Early changes in white matter pathways of the sensorimotor cortex in premanifest Huntington's disease

Objectives: To investigate the function–structure relationship of white matter within different stages of Huntington's disease (HD) using diffusion tensor imaging (DTI). Experimental design: From the TRACK‐HD study, an early stage HD group and a premanifest gene carrier group (PMGC) were age‐matched to two healthy control groups; all underwent 3‐T MRI scanning of the brain. Region of interest (ROI) segmentation of the corpus callosum, caudate nucleus, thalamus, prefrontal cortex, and sensorimotor cortex was applied, and the apparent fiber pathways of these regions were analyzed. Functional measures of motor, oculomotor, cognition, and behavior were correlated to DTI measures. Principle observations: In PMGC versus controls, higher apparent diffusion coefficient (ADC) was seen in white matter pathways of the sensorimotor cortex (P < 0.01) and in the ROI of corpus callosum (P < 0.017). In early HD, fiber tract analysis showed higher ADC in pathways of the corpus callosum, thalamus, sensorimotor, and prefrontal region (P < 0.01). ROI analysis showed higher diffusivity in the corpus callosum and caudate nucleus (P < 0.017). Motor, oculomotor, cognition, and probability of onset within 2 and 5 years, correlated well with ADC measures of the corpus callosum (P < 0.01 – P < 0.005), sensorimotor (P < 0.01 – P < 0.005), and prefrontal region (P < 0.01). Conclusions: Disturbances in the white matter connections of the sensorimotor cortex can be demonstrated not only in manifest HD but also in premanifest gene carriers. Connectivity measures are well related to clinical functioning. DTI measures can be regarded as a potential biomarker for HD, due to their ability to objectify changes in brain structures and their role within brain networks. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.     

Longitudinal diagnostic efficiency of DSM-IV criteria for obsessive-compulsive personality disorder: a 2-year prospective study

OBJECTIVE: To examine the longitudinal diagnostic efficiency of the DSM-IV criteria for obsessive-compulsive personality disorder (OCPD). METHOD: At baseline, criteria and diagnoses were determined using diagnostic interviews, and blinded assessments were performed 24 months later with 550 participants. Diagnostic efficiency indices (conditional probabilities, total predictive power, and kappa) were calculated for each criterion determined at baseline, using the independent OCPD diagnosis at follow-up as the standard. RESULTS: Longitudinal diagnostic efficiencies for the OCPD criteria varied; findings suggested the overall predictive utility of 'preoccupied with details', 'rigid and stubborn', and 'reluctant to delegate'. CONCLUSION: These findings suggest the predictive validity of three cognitive-interpersonal OCPD criteria.     

Application of image-guided surface coil P-31 MR spectroscopy to human liver, heart, and kidney

Localized phosphorus-31 magnetic resonance (MR) spectroscopy in humans has previously been accomplished with surface coils by means of depth-resolved surface coil spectroscopy or rotating frame experiments, in which the extent of tissue sampled critically depends on surface coil placement. The authors' goal was to modify the surface coil image-selected in vivo spectroscopy (ISIS) experiment to accomplish three-dimensional volume selection through application of selective pulses in the presence of B0 gradients. Advantages of ISIS include the ability to use proton images to define the volume of interest (VOI) and reduced dependence on exact positioning of the surface coil. However, rapid replication of the surface coil ISIS experiment can cause spectral contamination from signals originating outside the VOI. A modified version of the ISIS experiment was developed to alleviate contamination under conditions of rapid replication. Applications of localized P-31 MR spectroscopy for observation of high-energy phosphorus metabolites are presented in human liver, heart, and transplanted and normal kidney.     

Multimodality Rodent Imaging Chambers for Use Under Barrier Conditions with Gas Anesthesia

Purpose  The ability to reproducibly and repeatedly image rodents in noninvasive imaging systems, such as small-animal positron emission tomography (PET) and computed tomography (CT), requires a reliable method for anesthetizing, positioning, and heating animals in a simple reproducible manner. In this paper, we demonstrate that mice and rats can be reproducibly and repeatedly imaged using an imaging chamber designed to be rigidly mounted on multiple imaging systems. Procedures  Mouse and rat imaging chambers were made of acrylic plastic and aluminum. MicroCT scans were used to evaluate the positioning reproducibility of the chambers in multimodality and longitudinal imaging studies. The ability of the chambers to maintain mouse and rat body temperatures while anesthetized with gas anesthesia was also evaluated. Results  Both the mouse and rat imaging chambers were able to reproducibly position the animals in the imaging systems with a small degree of error. Placement of the mouse in the mouse imaging chamber resulted in a mean distance of 0.23 mm per reference point in multimodality studies, whereas for longitudinal studies the mean difference was 1.11 mm. The rat chamber resulted in a mean difference of 0.46 mm in multimodality studies and a mean difference of 4.31 mm in longitudinal studies per reference point. The chambers maintained rodent body temperatures at the set point temperature of 38°C. Conclusions  The rodent imaging chambers were able to reproducibly position rodents in tomographs with a small degree of variability and were compatible with routine use. The embedded anesthetic line and heating system was capable of maintaining the rodent’s temperature and anesthetic state, thereby enhancing rodent health and improving data collection reliability.     

Emotion Congruent Facilitation of Attention when Processing Anxious Stimuli

Researchers using spatial attention tasks have shown that anxious individuals are quick to orient to threatening information, but have difficulty disengaging attention from that location. We extended this line of research by investigating the influence of anxiety on attention across time rather than space. It was found that anxious words imbedded in a rapidly presented stream of distractors were correctly identified more often than neutral words, regardless of the emotional state of the participant. Having identified the first target in the stream, participants were able to detect a second target sooner when the first target was an anxious word and the participant was experiencing anxiety in comparison to conditions in which the first target was neutral or the participant was not anxious. The rapid recovery of the attentional system when there was emotional congruence between the state of the individual and the attended information, points to the unique influence that anxiety has on attention across time in comparison to its influence on spatial attention.     

Long-term course of pediatric obsessive–compulsive disorder: 3 years of prospective follow-up

Objective

This study assesses the long-term course of treatment-seeking youth with a primary diagnosis of DSM-IV OCD.

Method

Sixty youth and their parents completed intake interviews and annual follow-up interviews for 3 years using the youth version of the Longitudinal Interval Follow-up Evaluation (Y-LIFE) and Children's Yale–Brown Obsessive Compulsive Scale (CY-BOCS). Remission was defined as no longer meeting DSM-IV criteria for OCD for 8 weeks or more, and recurrence was defined as meeting full criteria for OCD for 4 consecutive weeks after having achieved symptom remission. Remission rates for youth were compared to rates of adults participating in the same study.

Results

The probability of achieving partial remission of OCD was 0.53 and the probability of achieving full remission was 0.27. Among the 24 youth participants who achieved remission, 79% stayed in remission throughout the study (mean of 88 weeks of follow-up) and 21% experienced a recurrence of symptoms. Better functioning at intake and a shorter latency to initial OCD treatment were associated with faster onset of remission (P < .001).

Conclusions

Remission is more likely among youth versus adults with OCD. Treatment early in the course of illness and before substantial impact on functioning predicted a better course.