Sean D. Kristjansson

Learn More
In this paper, we present the results of an analysis of the electrocardiogram (ECG) as a biométrie using a novel short-time frequency method with robust feature selection. Our proposed method incorporates heartbeats from multiple days and fuses information. Single lead ECG signals from a comparatively large sample of 269 subjects that were sampled(More)
BACKGROUND The dopamine D4 receptor gene (DRD4) has been implicated in psychiatric disorders in which deficits of self-regulation are a prominent feature (e.g., attention-deficit hyperactivity disorder and substance use disorders) and in dopamine D4 receptor insensitivity within prefrontal regions of the brain. Our hypothesis was that carriers of 7-repeats(More)
Despite the tremendous public health and financial burden of cigarette smoking, relatively little is understood about brain mechanisms that subserve smoking behavior. This study investigated the effect of lifetime regular smoking on brain processing in a reward guessing task using functional magnetic resonance imaging and a co-twin control study design in(More)
BACKGROUND Genetic risk for alcohol dependence has been shown to overlap with genetic factors contributing to variation in dimensions of personality. Although drinking motives have been posited as important mediators of the alcohol-personality relation, the extent to which the genetic covariance between alcohol use disorder (AUD) symptoms (i.e., abuse and(More)
A novel approach for remotely sensing mechanical cardiovascular activity for use as a biometric marker is proposed. Laser Doppler Vibrometry (LDV) is employed to sense vibrations on the surface of the skin above the carotid artery related to arterial wall movements associated with the central blood pressure pulse. Carotid LDV signals are recorded using(More)
Small, nonreflexive pupillary changes are robust physiological indicators of cognitive activity. In the present paper, we examined whether measures of pupillary changes could be used to detect phasic lapses in alertness during a vigilance task. A polynomial curve-fitting method for quantifying parameters from single task-evoked pupillary responses (TEPRs)(More)
Our goal was to evaluate an alternative to current methods for detecting deception in security screening contexts. We evaluated a new cognitive-based test of deception that measured participants' ocular-motor responses (pupil responses and reading behaviors) while they read and responded to statements on a computerized questionnaire. In Experiment 1,(More)
BACKGROUND Outcome expectancy is a central construct in models of addiction and relapse. Much expectancy research has been conducted in the context of alcohol; however, less is known about the structure of expectancies for marijuana and their associations with marijuana use outcomes. METHODS The data are taken from waves 3 and 4 of a longitudinal(More)
BACKGROUND We sought to apply modified labeling theory in a cross-sectional study of alcohol use disorder (AUD) to investigate the mechanisms through which perceived alcohol stigma (PAS) may lead to the persistence of AUD and risk of psychiatric disorder. METHODS We conducted structural equation modeling (SEM) including moderated mediation analyses of two(More)
INTRODUCTION There has been an increasing interest in studying the stigma of alcohol use disorders (AUDs) yet scant research has evaluated the conceptualization and measurement of alcohol stigma. This study examined the measurement properties (i.e., factor structure) and validity of the alcohol-adapted Perceived Devaluation-Discrimination scale (PDD), which(More)