Abnormalities in cortical gray matter density in borderline personality disorder.

BACKGROUND: Borderline personality disorder (BPD) is a chronic condition with a strong impact on patients' affective, cognitive and social functioning. Neuroimaging techniques offer invaluable tools to understand the biological substrate of the disease. We aimed to investigate gray matter alterations over the whole cortex in a group of Borderline Personality Disorder (BPD) patients compared to healthy controls (HC). METHODS: Magnetic resonance-based cortical pattern matching was used to assess cortical gray matter density (GMD) in 26 BPD patients and in their age- and sex-matched HC (age: 38 ± 11; females: 16, 61%). RESULTS: BPD patients showed widespread lower cortical GMD compared to HC (4% difference) with peaks of lower density located in the dorsal frontal cortex, in the orbitofrontal cortex, the anterior and posterior cingulate, the right parietal lobe, the temporal lobe (medial temporal cortex and fusiform gyrus) and in the visual cortex (P<0.005). Our BPD subjects displayed a symmetric distribution of anomalies in the dorsal aspect of the cortical mantle, but a wider involvement of the left hemisphere in the mesial aspect in terms of lower density. A few restricted regions of higher density were detected in the right hemisphere. All regions remained significant after correction for multiple comparisons via permutation testing. CONCLUSIONS: BPD patients feature specific morphology of the cerebral structures involved in cognitive and emotional processing and social cognition/mentalization, consistent with clinical and functional data.

Cognitive Rehabilitation in Alzheimer's Disease - A Conceptual and Methodological Review.

Within the last 20 years, several standardized cognitive trainings have been developed aiming at the delay of cognitive decline in older people who are at risk of Alzheimer's Disease (AD) or in mild stages of dementia. The transfer of cognitive training effects into activities of daily living was very limited in most previous studies. Therefore, multimodal Cognitive Rehabilitation approaches have been designed that aim to improve the activities of daily living. These approaches also attempt to integrate the patient's psychopathological and behavioral status as well as social relationships into the treatment plan. Contrary to other approaches, CR mainly focuses on compensation rather than restoration of impaired functionality. In this review, we define CR conceptually, and derive specific criteria to evaluate current CR approaches for individuals with mild cognitive impairment (MCI) and AD dementia. In addition, we perform a critical, methodical analysis of available CR studies, reviewing their short- and long-term treatment effects. Findings suggest that CR approaches improve memory performance and competence of activity of daily living (ADL) in mildly cognitively impaired subjects (MCI), when compensatory, integrative, as well as interactive elements and domain specificity are taken into account. Interactive and individual aspects also appear to be relevant to sustain long-term effects. In AD dementia, similar results emerged, although with smaller effect sizes. The efficacy of individualized CR approaches was comparable with theory-based, manual-guided concepts as long as promoting interaction was part of the treatment. So far, only few randomized controlled studies of sufficient sample size are available. Future systematic efficacy studies need to consider precisely defined outcome variables. This is necessary before one can draw conclusions of how CR can be used for secondary prevention of AD dementia as well as AD treatment.

The Road Ahead to Cure Alzheimer's Disease: Development of Biological Markers and Neuroimaging Methods for Prevention Trials Across all Stages and Target Populations.

Alzheimer's disease (AD) is a slowly progressing non-linear dynamic brain disease in which pathophysiological abnormalities, detectable in vivo by biological markers, precede overt clinical symptoms by many years to decades. Use of these biomarkers for the detection of early and preclinical AD has become of central importance following publication of two international expert working group's revised criteria for the diagnosis of AD dementia, mild cognitive impairment (MCI) due to AD, prodromal AD and preclinical AD. As a consequence of matured research evidence six AD biomarkers are sufficiently validated and partly qualified to be incorporated into operationalized clinical diagnostic criteria and use in primary and secondary prevention trials. These biomarkers fall into two molecular categories: biomarkers of amyloid-beta (Aß) deposition and plaque formation as well as of tau-protein related hyperphosphorylation and neurodegeneration. Three of the six gold-standard ("core feasible) biomarkers are neuroimaging measures and three are cerebrospinal fluid (CSF) analytes. CSF Aß1-42 (Aß1-42), also expressed as Aß1-42 : Aß1-40 ratio, T-tau, and P-tau Thr181 & Thr231 proteins have proven diagnostic accuracy and risk enhancement in prodromal MCI and AD dementia. Conversely, having all three biomarkers in the normal range rules out AD. Intermediate conditions require further patient follow-up. Magnetic resonance imaging (MRI) at increasing field strength and resolution allows detecting the evolution of distinct types of structural and functional abnormality pattern throughout early to late AD stages. Anatomical or volumetric MRI is the most widely used technique and provides local and global measures of atrophy. The revised diagnostic criteria for "prodromal AD" and "mild cognitive impairment due to AD" include hippocampal atrophy (as the fourth validated biomarker), which is considered an indicator of regional neuronal injury. Advanced image analysis techniques generate automatic and reproducible measures both in regions of interest, such as the hippocampus and in an exploratory fashion, observer and hypothesis-indedendent, throughout the entire brain. Evolving modalities such as diffusion-tensor imaging (DTI) and advanced tractography as well as resting-state functional MRI provide useful additionally useful measures indicating the degree of fiber tract and neural network disintegration (structural, effective and functional connectivity) that may substantially contribute to early detection and the mapping of progression. These modalities require further standardization and validation. The use of molecular in vivo amyloid imaging agents (the fifth validated biomarker), such as the Pittsburgh Compound-B and markers of neurodegeneration, such as fluoro-2-deoxy-D-glucose (FDG) (as the sixth validated biomarker) support the detection of early AD pathological processes and associated neurodegeneration. How to use, interpret, and disclose biomarker results drives the need for optimized standardization. Multimodal AD biomarkers do not evolve in an identical manner but rather in a sequential but temporally overlapping fashion. Models of the temporal evolution of AD biomarkers can take the form of plots of biomarker severity (degree of abnormality) versus time. AD biomarkers can be combined to increase accuracy or risk. A list of genetic risk factors is increasingly included in secondary prevention trials to stratify and select individuals at genetic risk of AD. Although most of these biomarker candidates are not yet qualified and approved by regulatory authorities for their intended use in drug trials, they are nonetheless applied in ongoing clinical studies for the following functions: (i) inclusion/exclusion criteria, (ii) patient stratification, (iii) evaluation of treatment effect, (iv) drug target engagement, and (v) safety. Moreover, novel promising hypothesis-driven, as well as exploratory biochemical, genetic, electrophysiological, and neuroimaging markers for use in clinical trials are being developed. The current state-of-the-art and future perspectives on both biological and neuroimaging derived biomarker discovery and development as well as the intended application in prevention trials is outlined in the present publication.

The dynamic marker hypothesis of Alzheimer's disease and its implications for clinical imaging.

In the last ten years the literature on Alzheimer's disease has focused on in vivo neurobiological changes. Extracellular beta-amyloid and intracellular hyperphosphorilated tau deposition are pivotal features and several authors have described their progression over time in pathological specimens. The revised criteria for Alzheimer's disease suggest that in vivo biomarkers reflecting neurobiological changes are useful for early diagnosis in the clinical practice. The most widely used biomarkers for the Alzheimer's disease are: Abeta42 and Tau levels in the cerebrospinal fluid (CSF); brain glucose hypometabolism detected by positron emission tomography (PET) using the 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG); brain structural and functional changes detected by magnetic resonance imaging and amyloid burden by PET using Carbon-11-labelled Pittsburgh compound-B [(11)C]PiB). In order to explain the latest in vivo observations, the dynamic biomarker hypothesis has been recently developed, integrating both pathological and clinical knowledge, and indicating which biomarkers might be more sensitive to disease state and progression at different stages. In this review, we will outline studies that support the dynamic hypothesis by: 1) testing slope differences among biomarkers; 2) describing how biomarkers map all neuropathological and clinical changes starting from the detection of amyloid burden, to neurodegeneration, and symptoms; and finally 3) identifying the best combination of biomarkers sensitive to prodromal AD in clinical practice.

Local amygdala structural differences with 3T MRI in patients with Alzheimer disease.

OBJECTIVE: Histologic studies show that the amygdala is affected by Alzheimer disease (AD) pathology, and its medial aspect is the most involved. We aimed to assess in vivo local structural differences in the amygdala of patients with AD using high-field MRI. METHODS: A total of 19 patients with AD (mean age 76, SD 6 years, mean Mini-Mental State Examination score [MMSE] 13, SD 4) and 19 healthy elderly controls (age 74, SD 5, MMSE 29, SD 1) were enrolled. The radial atrophy mapping technique was used to reconstruct the 3-dimensional surface of the amygdala. Maps of surface tissue loss in patients with AD vs controls were computed and statistically tested with permutation tests thresholded at p < 0.05, to correct for multiple comparisons. A digital atlas of the amygdalar nuclei was used to infer which nuclei were involved. RESULTS: Both amygdalar volumes were significantly smaller in patients with AD (right 1,508 mm³, SD 418; left 1,646, SD 419) than controls (right 2,129 mm³, SD 316; left 2,077, SD 376; p < 0.002). In the dorsomedial part, significant local tissue loss (20%-30%) was mapped in the medial and central nuclei. Ventrally, the lateral nucleus (La) and the basolateral ventral medial nucleus (BLVM) were also involved (20%-30% loss). CONCLUSIONS: We found in vivo local structural differences in the amygdala of patients with AD. The nuclei involved have known connections to the hippocampus (BLVM, La) and olfactory system (medial nucleus) and with cholinergic pathways (central nucleus). This pattern is consistent with the known pathophysiology of neural systems affected by AD.