An adaptive randomized trial of dialectical behavior therapy and cognitive behavior therapy for binge-eating.

BACKGROUND: Early weak treatment response is one of the few trans-diagnostic, treatment-agnostic predictors of poor outcome following a full treatment course. We sought to improve the outcome of clients with weak initial response to guided self-help cognitive behavior therapy (GSH). METHOD: One hundred and nine women with binge-eating disorder (BED) or bulimia nervosa (BN) (DSM-IV-TR) received 4 weeks of GSH. Based on their response, they were grouped into: (1) early strong responders who continued GSH (cGSH), and early weak responders randomized to (2) dialectical behavior therapy (DBT), or (3) individual and additional group cognitive behavior therapy (CBT+). RESULTS: Baseline objective binge-eating-day (OBD) frequency was similar between DBT, CBT+ and cGSH. During treatment, OBD frequency reduction was significantly slower in DBT and CBT+ relative to cGSH. Relative to cGSH, OBD frequency was significantly greater at the end of DBT (d = 0.27) and CBT+ (d = 0.31) although these effects were small and within-treatment effects from baseline were large (d = 1.41, 0.95, 1.11, respectively). OBD improvements significantly diminished in all groups during 12 months follow-up but were significantly better sustained in DBT relative to cGSH (d = -0.43). At 6- and 12-month follow-up assessments, DBT, CBT and cGSH did not differ in OBD. CONCLUSIONS: Early weak response to GSH may be overcome by additional intensive treatment. Evidence was insufficient to support superiority of either DBT or CBT+ for early weak responders relative to early strong responders in cGSH; both were helpful. Future studies using adaptive designs are needed to assess the use of early response to efficiently deliver care to large heterogeneous client groups.

Reliability of White Matter Microstructural Changes in HIV Infection: Meta-Analysis and Confirmation.

BACKGROUND: Diffusion tensor imaging has been widely used to measure HIV effects on white matter microarchitecture. While many authors have reported reduced fractional anisotropy and increased mean diffusivity in HIV, quantitative inconsistencies across studies are numerous. PURPOSE: Our aim was to evaluate the consistency across studies of HIV effects on DTI measures and then examine the DTI reliability in a longitudinal seropositive cohort. DATA SOURCES: Published studies and investigators. STUDY SELECTION: The meta-analysis included 16 cross-sectional studies reporting fractional anisotropy and 12 studies reporting mean diffusivity in the corpus callosum. DATA ANALYSIS: Random-effects meta-analysis was used to estimate study standardized mean differences and heterogeneity. DTI longitudinal reliability was estimated in seropositive participants studied before and 3 and 6 months after beginning treatment. DATA SYNTHESIS: Meta-analysis revealed lower fractional anisotropy (standardized mean difference, -0.43; P < .001) and higher mean diffusivity (standardized mean difference, 0.44; P < .003) in seropositive participants. Nevertheless, between-study heterogeneity accounted for 58% and 66% of the observed variance (P < .01). In contrast, the longitudinal cohort fractional anisotropy was higher and mean diffusivity was lower in seropositive participants (both, P < .001), and fractional anisotropy and mean diffusivity measures were very stable during 6 months, with intraclass correlation coefficients all >0.96. LIMITATIONS: Many studies pooled participants with varying treatments, ages, and disease durations. CONCLUSIONS: HIV effects on WM microstructure had substantial variations that could result from acquisition, processing, or cohort-selection differences. When acquisition parameters and processing were carefully controlled, the resulting DTI measures did not show high temporal variation. HIV effects on WM microstructure may be age-dependent. The high longitudinal reliability of DTI WM microstructure measures makes them promising disease-activity markers.

Efficacy of Double-Blind Peer Review in an Imaging Subspecialty Journal.

BACKGROUND AND PURPOSE: Many scientific journals use double-blind peer review to minimize potential reviewer bias concerning publication recommendations. However, because neuroradiology is a relatively small subspecialty, this process may be limited by prior knowledge of the authors' work or associated institutions. We sought to investigate the efficacy of reviewer blinding and determine the impact that unblinding may have on manuscript acceptance. MATERIALS AND METHODS: For manuscripts submitted to the American Journal of Neuroradiology (AJNR) from January through June 2015, reviewers completed a brief anonymous questionnaire after submitting their evaluations, assessing whether they were familiar with the research or had knowledge of the authors or institutions from which the work originated. RESULTS: The response rate for 1079 questionnaires was 98.8%; 12.9% of reviewers knew or suspected that they knew authors, and 15.3% knew or suspected that they knew the associated institutions. Reviewers correctly identified the authors in 90.3% of cases and correctly stated the institutions in 86.8% of cases. Unblinding resulted from self-citation in 34.1% for both authorship and institutions. The acceptance rate when reviewers knew or suspected that they knew the authors was 57/137 (41.6%) and 262/929 (28.2%) when reviewers did not. The acceptance rate when reviewers knew or suspected that they knew the institutions was 60/163 (36.8%) and 259/903 (28.7%) when they did not. The Fisher exact test showed that author (P < .038) and institution (P < .039) familiarity was associated with greater manuscript acceptance. CONCLUSIONS: While the AJNR process of double-blind peer review minimizes reviewer bias, perceived knowledge of the author and institution is associated with a higher rate of manuscript acceptance.

Speech acquisition predicts regions of enhanced cortical response to auditory stimulation in autism spectrum individuals.

A continuum of phenotypes makes up the autism spectrum (AS). In particular, individuals show large differences in language acquisition, ranging from precocious speech to severe speech onset delay. However, the neurological origin of this heterogeneity remains unknown. Here, we sought to determine whether AS individuals differing in speech acquisition show different cortical responses to auditory stimulation and morphometric brain differences. Whole-brain activity following exposure to non-social sounds was investigated. Individuals in the AS were classified according to the presence or absence of Speech Onset Delay (AS-SOD and AS-NoSOD, respectively) and were compared with IQ-matched typically developing individuals (TYP). AS-NoSOD participants displayed greater task-related activity than TYP in the inferior frontal gyrus and peri-auditory middle and superior temporal gyri, which are associated with language processing. Conversely, the AS-SOD group only showed enhanced activity in the vicinity of the auditory cortex. We detected no differences in brain structure between groups. This is the first study to demonstrate the existence of differences in functional brain activity between AS individuals divided according to their pattern of speech development. These findings support the Trigger-threshold-target model and indicate that the occurrence of speech onset delay in AS individuals depends on the location of cortical functional reallocation, which favors perception in AS-SOD and language in AS-NoSOD.

Activation of language cortex with automatic speech tasks.

OBJECTIVE: To identify automatic speech tasks that reliably demonstrate increased regional cerebral blood flow (rCBF) in Broca's and Wernicke's areas of the cortex using PET. BACKGROUND: Localizing language with direct cortical stimulation mapping requires that patients have a stable baseline on tests that engage eloquent cortex. For dysphasic patients or younger children, automatic speech tasks such as counting are often used in lieu of more complex language tests. Evidence from both lesion and neuroimaging studies suggests that these tasks may not adequately engage language cortices. In this study, we examined rCBF during automatic oromotor and speech tasks of varying complexity to identify those eliciting increased CBF in Broca's and Wernicke's areas. METHODS: Eight normal volunteers underwent PET during rest, tongue movements, and three automatic speech tasks: repeating a phoneme sequence, repeating the months of the year, and reciting a memorized prose passage. Images were averaged across subjects and compared across tasks for regional localization and laterality. RESULTS: Whereas all activation tasks produced increased relative CBF in brain regions that correlated with articulation and auditory processing, only the two tasks that used real words (versus phonemes) showed left-lateralized rCBF increases in posterior superior temporal lobe (Wernicke's area), and only the prose repetition task produced left lateralized activity in Broca's area. CONCLUSIONS: Whereas automatic speech typically does not engage language cortex, repeating a memorized prose passage showed unambiguous activation in both Broca's and Wernicke's areas. These results caution against the use of common automatic speech tasks for mapping eloquent cortex and suggest an alternative task for those with poor language abilities or acquired dysphasia who cannot perform standardized language tests reliably.

Functional MRI during word generation, using conventional equipment: a potential tool for language localization in the clinical environment.

OBJECTIVE: To test the accuracy of bilateral language mapping using a standard clinical magnetic resonance (MR) imaging device during word generation. DESIGN: A study of normal volunteers. SETTING: Volunteers from the Washington, DC, area. PARTICIPANTS: Nine normal, right-handed, native English speakers (four women, five men, mean age 31 years). INTERVENTIONS: During four MR acquisition periods, subjects would alternately rest and silently generate words. Sagittal MR images covered the middle and inferior frontal gyri, insulae, and part of the temporal and parietal lobes bilaterally. MAIN OUTCOME MEASURES: (1) Anatomic maps of task-related signal changes obtained by comparing, in each voxel, the signal during word generation and rest periods, and (2) analysis of the time course of the signal. RESULTS: Maximum responses were in the left hemisphere, mainly in the frontal lobe (Broca's area, premotor cortex, and dorsolateral prefrontal cortex) but also in posterior regions such as Wernicke's area. In agreement with previous studies, some degree of task-related changes was present in a subset of the corresponding regions in the right hemisphere. CONCLUSION: Despite certain limitations, it is possible, using widely available MR equipment, to obtain results consistent with previous studies. The technique may have important implications for assessment of cognitive functions in patients with neurologic disorders in a clinical environment.

A direct comparison of PET activation and electrocortical stimulation mapping for language localization.

Mapping eloquent language cortex in presurgical patients typically is accomplished using highly invasive direct cortical stimulation techniques. Functional imaging during language activation using positron emission tomography (PET) is a promising, noninvasive alternative that requires validation. In seven patients undergoing surgical evaluation for intractable epilepsy, we performed both direct cortical stimulation and PET activation mapping of language cortex using identical tasks. MRI, PET, and CT scans were coregistered to directly compare the location of language centers determined by cortical stimulation versus activation PET. We found that cortical regions that showed increased cerebral blood flow during both visual and auditory naming tasks were located in the same regions as subdural electrodes which disrupted language during electrical stimulation. Cortical regions underlying electrodes that did not disrupt language also showed no consistent changes in regional cerebral blood flow during PET activation. Used cautiously, PET activation produces language maps similar to those obtained with direct cortical stimulation, with more complete brain coverage and considerably less invasion.

Head movement in normal subjects during simulated PET brain imaging with and without head restraint.

UNLABELLED: Head movement during brain imaging is recognized as a source of image degradation in PET and most other forms of medical brain imaging. However, little quantitative information is available on the kind and amount of head movement that actually occurs during these studies. We sought to obtain this information by measuring head movement in normal volunteers. METHODS: Head position data were acquired for 40 min in each of 13 supine subjects with and without head restraint. These data were then used to drive a mathematically simulated head through exactly the same set of movements. The positions of point sources embedded in this head were computed at each location and these data summarized as movement at FWHM in each of the three coordinate directions. RESULTS: Head movement increased with the length of the sampling interval for studies of either type (with or without head restraint), but the amount and rate of increase with restraint was much smaller. In contrast, head movement during consecutive, short sampling intervals was small and did not increase with time. Spatial gradients in head movement were detected within each study type, and significant spatial differences in head movement were found between study types. CONCLUSIONS: Head movements in normal, supine subjects, though small, can cause the effective resolution of a brain imaging study to appear to vary in space and time. These effects can be reduced significantly with head restraint and may also be reduced by dividing the acquisition of a single image into a sequence of short images (instead of a single long image), aligning these images spatially and summing the result.

Regional cerebral blood flow during auditory responsive naming: evidence for cross-modality neural activation.

One issue of continuing debate in language research concerns whether the brain holds separate representations for semantic information through the auditory vs visual modalities. Regardless of whether we hear, see or read meaningful information, our brains automatically activate both auditory and visual semantic associations to the sensory input. The prominent models for how the brain makes these cross-modality associations holds that semantic information conveyed through either sensory input modality is represented in a shared semantic system comprising the traditionally identified language areas in the brain. A few recent case reports as well as activation imaging studies, have challenged this notion by demonstrating category-specific organization within the semantic system in spatially discrete brain regions. Neither view posits a role for primary sensory cortices in semantic processing. We obtained positron emission tomographic (PET) images while subjects performed an auditory responsive naming task, an auditory analog to visual object naming. Subjects heard and responded to descriptions of concrete objects while blindfolded to prevent visual stimulation. Our results showed that, in addition to traditional language centers, auditory language input produced reciprocal activation in primary and secondary visual brain regions, just as if the language stimuli had entered in the visual modality. These findings provide evidence for a distributed semantic system in which sensory-specific semantic modules are mutually interactive, operating directly onto early sensory processing centers.

Functional mapping of human memory using PET: comparisons of conceptual and perceptual tasks.

An experiment is reported in which regional cerebral blood flow (rCBF) as measured using positron emission tomography (PET) as participants performed conceptual and perceptual memory tasks. Blood flow during two conceptual tests of semantic cued recall and semantic association was compared to a control condition in which participants made semantic associations to nonstudied words. Analogously, rCBF during two perceptual tasks of word fragment cued recall and word fragment completion was compared to a word fragment nonstudied control condition. A direct comparison of conceptual and perceptual tasks showed that conceptual tasks activated medial and lateral left hemisphere in frontal and temporal regions as well as the lateral aspect of bilateral inferior parietal lobule. Perceptual tasks, in contrast, produced relatively greater activation in right frontal and temporal cortex as well as bilateral activation in more posterior regions. Comparisons of the memory tasks with their control conditions revealed memory-specific deactivations in left medial and superior temporal cortex as well as left frontal cortex for both conceptual tasks. In contrast, memory-specific deactivations for both perceptual fragment completion tests were localized in posterior regions including occipital cortex. Results from this and other functional imaging experiments provide evidence that conceptual and perceptual memory processes are subserved, at least in part, by different neurological structures in the human brain.

Enhanced mental image mapping in autism.

The formation and manipulation of mental images represents a key ability for successfully solving visuospatial tasks like Wechsler's Block Design or visual reasoning problems, tasks where autistics perform at higher levels than predicted by their Wechsler IQ. Visual imagery can be used to compare two mental images, allowing judgment of their relative properties. To examine higher visual processes in autism, and their possible role in explaining autistic visuospatial peaks, we carried out two mental imagery experiments in 23 autistic and 14 age and IQ matched, non-autistic adolescents and adults. Among autistics, 11 had significantly higher Block Design scores than predicted by their IQ. Experiment 1 involved imagining a letter inside a circle, followed by a decision concerning which of two highlighted portions of the circle would contain the greater proportion of the letter. Experiment 2 involved four classic mental rotation tasks utilizing two- and three-dimensional geometric figures, hands and letters. Autistics were more accurate in the formation and comparison of mental images than non-autistics. Autistics with a Block Design peak outperformed other participants in both speed and accuracy of mental rotation. Also, Performance IQ and Block Design scores were better predictors of mental rotation accuracy in autistic compared to non-autistic participants. The ability to form, access and manipulate visual mental representations may be more developed in autistics. We propose two complementary mechanisms to explain these processing advantages: (1) a global advantage in perceptual processing, discussed in the framework of the enhanced perceptual functioning model, and (2) particular strengths in veridical mapping, the ability to efficiently detect isomorphisms among entities and then to use these mappings to process stimulus characteristics, thereby facilitating judgments about their differences.

The information transmitted at final position in visually triggered forearm movements.

Visually triggered forearm movements were analyzed by an Information Theory approach. Human subjects made smooth movements which were characterized by moderate speeds, ranging about 100 degrees per second, by continuity in the position and velocity traces, and attainment of final average EMG levels before completion of the movement. We calculated the information transmitted by final position, biceps EMG, triceps EMG, and the ratio of the EMGs. The results were: (1) The information transmitted by final joint angle increased with number of targets but gradually levelled off. The maximum value was slightly over 3 bits, corresponding to an equivalent number of less than nine independent arm positions for a single movement. (2) The information transmitted by the ratio of the EMGs exceeds that transmitted by the biceps or triceps alone. (3) A previous theoretical prediction based on a spring model (Sakitt, 1980a) gives a moderately good fit to the experimental EMG ratio as a function of final position over a large range of angles. Our results lend consistency to two ideas about the nature of visually triggered forearm movements. First, our finding about the EMG ratio suggests that the basic motor program for final position is probably in terms of relative allocation of innervations, rather than looking up individual values. Second, single movements of this kind transmit surprisingly little information. If this is the case, it suggests that very fine accuracy is not achieved by a single program but requires feedback in order to program and execute additional movement.

Head surface digitization and registration: a method for mapping positions on the head onto magnetic resonance images.

We have developed a method for mapping positions on the head, such as anatomical landmarks, electrode locations, and stimulation sites, onto magnetic resonance (MR) images of the head. This method is based on the registration of two representations of the head surface: a series of contours obtained from MR images and a set of points measured from the head. The three-dimensional coordinates of each head point were acquired with the use of a magnetic digitizer, whose source was removed from the equipment and mounted on top of the subject's head. This arrangement seemed less uncomfortable for the subject than head immobilization and allowed the acquisition of many points without compromising the precision of the measurements. The digitized head surface was registered to MR image head contours using a surface registration algorithm. The registration provided the rotation and translation parameters needed for mapping head positions onto MR images. The precision of this mapping method has been estimated to be in the range of 3 to 8 mm. This method has been used to map dipole sources in electroencephalography and magneto-encephalography and to impose maps of scalp sites used in transcranial magnetic stimulation onto MR and PET images of the brain.

The role of posterior parietal cortex in visually guided reaching movements in humans.

Positron emission tomography (PET) was used to identify the brain areas involved in visually guided reaching by measuring regional cerebral blood flow (rCBF) in six normal volunteers while they were fixating centrally and reaching with the left or right arm to targets presented in either the right or the left visual field. The PET images were registered with magnetic resonance images from each subject so that increases in rCBF could be localized with anatomical precision in individual subjects. Increased neural activity was examined in relation to the hand used to reach, irrespective of field of reach (hand effect), and the effects of target field of reach, irrespective of hand used (field effect). A separate analysis on intersubject, averaged PET data was also performed. A comparison of the results of the two analyses showed close correspondence in the areas of activation that were identified. We did not find a strict segregation of regions associated exclusively with either hand or field. Overall, significant rCBF increases in the hand and field conditions occurred bilaterally in the supplementary motor area, premotor cortex, cuneus, lingual gyrus, superior temporal cortex, insular cortex, thalamus, and putamen. Primary motor cortex, postcentral gyrus, and the superior parietal lobule (intraparietal sulcus) showed predominantly a contralateral hand effect, whereas the inferior parietal lobule showed this effect for the left hand only. Greater contralateral responses for the right hand were observed in the secondary motor areas. Only the anterior and posterior cingulate cortices exhibited strong ipsilateral hand effects. Field of reach was more commonly associated with bilateral patterns of activation in the areas with contralateral or ipsilateral hand effects. These results suggest that the visual and motor components of reaching may have a different functional organization and that many brain regions represent both limb of reach and field of reach. However, since posterior parietal cortex is connected with all of these regions, we suggest that it plays a crucial role in the integration of limb and field coordinates.

Regional cerebral blood flow changes in motor cortical areas after transient anesthesia of the forearm.

To study the effect of deafferentation on cortical areas activated by movement of the proximal muscles, we measured regional cerebral blood flow with positron emission tomography and 15O-labeled water. Flexion-extension movements of the right elbow before deafferentation were associated with an increase of regional cerebral blood flow in the primary sensorimotor area bilaterally, posterior supplementary motor area bilaterally, ipsilateral cerebellum, contralateral putamen, premotor area, anterior cingulate area, and posterior parietal region. Transient anesthesia of the right forearm induced by ischemic block caused an increase of regional cerebral blood flow in the primary sensorimotor area bilaterally at rest, but there was no change of regional cerebral blood flow with movement, indicating that the movement-related change in cerebral blood flow was reduced. These findings are consistent with increased excitability of neurons as a result of deafferentation. In the supplementary motor area, anesthesia did not induce any change in regional cerebral blood flow at rest, but there was a decline with movement, again indicating a reduction of the change in cerebral blood flow related to movement. This might be due to a reduction in sensory feedback because of the anesthesia.

Neural systems underlying learning and representation of global motion.

We demonstrate performance-related changes in cortical and cerebellar activity. The largest learning-dependent changes were observed in the anterior lateral cerebellum, where the extent and intensity of activation correlated inversely with psychophysical performance. After learning had occurred (a few minutes), the cerebellar activation almost disappeared; however, it was restored when the subjects were presented with a novel, untrained direction of motion for which psychophysical performance also reverted to chance level. Similar reductions in the extent and intensity of brain activations in relation to learning occurred in the superior colliculus, anterior cingulate, and parts of the extrastriate cortex. The motion direction-sensitive middle temporal visual complex was a notable exception, where there was an expansion of the cortical territory activated by the trained stimulus. Together, these results indicate that the learning and representation of visual motion discrimination are mediated by different, but probably interacting, neuronal subsystems.

The visual deficit theory of developmental dyslexia.

Dyslexia is an impairment in reading that can result from an abnormal developmental process in the case of developmental dyslexia or cerebral insult in the case of acquired dyslexia. It has long been known that the clinical manifestations of developmental dyslexia are varied. In addition to their reading difficulties, individuals with developmental dyslexia exhibit impairments in their ability to process the phonological features of written or spoken language. Recently, it has been demonstrated with a variety of experimental approaches that these individuals are also impaired on a number of visual tasks involving visuomotor, visuospatial, and visual motion processing. The results of these studies, as well as the anatomical and physiological anomalies seen in the brains of individuals with dyslexia, suggest that the pathophysiology of developmental dyslexia is more complex than originally thought, extending beyond the classically defined language areas of the brain. Functional neuroimaging is a useful tool to more precisely delineate the pathophysiology of this reading disorder.

Activation of human primary visual cortex during visual recall: a magnetic resonance imaging study.

The degree to which the process involved in visual perception and visual imagery share a common neuroanatomical substrate is unclear. Physiological evidence for localization of visual imagery early in the visual pathways would have important bearing on current theories of visual processing. A magnetic resonance imaging technique sensitive to regional changes in blood oxygenation was used to obtain functional activation maps in the human visual cortex. During recall of a visual stimulus, focal increases in signal related to changes in blood flow were detected in V1 and V2 cortex in five of seven subjects. These experiments show that the same areas of the early visual cortex that are excited by visual stimulation are also activated during mental representation of the same stimulus. Some of the processes used in topographically mapped cortical areas during visual perception may also be utilized during visual recall.