Boosting diagnosis accuracy of Alzheimer's disease using high dimensional recognition of longitudinal brain atrophy patterns.

OBJECTIVE: Boosting accuracy in automatically discriminating patients with Alzheimer's disease (AD) and normal controls (NC), based on multidimensional classification of longitudinal whole brain atrophy rates and their intermediate counterparts in analyzing magnetic resonance images (MRI). METHOD: Longitudinal percentage of brain volume changes (PBVC) in two-year follow up and its intermediate counterparts in early 6-month and late 18-month are used as features in supervised and unsupervised classification procedures based on K-mean, fuzzy clustering method (FCM) and support vector machine (SVM). The most relevant features for classification are selected using discriminative analysis (DA) of features and their principal components (PC). Accuracy of the proposed method is evaluated in a group of 30 patients with AD (16 males, 14 females, age±standard-deviation (SD)=75±1.36 years) and 30 normal controls (15 males, 15 females, age±SD=77±0.88 years) using leave-one-out cross-validation. RESULTS: Results indicate superiority of supervised machine learning techniques over unsupervised ones in diagnosing AD and withal, predominance of RBF kernel over lineal one. Accuracies of 83.3%, 83.3%, 90% and 91.7% are achieved in classification by K-mean, FCM, linear SVM and SVM with radial based function (RBF) respectively. CONCLUSION: Evidence that SVM classification of longitudinal atrophy rates may results in high accuracy is given. Additionally, it is realized that use of intermediate atrophy rates and their principal components improves diagnostic accuracy.

Deodorant effects of a sage extract stick: Antibacterial activity and sensory evaluation of axillary deodorancy.

BACKGROUND: Deodorant products prevent the growth and activity of the degrading apocrine gland bacteria living in the armpit. Common antibacterial agents in the market like triclosan and aluminum salts, in spite of their suitable antibacterial effects, increase the risk of Alzheimer's disease, breast and prostate cancers or induce contact dermatitis. Therefore, plant extracts possessing antibacterial effects are of interest. The aim of the present study was to verify the in vitro antimicrobial effects of different sage extracts against two major bacteria responsible for axillary odor, and to evaluate the deodorant effect of a silicon-based stick containing sage extracts in different densities in humans. MATERIALS AND METHODS: Different fractions of methanolic extract of Salvia officinalis (sage) were evaluated on a culture of armpit skin surface of volunteers through agar microdilution antimicrobial assay. Then, randomized, double-blind placebo-controlled clinical trial with the best antibacterial fraction was conducted on 45 female healthy volunteers. Participants were treated with a single dose in four groups, each containing 15 individuals: Group 1 (200 µg/mL), 2 (400 µg/mL), 3 (600 µg/mL) of dichloromethane sage extract, and placebo (without extract). A standard sensory evaluation method for the evaluation of deodorant efficacy was used before, and two hours, four hours, and eight hours after single application of a deodorant or placebo (ASTM method E 1207-87 Standard Practice for the Sensory Evaluation of Axillary Deodorancy). RESULTS: The data were analyzed with two factors relating to densities and time. In 45 participants with a mean [± standard deviation (SD)] age of 61.5±11.8 years, statistically significant within-group differences were observed before and two, four, and eight hours after deodorant treatment for groups 1, 2, and 3. Groups 1, 2, and 3 had a significantly smaller odor score than placebo after two, four, and eight hours (P < 0.001). In a comparison of different deodorant densities, the interaction effect was not significant between deodorant 200 and 400 µg/mL, but was significant between 200 and 600 and between 400 and 600 µg/mL sage extract sticks (P < 0.001). Before running the sensory evaluation of the deodorant sticks on the subjects, a rabbit skin patch test was used to demonstrate that the formulation had no irritants. CONCLUSION: A single treatment with a stick deodorant containing dichloromethane sage extract of 200, 400, or 600 µg/mL concentrations was effective in reducing the axillary malodor level compared with the control, in healthy subjects.

Discriminant analysis of intermediate brain atrophy rates in longitudinal diagnosis of Alzheimer's disease.

Diagnosing Alzheimer's disease through MRI neuroimaging biomarkers has been used as a complementary marker for traditional clinical markers to improve diagnostic accuracy and also help in developing new pharmacotherapeutic trials. It has been revealed that longitudinal analysis of the whole brain atrophy has the power of discriminating Alzheimer's disease and elderly normal controls. In this work, effect of involving intermediate atrophy rates and impact of using uncorrelated principal components of these features instead of original ones on discriminating normal controls and Alzheimer's disease subjects, is inspected. In fact, linear discriminative analysis of atrophy rates is used to classify subjects into Alzheimer's disease and controls. Leave-one-out cross-validation has been adopted to evaluate the generalization rate of the classifier along with its memorization. Results show that incorporating uncorrelated version of intermediate features leads to the same memorization performance as the original ones but higher generalization rate. As a conclusion, it is revealed that in a longitudinal study, using intermediate MRI scans and transferring them to an uncorrelated feature space can improve diagnostic accuracy.