Measurement of the Q

We measured the g_{1} spin structure function of the deuteron at low Q^{2}, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W≈1.9 GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Γ_{1}^{d} and the spin polarizability γ_{0}^{d} are precisely determined down to a minimum Q^{2} of 0.02 GeV^{2} for the first time, about 2.5 times lower than that of previous data. We compare them to several χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain.

A preliminary neuroimaging study of preschool children with ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder that, by current definition, has onset prior to age 7 years. MRI studies have provided some insight into brain differences associated with ADHD, but thus far have almost exclusively focused on children ages 7 years and older. To better understand the neurobiological development of ADHD, cortical and subcortical brain development should be systematically examined in younger children presenting with symptoms of the disorder. High-resolution anatomical (MPRAGE) images, acquired on a 3.0T scanner, were analyzed in a total of 26 preschoolers, ages 4-5 years (13 with ADHD, 13 controls, matched on age and sex). The ADHD sample was diagnosed using DSM-IV criteria, and screened for language disorders. Cortical regions were delineated and measured using automated methods in Freesurfer; basal ganglia structures were manually delineated. Children with ADHD showed significantly reduced caudate volumes bilaterally; in contrast there were no significant group differences in cortical volume or thickness in this age range. After controlling for age and total cerebral volume, left caudate volume was a significant predictor of hyperactive/impulsive, but not inattentive symptom severity. Anomalous basal ganglia, particularly caudate, development appears to play an important role among children presenting with early onset symptoms of ADHD.

Probing quark-gluon interactions with transverse polarized scattering.

We have extracted QCD matrix elements from our data on doubly polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element d˜2, which arises strictly from quark-gluon interactions, to be unambiguously nonzero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer.

3He spin-dependent cross sections and sum rules.

We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

Proton spin structure in the resonance region.

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV

Recoil-proton polarization in high-energy deuteron photodisintegration with circularly polarized photons.

We measured the angular dependence of the three recoil-proton polarization components in two-body photodisintegration of the deuteron at a photon energy of 2 GeV. These new data provide a benchmark for calculations based on quantum chromodynamics. Two of the five existing models have made predictions of polarization observables. Both explain the longitudinal polarization transfer satisfactorily. Transverse polarizations are not well described, but suggest isovector dominance.

Precision Rosenbluth measurement of the proton elastic form factors.

We report the results of a new Rosenbluth measurement of the proton electromagnetic form factors at Q2 values of 2.64, 3.20, and 4.10 GeV2. Cross sections were determined by detecting the recoiling proton, in contrast to previous measurements which detected the scattered electron. Cross sections were determined to 3%, with relative uncertainties below 1%. The ratio mu(p)G(E)/G(M) was determined to 4%-8% and showed mu(p)G(E)/G(M) approximately 1. These results are consistent with, and much more precise than, previous Rosenbluth extractions. They are inconsistent with recent polarization transfer measurements of similar precision, implying a systematic difference between the techniques.

Experimental determination of the evolution of the Bjorken integral at low Q2.

We extract the Bjorken integral Gamma1(p-n) in the range 0.17 < Q2 < 1.10 GeV2 from inclusive scattering of polarized electrons by polarized protons, deuterons, and 3He, for the region in which the integral is dominated by nucleon resonances. These data bridge the domains of the hadronic and partonic descriptions of the nucleon. In combination with earlier measurements at higher Q2, we extract the nonsinglet twist-4 matrix element f2.

Reliability and validity of the brief behavioral distress scale: a measure of children's distress during invasive medical procedures.

OBJECTIVE: To evaluate the reliability and validity of a new observational measure of children's procedure-related distress behaviors, the Brief Behavioral Distress Scale (BBDS), to provide clinicians with an efficient, economical alternative measure that does not depend on continuous interval coding. METHODS: Forty-eight randomly selected videotaped invasive medical procedures performed on children (ages 2 to 10 years) with chronic illness were coded with the BBDS and the Observation Scale of Behavioral Distress (OSBD). Reliability and validity analyses along with item analysis were conducted. RESULTS: Total distress scores of the BBDS were highly correlated with six of seven concurrent validity measures from multiple sources (i.e., OSBD, parent ratings, two nurse ratings, child self-report, and a physiological arousal measure, heart rate) (range r =.57-.76, p <.001-.0001). A robust association was found between the BBDS distress scores and OSBD total distress scores (r =.72, p <.0001). For two concurrent validity measures, the BBDS demonstrated stronger associations than did the OSBD. Interrater reliability was high for each BBDS distress behavior category. CONCLUSIONS: Based on the findings reported, the BBDS is a reliable and valid measure of children's procedure-related distress with functional utility in both research and clinical settings.

Treating selective mutism in a paediatric rehabilitation patient by altering environmental reinforcement contingencies.

Selective mutism is a disorder which can cause severe social and academic impairment, and for which a wide variety of treatment approaches have been used, with varying degrees of success. Selective mutism can be conceptualized as the lack of generalization of a class of operant responses (e.g. audible and comprehensible verbalizations) across environmental contexts. The rehabilitation hospital setting, in which the patient is seen daily by multiple people in multiple settings, is particularly well-suited for implementing a systematic behavioural intervention to establish verbal behaviour and simultaneously reinforce its generalization. Data are presented on a 7-year-old female admitted to a rehabilitation hospital following orthopaedic surgery, who met the DSM-IV diagnostic criterion for selective mutism. Additional medical diagnoses included cerebral palsy, microcephaly, and mild mental retardation. A behavioural programme was developed and implemented to reinforce differentially first any communication, then verbal communication across staff and settings. Results were evaluated using a modified multiple baseline across settings design, and demonstrate that verbal, written, and tangible reinforcement effectively increased verbal behaviour where it previously rarely occurred. Results are discussed in terms of the relationship between selective mutism, social phobia and related disorders. The theoretical roles of behavioural phenomena (discriminative stimuli, stimulus generalization) in the development and treatment of these disorders are discussed.

Behavior problems of children with Down syndrome and life events.

Behavior problems of 44 children with Down syndrome between the ages of 6 and 15 and 44 controls without mental retardation matched for age, sex, and socioeconomic status were compared on the basis of mother and teacher ratings. Ratings from both sources indicated that children with Down syndrome had more behavior problems, in particular attention deficit, noncompliance, thought disorder, and social withdrawal. Life events from the past year were significantly associated with mother but not teacher ratings of Down syndrome behavior problems.

Using differential reinforcement to treat functional hypophonia in a paediatric rehabilitation patient.

Behaviour analysis studies have demonstrated the use of operant procedures for treating symptoms of psychiatric disorders. These symptoms are usually caused or maintained by a variety of variables including specific organic mechanisms, yet most can be modified by environmental social contingencies. In this case study, data is presented on a 16 year-old male admitted to a rehabilitation hospital following the onset of polymyositis. This patient also presented with functional hypophonia and met the DSM-IV diagnostic criterion for a conversion disorder. In conjunction with the medical team and a speech pathologist, a behavioural programme was developed and implemented to shape and differentially reinforce increasingly complex vocalizations. Results were evaluated using a moving treatment, multiple baseline across responses design. Differential reinforcement in the form of written and verbal feedback was effective in shaping normal speech. The protocol was applied comprehensively across staff and settings. Results are discussed in terms of basic behavioural research on 'learned non-use'.

Antecedent management and compliance training improve adolescents' participation in early brain injury rehabilitation.

Children and adolescents with serious brain injuries are surviving in greater numbers, often entering rehabilitation settings while still emerging from coma. As the child's or adolescent's level of consciousness improves, increased demands to begin participating in self-care and therapeutic activities are presented. When the patient is unable to participate because of disorientation and agitation, the benefits of the rehabilitation admission may be jeopardized, limited rehabilitation resources may be prematurely exhausted, and behavioural sequelae often escalate. A non-concurrent multiple baseline across subjects experimental design was used to examine the effects of a behaviour management approach employing both antecedent environmental manipulations and operant conditioning-based compliance training. Data are presented on therapy attendance, disruptive behaviour, and agitation ratings across three recently brain-injured adolescents as therapeutic demands were gradually introduced. In all three cases, therapy attendance stabilized at a high level, disruptive behaviour decreased, and agitation was maintained at a moderate to low level. The results demonstrate the importance of carefully controlling the environment and coordinating the introduction of both therapeutic demands and positive reinforcement contingencies during early recovery from brain injury.

A video system to help children cooperate with motion control for radiation treatment without sedation.

A behavioral program for teaching children to cooperate with radiation treatment without sedation was previously published in this journal. Outcome data from using that program with 11 more children are reported here. For these children, an apparatus was developed to display video cartoons and movies during their behavioral training, radiation therapy planning, and daily treatments. Literature supporting the use of video displays to provide relaxation, distraction, and counterconditioning during medical procedures is highlighted. With behavioral training and the video display, 9 of the 11 children were able to avoid any sedation for daily treatments. A 10th child was able to avoid general anesthesia for his last 10 daily treatments. The advantages and limitations of behavioral training as an alternative to repeated sedation or anesthesia for radiation treatment are discussed.

Behavioural training during acute brain trauma rehabilitation: an empirical case study.

Operant conditioning-based behavioural interventions are commonly used for the behavioural problems of individuals with mental retardation. There is also growing evidence of the benefits of these interventions for treating some of the behavioural problems of individuals with acquired cognitive deficits resulting from brain trauma. However, the effects of behavioural interventions on behavioural problems occurring during acute neurorehabilitation, when orientation and memory are most impaired, have not been studied. In this empirical case study, operant conditioning-based procedures were applied with an 8-year-old girl recovering from brain trauma and related neurosurgery. Screaming, non-compliance and aggression, which were disrupting rehabilitation therapies and follow-up neuroimaging, were treated using differential positive reinforcement techniques. Beneficial behavioural intervention effects were demonstrated using single-subject experimental methods. Aberrant behaviour during physical and occupational therapies was reduced, and cooperation with a computerized tomography (CT) scan without sedation was accomplished using operant behavioural intervention. Results support the use of operant interventions early in recovery from brain trauma, and highlight the importance of interdisciplinary collaboration for the implementation and further study of early behavioural interventions.

Simulation and counterconditioning as adjuncts to pharmacotherapy for invasive pediatric procedures.

Behavioral counterconditioning was conducted during simulated medical routines to supplement medical management of five children's distress during invasive procedures (bone marrow aspiration, lumbar puncture, tracheostomy care, venipuncture, and finger pricks). Preferred activities were paired in vivo with medical stimuli, and differential positive reinforcement was provided contingent on engagement with the preferred activities and on compliance with adult instructions, first during simulations and later during actual procedures. Data on cooperation, escape/avoidance, and negative vocalizations were evaluated using both single-subject experimental methods and a baseline-treatment group statistical comparison. Results support the benefits of this approach as an adjunctive intervention to decrease behavioral distress in some children requiring repeated invasive procedures. Discussion emphasizes the potential for training medical personnel to implement these techniques preventively, for decreasing or discontinuing sedation for some children treated under local anesthesia, and for preparing children with developmental disabilities for invasive procedures.

Behavioral training of motion control in young children undergoing radiation treatment without sedation.

Preschool-age children undergoing radiation treatment for malignancies often require daily sedation or general anesthesia to assure adequate motion control. A few older children with severe anxiety reactions, a history of behavior problems, or developmental handicaps have similar problems with radiotherapy. The use of sedation or anesthesia adds risk and expense to a procedure that does not require their administration for pain management. This report describes an alternative approach using behavior analysis to teach cooperation and motion control to preschoolers and older children with special needs. Outcome data are presented for 10 children between the ages of 3 and 7. Eight of the 10 appeared to benefit from the behavioral program. These eight cooperated with radiation treatments without the need for repeated sedation or anesthesia. The benefits and limitations of this approach are discussed along with the need for additional research.

Toward a functional analysis of self-injury.

This study describes the use of an operant methodology to assess functional relationships between self-injury and specific environmental events. The self-injurious behaviors of nine developmentally disabled subjects were observed during periods of brief, repeated exposure to a series of analogue conditions. Each condition differed along one or more of the following dimensions: (1) play materials (present vs absent), (2) experimenter demands (high vs low), and (3) social attention (absent vs noncontingent vs contingent). Results showed a great deal of both between and within-subject variability. However, in six of the nine subjects, higher levels of self-injury were consistently associated with a specific stimulus condition, suggesting that within-subject variability was a function of distinct features of the social and/or physical environment. These data are discussed in light of previously suggested hypotheses for the motivation of self-injury, with particular emphasis on their implications for the selection of suitable treatments.

Behavior analysis and intervention during hospitalization for brain trauma rehabilitation.

Continued problematic behavior in children and adolescents after brain trauma is a major barrier to medical care, rehabilitation, and eventual independent living. The present study demonstrates the application of already well-developed behavior analysis techniques to the early posttrauma expression of behavior problems during hospital recovery. To satisfy concerns regarding both cost and individualized treatment, interventions were carried out primarily by regular hospital staff (nurses and therapists), medical record data were used to document gains, and time series, within subject designs were used to show experimental control. Four patients (three male and one female) ranging in age from 10 to 16 years, received intervention based on behavior analysis techniques, which reduced disruption and increased cooperation with therapy and medical care. Behavior analysis techniques will be relevant to future rehabilitation research to the extent that the posttrauma patient's behavior is effected by environmental consequences as demonstrated here.