Biomedical subjects
Publications and source records attributed to Nancy R Barbas.
Nonmotor symptoms, including cognitive deterioration and dementia, depression and apathy, and psychosis, are common in Parkinson's disease. Their presence is associated with a tremendous burden for the patient and family members. This article reviews the pathophysiololgy, risks, impact, major features, diagnosis, and treatment of these symptoms in Parkinson's disease.
It is well recognized that headache, and especially migraine, runs in families. Recent studies into the heritability of primary headache subtypes, migraine, cluster and tension headache, and conditions in which headache is a prominent feature, such as the mitochondrial disease, mitochondrial encephalopathy, lactic acidosis, and strokelike episodes, and the arteriopathy, cerebral autosomal-dominant arteriopathy with subcortical infarctions and leukoencephalopathy, are improving our understanding of the genetic contribution to headache. Studies of the rare familial hemiplegic migraine are leading to advances in understanding the pathophysiological mechanisms of the more common migraine types. Current knowledge of hereditary and genetic features of headache subtypes is reviewed and the implications for understanding the pathophysiology of migraine are discussed.
Flurodeoxyglucose positron emission tomography (FDG-PET) is being explored to determine its ability to differentiate between a diagnosis of Alzheimer's disease (AD) and fronto-temporal dementia (FTD). We have examined statistical discrimination procedures to help achieve this purpose and compared the results to visual ratings of FDG-PET images. The methods are applied to a data set of 48 subjects with autopsy confirmed diagnoses of AD or FTD (these subjects come from a multi-centre collaborative study funded by the National Alzheimer's Coordinating Center). FDG-PET images are composed of thousands of voxels (volume elements) so one is left with a situation where there are vastly more variables than subjects. Therefore, it is necessary to perform a data reduction before a statistical procedure can be applied. Approaches using both the entire image and summary statistics calculated on a number of volumes of interest (VOI) are examined. We performed the data reduction techniques of principal components analysis (PCA) and partial least-squares (PLS) on the entire image and then used linear discriminant analysis (LDA), quadratic (QDA) or logistic regression (LR) to classify subjects as having AD or FTD. Some of these methods achieve diagnostic accuracy (as assessed by leave-one-out cross-validation) that is similar to visual ratings by expert raters. Methods using PLS appear to be more successful. Averaging or using VOI data may also be helpful.