conclusions Uremic xerosis can be managed successfully when an appropriate emollient therapy is used.

A total of 334 end-stage renal disease patients with moderate-to-severe uraemic xerosis were surveyed for quality of life assessment, using the generic Short-Form (SF-12) scale and the Dermatology Life Quality Index (DLQI). In parallel, the intensity of xerosis at four sites (the two lower legs, chest, forearm without arterio-venous shunt) was assessed, using a five-point lesional intensity score. Pruritus was auto-assessed by the patients, using a 100-mm visual analogue scale. Uraemic xerosis patients had a marked deterioration in the Physical Component Summary of SF-12 (mean ± SD: 34.92 ± 9.98) and DLQI (5.06 ± 4.73). Younger age (r = -0.20), xerosis intensity (r = 0.14), and the presence of pruritus (p < 0.0001) and its intensity (r = 0.50) were shown to be significant worsening factors of DLQI. Because a low, but significant, correlation between the intensity of xerosis and pruritus was also demonstrated (r = 0.18), the direct contribution of age, xerosis and pruritus on DLQI was analysed in a multiple linear regression model. Age and pruritus intensity, but not xerosis intensity, were found to be independent contributors to DLQI deterioration (p < 0.0005). On the other hand, uraemic xerosis without associated pruritus still resulted in DLQI alteration (3.24 ± 3.99). It was concluded that young age and intensity of uraemic pruritus compromise quality of life in uraemic xerosis patients. Some characteristics of uraemic xerosis other than xerosis intensity may also be involved in quality of life alteration.