49 research outputs found
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99mTc Hexamethyl-Propylene-Aminoxime Single-Photon Emission Computed Tomography Prediction of Conversion From Mild Cognitive Impairment to Alzheimer Disease
Objective—To examine the utility of single photon emission computed tomography (SPECT) to predict conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD)
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Questionable Dementia: Clinical Course and Predictors of Outcome
OBJECTIVE:To evaluate the clinical course and predictors of outcome in outpatients with cognitive impairment who do not meet criteria for dementia at initial evaluation. DESIGN: Naturalistic longitudinal study. METHODS: Cognitively impaired patients in a memory disorders clinic who fell between the “normal” and “dementia” categories were defined broadly as “questionable dementia” (QD).Of 127consecutiveQ D patients, 75were followed for a minimum of 1year (mean 2.5 years, SD 1.7).Baseline neuropsychological testing was conducted in 62 of these 75 QD patients. RESULTS:: At the final follow-up time-point, 41.3% met diagnostic criteria for dementia (27 of 31 patients with dementia had possible or probable Alzheimer’s Disease, AD), 44% were rated as not demented, and 14.7% remained as “uncertain” dementia. Increased age was associated with the final diagnosis of dementia, but duration of follow-up, Clinical Dementia Rating, and modified Mini Mental State (mMMS) scores were not predictive. Low scores on the mMMS delayed recall subtest, consistent long-term retrieval on the Selective Reminding Test, category naming for animals, and the WAIS-R digit symbol, picture arrangement, and block design subtests were predictive of the final diagnosis of dementia (all P 5.01). mMMS delayed recall showed 66.7% sensitivity and 71.4% specificity, the other five neuropsychological subtests together showed 66.7% sensitivity and 66.7% specificity, and the six tests together showed 81% sensitivity and 76.9% specificity. Similar predictive accuracy was obtained for the final diagnosis of AD. CONCLUSIONS:In Q D patients, poor performance on the mMMS delayed recall item may be a useful predictor of the diagnosis of dementia (and AD) on follow-up. Combining a screening instrument like the mMMS with specific neuropsy
Neuropsychiatric effects of neurodegeneration of the medial versus lateral ventral prefrontal cortex in humans
Animal evidence suggests that a brain network involving the medial and rostral ventral prefrontal cortex (PFC) is central for threat response and arousal and a network involving the lateral and caudal PFC plays an important role in reward learning and behavioral control. In this study, we contrasted the neuropsychiatric effects of degeneration of the medial versus lateral PFC in 43 patients with Frontotemporal dementia (FTD) and 11 patients with Corticobasal Syndrome (CBS) using MRI, the Neuropsychiatric Inventory (NPI), and the Sorting, Tower, Twenty Questions, and Fluency tests of the Delis-Kaplan Executive Function System (D-KEFS). Deviations in MRI grey matter volume from 86 age-matched healthy control subjects were determined for the patients using FreeSurfer. Multivariate regression was used to determine which brain areas were associated with specific neuropsychiatric and cognitive symptoms. Decreased grey matter volume of the right medial ventral PFC was associated with increased anxiety and apathy, decreased volume of the right lateral ventral PFC with apathy and inappropriate repetitive behaviors, and of the left lateral ventral PFC with poor performance on the sorting and Twenty Questions task in patients with FTD and CBS. Similar to in animal studies, damage to the medial OFC appears to be associated with a disruption of arousal, and damage to the lateral OFC appears to be associated with deficits in trial-and-error learning and behavioral dysregulation. Studies of brain dysfunction in humans are valuable to bridge animal and human neuropsychiatric research