Etiology of Dementia in Thai Patients.

INTRODUCTION: Molecular imaging has been developed and validated in Thai patients, comprising a portion of patients in the dementia registry. This should provide a more accurate diagnosis of the etiology of dementia, which was the focus of this study. METHODS: This was a multicenter dementia study. The baseline characteristics, main presenting symptoms, and results of investigations and cognitive tests of the patients were electronically collected in the registry. Functional imaging and/or molecular imaging were performed in patients with an equivocal diagnosis of the causes of dementia, especially in atypical dementia or young onset dementia (YOD). RESULTS: There were 454 patients in the study. The mean age of the patients was 78 years, with 60% female. Functional imaging and/or molecular imaging were performed in 57 patients (57/454 patients, 13%). The most common cause of dementia was Alzheimer's disease (AD; 50%), followed by vascular dementia (VAD; 24%), dementia with Lewy bodies (6%), Parkinson's disease dementia (6%), frontotemporal dementia (FTD; 2.6%), progressive supranuclear palsy (2%), multiple system atrophy (0.8%), and corticobasal syndrome (0.4%). YOD accounted for 17% (77/454 patients), with a mean age of 58 years. The causes of YOD were early onset amnestic AD (44%), VAD (16%), behavioral variant FTD (8%), posterior cortical atrophy (6.5%), and logopenic variant primary progressive aphasia (5.2%). CONCLUSION: AD was the most common cause of dementia in Thai patients and the distribution of other types of dementia and main presenting symptoms were similar to previous reports in Western patients; however, the proportion of YOD was higher.

A 10-year perspective on donepezil.

INTRODUCTION: Donepezil is the first cholinesterase inhibitor widely used for the treatment of Alzheimer's disease (AD). Its pharmacological actions are straightforward, enhancing cholinergic activity both in the brain and systemically, with a long-enough half-life to allow for once a day dosing. Its efficacy has been approved for use in mild-to-moderate AD stage for improvement of symptoms for 10 years, and now it is also approved for use in severe stage. AREAS COVERED: This review article will offer a 10-year perspective on the use of donepezil in clinical practice against AD and related disorders. In addition to discussing the information from randomized clinical trials and from the drug monograph, this article will seek to facilitate the clinical development and clinical use of the next generation of drugs for AD. EXPERT OPINION: Adjustments about expectations and safe use of donepezil were made over time based on such clinical experiences. Offering a cholinesterase inhibitor to patients with mild-to-moderate AD clearly showed advantages. If well tolerated, donepezil should be continued in the severe stages of AD as long as the patient appears to benefit from a slower clinical decline.

White matter abnormalities and structural hippocampal disconnections in amnestic mild cognitive impairment and Alzheimer's disease.

The purpose of this project was to evaluate white matter degeneration and its impact on hippocampal structural connectivity in patients with amnestic mild cognitive impairment, non-amnestic mild cognitive impairment and Alzheimer's disease. We estimated white matter fractional anisotropy, mean diffusivity and hippocampal structural connectivity in two independent cohorts. The ADNI cohort included 108 subjects [25 cognitively normal, 21 amnestic mild cognitive impairment, 47 non-amnestic mild cognitive impairment and 15 Alzheimer's disease]. A second cohort included 34 subjects [15 cognitively normal and 19 amnestic mild cognitive impairment] recruited in Montreal. All subjects underwent clinical and neuropsychological assessment in addition to diffusion and T1 MRI. Individual fractional anisotropy and mean diffusivity maps were generated using FSL-DTIfit. In addition, hippocampal structural connectivity maps expressing the probability of connectivity between the hippocampus and cortex were generated using a pipeline based on FSL-probtrackX. Voxel-based group comparison statistics of fractional anisotropy, mean diffusivity and hippocampal structural connectivity were estimated using Tract-Based Spatial Statistics. The proportion of abnormal to total white matter volume was estimated using the total volume of the white matter skeleton. We found that in both cohorts, amnestic mild cognitive impairment patients had 27-29% white matter volume showing higher mean diffusivity but no significant fractional anisotropy abnormalities. No fractional anisotropy or mean diffusivity differences were observed between non-amnestic mild cognitive impairment patients and cognitively normal subjects. Alzheimer's disease patients had 66.3% of normalized white matter volume with increased mean diffusivity and 54.3% of the white matter had reduced fractional anisotropy. Reduced structural connectivity was found in the hippocampal connections to temporal, inferior parietal, posterior cingulate and frontal regions only in the Alzheimer's group. The severity of white matter degeneration appears to be higher in advanced clinical stages, supporting the construct that these abnormalities are part of the pathophysiological processes of Alzheimer's disease.