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Introduction: Dimensional models of personality disorders (PD) in the DSM-5 and ICD-11 share a focus on impairments in self and interpersonal functioning to represent the general features and severity of PD. This new perspective has led to the development of numerous measures for assessing individual differences in PD severity. While this improves choices for researchers and practitioners, it also poses the challenge of an increasing lack of standardization. Objective: The aim of this study is to establish a common metric across 6 widely used self-report measures of PD severity using item response theory models. Methods: 849 participants completed a survey including the Inventory of Personality Organization-16-item version (IPO-16), the Level of Personality Functioning Scale-Brief Form 2.0, the Level of Personality Functioning Scale-Self-Report, the Operationalized Psychodynamic Diagnosis-Structure Questionnaire Short Form, the Personality Inventory for DSM-5-Brief Form Plus and the Standardized Assessment of Severity of Personality Disorder (SASPD). We fitted exploratory multidimensional graded response models and used bifactor rotation to extract a general factor across measures. Factor scores were linked to representative T scores using data from a representative survey of 2,502 participants who completed the IPO-16. Results: When using bifactor rotation in a 7-factor model, all items loaded positively on the general factor, and the general factor explained 65.5% of the common variance. With the exception of the SASPD, all measures provided highly discriminating items (factor loadings > 0.70) for measuring the general factor and reached an acceptable reliability (> 0.80) across a wide range of the latent continuum. We constructed a crosswalk table linking total scores of the 6 measures to each other and to representative T scores. Conclusions: Our results suggest that 6 different self-report measures of the severity of PD capture a strong common factor and can therefore be scaled along a single latent continuum. Our results may facilitate instrument-independent assessment of severity of PD and increase comparability across studies.

IntroductionThere is evidence suggesting a detrimental effect of asymptomatic carotid artery stenosis on cognitive function even in the absence of ischemic cerebral lesions. Hypoperfusion has been suggested as pathophysiological mechanism causing cognitive impairment. We aimed to assess cognitive performance and cerebral perfusion changes in patients with carotid artery stenosis without ischemic lesions by arterial spin labeling (ASL) and contrast enhanced (CE) perfusion MRI before and after revascularization therapy.Methods17 asymptomatic patients with unilateral high-grade (≥70%) carotid artery stenosis without evidence of structural brain lesions underwent ASL and CE perfusion MRI and cognitive testing (MMSE, DemTect, Clock-Drawing Test, Trail-Making Test, Stroop Test) before and 6–8 weeks after revascularization therapy by endarterectomy or stenting. Multiparametric perfusion maps (ASL: cerebral blood flow (ASL-CBF), bolus arrival time (ASL-BAT); CE: cerebral blood flow (CE-CBF), mean transit time (CE-MTT), cerebral blood volume (CE-CBV)) were calculated and analyzed by vascular territory. Relative perfusion values were calculated.ResultsMultivariate analysis revealed a significant impact of revascularization therapy on all perfusion measures analyzed. At baseline post-hoc testing showed significant hypoperfusion in MCA borderzones as assessed by ASL-CBF, ASL-BAT, CE-MTT and CE-CBV. All perfusion alterations normalized after revascularization. We did not observe any significant correlation of cognitive test results with perfusion parameters. There was no significant change in cognitive performance after revascularization.ConclusionWe found evidence of traceable perfusion alterations in patients with high grade carotid artery stenosis in the absence of structural brain lesions, which proved fully reversible after revascularization therapy. In this cohort of asymptomatic patients we did not observe an association of hypoperfusion with cognitive performance.