Serial monitoring of circulating tumor DNA in patients with primary breast cancer for detection of occult metastatic disease

Metastatic breast cancer is usually diagnosed after becoming symptomatic, at which point it is rarely curable. Cell-free circulating tumor DNA (ctDNA) contains tumor-specific chromosomal rearrangements that may be interrogated in blood plasma. We evaluated serial monitoring of ctDNA for earlier detection of metastasis in a retrospective study of 20 patients diagnosed with primary breast cancer and long follow-up. Using an approach combining low-coverage whole-genome sequencing of primary tumors and quantification of tumor-specific rearrangements in plasma by droplet digital PCR, we identify for the first time that ctDNA monitoring is highly accurate for postsurgical discrimination between patients with (93%) and without (100%) eventual clinically detected recurrence. ctDNA-based detection preceded clinical detection of metastasis in 86% of patients with an average lead time of 11 months (range 0–37 months), whereas patients with long-term disease-free survival had undetectable ctDNA postoperatively. ctDNA quantity was predictive of poor survival. These findings establish the rationale for larger validation studies in early breast cancer to evaluate ctDNA as a monitoring tool for early metastasis detection, therapy modification, and to aid in avoidance of overtreatment.

CSF Aβ42/Aβ40 and Aβ42/Aβ38 ratios: better diagnostic markers of Alzheimer disease

Objective

The diagnostic accuracy of cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease (AD) must be improved before widespread clinical use. This study aimed to determine whether CSF Aβ42/Aβ40 and Aβ42/Aβ38 ratios are better diagnostic biomarkers of AD during both predementia and dementia stages in comparison to CSF Aβ42 alone.

Methods

The study comprised three different cohorts (n = 1182) in whom CSF levels of Aβ42, Aβ40, and Aβ38 were assessed. CSF Aβs were quantified using three different immunoassays (Euroimmun, Meso Scale Discovery, Quanterix). As reference standard, we used either amyloid (¹⁸F‐flutemetamol) positron emission tomography (PET) imaging (n = 215) or clinical diagnosis (n = 967) of well‐characterized patients.

Results

When using three different immunoassays in cases with subjective cognitive decline and mild cognitive impairment, the CSF Aβ42/Aβ40 and Aβ42/Aβ38 ratios were significantly better predictors of abnormal amyloid PET than CSF Aβ42. Lower Aβ42, Aβ42/Aβ40, and Aβ42/Aβ38 ratios, but not Aβ40 and Aβ38, correlated with smaller hippocampal volumes measured by magnetic resonance imaging. However, lower Aβ38, Aβ40, and Aβ42, but not the ratios, correlated with non‐AD‐specific subcortical changes, that is, larger lateral ventricles and white matter lesions. Further, the Aβ42/Aβ40 and Aβ42/Aβ38 ratios showed increased accuracy compared to Aβ42 when distinguishing AD from dementia with Lewy bodies or Parkinson's disease dementia and subcortical vascular dementia, where all Aβs (including Aβ42) were decreased.

Interpretation

The CSF Aβ42/Aβ40 and Aβ42/Aβ38 ratios are significantly better than CSF Aβ42 to detect brain amyloid deposition in prodromal AD and to differentiate AD dementia from non‐AD dementias. The ratios reflect AD‐type pathology better, whereas decline in CSF Aβ42 is also associated with non‐AD subcortical pathologies. These findings strongly suggest that the ratios rather than CSF Aβ42 should be used in the clinical work‐up of AD.

Childhood sexual and physical abuse in adult patients with borderline personality disorder

Experiences of abuse and neglect were assessed in 24 adults diagnosed as having borderline personality disorder according to the Diagnostic Interview for Borderline Patients and in 18 depressed control subjects without borderline disorder. Significantly more of the borderline patients than depressed patients reported childhood sexual abuse, abuse by more than one person, and both sexual and physical abuse. There were no between-group differences for rates of neglect or physical abuse without sexual abuse. A stepwise logistic regression revealed that derealization, diagnostic group, and chronic dysphoria were the best predictors of childhood sexual abuse in this group of patients.

Q-space trajectory imaging for multidimensional diffusion MRI of the human brain

This work describes a new diffusion MR framework for imaging and modeling of microstructure that we call q-space trajectory imaging (QTI). The QTI framework consists of two parts: encoding and modeling. First we propose q-space trajectory encoding, which uses time-varying gradients to probe a trajectory in q-space, in contrast to traditional pulsed field gradient sequences that attempt to probe a point in q-space. Then we propose a microstructure model, the diffusion tensor distribution (DTD) model, which takes advantage of additional information provided by QTI to estimate a distributional model over diffusion tensors. We show that the QTI framework enables microstructure modeling that is not possible with the traditional pulsed gradient encoding as introduced by Stejskal and Tanner. In our analysis of QTI, we find that the well-known scalar b-value naturally extends to a tensor-valued entity, i.e., a diffusion measurement tensor, which we call the b-tensor. We show that b-tensors of rank 2 or 3 enable estimation of the mean and covariance of the DTD model in terms of a second order tensor (the diffusion tensor) and a fourth order tensor. The QTI framework has been designed to improve discrimination of the sizes, shapes, and orientations of diffusion microenvironments within tissue. We derive rotationally invariant scalar quantities describing intuitive microstructural features including size, shape, and orientation coherence measures. To demonstrate the feasibility of QTI on a clinical scanner, we performed a small pilot study comparing a group of five healthy controls with five patients with schizophrenia. The parameter maps derived from QTI were compared between the groups, and 9 out of the 14 parameters investigated showed differences between groups. The ability to measure and model the distribution of diffusion tensors, rather than a quantity that has already been averaged within a voxel, has the potential to provide a powerful paradigm for the study of complex tissue architecture.

Personality profiles in eating disorders: rethinking the distinction between axis I and axis II

OBJECTIVE

Like other DSM-IV axis I syndromes, eating disorders are diagnosed without respect to personality, which is coded on axis II. The authors assessed the utility of segregating eating disorders and personality pathology and examined the extent to which personality patterns account for meaningful variation within axis I eating disorder diagnoses.

METHOD

One hundred three experienced psychiatrists and psychologists used a Q-sort procedure (the Shedler-Westen Assessment Procedure-200) that assesses personality and personality pathology to describe a patient they were currently treating for bulimia or anorexia. Data were subjected to a cluster-analytic procedure (Q-analysis) to determine whether patients clustered into coherent groupings on the basis of their personality profiles. Categorical and dimensional personality diagnoses were then used to predict measures relevant to adaptation and etiology, controlling for axis I diagnosis.

RESULTS

Three categories of patients emerged: a high-functioning/perfectionistic group, a constricted/overcontrolled group, and an emotionally dysregulated/undercontrolled group. This categorization demonstrated substantial incremental validity beyond axis I diagnosis in predicting eating disorder symptoms, adaptive functioning (Global Assessment of Functioning scores and history of psychiatric hospitalization), and etiological variables (sexual abuse history).

CONCLUSIONS

Axis I symptoms are a useful component, but only one component, in the accurate diagnosis of eating disorders. Classifying patients with eating disorders by eating symptoms alone groups together patients with anorexic symptoms who are high functioning and self-critical with those who are highly disturbed, constricted, and avoidant, and groups together patients with bulimic symptoms who are high functioning and self-critical with those who are highly disturbed, impulsive, and emotionally dysregulated. These distinctions may be relevant to etiology, prognosis, and treatment.

Quantification of microscopic diffusion anisotropy disentangles effects of orientation dispersion from microstructure: applications in healthy volunteers and in brain tumors

The anisotropy of water diffusion in brain tissue is affected by both disease and development. This change can be detected using diffusion MRI and is often quantified by the fractional anisotropy (FA) derived from diffusion tensor imaging (DTI). Although FA is sensitive to anisotropic cell structures, such as axons, it is also sensitive to their orientation dispersion. This is a major limitation to the use of FA as a biomarker for "tissue integrity", especially in regions of complex microarchitecture. In this work, we seek to circumvent this limitation by disentangling the effects of microscopic diffusion anisotropy from the orientation dispersion. The microscopic fractional anisotropy (μFA) and the order parameter (OP) were calculated from the contrast between signal prepared with directional and isotropic diffusion encoding, where the latter was achieved by magic angle spinning of the q-vector (qMAS). These parameters were quantified in healthy volunteers and in two patients; one patient with meningioma and one with glioblastoma. Finally, we used simulations to elucidate the relation between FA and μFA in various micro-architectures. Generally, μFA was high in the white matter and low in the gray matter. In the white matter, the largest differences between μFA and FA were found in crossing white matter and in interfaces between large white matter tracts, where μFA was high while FA was low. Both tumor types exhibited a low FA, in contrast to the μFA which was high in the meningioma and low in the glioblastoma, indicating that the meningioma contained disordered anisotropic structures, while the glioblastoma did not. This interpretation was confirmed by histological examination. We conclude that FA from DTI reflects both the amount of diffusion anisotropy and orientation dispersion. We suggest that the μFA and OP may complement FA by independently quantifying the microscopic anisotropy and the level of orientation coherence.

Medial temporal lobe connectivity and its associations with cognition in early Alzheimer's disease

Human episodic memory critically depends on subregions of the medial temporal lobe, which are part of functional brain systems such as the anterior-temporal and the posterior-medial system. Here we analysed how Alzheimer's pathology affects functional connectivity within these systems. Data from 256 amyloid-β-negative cognitively unimpaired, 103 amyloid-β-positive cognitively unimpaired, and 83 amyloid-β-positive individuals with mild cognitive impairment were analysed. Amyloid-β and tau pathology were measured using the CSF amyloid-β42/40 ratio and phosphorylated tau, respectively. We found that amyloid-β-positive cognitively unimpaired individuals were mainly characterized by decreased functional connectivity between the medial temporal lobe and regions in the anterior-temporal system, most prominently between left perirhinal/entorhinal cortices and medial prefrontal cortex. Furthermore, correlation analysis in this group revealed decreasing functional connectivity between bilateral perirhinal/entorhinal cortices, anterior hippocampus and posterior-medial regions with increasing levels of phosphorylated tau. The amyloid-β-positive individuals with mild cognitive impairment mostly exhibited reduced connectivity between the medial temporal lobe and posterior-medial regions, predominantly between the anterior hippocampus and posterior cingulate cortex. In addition, they showed hyperconnectivity within the medial temporal lobe and its immediate proximity. Lower medial temporal-cortical functional connectivity networks resulting from the group comparisons of cognitively unimpaired individuals were associated with reduced memory performance and more rapid longitudinal memory decline as shown by linear mixed-effects regression analysis. Finally, we found that reduced medial temporal-cortical connectivity in mildly cognitively impaired individuals was related to reduced entorhinal thickness and white matter integrity of the parahippocampal cingulum and the fornix. No such relationships were found in cognitively unimpaired individuals. In conclusion, our findings show that the earliest changes in preclinical Alzheimer's disease might involve decreased connectivity within the anterior-temporal system, and early changes in connectivity might be related to memory impairment, but not to structural changes. With disease progression and increased tau pathology, medial temporal functional connectivity with posterior-medial regions seems to be increasingly impaired. In individuals with mild cognitive impairment, reduced functional connectivity is associated with structural brain changes as well as the emergence of locally increased connectivity patterns. Thus, functional connectivity between the medial temporal lobe and the anterior-temporal and posterior-medial system could serve as stage-specific functional markers in early Alzheimer's disease.

Increased blood-brain barrier permeability is associated with dementia and diabetes but not amyloid pathology or APOE genotype

Blood-brain barrier (BBB) dysfunction might be an important component of many neurodegenerative disorders. In this study, we investigated its role in dementia using large clinical cohorts. The cerebrospinal fluid (CSF)/plasma albumin ratio (Qalb), an indicator of BBB (and blood-CSF barrier) permeability, was measured in a total of 1015 individuals. The ratio was increased in patients with Alzheimer's disease, dementia with Lewy bodies or Parkinson's disease dementia, subcortical vascular dementia, and frontotemporal dementia compared with controls. However, this measure was not changed during preclinical or prodromal Alzheimer's disease and was not associated with amyloid positron emission tomography or APOE genotype. The Qalb was increased in diabetes mellitus and correlated positively with CSF biomarkers of angiogenesis and endothelial dysfunction (vascular endothelial growth factor, intracellular adhesion molecule 1, and vascular cell adhesion molecule 1). In healthy elderly, high body mass index and waist-hip ratio predicted increased Qalb 20 years later. In summary, BBB permeability is increased in major dementia disorders but does not relate to amyloid pathology or APOE genotype. Instead, BBB impairment may be associated with diabetes and brain microvascular damage.

Divergences between clinical and research methods for assessing personality disorders: implications for research and the evolution of axis II

OBJECTIVE

The purpose of this study was to examine the extent to which instruments for assessing axis II diverge from clinical diagnostic processes.

METHOD

Subjects in the first study were 52 clinicians with experience in assessment and treatment of patients with personality disorders, who were surveyed about the methods they use in clinical practice to make diagnoses and other aspects of the diagnostic process. A second study replicated the major findings with a random national sample of 1,901 experienced psychiatrists and psychologists.

RESULTS

Whereas current instruments rely primarily on direct questions derived from DSM-IV, clinicians of every theoretical persuasion found direct questions useful for assessing axis I disorders but only marginally so for axis II. They made axis II diagnoses, instead, by listening to patients describe interpersonal interactions and observing their behavior with the interviewer. In contrast to findings with current research instruments, most patients with personality disorders in clinical practice receive only one axis II diagnosis, and if they receive more than one, one is considered primary. Clinicians reported treating a substantial number of patients for enduring personality patterns that current axis II instruments do not assess, many of which meet neither axis I nor axis II criteria, notably problems with relatedness, work, self-esteem, and chronic subclinical depressive traits.

CONCLUSIONS

Measurements of axis II were constructed by using a model derived from axis I instruments that diverges from clinical diagnostic procedures in a way that may be problematic for the assessment of personality disorders and the development of a more clinically and empirically sound taxonomy.

The scientific status of unconscious processes: is Freud really dead?

At regular intervals for over half a century, critiques of Freud and psychoanalysis have emerged in the popular media and in intellectual circles, usually declaring that Freud has died some new and agonizing death, and that the enterprise he created should be buried along with him like the artifacts in the tomb of an Egyptian king. Although the critiques take many forms, a central claim has long been that unconscious processes, like other psychoanalytic constructs, lack any basis in scientific research. In recent years, however, a large body of experimental research has emerged in a number of independent literatures. This work documents the most fundamental tenet of psychoanalysis--that much of mental life is unconscious, including cognitive, affective, and motivational processes. This body of research suggests some important revisions in the psychoanalytic understanding of unconscious processes, but it also points to the conclusion that, based on controlled scientific investigations alone (that is, without even considering clinical data), the repeated broadside attacks on psychoanalysis are no longer tenable.

Identity disturbance in borderline personality disorder: an empirical investigation

OBJECTIVE

Identity disturbance is one of the nine criteria for borderline personality disorder in DSM-IV, yet the precise nature of this disturbance has received little empirical attention. This study examines 1) the extent to which identity disturbance is a single construct, 2) the extent to which it distinguishes patients with borderline personality disorder, and 3) the role of sexual abuse in identity disturbance in patients with borderline personality disorder.

METHOD

The authors constructed an instrument that consisted of 35 indicators of identity disturbance culled from relevant clinical and theoretical literature and asked clinicians to rate a patient on each of the items. The patient group consisted of 95 subjects diagnosed with borderline personality disorder (N=34), another personality disorder (N=20), or no personality disorder (N=41). Relevant diagnostic, demographic, and developmental history data were also collected. The authors used factor analysis to ascertain whether identity disturbance is a unitary construct and then examined the relation between dimensions of identity disturbance and borderline diagnosis after controlling for sexual abuse history.

RESULTS

Four identity disturbance factors were identified: role absorption (in which patients tend to define themselves in terms of a single role or cause), painful incoherence (a subjective sense of lack of coherence), inconsistency (an objective incoherence in thought, feeling, and behavior), and lack of commitment (e.g., to jobs or values). All four factors, but particularly painful incoherence, distinguished patients with borderline personality disorder. Although sexual abuse was associated with some of the identity factors, particularly painful incoherence, borderline pathology contributed unique variance beyond abuse history to all four identity disturbance factors. The data also provided further evidence for an emerging empirical distinction between two borderline personality disorder types: one defined by emotional dysregulation and dysphoria, the other by histrionic characteristics.

CONCLUSIONS

Identity disturbance is a multifaceted construct that distinguishes patients with borderline personality disorder from other patients. Some of its components are related to a history of sexual abuse, whereas others are not. Identity disturbance appears to be characteristic of borderline patients whether or not they have an abuse history.

Noninvasive mapping of water diffusional exchange in the human brain using filter-exchange imaging

We present the first in vivo application of the filter-exchange imaging protocol for diffusion MRI. The protocol allows noninvasive mapping of the rate of water exchange between microenvironments with different self-diffusivities, such as the intracellular and extracellular spaces in tissue. Since diffusional water exchange across the cell membrane is a fundamental process in human physiology and pathophysiology, clinically feasible and noninvasive imaging of the water exchange rate would offer new means to diagnose disease and monitor treatment response in conditions such as cancer and edema. The in vivo use of filter-exchange imaging was demonstrated by studying the brain of five healthy volunteers and one intracranial tumor (meningioma). Apparent exchange rates in white matter range from 0.8±0.08 s(-1) in the internal capsule, to 1.6±0.11 s(-1) for frontal white matter, indicating that low values are associated with high myelination. Solid tumor displayed values of up to 2.9±0.8 s(-1). In white matter, the apparent exchange rate values suggest intra-axonal exchange times in the order of seconds, confirming the slow exchange assumption in the analysis of diffusion MRI data. We propose that filter-exchange imaging could be used clinically to map the water exchange rate in pathologies. Filter-exchange imaging may also be valuable for evaluating novel therapies targeting the function of aquaporins.

The link between diffusion MRI and tumor heterogeneity: Mapping cell eccentricity and density by diffusional variance decomposition (DIVIDE)

The structural heterogeneity of tumor tissue can be probed by diffusion MRI (dMRI) in terms of the variance of apparent diffusivities within a voxel. However, the link between the diffusional variance and the tissue heterogeneity is not well-established. To investigate this link we test the hypothesis that diffusional variance, caused by microscopic anisotropy and isotropic heterogeneity, is associated with variable cell eccentricity and cell density in brain tumors. We performed dMRI using a novel encoding scheme for diffusional variance decomposition (DIVIDE) in 7 meningiomas and 8 gliomas prior to surgery. The diffusional variance was quantified from dMRI in terms of the total mean kurtosis (MK_T), and DIVIDE was used to decompose MK_T into components caused by microscopic anisotropy (MK_A) and isotropic heterogeneity (MK_I). Diffusion anisotropy was evaluated in terms of the fractional anisotropy (FA) and microscopic fractional anisotropy (μFA). Quantitative microscopy was performed on the excised tumor tissue, where structural anisotropy and cell density were quantified by structure tensor analysis and cell nuclei segmentation, respectively. In order to validate the DIVIDE parameters they were correlated to the corresponding parameters derived from microscopy. We found an excellent agreement between the DIVIDE parameters and corresponding microscopy parameters; MK_A correlated with cell eccentricity (r=0.95, p<10^-7) and MK_I with the cell density variance (r=0.83, p<10^-3). The diffusion anisotropy correlated with structure tensor anisotropy on the voxel-scale (FA, r=0.80, p<10^-3) and microscopic scale (μFA, r=0.93, p<10^-6). A multiple regression analysis showed that the conventional MK_T parameter reflects both variable cell eccentricity and cell density, and therefore lacks specificity in terms of microstructure characteristics. However, specificity was obtained by decomposing the two contributions; MK_A was associated only to cell eccentricity, and MK_I only to cell density variance. The variance in meningiomas was caused primarily by microscopic anisotropy (mean±s.d.) MK_A=1.11±0.33 vs MK_I=0.44±0.20 (p<10^-3), whereas in the gliomas, it was mostly caused by isotropic heterogeneity MK_I=0.57±0.30 vs MK_A=0.26±0.11 (p<0.05). In conclusion, DIVIDE allows non-invasive mapping of parameters that reflect variable cell eccentricity and density. These results constitute convincing evidence that a link exists between specific aspects of tissue heterogeneity and parameters from dMRI. Decomposing effects of microscopic anisotropy and isotropic heterogeneity facilitates an improved interpretation of tumor heterogeneity as well as diffusion anisotropy on both the microscopic and macroscopic scale.

Relationship between cortical iron and tau aggregation in Alzheimer's disease

A growing body of evidence suggests that the dysregulation of neuronal iron may play a critical role in Alzheimer's disease. Recent MRI studies have established a relationship between iron accumulation and amyloid-β aggregation. The present study provides further insight demonstrating a relationship between iron and tau accumulation using magnetic resonance-based quantitative susceptibility mapping and tau-PET in n = 236 subjects with amyloid-β pathology (from the Swedish BioFINDER-2 study). Both voxel-wise and regional analyses showed a consistent association between differences in bulk magnetic susceptibility, which can be primarily ascribed to an increase in iron content, and tau-PET signal in regions known to be affected in Alzheimer's disease. Subsequent analyses revealed that quantitative susceptibility specifically mediates the relationship between tau-PET and cortical atrophy measures, thus suggesting a modulatory effect of iron burden on the disease process. We also found evidence suggesting the relationship between quantitative susceptibility and tau-PET is stronger in younger participants (age ≤ 65). Together, these results provide in vivo evidence of an association between iron deposition and both tau aggregation and neurodegeneration, which help advance our understanding of the role of iron dysregulation in the Alzheimer's disease aetiology.

The importance of axonal undulation in diffusion MR measurements: a Monte Carlo simulation study

Many axons follow wave-like undulating courses. This is a general feature of extracranial nerve segments, but is also found in some intracranial nervous tissue. The importance of axonal undulation has previously been considered, for example, in the context of biomechanics, where it has been shown that posture affects undulation properties. However, the importance of axonal undulation in the context of diffusion MR measurements has not been investigated. Using an analytical model and Monte Carlo simulations of water diffusion, this study compared undulating and straight axons in terms of diffusion propagators, diffusion-weighted signal intensities and parameters derived from diffusion tensor imaging, such as the mean diffusivity (MD), the eigenvalues and the fractional anisotropy (FA). All parameters were strongly affected by the presence of undulation. The diffusivity perpendicular to the undulating axons increased with the undulation amplitude, thus resembling that of straight axons with larger diameters. Consequently, models assuming straight axons for the estimation of the axon diameter from diffusion MR measurements might overestimate the diameter if undulation is present. FA decreased from approximately 0.7 to 0.5 when axonal undulation was introduced into the simulation model structure. Our results indicate that axonal undulation may play a role in diffusion measurements when investigating, for example, the optic and sciatic nerves and the spinal cord. The simulations also demonstrate that the stretching or compression of neuronal tissue comprising undulating axons alters the observed water diffusivity, suggesting that posture may be of importance for the outcome of diffusion MRI measurements.

Increased CSF biomarkers of angiogenesis in Parkinson disease

Objective:

To study biomarkers of angiogenesis in Parkinson disease (PD), and how these are associated with clinical characteristics, blood–brain barrier (BBB) permeability, and cerebrovascular disease.

Methods:

In this cross-sectional analysis, 38 elderly controls and 100 patients with PD (82 without dementia and 18 with dementia) were included from the prospective Swedish BioFinder study. CSF samples were analyzed for the angiogenesis biomarkers vascular endothelial growth factor (VEGF); its receptors, VEGFR-1 and VEGFR-2; placental growth factor (PlGF); angiopoietin 2 (Ang2); and interleukin-8. BBB permeability, white matter lesions (WMLs), and cerebral microbleeds (CMB) were assessed. CSF angiogenesis biomarkers were also measured in 2 validation cohorts: (1) 64 controls and 87 patients with PD with dementia; and (2) 35 controls and 93 patients with neuropathologically confirmed diagnosis of PD with and without dementia.

Results:

Patients with PD without dementia displayed higher CSF levels of VEGF, PlGF, and sVEGFR-2, and lower levels of Ang2, compared to controls. Similar alterations in VEGF, PlGF, and Ang2 levels were observed in patients with PD with dementia. Angiogenesis markers were associated with gait difficulties and orthostatic hypotension as well as with more pronounced BBB permeability, WMLs, and CMB. Moreover, higher levels of VEGF and PlGF levels were associated with increased CSF levels of neurofilament light (a marker of neurodegeneration) and monocyte chemotactic protein–1 (a marker of glial activation). The main results were validated in the 2 additional cohorts.

Conclusions:

CSF biomarkers of angiogenesis are increased in PD, and they are associated with gait difficulties, BBB dysfunction, WMLs, and CMB. Abnormal angiogenesis may be important in PD pathogenesis and contribute to dopa-resistant symptoms.

Limitations of axis II in diagnosing personality pathology in clinical practice

OBJECTIVE

DSM-IV's axis II is limited to severe personality disturbances, posing difficulty for diagnosing less severe but nonetheless clinically significant personality pathology. The authors examined the percentage of patients treated in clinical practice for personality pathology who are diagnosable with DSM-IV.

METHOD

Psychiatrists and psychologists from a random national sample provided diagnostic data on 714 patients treated for enduring, maladaptive personality patterns.

RESULTS

Only 39.4% of the patients had diagnosable axis II disorders. This percentage was relatively stable across clinicians' theoretical orientations and did not vary substantially when axis I diagnosis was controlled for.

CONCLUSIONS

DSM-IV cannot be used to diagnose most patients being treated for personality problems. The range of axis II should be broadened to encompass the range of personality pathology seen in clinical practice.

Affect regulation and affective experience: individual differences, group differences, and measurement using a Q-sort procedure

This article describes the development of, and preliminary findings with, the Affect Regulation and Experience Q-Sort (the AREQ), an observer-based assessment of affect regulation and experience. In Study 1, 31 clinicians provided Q-sort descriptions of 90 patients. Factor scores correlated in predicted ways with criteria such as suicide attempts and hospitalizations, as well as with clinicians' ratings of functioning in a variety of domains. Correlations between prototype Q-sorts and actual Q-sort profiles for patients sharing a diagnosis (dysthymia, borderline personality disorder, and narcissistic personality disorder) also provided evidence for convergent and discriminant validity. The data also suggested the importance of distinguishing 2 kinds of negative affect that have very different correlates. Study 2 showed that the AREQ can be applied reliably using an interview that avoids many of the problems of self-report.

A prototype matching approach to diagnosing personality disorders: toward DSM-V

The current diagnostic system for personality disorders (PD) has a number of problems that may require a thorough revision for DSM-V. This article (a) outlines problems with the current taxonomy that suggest the need for a different approach to PD diagnosis that preserves the strengths of the current system while addressing some inherent weaknesses; (b) discusses key issues that must be addressed in moving toward DSM-V, such as revising the distinction between Axis I and Axis II and combining categorical and dimensional diagnosis; and (c) describes a prototype matching approach to diagnosis, which we believe has the potential to be both psychometrically sound and faithful to the clinical data.

In vivo retention of 18F-AV-1451 in corticobasal syndrome

Objective:

To study the usefulness of ¹⁸F-AV-1451 PET in patients with corticobasal syndrome (CBS).

Methods:

We recruited 8 patients with CBS, 17 controls, 31 patients with Alzheimer disease (AD), and 11 patients with progressive supranuclear palsy (PSP) from the Swedish BioFINDER study. All patients underwent clinical assessment, ¹⁸F-AV-1451 PET, MRI, and quantification of β-amyloid pathology. A subset of participants also underwent ¹⁸F-FDG-PET.

Results:

In the 8 patients with CBS, 6 had imaging findings compatible with the corticobasal degeneration pathology and 2 with typical AD pathology. In the 6 patients with CBS without typical AD pathology, there were substantial retentions of ¹⁸F-AV-1451 in the motor cortex, corticospinal tract, and basal ganglia contralateral to the most affected body side. These patients could be clearly distinguished from patients with AD dementia or PSP using ¹⁸F-AV-1451. However, cortical atrophy was more widespread than the cortical retention of ¹⁸F-AV1451 in these CBS cases, and cortical AV-1451 uptake did not correlate with cortical thickness or glucose hypometabolism. These results are in sharp contrast to AD dementia, where ¹⁸F-AV-1451 retention was more widespread than cortical atrophy, and correlated well with cortical thickness and hypometabolism.

Conclusions:

Patients with CBS without typical AD pathology exhibited AV-1451 retention in the motor cortex, corticospinal tract, and basal ganglia contralateral to the affected body side, clearly different from controls and patients with AD dementia or PSP. However, cortical atrophy measured with MRI and decreased ¹⁸F-fluorodeoxyglucose uptake were more widespread than ¹⁸F-AV-1451 uptake and probably represent earlier, yet less specific, markers of CBS.

Classification of evidence:

This study provides Class III evidence that ¹⁸F-AV-1451 PET distinguishes between CBS and AD or PSP.

Plasma markers predict changes in amyloid, tau, atrophy and cognition in non-demented subjects

It is currently unclear whether plasma biomarkers can be used as independent prognostic tools to predict changes associated with early Alzheimer's disease (AD). In this study we sought to address this question by assessing whether plasma biomarkers can predict changes in amyloid load, tau accumulation, brain atrophy and cognition in non-demented individuals. To achieve this, plasma amyloid-β 42/40 (Aβ42/40), phosphorylated-tau181 (P-tau181), phosphorylated-tau217 (P-tau217) and neurofilament light (NfL) were determined in 159 non-demented individuals, 123 patients with AD dementia and 35 patients with a non-AD dementia from the Swedish BioFINDER-2 study, who underwent longitudinal amyloid (18 F-flutemetamol) and tau (18 F-RO948) positron emission tomography (PET), structural magnetic resonance imaging (T1-weighted) and cognitive testing. Our univariate linear mixed effect models showed there were several significant associations between the plasma biomarkers with imaging and cognitive measures. However, when all biomarkers were included in the same multivariate linear mixed effect models, we found that increased longitudinal amyloid-PET signals were independently predicted by low baseline plasma Aβ42/40 (p = 0.012), whereas increased tau-PET signals, brain atrophy and worse cognition were independently predicted by high plasma P-tau217 (p < 0.004). These biomarkers performed equally well or better than the corresponding biomarkers measured in the cerebrospinal fluid. In addition, they showed a similar performance to binary plasma biomarker values defined using the Youden index, which can be more easily implemented in the clinic. In addition, plasma Aβ42/40 and P-tau217 did not predict longitudinal changes in patients with a non-AD neurodegenerative disorder. In conclusion, our findings indicate that plasma Aβ42/40 and P-tau217 could be useful in clinical practice, research and drug development as prognostic markers of future AD pathology.

Refining the measurement of axis II: a Q-sort procedure for assessing personality pathology

The measurement of personality disorders (PDs) has proven to be a difficult enterprise. This article describes two initial studies of the validity and reliability of the Shedler-Westen Assessment Procedure (SWAP), a Q-sort procedure that quantifies clinical judgment, which may be useful both for assessing personality pathology and for empirically refining Axis II categories and diagnostic criteria. In the first study, 153 clinicians from a random national sample used a version of the Q-sort to describe either a prototype or actual patient with either a borderline, antisocial, histrionic, or narcissistic personality disorder. Correlations between aggregated prototype and actual patient profiles provided evidence for convergent and discriminant validity, and a cluster-analytic procedure (Q-factor analysis) produced revised criteria for the four disorders that minimized the problem of comorbidity. In Study 2, a pilot sample of patients were interviewed using a clinical research interview that mirrors the way clinicians assess personality and PDs. The study yielded promising results with respect to the possibility of obtaining reliable Q-sort descriptions based on an interview that resembles a clinical interview rather than the direct-question format used in current Axis II structured interviews. It also produced strong correlations between Q-sort descriptions made by interview and those made independently by the treating clinician, further supporting the validity of the instrument. The findings suggest the potential utility of the SWAP as a measure of PDs and as a method for empirically refining Axis II categories and criteria.

Searching for the neurite density with diffusion MRI: Challenges for biophysical modeling

In vivo mapping of the neurite density with diffusion MRI (dMRI) is a high but challenging aim. First, it is unknown whether all neurites exhibit completely anisotropic ("stick-like") diffusion. Second, the "density" of tissue components may be confounded by non-diffusion properties such as T2 relaxation. Third, the domain of validity for the estimated parameters to serve as indices of neurite density is incompletely explored. We investigated these challenges by acquiring data with "b-tensor encoding" and multiple echo times in brain regions with low orientation coherence and in white matter lesions. Results showed that microscopic anisotropy from b-tensor data is associated with myelinated axons but not with dendrites. Furthermore, b-tensor data together with data acquired for multiple echo times showed that unbiased density estimates in white matter lesions require data-driven estimates of compartment-specific T2 values. Finally, the "stick" fractions of different biophysical models could generally not serve as neurite density indices across the healthy brain and white matter lesions, where outcomes of comparisons depended on the choice of constraints. In particular, constraining compartment-specific T2 values was ambiguous in the healthy brain and had a large impact on estimated values. In summary, estimating neurite density generally requires accounting for different diffusion and/or T2 properties between axons and dendrites. Constrained "index" parameters could be valid within limited domains that should be delineated by future studies.

Mild behavioral impairment and its relation to tau pathology in preclinical Alzheimer's disease

Mild behavioral impairment (MBI) is suggested as risk marker for neurodegenerative diseases, such as Alzheimer's disease (AD). Recently, pathologic tau deposition in the brain has been shown closely related to clinical manifestations, such as cognitive deficits. Yet, associations between tau pathology and MBI have rarely been investigated. It is further debated if MBI precedes cognitive deficits in AD. Here, we explored potential mechanisms by which MBI is related to AD, this by studying associations between MBI and tau in preclinical AD. In all, 50 amyloid-β-positive cognitively unimpaired subjects (part of the BioFINDER-2 study) underwent MBI-checklist (MBI-C) to assess MBI, and the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog) delayed word recall (ADAS-DR) to assess episodic memory. Early tau pathology was determined using tau-PET ([¹⁸F]RO948 retention in entorhinal cortex/hippocampus) and cerebrospinal fluid (CSF) P-tau₁₈₁. Regression models were used to test for associations. We found that higher tau-PET signal in the entorhinal cortex/hippocampus and CSF P-tau₁₈₁ levels were associated with higher MBI-C scores (β = 0.010, SE = 0.003, p = 0.003 and β = 1.263, SE = 0.446, p = 0.007, respectively). When MBI-C and ADAS-DR were entered together in the regression models, tau-PET (β = 0.009, p = 0.009) and CSF P-tau₁₈₁ (β = 0.408, p = 0.006) were predicted by MBI-C, but not ADAS-DR. We conclude that in preclinical AD, MBI is associated with tau independently from memory deficits. This denotes MBI as an important early clinical manifestation related to tau pathology in AD.