CCCDTD5: research diagnostic criteria for Alzheimer's Disease.

The CCCDTD5 reviewed the research diagnostic criteria for Alzheimer's disease proposed in the NIA-AA Research Framework and supports their use in research but not in clinical practice.

Vascular retinal biomarkers improves the detection of the likely cerebral amyloid status from hyperspectral retinal images.

INTRODUCTION: This study investigates the relationship between retinal image features and ß-amyloid (Aß) burden in the brain with the aim of developing a noninvasive method to predict the deposition of Aß in the brain of patients with Alzheimer's disease. METHODS: Retinal images from 20 cognitively impaired and 26 cognitively unimpaired cases were acquired (3 images per subject) using a hyperspectral retinal camera. The cerebral amyloid status was determined from binary reads by a panel of 3 expert raters on 18F-florbetaben positron-emission tomography (PET) studies. Image features from the hyperspectral retinal images were calculated, including vessels tortuosity and diameter and spatial-spectral texture measures in different retinal anatomical regions. RESULTS: Retinal venules of amyloid-positive subjects (Aß+) showed a higher mean tortuosity compared with the amyloid-negative (Aß-) subjects. Arteriolar diameter of Aß+ subjects was found to be higher than the Aß- subjects in a zone adjacent to the optical nerve head. Furthermore, a significant difference between texture measures built over retinal arterioles and their adjacent regions were observed in Aß+ subjects when compared with the Aß-. A classifier was trained to automatically discriminate subjects combining the extracted features. The classifier could discern Aß+ subjects from Aß- subjects with an accuracy of 85%. DISCUSSION: Significant differences in texture measures were observed in the spectral range 450 to 550 nm which is known as the spectral region known to be affected by scattering from amyloid aggregates in the retina. This study suggests that the inclusion of metrics related to the retinal vasculature and tissue-related textures extracted from vessels and surrounding regions could improve the discrimination performance of the cerebral amyloid status.

A MEG study of the neural substrates of semantic processing in semantic variant primary progressive aphasia.

Despite a well-documented pattern of semantic impairment, the patterns of brain activation during semantic processing in semantic variant primary progressive aphasia (svPPA) still remain poorly understood. In the current study, one svPPA patient (EC) and six elderly controls carried out a general-level semantic categorization task while their brain activity was recorded using magnetoencephalography (MEG). Despite similar behavioral performance, EC showed hyperactivation of the left inferior temporal gyrus (ITG) and right anterior temporal lobe (ATL) relative to controls. This suggests that periatrophic regions within the ATL region may support preserved semantic abilities in svPPA.

Prevalence of glaucoma in hospitalized older adults with Alzheimer's disease.

OBJECTIVE: To determine the prevalence of glaucoma in older adults with dementia of the alzheimer's type (DAT). METHODS: retrospective chart review: the prevalence of glaucoma was determined in older adults with a diagnosis of DAT or mixed dementia (DAT with vascular contribution) admitted to the geriatric and neurology units of the Centre hospitalier de l'université de Montréal and the hôpital Maisonneuve-rosemont between april 2008 and april 2009 (n=220; DAT group). they were matched for age and date of hospitalisation to the first 220 individuals without dementia (control group) recruited from other medical units in the same hospitals: gastroenterology, internal medicine or cardiology. a diagnosis of glaucoma was deemed positive if recorded in the chart or if there was a medication compatible with this diagnosis. Chi-square tests were used for between-group comparisons. RESULTS: Subjects' age ranged from 66 to 101 years. the prevalence of glaucoma was 6.8% in our study population (n=30/440). glaucoma was significantly more prevalent in the DAT group (n= 21; 9.5%) than in the control group (n= 9; 4.1%) [χ1² = 5.15; p = 0.023]. CONCLUSIONS: the prevalence of glaucoma was higher in a group of older adults with DAT than in a comparable control group. these results underscore the importance of providing regular eyecare for persons affected by DAT.

Cooking "shrimp à la créole": a pilot study of an ecological rehabilitation in semantic dementia.

New learning in semantic dementia (SD) seems to be tied to a specific temporal and spatial context. Thus, cognitive rehabilitation could capitalise upon preserved episodic memory and focus on everyday activities which, once learned, will have an impact in everyday life. This pilot study thus explores the effectiveness of an ecological approach in one patient suffering from SD. EC, a 68-year-old woman with SD, stopped cooking complex meals due to a substantial loss of knowledge related to all food types. The therapy consisted of preparing a target recipe. She was asked to generate semantic attributes of ingredients found in one target, one control and two no-therapy recipes. The number of recipes cooked by EC between therapy sessions was computed. She was also asked to prepare a generalisation recipe combining ingredients from the target and control recipes. EC's generated semantic attributes (GSA) of ingredients pertaining to the target and control recipes increased significantly (p < .001), compared to the no-therapy recipes (ps > .79). The proportion of meals cooked also increased significantly (p = .021). For the generalisation recipe, she could not succeed without assistance. Frequent food preparation may have provided EC with new memories about the context, usage and appearance of some concepts. These memories seem very context-bound, but EC nonetheless re-introduced some recipes into her day-to-day life. The impact of these results on the relationship between semantic, episodic and procedural memory is discussed, as well as the relevance of an ecological approach in SD.

The relation between depressive symptoms and semantic memory in amnestic mild cognitive impairment and in late-life depression.

Semantic deficits have been documented in the prodromal phase of Alzheimer's disease, but it is unclear whether these deficits are associated with non-cognitive manifestations. For instance, recent evidence indicates that cognitive deficits in elders with amnestic mild cognitive impairment (aMCI) are modulated by concomitant depressive symptoms. The purposes of this study were to (i) investigate if semantic memory impairment in aMCI is modulated according to the presence (aMCI-D group) or absence (aMCI group) of depressive symptoms, and (ii) compare semantic memory performance of aMCI and aMCI-D groups to that of patients with late-life depression (LLD). Seventeen aMCI, 16 aMCI-D, 15 LLD, and 26 healthy control participants were administered a semantic questionnaire assessing famous person knowledge. Results showed that performance of aMCI-D patients was impaired compared to the control and LLD groups. However, in the aMCI group performance was comparable to that of all other groups. Overall, these findings suggest that semantic deficits in aMCI are somewhat associated with the presence of concomitant depressive symptoms. However, depression alone cannot account solely for the semantic deficits since LLD patients showed no semantic memory impairment in this study. Future studies should aim at clarifying the association between depression and semantic deficits in older adults meeting aMCI criteria. (JINS, 2011, 17, 865-874).

The cognitive and neural expression of semantic memory impairment in mild cognitive impairment and early Alzheimer's disease.

Semantic deficits in Alzheimer's disease have been widely documented, but little is known about the integrity of semantic memory in the prodromal stage of the illness. The aims of the present study were to: (i) investigate naming abilities and semantic memory in amnestic mild cognitive impairment (aMCI), early Alzheimer's disease (AD) compared to healthy older subjects; (ii) investigate the association between naming and semantic knowledge in aMCI and AD; (iii) examine if the semantic impairment was present in different modalities; and (iv) study the relationship between semantic performance and grey matter volume using voxel-based morphometry. Results indicate that both naming and semantic knowledge of objects and famous people were impaired in aMCI and early AD groups, when compared to healthy age- and education-matched controls. Item-by-item analyses showed that anomia in aMCI and early AD was significantly associated with underlying semantic knowledge of famous people but not with semantic knowledge of objects. Moreover, semantic knowledge of the same concepts was impaired in both the visual and the verbal modalities. Finally, voxel-based morphometry analyses revealed that semantic impairment in aMCI and AD was associated with cortical atrophy in the anterior temporal lobe (ATL) region as well as in the inferior prefrontal cortex (IPC), some of the key regions of the semantic cognition network. These findings suggest that the semantic impairment in aMCI may result from a breakdown of semantic knowledge of famous people and objects, combined with difficulties in the selection, manipulation and retrieval of this knowledge.

Single- and multiple-domain amnestic mild cognitive impairment: two sides of the same coin?

BACKGROUND: Amnestic mild cognitive impairment (aMCI) is considered a transition stage between normal aging and Alzheimer's disease (AD). Two main clinical subtypes of aMCI have been identified: (1) single-domain aMCI (aMCI-SD), with isolated episodic memory impairments, and (2) multiple-domain aMCI (aMCI-MD), with episodic memory impairments and deficits in one or more other cognitive domains. AIMS: To map the pattern of gray matter (GM) atrophy associated with aMCI-SD, aMCI-MD and mild AD. METHODS: A group of aMCI-SD, aMCI-MD characterized by executive function disorders, mild AD and cognitively unimpaired subjects underwent a comprehensive neuropsychological assessment and a high-definition MR brain scan. Voxel-based morphometry analysis was used to characterize the GM tissue loss in each patient group, and the common pattern of GM atrophy in aMCI-SD and aMCI-MD. RESULTS: aMCI-SD and aMCI-MD are characterized by a common pattern of GM atrophy within the medial temporal cortex, predisposing to AD and correlating with the severity of verbal memory symptoms. Moreover, the pattern of GM atrophy observed in aMCI-SD, aMCI-MD and mild AD revealed that, from an anatomical point of view, these three clinical syndromes could represent three severity points along the continuum between normal aging and AD.